E

• e- 1. word element. [L.] away from, without, outside. 2. for words beginning thus, see also those with alternate spelling oe-.

• ε epsilon, small letter; fifth letter in the Greek alphabet. Used to designate random error in regression analysis.

• η eta, small letter; seventh letter in the Greek alphabet.

• EAE 1. experimental allergic encephalomyelitis. 2. enzootic abortion of ewes.

• EAEC enteroaggregative or enteroadherent Escherichia coli.

• eagle [e′g l] raptor bird of the family Accipitridae. Generally large powerful birds with very good vision, a hooked beak and powerful talons making them formidable predators. Includes the harpy eagle (Harpia harpyja), golden eagle (Aquila chrysaetos), tawny eagle (Aquila rapax). wedge-tailed eagle (Aquila audax) and bald eagle (Haliaeetus leucocephalus).

• EAN experimental allergic neuritis.

• ear [ēr] the organ of hearing and of equilibrium. The ear is made up of the outer (external) ear, the middle ear, and the inner (internal) ear. The anatomical parts of all three can be found under their specific names. See also auricular, auditory, external ear. The outer ear consists of the auricle, or pinna, and the external acoustic meatus. The auricle collects sound waves and directs them to the external acoustic meatus, which conducts them to the tympanum. The tympanic membrane (eardrum) separates the outer ear from the middle ear. The middle ear contains three ossicles, the malleus (hammer), incus (anvil), and stapes (stirrup), so called because of their resemblance to these objects. These three small bones form a chain across the middle ear from the tympanum to the oval window of the inner ear. The middle ear is connected to the nasopharynx by the auditory tube, through which the air pressure on the inner side of the eardrum is equalized with the air pressure on its outside surface. Two muscles attached to the ossicles contract when loud noises strike the tympanic membrane (the stapedius and tensor tympani) that limit its vibration and thus protect it and the inner ear from damage. The inner ear contains a bony labyrinth that supports a membranous labyrinth made up of the cochlea, semicircular canals, utriculus, and sacculus. When a sound strikes the ear, it causes the tympanic membrane to vibrate. The ossicles function as levers, gearing down the motion of the tympanic membrane so that its impedance of a membrane vibrating in air, matches the impedance of vibration in the fluid occurring in the inner ear, and passing the vibrations on to the cochlea. From there the vestibulocochlear (eighth cranial) nerve transmits the vibrations, translated into nerve impulses, to the auditory center in the brain. See also hearing. The semicircular canals, utriculus, and sacculus provide essential information for the sense of balance. See also equilibrium.

  • e. alopecia see pinnal alopecia.
  • bat e. an erect, broad-based ear in some dogs, especially the French bulldog and Welsh corgi.
  • bear e. one with a very rounded tip.
  • break in e. the fold line in the semi-dropped ear of dogs.
  • broken e. deformed or misshapen ears, as a result of injury or congenital defect. Most often of concern in dog breeds that are supposed to have erect or specifically defined ear conformation, e.g., Collie, German shepherd dog, Chihuahua.
  • button e. in dogs, an ear flap lying close to the head, and pointing toward the eye. Seen in fox terriers.
  • e. cancer a squamous cell carcinoma of the ear of sheep. The lesion commences around the free edge and then invades the entire ear.
  • e. canker a lay term applied generally to otitis externa but sometimes specifically to that caused by ear mites.
  • e. carriage drooped, erect, alert, all indicative of mental state or state of muscle tone. Also a specified feature of breed standards for dogs.
  • e. cartilage see auricular cartilage.
  • e. chewing a vice of confined pigs due largely to boredom and overcrowding.

    E-01.

    

    Structures of the ear.

  • e. cyst a misplaced tooth germ or ear tooth in horses; occur unilaterally at the base of the ear, attached to the temporal bone. Called also heterotopic polyodontia.
  • drop e. an ear that is normally not erect; the end folds over or droops forward. Seen in many dog breeds.
  • drooping e. inability of the ear to remain in an upright position in those species in which that is the norm. It may be a congenital abnormality, due to injury that has damaged the cartilage, or a sign of neurological deficit.
  • e. hematoma see auricular hematoma.
  • e. mange see psoroptic mange, Otodectes cynotis, Raillietia.
  • e. mark patterned pieces of cartilage punched out as a means of identification. Very popular at one time with intricate codes to identify age and family groups of pigs. Marks nicked out of the edges but also the centers of the ears.
  • e. notch see ear mark (above).
  • e. notch test used for detecting cattle persistently infected with bovine virus diarrhea virus using immunohistochemistry on the ear notch sample. Provides an easily collected sample and a less expensive antemortem diagnostic test.
  • e. plaque see aural plaque.
  • e. points see auricular points.
  • e. punch alligator forceps with cup-shaped opposing blades up to 1.5 inch diameter. A biopsy instrument for use in the depths of the ear canal.
  • e. resection see lateral ear resection, vertical ear canal resection.
  • e. rigid ear pricked and patient unable to move them; indicative of general skeletal muscle tetany.
  • rose e. a requirement for the Bulldog: the lower edge folds inward while the upper edge folds outward and backward, so that the ear is folded down but the inner part of the pinnae is exposed.
  • e. sloughing result of phlebitis and venous thrombosis occurring in many septicemias. It is most common in pigs where it begins as purple discoloration of the ears and surrounding skin. Also a feature of Salmonella dublin infection in calves. Also part of the response in peripheral gangrene syndrome caused by ingestion of ergot alkaloids.
  • spinose e. tick see Otobius megnini.
  • e. sucking a vice occurring in penned pigs and calves caused by boredom. Has no serious effect unless it leads to cannibalism in pigs.
  • e. tag a technique of animal identification favored in sheep and cattle. Has the disadvantage that tags are often lost. This can be avoided by putting duplicates in each ear. The need to catch the animal to read the tag is overcome by using large placard type tags. For cattle being worked through a chute, tail tags are more convenient. Insecticides can be incorporated into the tag to provide protection against horn fly and head fly. May contain transponders for individual identification or trace back.
  • e. tick see Otobius megnini.
  • e. tipping clipping off the tip of the external ear so that the animal can be identified from a distance. Limited categories available.
  • e. tip necrosis a common problem in individual pig herds; sporadic cases usually related to frostbite, thrombosis after septicemic disease, especially Salmonella dublin in young calves; herd problems may be due to ergot poisoning or endophyte-containing hay, or an ear-sucking habit.
  • e. tooth see ear cyst (above).
  • e. trimming see ear cropping.

• ear cropping [ēr] a cosmetic surgical procedure carried out on dogs of certain breeds, including Boxer, Great Dane, Schnauzer, Doberman pinscher and Bouvier des Flandres, that removes approximately one-third of the distal ear flap and braces the remainder so it stands erect. Practiced widely in the US, but considered inhumane and an unethical procedure in most of the British Commonwealth countries and some European countries.

  • e. c. clamps two aluminum bars with thumbscrews at both ends to screw the bars together, with the part of the ear to be cropped protruding from the edge. They act as a template for cutting the ears of dogs in the correct shape.

• eardrum [ēr′dr m] see tympanic membrane.

• early warning system a specific procedure for the early detection of any departure from normal frequencies of clinical cases or serological reactors of specific diseases by monitoring a sample of the population at risk. An essential requirement for effective containment and control of epidemic animal diseases and zooonoses.

  E-02.

  

  Calf double-tagged with large plastic identification tags in the ears.

  E-03.

  

  Ear tip necrosis in a calf associated with Salmonella dublin infection.

• earmark [ēr′mahrk] taking a piece out of the edge or center of the ear with a punch as an identification mark. The shape of the mark may be registerable under local legislation.

• earsore [ēr′sor] dermatitis around the ear of water buffalo caused by Stephanofilaria zaheeri.

• earth [ rth] 1. soil; softer part of the land, as distinct from rock. 2. metallic oxides in the form of unchangeable powder.

  • diatomaceous e. a fine white powder composed of the siliceous skeletons of diatoms; used in treating diarrhea and as a feed additive. Called also infusorial earth, purified siliceous earth.
  • infusorial e. see diatomaceous earth (above).
  • siliceous e. see diatomaceous earth (above).

• earth-eating most commonly associated with nutritional deficiency of sodium chloride. See also pica.

• earthing [ rth′ing] the safety device of connecting an electrical system in a building to the earth, especially in a milking shed. Failure of the connection causes electrification of parts of the building. This may cause poor milk letdown, restlessness, convulsions, or sudden death depending on the strength of the current and the completeness of the animals’ contact with the floor. See also electrocution, free electricity.

• earthworm [ rth′werm] a common oligochete earthworm of the genera Lumbricus, Allobophora, Eisenia, etc.; they act as intermediate or transport hosts for a number of internal parasites of livestock and are reputed to bring anthrax spores to the surface and precipitate an outbreak of the disease.

• earwax [ēr′waks] see cerumen.

  • e. remover various proprietary mixtures are used to aid in the removal of cerumen in the treatment of otitis externa.

• earworm [ēr′werm] infestation of the ears of cattle by Rhabditis bovis, often complicated by blowfly infestation.

• ease of fracture bones fracture easily due to local weakness of structure and calcification due to osteomyelitis or generalized osteoporosis. Can be the presenting indication of a copper deficiency problem in mature cattle.

• East African sleeping sickness a disease of humans caused by Trypanosoma rhodesiense. The parasite is infectious for many animal species that act as reservoirs for humans. The disease is fatal in humans if it is not treated. Keratitis and encephalitis occur in goats and sheep, facial paralysis and emaciation in horses.

• East African swine fever see African swine fever.

• East Coast fever a disease of cattle caused by Theileria parva and transmitted by the tick Rhipicephalus appendiculatus. Other ticks are known to be capable of transmitting the infection. Resident and zebu cattle are resistant to infection. Clinical signs in susceptible animals are high fever, lymphadenopathy, nasal discharge, lacrimation, diarrhea, and dysentery. The mortality rate is high.

• East Friesian, East Friesland marsh-type dairy sheep, polled, with a woolless rat-tail.

• East–West front in dog conformation, front feet turned outward.

• Easter lily see Lilium longiflorum.

• Easter rose Helleborusniger.

• Eastern equine encephalitis see Eastern equine encephalomyelitis.

• Easton’s syrup an antiquated proprietary medicine from the era of empirical remedies and nonspecific stimulants. Contains strychnine (used as a stimulant), iron phosphate (listed as a ‘brain food’), and quinine (an appetite and general stimulant).

• easy-care sheep sheep of any breed but selected for ease of lambing. Is a response to the need to reduce labor inputs into sheep husbandry.

• easy keeper an animal of any species that grows or fattens on a smaller intake than average.

• eating [ēt′ing] combined prehension, mastication, and swallowing.

  E-04.

  

  East Friesian or East Friesland dairy sheep.

  • e. disorders see anorexia, regurgitation, quidding, dysphagia, polyphagia, pica.

• EBA enzootic bovine abortion.

• EBHS European brown hare syndrome.

• Ebola virus [eb′o-l ] see Filoviridae.

• Ebstein’s anomaly [eb′shtīn] congenital defect/malformation of the tricuspid valve and right ventricle characterized by downward (apical) displacement of the annulus, valve leaflet abnormalities, and dilation of the “atrialized” portion of the right ventricle.

• eburnation [e″b r-na′sh n] formation of smooth, dense bone surfaces in false joints, or joints whose articular cartilage has been destroyed.

• EBV estimated breeding value.

• ec- word element. [Gr.] outward, out of.

• E&C euthanasia and cremation.

• ECAAH European College of Aquatic Animal Health. See also European Board of Veterinary Specialisation.

• ECAR European College of Animal Reproduction. See also European Board of Veterinary Specialisation.

• ecaudate [e-kaw′dāt] tailless.

• ECAWBM European College of Animal Welfare and Behavioural Medicine. See also European Board of Veterinary Specialisation.

• Ecballium elaterium toxic plant in the family Cucurbitaceae; contains cucurbitacins, which cause diarrhea and enteritis. Called also squirting cucumber.

• ECBHM European College of Bovine Health Management. See also European Board of Veterinary Specialisation.

• ecbolic [ek-bol′ik] oxytocic; promotes myometrial contractions.

• eccentrocyte an erythrocyte in which the hemoglobin is localized to one side of the cell, leaving a portion with little hemoglobin. Caused by oxidative injury to the cell. Called also hemighost.

• ecchondroma, ecchondrosis [ek″on-dro′m , ek″on-dro′sis] a hyperplastic growth of cartilaginous tissue on the surface of a cartilage or projecting under the periosteum of a bone.

• ecchymoma [ek-ľ-mo′m ] swelling due to blood extravasation.

• ecchymosis [ek″ľ-mo′sis] pl. ecchymoses [Gr.] a hemorrhagic spot, larger than a petechia, in the skin or mucous membrane, forming a nonelevated, rounded or irregular, blue or purplish patch.

• ecchymotic hemorrhage [ek-ľ-mot′ik] see ecchymosis.

• eccrine [ek′rin] exocrine, with special reference to glands that secrete their product without loss of cytoplasm. See sweat glands.

  • e. tumors adenomas and adenocarcinomas occur rarely.

• eccritic 1. promoting excretion. 2. an agent that promotes excretion.

• eccyesis [ek″si-e′sis] ectopic pregnancy; implantation of the embryo ion an abnormal location. Called also tubal pregnancy.

• ECD equine Cushing’s disease. See equine pituitary pars intermedia dysfunction

• ecdysis [ek′dľ-sis] shedding of the external layers of the skin in reptiles, insects or arthropods; only the epidermis participates. Is controlled by the endocrine glands. Called also moult, shed or exuviate. See also dysecdysis.

• ECEIM European College of Equine Internal Medicine. See also European Board of Veterinary Specialisation.

• ECF 1. extracellular fluid. 2. early conception factor

• ECF-A eosinophil chemotactic factor of anaphylaxis.

• ECG electrocardiogram. Called also EKG.

• eCG equine chorionic gonadotropin. A glycoprotein hormone with both FSH and LH activity and used for ovarian stimulation in ruminants. Called also pregnant mare serum gonadotropin.

• echidna [e-kid′n ] a small (up to 15 lb.) monotreme, covered in coarse hair and sharp spines. The short-beaked echidna (Tachyglossus aculeatus) is found in Australia, and three species from the genus Zaglossus occur in New Guinea. They have no teeth and use their sticky tongue for feeding on a diet predominantly of ants and termites. Males have prominent hindlimb spurs, and the male’s penis is divided into four heads, each with a branch of the urethra. As monotremes, the female lays her egg 22 days after fertilization directly into a shallow abdominal pouch and feeds her young with milk expressed directly onto the skin of the pouch from two milk patches. The young are called puggles. Called also spiny anteater.

  E-05.

  

  Ecchymoses.

  E-06.

  

  A monitor lizard (Varanus spp.) undergoing ecdysis here sheds the outer layer of transparent skin that covers the tympanic membrane.

• Echidnophaga [ek″id-nof′ -g] a genus of fleas that remain attached to the host for long periods. Includes E. myrmecobii (in rabbits) and E. perilis (in rats).

  • E. gallinacea causes insect worry and blood loss in poultry. Does not transmit disease in animals but may transmit endemic murine typhus to humans. Called also stickfast flea.

• echimidine one of the toxic pyrrolizidine alkaloids in Echium plantagineum.

• Echinacea [ek″ľ-na′sh ] a genus of plants in the family Asteraceae; common examples include Echinacea purpurea and E. angustifolia; source of the popular herbal product echinacea, used mainly as an immune system stimulant. All parts of the plant are used, particularly the roots and the flowers.

• echinatine a toxic alkaloid in Cynoglossum officinale.

  E-07.

  

  Echidna.

  E-08.

  

  Adult Echidnophaga gallinacea, the sticktight flea of poultry. A common flea of chickens and guinea fowl, it also feeds on dogs and cats.

• echinocandins a class of fungicidal agents that inhibit β-glucan synthase in fungal cell walls; effective against Candida spp., Aspergillus spp. and Pneumonocystis carinii, but not Cryptococcus neoformans. Includes caspofungin, micafungin and anidulafungin.

• Echinochasmus [e-ki″no-kaz′m s] a genus of flukes of the family Echinostomatidae. Includes E. perfoliatus in intestines of carnivores.

• Echinochloa genus of grasses in the family Poaceae. Mostly good forage plants but linked anecdotally with outbreaks of primary photosensitization in grazing ruminants. Toxin unidentified but some plants contain high concentrations of nitrate. Includes E. crus-galli (barnyard grass, Japanese millet), E. pyramidalis (antelope grass), E. utilis.

• echinococcosis [e-ki″no-kok-o′sis] an infection of humans and animals, usually of the liver or lungs, caused by the larval stage (hydatid cysts) of tapeworms of the genus Echinococcus, marked by the development of expanding cysts. See also hydatid disease. A disease notifiable to the OIE (see Table 20). Principal species involved are E. granulosus and E. multilocularis.

• Echinococcus [e-ki″no-kok′ s] a genus of small tapeworms of the family Taeniidae.

  • E. granulosus a species parasitic in dogs and wolves and occasionally in foxes and cats; its larvae may develop in ungulates and macropods, forming hydatid cysts in the liver, lungs, kidneys, and/or other organs.
  • E. multilocularis a species whose adult stage usually parasitizes the fox, dog and cat. It resembles E. granulosus, but the larval stage in the intermediate host represents alveolar or multilocular rather than unilocular cysts, which occur principally in rodents but infect humans.
  • E. oligarthus occurs in wild cats with larval stages in rodents.
  • E. vogeli occurs in domestic and wild dogs with intermediate stages in rodents and humans.

• echinocyte [e-ki′no-sīt] a spiculated erythrocyte with different configurations. Artifactual echinocytes, which can be found in old blood or caused by excess EDTA, are called crenated erythrocytes. Also associated with snake envenomation, doxorubricin toxicosis, and phosphokinase deficiency in dogs. An expected finding in a smear of porcine blood. Called also burr cell.

• Echinolaelaps echidninus [e-ki″no-le′l ps] the spiny rat mite, transmitter of Hepatozoon spp., the protozoan blood parasite. A mite of the family Laelapidae.

• Echinoparyphium a genus of the fluke family Echinostomatidae.

  • E. paraulum see Echinostoma revolutum.
  • E. recurvatum occurs in the small intestine of doves, pigeons, and domesticated birds and can cause emaciation and anemia.

    E-09.

    

    Echinococcus multilocularis in a rat.

    E-10.

    

    Echinocytes in a feline blood smear.

• Echinophthirius horridus a sucking louse of seals; cause pruritus and self-injury.

• Echinopogon genus of grasses in the Poaceae family; toxic species contain a fungal endophyte that produces an unidentified tremorgenic toxin causing incoordination, convulsions, and distressed breathing. Includes E. ovatus, E. caespitosus. Called also rough-bearded grass, hedgehog grass.

• Echinorhynchus salmonis [e-ki″no-ring′k s] acanthocephalan parasite of freshwater and marine fish. Found in the intestine of salmonids.

• Echinostoma [ek″ľ-nos′to-m ] a genus of flukes in the family Echinostomatidae. Includes, besides those listed below, Echinostoma aphylactum, E. caproni, E. hortense, E. jassyenese, E. lindoensis, and E. suinum.

  • E. iliocanum found in the intestine of dogs, rodents, and humans and may cause enteritis.
  • E. revolutum (syn. E. paraulum) found in the rectum and ceca of birds and in humans. Severe infestations may cause enteritis.

• Echinostomatidae [ek″ľ-no-sto-mat′ľde] a family of flukes (digenetic trematodes) found in birds.

• echinulate [e-kin′u-lāt] having small spikes or prickles.

• Echinuria a genus of spiruroid nematodes of the family Acuariidae. Includes E. uncinata (infests the upper alimentary tract of birds, causing caseous nodules in the wall of the esophagus).

• Echium a genus of the Boraginaceae family of plants; contains a series of hepatotoxic pyrrolizidine alkaloids and continued ingestion of the plants causes chronic liver damage. The plant also contributes to the development of toxemic jaundice, the end-stage of chronic copper poisoning in sheep. Includes E. plantagineum (E. lycopsis), E. sericeum, E. vulgare. Called also Paterson’s curse, Salvation Jane, Viper’s buglos, Lady Campbell weed.

• echiumidine one of the hepatotoxic pyrrolizidine alkaloids in Echium plantagineum.

• echo [ek′o] a reflected sound; the basis for echocardiography and ultrasonography. Often used as an abbreviation for echocardiography.

• echo-ranging [ek″o-rānj′ing] in ultrasonography, determination of the position or depth of a body structure on the basis of the time interval between the moment an ultrasonic pulse is transmitted and the moment its echo is received.

• echocardiogram [ek″o-kahr′de-o-gram″] the record produced by echocardiography.

• echocardiography [ek″o-kahr″de-og′r -fe] sonology of the heart. Used to assess the structure and function of the heart. Echocardiography is particularly useful in evaluating, without danger to the patient, functional, valvular, and structural deformities of the heart that formerly required cardiac catheterization for accurate diagnosis. See also ultrasonography.

  • contrast e. microbubbles in liquid are used as a vascular contrast medium. When injected intravenously in a selected or non-selected location, these can be tracked using ultrasound to demonstrate abnormalities of blood flow.
  • transesophageal e. a specialized ultrasound probe is positioned in the esophagus over the base of the heart in order to image the heart.
  • transthoracic e. The ultrasound probe is placed on the thoracic wall for imaging the heart.

• echocontrast agents [ek″o-kon′trast] see contrast echocardiography, contrast ultrasound.

• echoencephalogram [ek″o-en-sef′ -lo-gram] the record produced by echoencephalography.

• echoencephalography [ek″o-en-sef″ -log′r -fe] a diagnostic technique in which pulses of ultrasonic waves are beamed through the head from both sides, and echoes from the midline structures of the brain are recorded graphically; shifts from any midline may indicate a centrally placed mass. No longer in common use.

• echogenic [ek″o-jen′ik] in ultrasonography, giving rise to reflections (echoes) of ultrasound waves; hyperechoic.

• echogenicity [ek″o-jen-is′ľ-te] the characteristic ability of a tissue or substance to reflect sound waves and produce echoes. Bone and gas are most echogenic and fluids such as urine and bile the least. Organ parenchyma and soft tissues are intermediate, but each differs slightly from the other in the normal patient.

• echogram [ek′o-gram] the record made by echography.

• echography [-kog′r -fe] sonography or ultrasonography; the use of ultrasound as a diagnostic aid. Ultrasound waves are directed at the tissues and the echo of the returning sound is used to create the ultrasound image.

• echolocation [ek″o-lo-ka′sh n] producing, receiving, and interpreting ultra-high frequency sound waves for navigation or location of prey. Used by bats and toothed whales. Called also biosonar.

• echolucent [ek″o-loo′s nt] permitting the passage of ultrasonic waves without giving rise to echoes, the representative areas appearing black on the sonogram. This term in no longer recommended, use anechoic.

• echophonocardiography [ek″o-fo″no-kahr″de-og′r -fe] the combined use of echocardiography and phonocardiography.

• echopoor a dark region on an ultrasound image. The preferred term is hypoechoic or anechoic depending on the relative echogenicity to the surrounding tissue.

• echovirus [ek′o-vi″r s] some viruses, which were originally considered nonpathogenic, in the family Picornaviridae, genus Enterovirus. The name is derived from the first letters of the description ‘enteric cytopathogenic human orphan’, but similar viruses ECBO and ECPO (for bovine and porcine, respectively, and other species) are also recognized. At the time of the isolation of the viruses the diseases they caused were not known, hence the term ‘orphan’, but it is now known that some of these viruses produce many different types of human disease, especially aseptic meningitis, and diarrhea and various respiratory diseases. The members of the group are now included in the enteroviruses.

• Eck’s fistula [ek] an artificial communication made between the portal vein and the vena cava in order to divert the portal blood flow from the liver.

• eclabium eversion of a lip.

• ECLAM European College of Laboratory Animal Medicine. See also European Board of Veterinary Specialisation.

• eclampsia [-klamp′se-] a syndrome including convulsions and coma occurring in animals soon after birth of the young; non-specific because the etiology and clinical features vary depending on which species is involved.

  • bitch e. see puerperal tetany.
  • guinea pig e. see pregnancy toxemia (3).
  • mare e. see lactation tetany (2).
  • puerperal e. see puerperal tetany.
  • sow e. a poorly defined condition of older sows after farrowing that responds to treatment with calcium and magnesium.

• eclamptogenic [ -klamp″to-jen′ik] causing eclampsia.

• Eclectus roratus small, wax-billed parrot in the family Psittacidae; exhibits extreme sexual dimorphism with the males green, the females wine-red; called also eclectus parrot. Popular as an aviary bird.

• eclipse period [e-klips′] the time interval between viral penetration and the production of progeny virions.

• ecological emanating from or pertaining to ecology.

  • e. biome see biome.
  • e. climax the state of balance in an ecosystem when its inhabitants have established their permanent relationships with each other.
  • e. fallacy bias following misinterpretation that ecological factors affect all individuals equally.
  • e. imbalance the naturally occurring changes in the environment, e.g., bushfires, floods, volcanic fallout, which leave it unbalanced with respect to the type and quality of the feed they provide.
  • e. interface the border between two ecosystems.
  • e. mosaic a pattern of interspersed ecosystems.
  • e. niche 1. the position occupied by an organism in relation to other organisms and to the environment. 2. a particular part of an ecological environment in which a particular plant or animal species prospers. It is the set of terms, in relation to food and water supply and relationship with predators and disease and with competitors, by which the organism achieves its full biological potential.

• ecologist [e-kol′o-jist] a person skilled in ecology.

• ecology [e-kol′ -je] the science of organisms as affected by environmental factors; the study of the environment and the life history of organisms.

• econazole [-kon′ -zōl] an imidazole antifungal agent related to miconazole; used topically in the treatment of fungal infections of the skin.

• EcoR1 EcoR1 restriction endonuclease. A type II restriction endonuclease isolated from E. coli.

• ecosystem [e′ko-sis″t m] the fundamental unit in ecology, comprising the living organisms and the nonliving elements interacting in a certain defined area. In more sophisticated terms, a biotic community living in its biotope.

• ecotaxis [e′ko-tak′sis] the movement or ‘homing’ of a circulating cell, e.g., a lymphocyte, to a specific anatomical compartment. See homing.

• ecotype [e′ko-tīp] a breed or race within a species adapted to a specific environment.

• ECPHM uropean College of Porcine Health Management. See also European Board of Veterinary Specialisation.

• ECPVS European College of Poultry Veterinary Science. See also European Board of Veterinary Specialisation.

• ECSRHM European College of Small Ruminant Health Management. See also European Board of Veterinary Specialisation.

• ECSU extracorporeal circulatory support unit.

• ECT electroconvulsive therapy.

• ectasia [ek-ta′zh ] expansion, dilatation or distention.

• ectasis [ek′t -sis] see ectasia.

• -ectasis word element meaning expansion.

• ectental [ek-ten′t l] pertaining to the ectoderm and endoderm, and to their line of junction.

• ecthyma [ek-thi′m ] a shallowly eruptive form of impetigo.

  • contagious e. a specific dermatitis of sheep caused by a poxvirus in the genus Parapoxvirus. The virus is strongly antigenic, and an attack of the disease or vaccination provides long-lasting immunity. If the flock has previously been exposed, the disease is restricted in occurrence to lambs and young sheep. The characteristic lesions occur mostly on the lips and the skin around the mouth but have appeared wherever skin contact has been made with a source of infective virus, e.g., ear tagging, tail docking. Lesions are first papules, then crusts, and finally discrete thick tenacious scabs over vigorous granulation tissue. Very young lambs develop an extensive form of the disease involving even the alimentary tract. Occasional older sheep also have extensive lesions on other skin areas such as the coronets and at the other mucocutaneous junctions. The disease is transmissible to humans. Called also orf, scabby mouth, contagious pustular dermatitis.

• ect(o)- word element. [Gr.] external, outside.

• ectoantigen [ek″to-an′t -j n] 1. an antigen that seems to be loosely attached to the outside of bacteria. 2. An antigen formed in the ectoplasm (cell membrane) of a bacterium.

• ectoblast [ek′to-blast] the ectoderm.

• ectocardia [ek″to-kahr′de- ] congenital displacement of the heart; exocardia.

• ectocervix [ek″to-sur′viks] the vaginal part of the cervix. Called also portio vaginalis.

• ectoderm [ek′to-d rm] the outermost of the three primitive germ layers of the embryo; from it are derived the epidermis and epidermal derivatives, such as the claws, hair and glands of the skin, the nervous system, external sense organs (eye, ear, etc.), and mucous membrane of the mouth and anus.

• ectodermal [ek″to-dur′m l] pertaining to the ectoderm.

  E-11.

  

  Proliferative lesions of contagious ecthyma on the face of a Suffolk sheep. Suffolk sheep have a particular propensity to develop proliferative, strawberrylike lesions, with this infection.

  E-12.

  

  Orf (contagious ecthyma) affecting foot.

  • anhidrotic e. dysplasia a disorder characterized by abnormal development of tissues and organs of ectodermal origin. Manifest with hypotrichosis, reduced number of sweat glands, and incisor anodontia in cattle; caused by a deletion in the bovine EDA gene on the X-chromosome. Called also congenital hypotrichosis with anodontia, congenital X-linked ectodermal dysplasia.

• ectodermosis [ek″to-d r-mo′sis] a disorder based on congenital maldevelopment of organs derived from the ectoderm.

• ectoentad [ek″to-en′tad] from without inward.

• ectoenzyme [ek″to-en′zīm] an extracellular enzyme.

• ectogenous [ek-toj′ -n s] originating outside the organism.

• ectoglobular [ek″to-glob′u-l r] formed outside the blood cells.

• ectomere [ek′to-mēr] one of the blastomeres taking part in formation of the ectoderm.

• -ectomy word element. [Gr.] excision, surgical removal.

• ectoparasite [ek″to-par′ -sīt] a parasite living on the surface of the host’s body.

• ectoparasitism [ek″to-par′ -si-tiz- m] the state in which the ectoparasite is living on the surface of the host’s body.

• ectophyte [ek′to-fīt] a plant parasite living on the surface of the host’s body.

• ectopia [ek-to′pe- ] [L.] ectopy displacement or malposition, especially if congenital..

  • e. cordis congenital displacement of the heart outside the thoracic cavity.
  • e. lentis displacement of the crystalline lens away from its usual site of attachment to the ciliary body via the lens zonules. Now called lens dislocation. An inherited syndrome of Jersey cattle; the calves are normal in other respects. Also occurs in Marfan syndrome.

• ectopic [ek-top′ik] 1. pertaining to or characterized by ectopy. 2. located away from normal position. 3. arising or produced at an abnormal site or in a tissue where it is not normally found. See also specific sites or structures.

  • e. ACTH syndrome production of ACTH by nonpituitary tumors occurs in humans and is a cause of adrenal hyperplasia and hyperadrenocorticism. It has not been reported in animals.
  • e. endocrinopathy production of hormones by nonendocrinal, usually neoplastic, tissues. The most common example in animals is pseudohyperparathyroidism in dogs caused by a variety of tumors, particularly apocrine adenocarcinomas of the anal sacs and lymphosarcoma.
  • e. heart see ectopia cordis.
  • e. kidney a congenital defect where one or both kidneys is abnormally located.
  • e. teeth see dental cyst.
  • e. ureter common congenital abnormality where the ureter empties into the urinary tract distal to the bladder instead of the trigone of the bladder. In males, this includes the vas deferens, vesicular gland, or urethra. In females, this includes opening into the bladder neck, urethra, or vagina. Most commonly seen in dogs.
  • e. ossification the formation of non-neoplastic bone in non-osseous sites.

• ectoplacental cone [ek″to-pl -sen′t l] a syncytial body formed in the murine trophoblast; an essential component of the nidation process in this species.

• ectoplasm [ek′to-plaz″ m] an old-fashioned term that referred to a peripheral band of gel-like cytoplasm, free of organelles, found in free and motile cells.

• ectopy [ek′to-pe] ectopia.

• ectosteal [ek-tos′te- l] pertaining to or situated on the outside of a bone. See also periosteal.

• ectostosis [ek″to-sto′sis] ossification beneath the perichondrium of a cartilage or the periosteum of a bone.

• ectothermic animals whose body temperature is not internally regulated; they gain heat from the environment. Includes all animals except mammals and birds.

• ectothrix [ek′to-thriks] a conspicuous sheath of spores or hyphae around a hair shaft produced by a dermatophyte.

• ectoturbinates [ek″to-tur′bľ-nāts] papyraceous bones in the nasal cavity which are interleaved with endoturbinates.

• ectozoon [ek″to-zo′on] ectoparasite.

• ectrodactylia [ek′tro-dak-til′e- ] see ectrodactyly.

• ectrodactyly [ek″tro-dak′t -le] inherited, congenital skeletal defect in pups and kittens; there is incomplete fusion of the three rays that develop from the forelimb bud in the embryo; the paw is split up the middle as far as the metacarpals or to the carpus in some. Typically, the third metacarpal and digit are missing. Called also split-hand or lobster claw deformity, ectrodactylia, ectrodactylism.

• ectrogeny [ek-troj′ -ne] congenital absence or defect of a part.

• ectromelia [ek″tro-me′le- ] 1. gross hypoplasia or aplasia of one or more long bones of one or more limbs. 2. a generalized poxvirus disease of mice resembling smallpox in humans. Used in studies as a model of generalized virus infections.

• ectromelus [ek-trom′ -l s] exhibiting ectromelia.

• ectropion [ek-tro′pe-on] eversion or turning outward, as of the margin of an eyelid.

  • cicatricial e. caused by contraction of scar tissue following injury or surgery to the eyelid; most commonly seen in horses and dogs.
  • congenital e. ectropion present at birth; a conformational feature seen in some breeds of dogs, such as Saint Bernard, Bloodhound, Newfoundland, Shar pei and Mastiff.
  • e. uveae eversion or rolling out of the pupillary margin; seen clinically or histologically with chronic iritis; called also iridectropium.

• ECVAA European College of Veterinary Anaesthesia and Analgesia. See also European Board of Veterinary Specialisation.

• ECVCN European College of Veterinary and Comparative Nutrition. See also European Board of Veterinary Specialisation.

• ECVCP European College of Veterinary Clinical Pathology. See also European Board of Veterinary Specialisation.

• ECVD European College of Veterinary Dermatology. See also European Board of Veterinary Specialisation.

• ECVDI European College of Veterinary Diagnostic Imaging. See also European Board of Veterinary Specialisation.

• ECVECC European College of Veterinary Emergency and Critical Care. See also European Board of Veterinary Specialisation.

• ECVIM-CA European College of Veterinary Internal Medicine–Companion Animals. See also European Board of Veterinary Specialisation.

• ECVM European College of Veterinary Microbiology. See also European Board of Veterinary Specialisation.

• ECVN European College of Veterinary Neurology. See also European Board of Veterinary Specialisation.

• ECVO European College of Veterinary Ophthalmologists. See also European Board of Veterinary Specialisation.

• ECVP European College of Veterinary Pathologists. See also European Board of Veterinary Specialisation.

• ECVPH European College of Veterinary Public Health. See also European Board of Veterinary Specialisation.

• ECVPT European College of Veterinary Pharmacology and Toxicology. See also European Board of Veterinary Specialisation.

• ECVS European College of Veterinary Surgeons. See also European Board of Veterinary Specialisation.

• eczema [ek′z -m] a general term used in humans to describe any superficial inflammatory process involving primarily the epidermis; the term is used in a number of lay terms for skin diseases in animals; most common as a lay description of atopic dermatitis and acute skin reactions in dogs and cats.

  • facial e. see facial eczema.
  • miliary e. see feline miliary dermatitis.
  • moist e. see pyotraumatic dermatitis.
  • nasal e. see solar dermatitis. Called also Collie nose.
  • summer e. see equine allergic dermatitis.
  • watery e. an exudative epidermitis.

• eczematous [ek-zem′ -t s] characterized by or of the nature of eczema. Not a term used in veterinary medicine.

• ECZM European College of Zoological Medicine. See also European Board of Veterinary Specialisation.

• E&D euthanasia and disposal.

  E-13.

  

  Ectropion of the lower eyelid (and unrelated immature cataract) in an 8-year-old Saint Bernard.

• ED₅₀ median effective dose; the dose that is clinically effective in 50% of test subjects.

• EDB ethylene dibromide; a grain fumigant toxic to chickens.

• edema [-de′m] an abnormal accumulation of fluid in the cavities and intercellular spaces of the body. Result of diminished capacity of small blood vessels to retain water and solutes within their lumens. This in turn is caused by three factors acting singly or in combination: (1) decreased colloid osmotic pressure within blood vessels, usually due to hypoproteinemia; (2) decreased hydrostatic pressure differential between arterial and venous ends of blood capillaries (seen in heart failure or restricted venous or lymphatic drainage); and (3) increased capillary permeability caused by inflammation or other endothelial disturbance. See also anasarca, ascites, hydrothorax, hydropericardium and anatomically located edemas, e.g., brain, corneal, pulmonary edema.

  • angioneurotic e. see angioedema.
  • cardiac e. is part of the syndrome of congestive heart failure. It comprises ‘bottle jaw’, jugular vein engorgement, edema of the brisket and underline, and ascites, hydrothorax, and hydropericardium. See also congestive heart failure.
  • cerebral e. see cerebral edema.
  • dependent e. edema affecting most severely the lowermost parts of the body.
  • e. disease 1. in pigs, a highly fatal disease of young pigs in the weaner and grower age groups characterized by incoordination, a hoarseness of voice, weakness, flaccid paralysis, and blindness. Edema of the eyelids, face, and ears is diagnostic but is seldom visible on clinical examination. The course is short, often less than 24 hours, and many pigs are just found dead. The disease is caused by the opportunistic proliferation of specific serotypes of Escherichia coli in an intestinal environment brought about by a change to a diet more dense in carbohydrates. These have pilus attachment antigens that allow attachment of the organism to the small intestines and produce a verotoxin (VT2e), which produces an increase in vascular permeability in the target vessels in the CNS with resultant neurological disease. Called also gut edema, bowel edema. 2. in goats a disease caused by Mycoplasma F38; a fatal cellulitis.
  • gravitational e. see dependent edema (above).
  • gut e. see edema disease (above).
  • hepatic e. edema is a common accompaniment of hepatic disease because of the decline in production of plasma proteins and a fall in the blood’s hydrostatic pressure. Ascites may occur independently because of portal hypertension when there is severe liver disease and obstruction to blood flow in the portal vein.
  • hypoproteinemic e. caused by insufficient production of albumin or excess loss through a protein losing enteropathy. See hepatic edema (above), Johne’s disease, proliferative enteropathy, type II ostertagiasis.
  • laryngeal e. see laryngeal edema.
  • leg e. a disease of market age turkeys of unknown cause and characterized by edema of the legs and focal muscle necrosis.

    E-14.

    

    Dependant edema in the subcutaneous tissues of the ventral abdomen and in the prepuce of a horse.

    E-15.

    

    Edema disease. Recumbent depressed pig showing edema of eyelid and forehead. Courtesy of J.T. Done.

  • neurogenic pulmonary e. results from head trauma, central nervous system lesions, and toxins, which may cause increased pulmonary blood pressure and alteration to sympathetic innervation leading to fluid leakage from vessels. Known also as non-cardiogenic pulmonary edema.
  • pitting e. edema in which pressure by the clinician’s finger leaves a persistent depression in the tissues.
  • pulmonary e. an effusion of serous fluid into the pulmonary interstitial tissues and alveoli. Preceded by pulmonary congestion or by increased alveolar capillary permeability. If sufficiently severe may cause hypoxemia. The breathing will then be labored, the normal breath sounds on auscultation may be absent, and a frothy nasal discharge, often blood-tinged, may appear. At this stage the animal’s life is about to terminate.
  • subcutaneous e. may be generalized and constitute anasarca. Local areas of edema occur in such other conditions as angioedema and urticaria, edematous plaques in dourine and infectious equine anemia, and in purpura hemorrhagica.
  • vasogenic e. see vasogenic cerebral edema.

• edemagen [-de′m -jen] an agent, force, or process that induces edema by causing capillary leakage or inhibiting venous or lymphatic outflow from the site, without the cellular response of inflammation. For example, gravity is edemagenic when inactivity is combined with a condition that compromises vascular or lymphatic drainage from the limb. The equine distal limb is particularly susceptible to edemagens, owing to its unique lymphatic anatomy.

  • plant e. plant substances that cause edema in animals, e.g., 3-methyl indole, produced in the rumen from tryptophan. Plant substances that have the opposite effect include extracts of horse chestnut, Aesculus hippocastanum.

• edematogenic [-dem″ -to-jen′ik] producing or causing edema.

• edentate [e-den′tāt] an animal without teeth, e.g., giant anteater.

• edentia [e-den′sh ] absence of the teeth.

• edetate [ed′ -tāt] any salt of ethylenediaminetetraacetic acid (EDTA), including edetate disodium calcium, used in the diagnosis and treatment of lead poisoning, and edetate disodium, used in the treatment of poisoning with lead and other heavy metals, and, because of its affinity for calcium, in the treatment of hypercalcemia. Also commonly used as anticoagulants for blood samples collected for laboratory analysis, particularly hematology.

• edetic acid [ -det′ik] ethylenediamine tetra-acetic acid (EDTA).

• EDIM epizootic diarrhea of infant mice. See murine epizootic diarrhea.

• Edles Warmblut horse German light horse.

• EDM see equine degenerative myeloencephalopathy

• EDRF endothelium-derived relaxing factor.

• edrophonium [ed″ro-fo′ne- m] a cholinergic used in the form of the chloride salt as a curare antagonist; used in the edrophonium challenge test to diagnose myasthenia gravis. See also Tensilon.

• EDS see egg drop syndrome.

• EDTA ethylenediaminetetraacetic acid. See edetate.

  • Ca-EDTA calcium ethylenediaminetetraacetic acid. See edetate.
  • Cr⁵¹ EDTA see Cr⁵¹ EDTA.

  E-16.

  

  Pulmonary edema. Sheep with frothy and blood-stained nasal and oral discharge.

• Educational Commission for Foreign Veterinary Graduates (ECFVG) a committee of the American Veterinary Medical Association overseeing the procedures for acceptance of veterinary graduates of foreign colleges to be licensed to practice veterinary medicine in the US. The ECFVG certification program is an educational prerequisite in the US for veterinary licensure in most states and for certain federal programs for graduates of foreign, non–AVMA-accredited schools. It requires successful completion of an educational equivalency assessment certification program, which comprises four steps. The first is to confirm an applicant’s veterinary college credentials, the second is to assess a candidate’s English language ability, the third to assess a candidate’s basic and clinical veterinary science knowledge by passing the Basic and Clinical Sciences Examination (BCSE), and the fourth, the Clinical Proficiency Examination (CPE) to assess a candidate’s hands-on clinical veterinary medical skills.

• Edwards medium [ed′w rdz] agar medium selective for streptococci, also differentiating those that hydrolyze esculin.

• Edwardsiella [ed-wahrd″se-el′ ] a genus of bacteria of the family Enterobacteriaceae. Inhabit the intestines of snakes and fish; found also in water.

  • E. ictaluri causes enteric septicemia in catfish.
  • E. tarda (syn. E. anguillimortifera) causes edwardsiellosis, septicemia in catfish and eels, characterized by the appearance of foul-smelling, gas-filled cavities in muscle. Also a reported cause of diarrhea in dogs, pigs, and calves.

• edwardsiellosis disease caused by infection with Edwardsiella spp. See enteric septicemia of catfish.

• EEE Eastern equine encephalomyelitis.

• EEG electroencephalogram.

• eel [ēl] elongated, serpent-like fish with no scales. Most are marine species but there are some freshwater types. They are members of the order Apodes and constitute a number of suborders.

  • e. rhabdovirus several isolates from eels have not been shown to be associated with disease in eels, but some are pathogenic for trout and salmon.
  • e. stomatopapilloma cauliflower-like growths in European eels. Several viruses have been isolated from lesions, but none yet shown to be the etiologic agent. Called also cauliflower disease.

• EENT eye–ear–nose–throat; see otolaryngology.

• EF elongation factor; soluble proteins involved in the elongation cycle of protein biosynthesis.

• EF-4 eugonic fermenter-4.

• EFA essential fatty acid.

• EFF Elokomin fluke fever.

• effacement [-fās′m nt] the obliteration of form or features; applied to the cervix uteri during labor when it is so changed that only the ostium uteri remains.

  • border e. in radiology, the obscuring of the borders of a structure due to an adjacent structure of the same opacity. Commonly seen in thoracic radiology when pleural fluid is present leading to the inability to visualize the borders of the heart and diaphragm. This term has replaced the term silhouette sign.

• effect [ -fekt′] a result produced by an action. The relationship between the two can be expressed in linear form. The total association between them may be the sum of a number of effects. The effect may be direct when it is exerted without being transmitted through intervening factors, or indirect when it is. It may also be a spurious effect when the observed changes are due to causes and correlations common to both.

  • additive e. the combined effect produced by the action of two or more agents, being equal to the sum of their separate effects.
  • Coolidge e. the stimulation of sexual behavior in a male animal upon exposure to a new female.
  • cumulative e. cumulation action.
  • direct e. the effect of one variable on another without passing through a third variable.
  • experimenter e’s demand characteristics; the characteristics supplied by the experimental subject in response to what it perceives are the demands of the experimenter.
  • e. modifier a factor that modifies the effect of a causal factor under study. Called also interaction.
  • position e. in genetics, the changed effect produced by alteration of the relative positions of various genes on the chromosomes.
  • pressure e. the sum of the changes that are due to obstruction of tissue drainage by pressure.
  • side e. a consequence other than that for which an agent is used, especially an adverse effect on another organ system.

• effective [ -fek′tiv] exerting a measurable effect.

  • e. circulating volume that part of the blood volume that is effectively perfusing the tissues at a particular time.
  • e. refractory period time interval during which the effector cell remains unresponsive after a previous reaction to a stimulus: see also refractory period.

• effectiveness [ -fek′tiv-nis] the ability to produce a specific result or to exert a specific measurable influence.

  • relative biological e. an expression of the effectiveness of other types of radiation in comparison with that of gamma or x-rays.

• effector [-fek′t r] 1. a muscle or gland that contracts or secretes, respectively, in direct response to nerve impulses. 2. a molecule that binds to an enzyme with an effect on its catalytic activity, i.e., either an activator or inhibitor.

  • allosteric e. one that regulates the activity of an enzyme by binding at a site other than the active site.
  • e. cell cell in the immune system that mediates an immune function.

• effemination [-fem″ľ-na′sh n] feminization.

• efferent [ef′ r- nt] conducting or progressing away from a center or specific site of reference, as an efferent nerve.

  • e. arterioles see efferent arteriole.
  • e. ductules conducting tubules from the rete testis to the head of the epididymis, forming part of the transport mechanism for spermatozoa in the testis.
  • γ e’s small nerves supplying intrafusal muscle fibers.
  • e. nerve any nerve that carries impulses from the central nervous system toward the periphery, as a motor nerve. See also neuron.

• efficacy [ef′ľ-k -se] 1. intrinsic activity; is equal to the magnitude of the maximal response. 2. the therapeutic effect that can be achieved with a given drug.

• efficiency [-fish′ n-se] 1. in clinical practice equals the effect achieved in relation to the expenditure and effort expended. 2. in physiological terms, efficiency of any organ or tissue is equal to the ratio of useful energy produced to total energy expended.

• effleurage [ef-l $\stackrel{⌣}{o}$ $\stackrel{⌣}{o}$ -rahzh′] [Fr.] stroking movement in massage, intended to encourage venous and lymphatic return.

• efflorescence [ef″lo-res′ ns] 1. the quality of being efflorescent. 2. a rash or eruption.

• efflorescent [ef″lo-res′ nt] becoming powdery by losing the water of crystallization.

• effluent [ef′floo- nt] waste from an abattoir carried away in liquid form. Disposal is a major problem because of the need to avoid pollution of waterways. See aerobic effluent treatment, anaerobic effluent treatment.

• effluvium [-floo′ve- m] pl. effluvia [L.] 1. marked shedding of hairs with little or no traction; occurs as a result of systemic disease that causes hairs to synchronize in telogen and shed at one time. 2. an exhalation or emanation, especially one of noxious nature.

  • anagen e. see anagen defluxion.

• effusion [-fu′zh n] 1. escape of a fluid into a part; exudation or transudation. See also specific anatomic sites. 2. an exudate or transudate.

• eflornithine [ef-lor′nľ-thēn″] an antiprotozoal agent, used as the hydrochloride in trypanosomiasis and Pneumocystis carinii pneumonia.

• eft [ ft] the terrestrial juvenile stage of newts, following metamorphosis from tadpoles and before adulthood.

• EGD esophagogastroduodenoscopy.

• egesta [e-jes′t ] undigested material discharged from the body.

• egestion [e-jes′ch n] the casting out of undigested material, as in birds that eject from the gizzard.

• egg [eg] 1. an ovum; a female gamete. 2. an oocyte. 3. a female reproductive cell at any stage before fertilization and its derivatives after fertilization and even after some development. 4. hen egg, consisting of a blastodisk, remnant of the nucleus in a mass of white yolk sitting on top of the yellow yolk, the yolk suspended by two twisted strands of mucin-like protein, the chalazae, from the two poles of the egg, two yolk membranes that separate the yolk from the albumen, the albumen or white of the egg, which is in four separate layers of liquid and jelly material, two thin shell membranes, and an eggshell. See also avian oogenesis. 5. helminth egg.

  • e. bound a disease of cage birds, birds in zoological collections, reptiles, and in fish in which the egg cannot be passed/laid. In birds, the hen may show pain and be straining, and the egg may be palpable. The syndrome is comparable with dystocia in a viviparous animal. In fish, the signs can include distention of the belly and wrinkled, shriveled eggs.
  • e. count counting of helminth eggs as an estimate of the parasite status in an animal or group. Flotation techniques and special counting chambers are used. The results are expressed as eggs per gram (e.p.g) of feces.
  • e. dipping dipping of hatchery eggs in antibiotic solutions, especially erythromycin or tylosin, to prevent the transmission of infections from adults to chickens.
  • e. drop syndrome occurs in chickens and Japanese quails, caused by an adenovirus and characterized by the hens laying a reduced number of thin-shelled or shell-less eggs. Subsequently the egg yield is reduced. First observed in 1976 and also known as egg drop syndrome 76. A similar disease in ducks, called duck egg drop syndrome, has recently been associated with a flavivirus in China.
  • e. eating a vice that begins without apparent reason. A high rate of egg breaking in the unit encourages birds to begin. Many techniques are used in prevention, but frequent egg removal is essential.
  • grader e. a reject from those destined for household use; used in petfood manufacture.
  • e. heating heating eggs in a hot-air incubator for 12–14 hours to reduce the transmission of infection on the egg exterior.
  • e. peritonitis see egg peritonitis.
  • e. retention see egg bound (above).
  • e. shell secreted around the egg mass and membranes during its last 15 hours in the uterus; composed of calcium carbonate and a glycoprotein matrix; surrounded by the cuticle.
  • thin-shelled e. occurs in egg drop syndrome (see above), DDT poisoning. The shell of the egg is very thin, often missing altogether.
  • e. tooth the additional tip to the beak in birds, and mouth parts of reptiles, used by the hatching chick to peck out the circular hatch of shell to allow it to emerge. The egg tooth of birds drops off in a few days. Called also bean.
  • e. transmission transmission of disease from hen to chicken and between chickens via infection in the egg, e.g., Mycoplasma gallisepticum, M. meleagridis.
  • e. white injury the effects of biotin deficiency induced by feeding of raw egg whites (albumen). The factor responsible is avidin that binds biotin, preventing absorption.
  • e. yield varies with breed; in domestic fowl the normal annual average in the US is about 280 eggs per bird; good units average over 300.

• Eggers bone plate [eg′ rz] slotted contact plate for orthopedic use in stainless steel or vitallium. Fitted with matching screws.

• eggplant [eg′plant] Solanum melongena.

• egobronchophony [e″go-brong-kof′o-ne] increased vocal resonance with a high-pitched bleating quality of the transmitted voice or other sound, detected by auscultation of the lungs, especially over lung tissue compressed by pleural effusion.

• egophony [e-gof′o-ne] egobronchophony.

• egret wading birds in the family of herons (Ardeidae) and particularly of the genera Egretta and Ardea with long legs and bills; highly prized for ornamental plumage.

  • cattle e. (Bubulcus ibis) a member of the heron family Ardeidae, but not confined to aquatic habitats. An opportunistic feeder, it is commonly associated with grazing animals and may be seen perching on their backs.
  • great e. (Ardea alba) is widely distributed in temperate and tropical habitats, known also as common egret, large egret or great white heron.

• Egyptian mau a medium-sized, muscular, rare breed of cats with green eyes and a distinctive medium length, patterned coat with a mixture of spots and stripes on the hair tips.

• EHD epizootic hemorrhagic disease.

• EHDV epizootic hemorrhagic disease virus.

• EHEC enterohemorrhagic Escherichia coli.

• Ehlers–Danlos syndrome [a′l rz dahn-los′] a congenital hereditary syndrome of joint hyperextensibility, hyperelasticity and fragility of the skin, poor wound healing leaving parchment-like scars, capillary fragility and subcutaneous nodules after trauma. Called also cutis hyperelastica, cutaneous asthenia, hereditary collagen dysplasia. In humans a series of these disorders, listed as Ehlers–Danlos syndrome Type I to Type VII, represent different errors in collagen synthesis and maintenance with subsequent variations in clinical and pathological manifestations.

• Ehmer sling Used in the management of hip luxation to maintain the pelvic limb in a flexed position, preventing weight bearing, and providing abduction and inward rotation of the hip post reduction.

• Ehretia membranifolia member of the Boraginaceae plant family; may cause nitrate–nitrite poisoning.

  E-17.

  

  Ehlers-Danlos syndrome in a 5-monthold Weimaraner showing the characteristic skin elasticity.

  E-18.

  

  Ehmer sling.

• Ehrlichia [ār-lik′e- ] a genus of bacteria in the family Anaplasmataceae, order Rickettsiales, recently reclassified so that some species are now classified as Anaplasma and some as Neorickettsia. All are intracellular parasites of leukocytes and endothelial cells of animals or humans and require a vector for transmission. See also Rickettsia, Anaplasma, Neorickettsia.

  • E. bovis now classified as Anaplasma bovis.
  • E. canis causes canine ehrlichiosis.
  • E. chaffeensis a less common cause of canine ehrlichiosis.
  • E. equi now classified as Anaplasma phagocytophilum.
  • E. ewingii causes canine granulocytic ehrlichiosis.
  • E. ondiri causes Ondiri disease. Called also bovine petechial fever.
  • E. ovina now classified as Anaplasma phagocytophilum; causes benign ovine rickettsiosis.
  • E. phagocytophila now classified as Anaplasma phagocytophilum.
  • E. platys now classified as Anaplasma platys.
  • E. risticii now classified as Neorickettsia risticii.
  • E. ruminantium cause of heartwater in cattle and transmitted by Amblyomma spp. Previously classified as Rickettsia ruminantium and Cowdria ruminantium. E. sennetsu now classified as Neorickettsia sennetsu.

• ehrlichial colitis [ār-lik′e- l] see equine monocytic ehrlichiosis.

• ehrlichiosis [ar-lik″e-o′sis] disease caused by infection with members of the genus Ehrlichia, as well as some former members now in the genera Anaplasma and Neorickettsia.

  • canine e. infection by Ehrlichia canis, E. ewingii or E. chaffeensis, transmitted by ticks, may be subclinical or cause transient, mild to severe clinical signs of fever, anorexia, and lymphadenopathy, with usually asymptomatic leukopenia and thrombocytopenia in dogs. Persistent subclinical infection is common; E. canis may also cause a chronic clinical phase in which there may be anemia, pancytopenia, bleeding tendencies, weight loss, anterior uveitis, retinal detachment, edema, neurologic signs, polyuria and polydispia, polymyositis, and immune suppression. Organisms may be seen in monocytes (E. canis, E. chaffeensis) or neutrophils (E. ewingii).
  • equine granulocytic e. is a tick-borne infectious disease caused by Anaplasma phagocytophilum. The clinical syndrome comprises high fever, hemolytic anemia, petechial hemorrhage, incoordination, and edema of the extremities. The disease bears a strong resemblance to equine infectious anemia. Diagnosis is by detection of cytoplasmic inclusion bodies present in the neutrophilic and occasionally eosinophilic granulocytes and PCR analysis.

    E-19.

    

    Canine neutrophil that contains an Ehrlichia morula.

  • equine monocytic e. infectious, but not contagious, enterocolitis of horses caused by Neorickettsia risticii. Infection occurs by ingestion of aquatic insects (caddis flies) infected by the organism and disease is more common near rivers or large bodies of water. Infection may be inapparent, or with transient fever or result in severe disease characterized by high fever, acute diarrhea and colic and laminitis. Abortion can be a sequela in pregnant mares. Diagnosis is by culture, PCR analysis, and serology. Called also Potomac horse fever, Shasta River crud, equine ehrlichial colitis. See equine neorickettsiosis.

• ehrlichosis [ar-lik″o′sis] ehrlichiosis.

• Ehrlich’s test [ār′lik] used to examine urine for the presence of urobilinogen; based on the use of Ehrlich’s diazo reagent, a sodium pdiazobenzenesulfonate solution.

• EHV equine herpesvirus.

  • EHV1, EHV2, EHV3, EHV4, EHV5 see equine herpesvirus.

• EIA equine infectious anemia.

• eicosanoids [i-ko′s -noidz] a family of compounds derived from C20 polyunsaturated fatty acids including arachidonic acid (eicosatetraenoic acid), eicosapentaenoic acid and dihomo-γ-linolenate (eicosatrienoic acid). Includes prostaglandins, prostacyclins, leukotrienes, lipoxins and thromboxanes, the principal mediators of inflammation.

• eicosapentaenoic acid (EPA) a 20-carbon polyunsaturated fatty acid with five double bonds; a precursor of series 3 prostaglandins, series 3 thromboxanes and series 5 leukotrienes.

• eicosatetraenoic acid [i-ko″s -pen″t -e-no′ik] arachidonic acid.

• EIEC enteroinvasive Escherichia coli.

• eigenvalues statistical term meaning latent root.

• Eight Principles in traditional Chinese medicine, the four pairs of opposites that are the basis for all diagnoses: Yin and Yang, internal and exterior, cold and heat, deficiency and excess. Called also guiding principles.

• Eimeria [i-mēr′e- ] a genus of protozoan parasites in the family Eimeriidae. There are many species (see below), mostly in birds and herbivores. They are the principal cause of coccidiosis, which also has other causes. See Cystoisospora, Isospora, Tyzzeria, Wenyonella. Commonly listed Eimeria spp. and their hosts are listed below: E. abramovi—wild duck, geese; E. acervulina—domestic poultry, quail; E. adenoides—turkey; E. ahsata—sheep, goats; E. alabamensis—cattle; E. alijevi—goats; E. alpacae—llama, alpaca; E. anatis—mallard, domestic duck; E. ankarensis—water buffalo; E. anseris—domestic geese, wild geese; E. aspheronica—goats; E. arkhari—sheep, goats; E. arloingi—sheep, goats; E. auburnensis—cattle; E. augusta—grouse; E. aurata—fish; E. azerbaidschanica—water buffalo. E. bactriani—one- and two-humped camel; E. bakuensis—sheep; E. bareillyi—water buffalo; E. battakhi—domestic duck; E. bombaynsis—zebu cattle; E. bonasae—grouse; E. boschadis—wild duck, geese; E. bovis—cattle, zebu, water buffalo; E. brantae—wild duck, geese; E. brasiliensis—cattle, zebu, water buffalo; E. brinkmanni—rock ptarmigan; E. brunetti—domestic poultry; E. bucephalae—wild duck, geese; E. bukidnonensis—cattle, zebu, buffalo. E. cameli—one- and two-humped camels; E. canadensis—domestic cattle, zebu, bison, water buffalo; E. canis—dogs and cats; E. caprina—goats; E. caprovina—goats; E. carinii—rats; E. carpelli—fish; E. caviae—guinea pig; E. cerdonis—pig; E. christenseni—domestic goat; E. christianseni—mute swan; E. clarkei—lesser snow goose; E. coecicola—rabbit; E. colchici—pheasant; E. columbae—pigeon; E. columbarum—rock dove; E. coturnicus—quail; E. crandallis—domestic sheep, small wild ruminants; E. cylindrica—domestic cattle, zebu, water buffalo; E. cyprini—fish. E. danailovi—mallard; E. danielle—domestic sheep; E. debliecki—pig; E. dispersa—turkey; E. dolichotis—Patagonian cavy; E. dromedarii—one- and two-humped camels. E. ellipsoidalis—domestic cattle, zebu, Euro-pean bison, water buffalo; E. elongata—domestic rabbit; E. exigua—rabbit, Greenland hare. E. falciformis—mouse; E. fanthami—rock ptarmigan; E. farri—white fronted goose; E. faurei—sheep, small wild ruminants; E. ferrisi—mouse; E. fulva—wild geese. E. gallopavonis—turkey; E. gilruthi—sheep, goats; E. gokaki—buffalo; E. gonzalei—sheep; E. gorakhpuri—guinea fowl; E. granulosa—domestic and wild sheep; E. grenieri—guinea fowl; E. guevarai—pig. E. hagani—poultry; E. hasei—rats; E. hawkinsi—sheep, goats; E. hermani—wild geese; E. hindlei—mouse; E. hirci—goats. E. illinoisensis—cattle; E. innocua—turkey; E. intestinalis—rabbit; E. intricata—sheep, wild small ruminants; E. irresidua—rabbit, jackrabbit. E. jolchijevi—goats; E. keilini—mouse; E. kocharli—goats; E. kofoidi—partridge; E. koganae—wild duck, geese; E. kosti—cattle; E. kotlani—domestic geese; E. krijgsmanni—mouse. E. labbeana—pigeon; E. lagopodi—ptarmigan; E. lamae—alpaca; E. langeroni—pheasant; E. leuckarti—horse; E. lyruri—partridge. E. macusaniensis—llama, alpaca; E. magna—rabbit, hare; E. magnalabia—wild geese; E. mandali—peafowl; E. marsica—sheep; E. matsubayashii—domestic rabbit; E. maxima—poultry; E. mayurai—peafowl; E. media—domestic and wild rabbit; E. megalostromata—pheasant; E. meleagridis—turkey; E. meleagrimitis—domestic turkey; E. mitis—poultry; E. mivati—domestic fowl; E. miyairii—rat; E. mundaragi—cattle, zebu; E. musculi—mouse. E. nadsoni—grouse; E. nagpurensis—rabbit; E. necatrix—domestic fowl; E. neodebliecki—pig, wild pig; E. neoleporis—rabbit; E. nieschultzi—rat; E. ninakohlyakimovae—sheep, goats and small wild ruminants; E. nocens—domestic and wild geese; E. nochti—rat; E. norvegicus—rat; E. numida—guinea fowl. E. ovina—domestic sheep, small wild ruminants; E. ovoidalis—buffalo. E. pacifica—pheasant; E. pallida—domestic sheep and goats; E. parva—domestic sheep and goats, small wild ruminants; E. parvula—gooses; E. pavonina—peafowl; E. pavonis—peafowl; E. pelleryi—bactrian camel; E. pellita—cattle; E. perforans—rabbit, hare; E. perminuta—pig; E. peruviana—llama; E. phasiani—pheasant; E. piriformis—domestic rabbit; E. polita—pig; E. porci—pig; E. praecox—poultry; E. procera—partridge; E. punctata—sheep; E. punoensis—alpaca. E. rajasthani—dromedary; E. ratti—rat. E. saitamae—duck; E. scabra—domestic and wild pig; E. schachdagica—duck; E. schueffneri—mouse; E. scrofae—pig; E. separata—rat; E. solipedum—horse; E. somateriae—wild duck; E. spinosa—pig; E. stiedai—rabbit, hare; E. stigmosa—domestic goose; E. striata—wild goose; E. subepithelialis—carp; E. subrotunda—turkey; E. subspherica—cattle, zebu, water buffalo; E. suis—domestic pig. E. tenella—domestic poultry; E. tetricis—grouse; E. thianethi—buffalo; E. tropicalis—pigeon; E. truncata—domestic and wild goose; E. truttae—salmon. E. uniungulati—horse, mule; E. weybridgensis—sheep; E. wyomingensis—cattle, zebu, water buffalo; E. zuernii—cattle, zebu, water buffalo.

• einsteinium (Es) [īn-sti′ne- m] a chemical element, atomic number 99, atomic weight 254.

• Einthoven [īn′to-v n] Dutch physiologist, inventor of the electrocardiogram.

  • E.’s law the potential differences between the bipolar leads measured simultaneously will, at any given moment, have the values II = I + III.
  • E. triangle an equilateral triangle used as a model of the standard limb leads used in electrocardiography.

• EIPH exercise induced pulmonary hemorrhage. See exercise-induced pulmonary hemorrhage and epistaxis

• Eisenmenger [i′s n-meng″ r] Victor Eisenmenger, Austrian physician (1864–1932).

  • E. complex pulmonary vascular obstructive disease that develops as a consequence to large preexisting left to right shunts such that pulmonary arterial pressure approaches systemic pressures.
  • E. syndrome clinical signs associated with Eisenmenger complex and characterized by cyanosis, exercise intolerance, often erythrocytosis, and possibly a murmur or thrill (the murmur and thrill are not always present), owing the pressure gradient from the right side to the left side. Characterized by exercise intolerance, cyanosis, palpable thrill, and cardiac murmur.

• ejaculate [e-jak′u-lāt] 1. to expel an ejaculate. 2. the products of an ejaculation. See also ejaculation.

• ejaculatio [e-jak″u-la′she-o] ejaculation.

• ejaculation [e-jak″u-la′sh n] forcible, sudden expulsion; especially expulsion of semen from the male urethra, a reflex action that occurs as a result of sexual stimulation. Includes lubricating fluid from bulbourethral glands, prostatic and vesicular glands (seminal vesicular) fluids and semen. Called also seminal ejaculation.

  • chemical e. see ex-copula ejaculation (below).
  • electrical e. see electroejaculation.
  • ex-copula e. ejaculation in the absence of copulation; the ejaculate is often obtained by injection of drugs (imipramine hydrochloride and xylazine) and is commonly used in stallions that are unable to mount because of injuries. Called also chemical ejaculation.
  • incomplete e. the process of ejaculation of semen is not completed, and semen does not reach the external urethral orifice, due usually to a defect in the sympathetic innervation of the region.
  • retrograde e. after intercourse, in which no semen is ejaculated from the external urethral orifice, semen is found in the urinary bladder.

• ejecta [e-jek′t ] refuse cast off from the body.

• ejection [e-jek′sh n] forcible expulsion through a narrow orifice.

  • e. fraction is the percentage of blood in the ventricle at the end of diastole that is ejected during a cardiac contraction. Calculated as the ratio of the stroke volume to end-diastolic volume.
  • ventricular e. time that part of the cardiac ventricular contraction time when blood is actually discharged through the semilunar valves.

• ejection fraction [e-jek′sh n] in echocardiography, the fractional volume of blood leaving the left ventricle in systole.

• ejiao a gelatin stewed from the skin of donkeys and used in traditional Chinese medicine. Trade in donkeys for this purpose has markedly increased their monetary value in developing countries, making them less accessible for traditional purposes of travel and farming. There is also an illicit trade. Called also donkey hide gelatin.

• EKG electrocardiogram.

• EKY electrokymogram.

• elaborate [e-lab′o-rāt] to produce complex substances out of simpler materials.

• elaboration [e-lab″ -ra′sh n] the process of producing complex substances out of simpler materials.

• Elaeodendron buchananii African tree in family Celastraceae, whose leaves, if ingested, cause death after a clinical illness with signs of dyspnea, incoordination, and diarrhea in those animals that live for several days. A causative toxin has not been identified. Called also Cassine buchananii, Elaeodendron kiniense.

• Elaeophora [el″e-of′ -r] a genus of filarioid nematodes in the family Onchocercidae.

  • E. bohmi found in the arteries and veins of the extremities of horses. Called also Onchocerca bohmi.
  • E. poeli found in the aorta of cattle and other ruminants.
  • E. sagittus found in bovine hearts. Called also Cordophilus sagittus.
  • E. schneideri found in arteries of deer, elk and sheep; causes elaeophoriasis.

• elaeophoriasis [el″e-of″ -ri′ -sis] dermatitis caused by vascular lesions of infestation with microfilariae of Elaeophora schneideri. The parasite can also cause rhinitis, keratoconjunctivitis, and stomatitis in sheep infected by bites of horse flies. This and other species may also cause sporadic cases of disease due to vascular obstruction.

• elaeophorosis [el″e-of″ -ro′sis] see elaeophoriasis.

• Elam gag a gag used in horses and cattle to obtain access to the interior of the mouth. Shaped like a stringless tennis racquet with two horizontal bars, one of which can be moved by manipulating a screw drive. The gag is inserted in the mouth in a horizontal position and immediately brought to the vertical position with the bars located caudad to the incisor teeth. The bars are now screwed apart giving unimpeded access to the interior of the mouth.

• eland (Taurotragus spp.) large African antelopes characterized by their corkscrew horns and a prominent dewlap, capable of domestication and farming for meat, milk, and hides and favored for game ranches. The two species are T. oryx (common eland) and T. derbianus (giant eland).

• elands wattle see Elephantorrhiza elephantina.

• elaphostrongyliasis infestation with species of Elaphostrongylus. See neurofilariasis.

• Elaphostrongylus a genus of metastrongyloid nematodes of the family Protostrongylidae.

  • E. cervi found in connective tissue and central nervous system of deer. Causes cerebrospinal nematodiasis.
  • E. panticola found in the brain of deer.
  • E. rangiferi occurs in the central nervous system and muscles of reindeer. See also cerebrospinal nematodiasis.
  • E. tenuis see Parelaphostrongylus tenuis.

• elapid [el′ -pid] a snake belonging to the Elapidae family.

• Elapidae a family of venomous front-fanged snakes; includes cobras, kraits, mambas, coral snakes, copperheads, death adders, and tiger snakes. They have hollow, forward fixed fangs (proteroglyphous snakes), and the venom is largely neurotoxic.

• elasmobranch [e-las′mo-brank] members of the class Elasmobranchii; includes sharks and rays.

• elastase [se-las′tās] a protease enzyme that breaks down elastin, a component of connective tissue. Elastase-1 is secreted by the exocrine pancreas and takes part in protein digestion in the small intestine. Elastase-2 is produced by neutrophils and breaks down bacterial membrane proteins. An ELISA test for fecal elastase has been used to investigate exocrine pancreatic insufficiency in dogs.

• elastic [e-las′tik] capable of resuming normal shape after distortion.

  • e. modulus the constant or scale factor that defines quantitatively the relationship between the deformation of the vascular wall (or other elastic medium) and the deforming force.
  • e. tissue connective tissue made up of yellow elastic fibers, frequently massed into sheets.

• elasticity [e″las-tis′ľ-te] the quality of being elastic.

  • blood vessel e. a composite value of the combined elasticities of the smooth muscle, collagen and elastin of which the walls are composed.

• elastin [e-las′tin] a yellow scleroprotein, the essential constituent of elastic connective tissue; it is brittle when dry, but flexible and elastic when moist.

• elastofibroma [e-las″to-fi-bro′m ] a tumor consisting of both elastin and fibrous elements.

• elastolysis [e″las-tol′ -sis] the digestion of elastic substance or tissue.

• elastoma [e″las-to′m ] a tumor or focal excess of elastic tissue fibers or abnormal collagen fibers of the skin.

• elastometer [e″las-tom′ -t r] an instrument for measuring the elasticity of tissues.

• elastorrhexis [e-las″to-rek′sis] a rupture of fibers composing elastic tissue.

• elastosis [e las-to′sis] 1. degeneration of elastic tissue. 2. degenerative changes in the dermal connective tissue with increased amounts of elastotic material. 3. any disturbance of the dermal connective tissue.

  • solar e. degenerative changes in superficial dermal collagen and elastin caused by solar radiation. Seen in solar dermatitis.

• elastotic [e-las-tot′ik] 1. pertaining to or characterized by elastosis. 2. resembling elastic tissue; having the staining properties of elastin.

• elastration [e-las-tra′sh n] see elastrator.

• elastrator an implement used for castration and tail docking by applying elastrator rings to animals. Closing the handles of this double-action, scissor-like instrument opens the jaws and dilates the rubber ring. This is slipped over the scrotum or tail and the handles released. The ring is now in place and the tool is withdrawn.

  • e. ring a specially constructed, thick, and very strong rubber ring for use in an elastrator. Has sufficient strength to close off all the blood vessels to a part and cause it to slough.

• elbow [el′bo] 1. the bend of the lower forelimb. 2. the joint connecting the humerus, radius, and ulna. It is one of the body’s more versatile joints, with a combined hinge and rotating action allowing the limb to bend and paw to make a half turn. The flexibility of the elbow and shoulder joints together permits a nearly infinite variety of paw movements. In ungulates, the elbow is a simple hinge.

  • e. abduction in the standing posture, the elbows are constantly abducted from the chest; usually a posture indicative of pleural pain.
  • e. dysplasia includes the inherited developmental defects, ununited anconeal process, fragmented (ununited) coronoid process, osteochondritis of the medial humeral condyle, and radio-ulnar incongruence, which occur in young, actively growing, large breed dogs, causing lameness and later arthritis of the elbow.
  • e. flexion a frequent malposition of a forelimb causing dystocia in cows. The foot is presented but is a long way back from the one on the opposite limb. The flexed limb increases the diameter of the fetus significantly.
  • e. luxation uncommon in most species because of the innate stability of the elbow joint; can be congenital or caused by trauma, sometimes associated with fractures.
  • point of the e. the summit of the olecranon process.

• elder [el′d r] see Sambucus.

  • poison e. Toxicodendronvernix. called also poison sumac.

• elderberry see Sambucus

  E-20.

  

  Elbow joint of a dog, lateral view.

• elderly animals see geriatric.

• ELDU extra-label drug use.

• elective [e-lek′tiv] non-urgent; at an elected time, e.g., of surgery.

• electrical [e-lek′trľ-k l] producing, produced by or powered by electricity.

  • e. ignition sources electric power outlets, switches and electrical equipment in the surgery can be the cause of explosion if flammable solvents, anesthetic agents, or oxygen are being used.
  • e. injuries shock caused by the passage of electric current passing through the body can cause irritation, unconsciousness, burns, or immediate death depending on the voltage, the amperage of the current, the efficiency of the patient as an earth contact, and the duration of the shock. Signs and the fatal outcome are due to paralysis of medullary centers in the medulla oblongata. Burns when they occur are usually at the points of contact between the animal and the earth. High-voltage current will cause sudden death (electrocution). Low-voltage house current will knock a cow down and may cause death; trickle current loss will cause cows to bellow and to kick. Lower-voltage current still has been associated with a high prevalence rate of mastitis. See also lightning injury. Household pets, particularly puppies and kittens, most often are injured from chewing on electrical cords. If not electrocuted, they incur burns of the mouth or lips that vary from small, punctate lesions to large areas. These are caused by coagulation and necrosis and do not become apparent until 2–3 weeks after the incident, making the diagnosis very difficult. Pulmonary edema is also a major feature of electrical injury in dogs and cats, and it can be the cause of death.

• electroacupuncture [e-lek ″tro-ak″u-punk′ch r] the application of electrical stimulation to acupuncture points, either through contact electrodes or implanted acupuncture needles. The strength of stimulation can be adjusted by varying the current used.

• electroaffinity [e-lek″tro- -fin′ľ-te] see electronegativity.

• electroanalgesia [e-lek ″tro-an″ l-je′ze-] the reduction of pain by electrical stimulation of a peripheral nerve or the dorsal column of the spinal cord.

• electroanesthesia [e-lek″tro-an″es-the′zh ] see electrical immobilization, electronarcosis.

• electrocardiogram (ECG) [e-lek″tro-kahr′de-o-gram″] the record produced by electrocardiography; a tracing representing the heart’s electrical action derived by amplification of the minutely small electrical impulses normally generated by the heart. Called also EKG.

• electrocardiograph [e-lek″tro-kahr′de-o-graf″] the apparatus used in electrocardiography.

• electrocardiographic [e-lek″tro-kahr-de-o-graf′ik] emanating from or pertaining to electrocardiography.

  • e. monitoring maintenance of a more or less continuous surveillance of a patient’s cardiac status by means of electrocardiography.

• electrocardiography [e-lek″tro-kahr″de-og′r -fe] the graphic recording from the body surface of the potential of electric currents generated by the heart, as a means of studying the rate and pattern of depolarization of the heart muscle and inferring changes in cardiac function and structure. With the modern electrocardiograph, the current that accompanies the action of the heart is amplified 3000 times or more, and it moves a small, sensitively balanced lever in contact with moving paper. The pattern of heart waves that is traced on the paper indicates the heart’s rhythm and other actions. The normal electrocardiogram is composed of a P wave, Q, R, and S waves known as the QRS complex, or QRS wave, and a T wave. The P wave occurs at the beginning of each contraction of the atria. The QRS wave occurs at the beginning of each contraction of the ventricles. The T wave seen in a normal electrocardiogram occurs as the ventricles recover electrically and prepare for the next depolarization. There is a refractory period after each P wave and QRS complex during which the myocardium is refractory to stimulation (depolarization and therefore contraction). The electric impulses in the heart muscle are picked up and conducted to the electrocardiograph by electrodes or leads connected to the body by small metal plates or other methods. The metal plates are moistened with a conductive paste and attached to the limbs and chest (cardiac area) of the animal.

  E-21.

  

  Portable electrocardiograph used during exercise.

  E-22.

  

  Example of a lead II ECG trace with the major reflections (waves) and intervals marked.

• electrocautery [e-lek -kaw′t r-e] cauterization of tissue by means of an electrode that consists of a red hot piece of metal, such as a wire, held in a holder, and is heated by either direct or alternating current. The term electrocautery is used to refer to both the procedure and the instrument used in the procedure.

• electrochemical [e-lek ″tro-kem′ľ-k l] emanating from or pertaining to electrochemistry.

  • e. equivalent the atomic weight divided by the ionic valence of an electrolyte. Provides a quantitative indication of the combining properties of an electrolyte solution. The relationship between weight per volume and milliequivalents can be expressed as:
  • e. conversion factor mEq/L = (mg/dL × 10 × valence)/molecular weight.
  • e. gradient the differences in electrochemical potential between two points.
  • intestinal e. gradient electrical potential differences and ion concentration differences across the external membrane of the intestinal mucosa arising from the active transport of most electrolytes and some nonelectrolytes across the membrane.

• electrochemistry [e-lek ″tro-kem′is-tre] the study of chemical changes produced by electric action and the production of energy by chemical changes.

• electrocoagulation [e-lek″tro-ko-ag″u-la′sh n] a method of electrosurgery used to coagulate tissue, and in particularly to reduce hemorrhage in the surgical field. Employs moderately damped or modulated undamped alternating current, and requires both an active concentrating electrode and an inactive dispersing electrode. See also electrosurgery.

  • bipolar e. the electrical current passes between two tips of a handpiece.
  • monopolar e. the electrical current passes from the handpiece to a ground plate, passing through the patient.

• electrocochleography [e-lek ″tro-kok″le-og′r -fe] measurement of electrical potentials of the eighth cranial nerve in response to acoustic stimuli applied by an electrode to the external acoustic canal, promontory or tympanic membrane.

• electrocontractility [e-lek″tro-kon″trak-til′ľ-te] contractility in response to electric stimulation.

• electrocorticography [e-lek″tro-kor″tľ-kog′r -fe] electroencephalography with the electrodes applied directly to the cerebral cortex.

• electrocution [e-lek″tro-ku′sh n] causing death by the passage of an electric current through the body of the patient. May be intentional, as a means of euthanasia, or accidental by lightning strike or electrical current. See electrical injuries.

• electrocutting [e-lek″tro-kut′ing] making an incision using an electroscalpel which generates an undamped sine wave causing microcoagulation at the point of contact. See also electrocoagulation.

• electrodermal [e-lek″tro-dur′m l] pertaining to the electrical properties of the skin, especially to changes in its resistance.

• electrodesiccation [e-lek″tro-des″ľ-ka′sh n] a method of electrosurgery that desiccates tissue by dehydration. A highly or moderately damped alternating electrical current is radiated through a monoterminal active electrode that is applied directly to or inserted into the tissue being treated. See also electrosurgery.

• electrodiagnosis [e-lek-tro-di″ g-no′sis] the use of electrical recording devices such as electromyography, electroencephalography, cystometrography, electrocardiography, in making a clinical diagnosis.

• electrodialyzer [e-lek″tro-di″ -li′z r] a blood dialyzer utilizing an applied electric field and semipermeable membranes for separating the colloids from the solvent.

• electroejaculation [e-lek″tro-e-jak″u-la′sh n] a method used for the collection of semen for artificial insemination or for examination. Electrical stimulation has to be provided by electrodes applied to the lumbar sympathetic nerves to promote semen emission and to the pelvic splanchnic and internal pudendal nerves to promote ejaculation and erection of the penis. The electrodes are contained in a probe placed in the rectum.

• electroejaculator [e-lek″tro-e-jak′u-la″t r] a device consisting of a rectal probe and a power control system that gives stepwise control over the current applied and a stimulator control that permits variation within the steps. Probes vary in their construction, and a good design will direct stimulation at the relevant nerves, reducing the stimulation of the back and the hindlimbs; see electroejaculation.

• electroencephalogram (EEG) [e-lek″tro-en-sef′ -lo-gram″] the record produced by electroencephalography; a tracing of the electric impulses of the brain.

• electroencephalograph [e-lek″tro- n-sef′ -lo-graf″] the instrument used in electroencephalography.

• electroencephalography [e-lek″tro- n-sef′-log′r -fe] the recording of changes in electric potentials in various areas of the brain by means of electrodes placed on the head or on or in the brain itself, and connected to an amplifier, which augments the impulses more than a million times. Electroencephalography is used most commonly to detect activity associated with seizures in order to confirm a diagnosis of epilepsy and may be used to localize the origin of seizures.

• electroendosmosis [e-lek″tro-en″dos-mo′sis] osmosis under the influence of an electric field as in electrophoresis.

• electroepilation [e-lek″tro-ep″ľ-la′sh n] use of electrosurgical methods, such as electrocautery or diathermy, for destroying hair follicles; used in the treatment of distichiasis.

• electrofulguration [e-lek″tro-ful″gur-ra′shun] a method of electrosurgery used to produce superficial desiccation of tissue, which employs a highly or moderately damped alternating electrical current that is radiated through a monoterminal active electrode that is held close to the patient so that sparks spray over the lesion being treated. See also electrosurgery.

• electrogastrograph [e-lek″tro-gas′tro-graf] an instrument for recording the electrical activity of the stomach by means of swallowed gastric electrodes.

• electrogastrography [e-lek″tro-gas-trog′r -fe] the recording of the electrical activity of the stomach as measured between its lumen and the body surface.

• electrogoniometer [e-lek″tro-go″ne-om′ -t r] an instrument for measuring angles, e.g. the angle of a joint. Used in gait research. See also goniometer.

• electrogoniometry [e-lek″tro-go″ne-om′ -tre] the science of measuring angles and the changes in them. Much used in the study of gait.

• electrogram [e-lek′tro-gram] any record produced by changes in electric potential.

  • His bundle e. an intracardiac electrocardiogram of potentials in the bundle of His, done through a cardiac catheter.

• electrohemostasis [e-lek″tro-he-mos′t -sis] arrest of hemorrhage by electrocautery.

• electrohysterography [e-lek″tro-his″t r-og′r -fe] the recording of changes in electric potential associated with contractions of the uterine muscle.

• electro-immobilization [e-lek″tro-ľ-mo″bil-ľ-za′sh n] see electrical immobilization.

• electroimmunoassay [e-lek″tro-im″u-no-as′a] see immunoelectrophoresis.

• electroimmunodiffusion [e-lek″tro-im″u-no-dľ-fu′zh n] see immunoelectrophoresis.

• electroincision [e-lek″tro-in-sizh′ n] cutting of tissue by an electrosurgical device.

• electrokymogram [e-lek″tro-ki′mo-gram] the record produced by electrokymography.

• electrokymograph [e-lek″tro-ki′mo-graf] the instrument used in electrokymography.

• electrokymography [e-lek″tro-ki-mog′r -fe] the photography of the motion of the heart or of other moving structures that can be visualized radiographically. No longer in common use.

• electrolysis [e″lek-trol′ -sis] destruction by passage of a galvanic current, as in disintegration of a chemical compound in solution or destruction of hairs such as cilia from eyelids in distichiasis or trichiasis.

• electrolyte [e-lek′tro-līt] a chemical substance that, when dissolved in water or melted, dissociates into electrically charged particles (ions), and thus is capable of conducting an electric current. The principal positively charged ions in the body fluids (cations) are sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺). The most important negatively charged ions (anions) are chloride (Cl⁻), bicarbonate (HCO³⁻), and phosphate (PO₄ ³⁻). These electrolytes are involved in metabolic activities and are essential to the normal function of all cells. Concentration gradients of sodium and potassium across the cell membrane produce the membrane potential and provide the means by which electrochemical impulses are transmitted in nerve and muscle fibers. The concentration of the various electrolytes in body fluids is maintained within a narrow range. However, the optimal concentrations differ in the extracellular fluid and intracellular fluid. An electrolyte imbalance exists when the serum concentration of an electrolyte is either too high or too low. Stability of the electrolyte balance depends on adequate intake of water and the electrolytes and on homeostatic mechanisms within the body that regulate the absorption, distribution, and excretion of water and its dissolved particles. The effects of an electrolyte imbalance are not isolated to a particular organ or system. In general, however, imbalances in calcium concentrations affect the bones, kidney, and gastrointestinal tract. Calcium also influences the permeability of cell membranes and thereby regulates neuromuscular activity. Sodium affects the osmolality of blood and therefore influences blood volume and pressure and the retention or loss of interstitial fluid.

• Potassium affects muscular activities, notably those of the heart, intestines, and respiratory tract, and also affects neural stimulation of the skeletal muscles.

  • e. clearance ratio see fractional excretion tests.
  • e. disturbances include hyper- and hypo-potassemia, natremia, phosphatemia, calcemia, chloremia.
  • e. fluid balance balance between fluid and electrolytes.
  • e. homeostasis maintenance of the osmotic pressure of the blood and tissue fluids by the maintenance of a proper balance between the normal electrolytes in the fluid, and at the same time maintaining adequate concentrations of calcium and magnesium and the proper acid–base balance.
  • e. solution therapy see fluid therapy.

• electrolytic [e-lek″tro-lit′ik] pertaining to electrolysis or to an electrolyte.

• electromagnetic [e-lek″tro-mag-net′ik] pertaining to or emanating from electromagnetism.

  • e. flowmeter measures the electromagnetic force generated when the blood flowing through a vessel of known diameter passes through a magnetic field at right angles to the magnetic lines of force.
  • e. receptors receptors that perceive electromagnetic stimuli.

• electromagnetism [e-lek″tro-mag′n -tiz- m] magnetism developed by an electric current.

• electromechanical coupling [e-lek″tro-m -kan′ľ-k l] the coupling which transforms an electrical impulse into a mechanical action, e.g., in smooth muscle.

• electromechanical dissociation [e-lek″tro-m -kan′ľ-k l] See dissociation.

• electromyogram (EMG, EMyG) [e-lek″tro-mi′o-gram] the record obtained by electromyography.

• single fiber e. a selective EMG that records action potentials from individual muscle fibers.

• electromyograph (EMG) [e-lek″tro-mi′o-graf] the instrument used in electromyography.

• electromyography [e-lek″tro-mi-og′r -fe] the recording and study of the intrinsic electrical properties of skeletal muscle. When it is at rest, normal muscle is electrically silent, but when the muscle is active, diseased, or denervated, spontaneous electrical activity is generated. In electromyography, the electrical impulses are picked up by needle electrodes inserted into the muscle and amplified. Common waveforms seen originating from denervated muscle include prolonged insertional activity, fibrillation potentials, and positive sharp waves. In damaged or diseased muscle, complex repetitive discharges, myotonic discharges, and pseudomyotonic discharges may be seen. In addition, recordings taken from muscle undergoing volitional contraction can yield information about motor units in the form of recruitment patterns.

• electron [e-lek′tron] any of the negatively charged particles arranged in orbits around the nucleus of an atom and determining all of the atom’s physical and chemical properties except mass and radioactivity. Electrons flowing in a conductor constitute an electric current; when ejected from a radioactive substance, they constitute the beta particles.

  • e. acceptor see oxidant.
  • e. beam the stream of electrons that flows from the anode to the cathode in the x-ray tube and then interacts with the tungsten target to produce x-rays.
  • e. carrier a molecule associated with membrane-bound proteins that accepts and transfers electrons.
  • e. donor see reductant.
  • e. transport transport of electrons in the electron transport chain.
  • e. transport chain series of reactions in which electrons are transferred from a donor such as NADH to an acceptor along a chain of carrier proteins with molecular oxygen as the final acceptor; the process generates the proton motive force which drives the production of ATP in oxidative phosphorylation. Called also the respiratory chain.

• electron-dense in electron microscopy, having a density that prevents electrons from penetrating.

• electronarcosis [e-lek″tro-nahr-ko′sis] narcosis produced by passage of an electric current through electrodes placed on the head.

• electronegative [e-lek″tro-neg′ -tiv] bearing a negative electric charge or an excess of electrons.

• electronegativity [e-lek″tro-neg″ -tiv′ľ-te] the relative power of an atom to attract electrons.

• electroneurography [e-lek″tro-noo-rog′r -fe] the measurement of the conduction velocity and latency of peripheral nerves.

• electroneuromyography [e-lek″tro-noo″ro-mi-og′r -fe] electromyography in which the nerve of the muscle under study is stimulated by application of an electric current.

• electronystagmography [e-lek″tro-nis″tag-mog′r -fe] electroencephalographic recordings of eye movements that provide objective documentation of induced and spontaneous nystagmus.

• electro-olfactogram (EOG) [e-lek″tro-ol-fak′to-gram] a recording of electrical activity detected by an electrode placed on the olfactory mucosa as it is exposed to odorous stimuli.

• electropexy electric shock. See also electrical stunner.

• electropherogram [e-lek″tro-fer′o-gram] electrophoretogram.

• electrophile [e-lek′tro-fīl] a chemical compound that serves as an electron acceptor in a chemical reaction.

• electrophoresis [e-lek″tro-f -re′sis] the movement of charged particles suspended in a liquid through various media, e.g., paper, cellulose acetate, gel, liquid, under the influence of an applied electric field. The various charged particles of a particular substance migrate in a definite and characteristic direction—toward either the anode or the cathode—and at a characteristic speed. This principle has been widely used in the separation of proteins and nucleic acids and is therefore valuable in the study of diseases in which the serum and plasma proteins are altered. See also immunoelectrophoresis.

  E-23.

  

  Cellulose acetate electrophoretogram.

  • SDS–polyacrylamide gel e. (SDS–PAGE) a procedure that revolutionized the analysis of complex mixtures of proteins. The proteins are solubilized by the powerful, negatively charged detergent sodium dodecyl sulfate (SDS) that causes proteins to unfold into extended, single polypeptide chains. A reducing agent such as mercaptoethanol is usually added to break disulfide bonds. The constituent polypeptides are then electrophoresed through an inert matrix of highly cross-linked gel of polyacrylamide. The pore size of the gel can be varied by altering the concentration of polyacrylamide.
  • two-dimensional gel e. a SDS–polyacrylamide gel electrophoresis run, first in one direction, then again at right angles. In the first dimension, an isoelectric-focusing gel is run, and in the second dimension, the proteins are separated in SDS–PAGE. A greater number of individually different proteins can be resolved in a highly repeatable fingerprint-like pattern.

• electrophoretogram [e-lek″tro-f -ret′o-gram] the recording produced by bands of material as they have been separated on the support medium by the electrophoresis process.

• electrophysiologic testing [e-lek″tro-fis″ľ-o-loj′ik] see electromyography, electrocardiography.

• electrophysiology [e-lek ″tro-fiz″e-ol′ -je] study of the electrical phenomena involved in physiological processes.

• electroplectic emanating from or pertaining to electroplexy.

  • e. fit the extensor tonus or tetanic fit experienced by most animals that are stunned for slaughter by electric shock.

• electroporation [e-lek″tro-p -ra′sh n] a means of increasing permeability of a cell by application of a low-voltage electric charge. Small pores are transiently opened in the cell membrane by the voltage, allowing entry of a gene construct or other substance into the cell.

• electropositive [e-lek″tro-poz′ľ-tiv] bearing a positive electric charge.

• electroreceptors [e-lek″tro-re-sep′t rs] nerve endings that perceive differences in voltage fields; a feature of fish and monotremes.

• electroresection [e-lek″tro-re-sek′sh n] electrosection.

• electroretinogram (ERG) [e-lek″tro-ret′ľ-no-gram] the record obtained by electroretinography.

• electroretinograph [e-lek″tro-ret′ľ-no-graf] an instrument for measuring the electrical response of the retina to light stimulation.

• electroretinography [e-lek″tro-ret″ľ-nog′r -fe] the recording of electrical changes in the retina in response to stimulation by light. Used to assess retinal function, particularly prior to cataract surgery and for the diagnosis of sudden acquired retinal degeneration and progressive retinal atrophy/degeneration.

• electroscission [e-lek″tro-sizh′ n] cutting of tissue by means of electrosurgery.

• electroscope [e-lek′tro-skōp] an instrument for measuring radiation intensity which really measures the electrical charge.

• electrosection [e-lek″tro-sek′sh n] a method of electrosurgery used to incise or excise tissue, which employs a slightly damped, modulated undamped, or undamped alternating electrical current, and requires both an active concentrating electrode and an inactive dispersing electrode. Called also electroresection. See also electrosurgery.

• electrostatic [e-lek″tro-stat′ik] pertaining to static electricity.

  • e. unit (esu) a measure of electrical energy. 1 esu. = 2.08 × 10⁹ electrons. Relative to radiological output 1 roentgen (R) = amount of x- or gamma radiation that produces 1 esu/ml in dry air. Replaced by the SI unit, coulomb (2).

• electrostimulation [e-lek″tro-stim″u-la′sh n] electric stimulation of tissues.

• electrostriatogram [e-lek″tro-stri-āt′o-gram] an electroencephalogram showing differences in electric potential recorded at various levels of the corpus striatum.

• electrosurgery [e-lek″tro-sur′j r-e] the use of high-frequency alternating current to remove, incise or destroy tissue. This is accomplished by converting the electrical energy into heat through tissue resistance to the passage of the electrical current. Called also surgical diathermy. Two types of current are utilized in electrosurgery, damped and undamped; a damped current destroys and coagulates tissue and stops bleeding, and undamped current destroys minimal tissue and incises tissue. Basically, there are four types of electrosurgical techniques: electrodesiccation, electrofulguration, electrocoagulation, and electrosection.

• electrotaxis [e-lek″tro-tak′sis] taxis in response to electric stimuli.

• electrotherapeutics [e-lek″tro-ther″ -pu′tiks] see electrotherapy.

• electrotherapy [e-lek″tro-ther′ -pe] treatment of disease by means of electricity. See also diathermy.

• electrotonic [e-lek″tro-ton′ik] 1. pertaining to electrotonus. 2. denoting the direct spread of current in tissues by electrical conduction, without the generation of new current by action potentials.

  • e. junctions see gap junctions.

• electrotonus [e-lek-trot′ -n s] the altered electrical state of a nerve or muscle cell when a constant electric current is passed through it.

• electroureterography [e-lek″tro-u-re″t r-og′r -fe] electromyography in which the action potentials produced by peristalsis of the ureter are recorded.

• electrovalence [e-lek″tro-va′l ns] the number of charges an atom acquires in a chemical reaction by gain or loss of electrons.

• electroversion [e-lek″tro-vur′zh n] the act of electrically terminating a cardiac dysrhythmia.

• electrovert [e-lek′tro-v rt] to apply electricity to the heart or precordium to depolarize the heart and terminate a cardiac dysrhythmia. See also defibrillation, cardioversion.

• electuary [e-lek′tu-ar″e] a medicinal preparation consisting of a powdered drug made into a paste with honey or syrup.

• eledoisin [el- -doi′sin] a decapeptide from the posterior salivary gland of a species of snail (Eledone), which is a precursor of a large group of biologically active peptides; it has vasodilator, hypotensive, and extravascular smooth muscle stimulant properties.

• eleidin [el-e′ľ-din] a substance, allied to keratin, found in the cells of the stratum lucidum of the skin.

• element [el′ -m nt] 1. any of the primary parts or constituents of a thing. 2. in chemistry, a simple substance that cannot be decomposed by ordinary chemical means; the basic ‘stuff’ of which all matter is composed. Chemical elements are made up of atoms. Each atom consists of a nucleus with a cloud of negatively charged particles (electrons) revolving around it. The two major components of the nucleus are protons and neutrons. The number of protons in the atoms of a particular element is always the same, and therefore the physical and chemical properties of the element are always the same. It is possible, however, for a chemical element to exist in several different forms, the difference depending on the number of neutrons in the nucleus of its atoms. Different forms of the same element are called isotopes. There are at least 118 different chemical elements known. The atomic number of an element is determined by the number of protons in the nucleus of an atom of the element. The mass number of an isotope is determined by the total number of neutrons and protons in the nucleus.

  • formed e’s (of the blood) erythrocytes, leukocytes, and platelets.
  • e. points see horary points.
  • trace e. a chemical element present or needed in extremely small amount by plants and animals, such as manganese, copper, cobalt, zinc, iron. See also trace element.

• ele(o)- word element. [Gr.] a relationship to oil.

• eleoma [el″e-o′m ] a tumor or swelling caused by injection of oil into the tissues.

• elephant [el′ -f nt] a member of the order Proboscidae, family Elephantidae. The largest land mammals, they are immediately recognizable by their trunk (proboscis) and, in the males, tusks, which are elongated, second upper incisors. Consists of three species, the African bush elephant or African savanna elephant (Loxodonta africana), African forest elephant (L. cyclotis) and the Asian elephant (Elephas maximus).

  • African e. there are two species, the African bush elephant (Loxodonta africana), the larger of the two, and the African forest elephant (L. cyclotis).
  • Asian e., Asiatic e. (Elephas maximus) native to South and, some parts of, Southeast Asia, it is smaller than the African elephant and has smaller ears. Although it is revered in some cultures and is domesticated widely, demand for its use as a work animal has decreased, as has its habitat. It is an endangered species.
  • e. foot callus see hypertrophic callus.
  • e. skin see lichenification.

• elephant ears Alocasia spp., Colocasia esculenta.

• elephant grass see Pennisetum purpureum.

• Elephantorrhiza elephantina African plant in the legume family Mimosaceae; contains toxic tannins that cause diarrhea. Called also elandsboontjie.

• Eleusine grasses in the family Poaceae; some species, e.g., E. indica (Indian goosegrass), are capable of causing nitrite or cyanide poisoning.

• elevator [el′ -va″t r] a range of surgical instruments.

  • dental e. an instrument gently worked into the space between the tooth and the alveolar bone or between sectioned crown-root segments and then carefully rotated to around the shank’s long axis to break down the periodontal ligament fibers.
  • periosteal e. see periosteal elevator.
  • rib e. usually combined with a periosteum stripper, e.g., Sayre double-ended periosteal elevator, Matson rib stripper and elevator.

• elimination [e-lim″ľ-na′sh n] 1. discharge from the body of indigestible materials and of waste products of body metabolism. See also elimination behavior, defecation, urination. 2. of a disease; equivalent to eradication.

• ELISA [e-li′s ] enzyme-linked immunosorbent assay. A type of primary binding test used to detect and measure either antigen or antibody that utilizes antibody binding sites for specificity. In the most simple applications, either antigen or antibody is bound to a solid substrate (polystyrene surface), and a second antibody to which enzyme is conjugated is added, followed by a substrate for the enzyme.

  • competitive E. detection of the analyte is based on its ability to quantitatively inhibit the binding of a known amount of a standard analyte to a limiting amount of antibody.
  • direct E. the primary antigen-antibody interaction is directly measured as the enzyme is directly labeled to one or the other.
  • indirect E. the primary antigen-antibody reaction is detected with the use of an enzyme-labeled antiglobulin (secondary antibody).
  • sandwich E. the analyte is captured by one antibody and detected by another enzyme-linked antibody.

• elixir [e-lik′s r] a clear, sweetened, usually hydroalcoholic liquid containing flavoring substances and active medicinal ingredients, for oral use.

• Elizabethan collar a rigid material fashioned so as to project outward from around the neck of a dog or cat like a lampshade and prevent the mouth or teeth from damaging skin, casts or dressings on the legs or body. X-ray film or heavy plastic sheeting are usually used for this purpose. Also used in birds. Called also buster collar.

  • reversed E. c. in birds, reversing the collar permits better movement and is better tolerated.
  • E. c. test improvement of alopecia or traumatic skin lesions after placement of an Elizabethan collar for a short period of time will identify the cause as self trauma or excessive grooming.

• elk [elk] (Cervus canadensis) a very large deer, native to North America and Asia, where they are called wapiti. Antlers in males can be very large with multiple tines. A game species, they are hunted for the meat and antlers. They are susceptible to chronic wasting disease and brucellosis. In Europe, the name refers to Alces alces, which is known elsewhere as the moose.

  • e. lip a blemish in a horse, a heavy, overhanging top lip.
  • tule e. (C. canadensis canadensis) a subspecies native to California.

• Elkhound see Norwegian elkhound.

• Ellangowan poison bush Eremophiladeserti.

• Elliottdale Australian carpetwool sheep, derived from the Romney Marsh by mutation; wool of 35-45 microns, white face, and dark hooves; mostly polled.

• ellipsoid body [e-lip′soid] see ellipsoid body.

  E-24.

  

  Elizabethan collar on a cat with a nasogastric feeding tube.

  E-25.

  

  Elliptocytes in blood from a normal llama. Wright-Giemsa stain.

• elliptical excision the use of converging curved incisions around a lesion to enable its removal and subsequent linear closure of the skin defect. surgical undermining of the edges of a wound that is too wide to be sutured. Frees up the edges so that they can be approximated.

• elliptocyte [e-lip′to-sīt] an oval-shaped erythrocyte. The normal erythrocyte shape in camelid, avian, reptilian, and amphibian species; otherwise, is associated with myelofibrosis in dogs and hepatic lipidosis in cats, as well as other conditions. A hereditary elliptocytosis occurs in dogs. Called also ovalocyte.

• elliptocytosis [e-lip″to-si-to′sis] the presence of elliptocytes (ovalocytes) in the peripheral blood. Anormal finding in camelids, reptiles and amphibians.

• hereditary e. erythrocyte membrane defects (deficiency of protein band 4.1) in dogs have been reported, but apart from causing elliptocytosis, the clinical effects have been minimal to inapparent.

• elliptone an insecticidal substance, other than rotenone, found in derris root.

• Ellis pin a device used in fracture repair that has threads at the tip, designed to engage only the opposite cortex of the bone in which it is inserted.

• elodont a tooth that increases in length throughout its life; occur in rabbits, chinchillas and guinea pigs.

• Elokomin fluke fever a disease of Canidae, ferrets, bears and raccoons caused by Neorickettsia elokominica, transmitted by a fluke, Nanophyetus salmincola. Fish are the intermediate host of the fluke and dogs are infected with the bacteria by eating the fish. Clinical signs are similar to, but milder than, those of salmon poisoning.

• elongation [e″long-a′sh n] 1. in protein synthesis, the cyclic process of growth of a polypeptide chain from mRNA attached to ribosomes. Requires mRNA, ribosomes, activated aminoacyl-tRNA, elongation factor EF-Tu activated with GTP. 2. in fatty acids, the process of adding carbon from acetyl CoA to a lengthening acyl chain. Mechanism for achieving diversity of fatty acids in biological systems.

  • e. factor one in a group of proteins involved in the elongation of polypeptide chains during protein synthesis.

• Elso heel an inherited spastic paresis of calves that develops after birth. Signs are stiffness of one or both hindlimbs on rising but with the stiffness passing after a few minutes. Affected animals spend increased time lying down and lose weight and are usually destroyed at about 12 months of age. A partial tibial neurectomy can be an effective treament. No lesion has yet been identified as being involved in the pathogenesis of the disease. See also inherited spastic paresis.

• eluate [el′u-āt] the substance separated out by, or the product of, elution or elutriation.

• eluent [e-loo′ nt] the solution used in elution.

• elution [e-loo′sh n] in chemistry, extraction of a substance that is adsorbed to another by washing. In chromatography, the emergence of substances from a column in the mobile phase.

• elutriation [e-loo″tre-a′sh n] separation of particles according to size by passing a solvent upward through them in a vertical tube and slowly increasing the flow rate. The most slowly sinking particles emerge from the top of the tube first and larger, denser particles follow at high flow rates.

• EM electron microscope.

• emaciation [e-ma″she-a′sh n] excessive leanness; a wasted condition of the body; generally taken to mean that the body weight is less than 50% of the normal expected for a comparable normal animal.

• emanation [em″ -na′sh n] that which is given off, such as a gaseous disintegration product given off from radioactive substances, or an effluvium.

• emasculation [e-mas″ku-la′sh n] removal of the penis or testes.

• emasculatome instrument for bloodless castration of cattle or sheep. Works on the principle of crushing spermatic cord without breaking the skin of the neck of the scrotum. Several types available. See Burdizzo emasculatome.

• emasculator [e-mas′ku-la-t r] instrument for simultaneous crushing and cutting of exposed spermatic cord in open castration. Cutting the cord is simple; crushing the vessels so that hemorrhage is avoided in a mature stallion is much more difficult. Crushing is effected by having one or a series of opposing ridged surfaces on the horse side of the cutting edge. Complexity of crushing apparatus varies from a single crushing face, e.g., the Frank emasculator, to a multiple with ratchet handle so that the apparatus can be left in place for a short time, e.g., the Reimer emasculator.

  • Frank e. a single crush emasculator with a thumbscrew at the joint.
  • Reimer e. a complicated, multiple-crush emasculator for horses. A scissor type with the main pair of handles ratcheted. The crushing jaws are multiple and there is a secondary crushing jaw operated by a third handle or lever. There are two blades on either side; these interlock, and it is important that the instrument is applied in the correct way so that the last crushing action is applied to the cord that remains in the horse.
  • Serra e. single action emasculator with a ratchet on the handle so that the jaws can be clamped shut. One of the jaws is a single, curved blade that closes between two blades on the other side. Designed for use in horses.
  • White e. a triple crush emasculator for use on horses. The central pivot is a thumb screw so that the joint can be tightened or the instrument dismantled.

• EMB eosin-methylene blue.

• embalming [em-bahm′ing] chemical treatment of a dead body to retard decomposition.

• embarrass [m-bar′ s] to impede the function of; to obstruct.

• Embden–Meyerhof pathway [em′d n mi′ r-hof] the series of enzy-matic reactions in the anaerobic conversion of glucose to lactic acid, resulting in energy in the form of adenosine triphosphate (ATP). More commonly known as glycolysis.

• embedding [ m-bed′ing] fixation of tissue in a firm medium, in order to keep it intact during cutting of thin sections for pathological examination.

• embole [em′b -le] the reducing of a dislocated joint.

• embolectomy [em″b -lek′t -me] surgical removal of an embolus.

• emboli [em′b -li] plural of embolus.

• embolic [em-bol′ik] pertaining to embolism or an embolus.

  • e. endarteritis see endarteritis.
  • e. glomerulitis glomerular inflammation as a result of lodgment of an infected embolus, e.g., secondary to endocarditis.
  • fibrocartilaginous e. myelopathy necrotizing myelopathy as a result of vascular obstruction by a fibrocartilaginous embolus.
  • e. pneumonia see embolic pneumonia.

• embolism [em′b -liz- m] the sudden blocking of an afferent vessel (usually an artery, but may be the portal vein) by a body of material (embolus) that has been brought to the site of lodgment by the blood current. The obstructing material is most often a thrombus, but may be a fat globule, air bubble, piece of tissue (e.g., degenerated intervertebral disk), or clump of bacteria. It may therefore be the site of origin of a shower of microabscesses or a neoplastic metastasis. See also saddle thrombus, iliac artery thrombosis.

  • air e. air injected accidentally into veins that may cause temporary paralysis or dyspnea, or may be fatal if the embolism occurs in the heart or brain. Has been reported after intravascular catheter disconnection and associated with surgical procedures.
  • cerebral e. embolism of a cerebral artery; one of the causes of cerebral vascular accident.
  • fibrocartilaginous e. embolism of one of the arteries supplying the spinal cord or brain, causing a peracute onset myelopathy. Proposed to be the result of intervertebral disc material entering blood vessels near the spinal cord.
  • renal e. embolism in the kidney often causes no observable clinical effect unless it involves a large enough area to cause renal failure.

• embolization [em″b -lľ-za′sh n] 1. the process or condition of becoming an embolus. 2. therapeutic introduction of a substance into a vessel in order to occlude it.

• embolus [em′bo-l s] pl. emboli [Gr.] a clot or other plug, usually part or all of a thrombus, brought by the blood from another site and forced into a smaller one, thus obstructing circulation. See also embolism.

  • fibrocartilaginous e. see fibrocartilaginous embolism.
  • saddle e. one situated at the bifurcation of a large artery, usually the terminal aorta, blocking both branches. See also aortic embolism, saddle thrombus.

• embrocation [em″bro-ka′sh n] a liquid medication for external use; see liniment.

• embryo [em′bre-o] a new organism in the earliest stage of development, i.e., from the time that the fertilized embryo begins to develop a long axis up to the time that the major structures have begun to develop, when it becomes a fetus.

  • e. collection collection of an embryo from the genital tract for the purposes of embryo transfer; surgical and nonsurgical techniques available.
  • e. cryopreservation preservation of embryos by freezing.
  • hexacanth e. the larva with six hooks present in the cestode egg, released from the uterus/segment of the adult tapeworm. Called also oncosphere.
  • e. micromanipulation handling of an embryo under a microscope, for examination, dissection.
  • e. transfer collection of fertilized ova from one female before they become implanted and transfer to another female to complete the gestation. The donor is usually superovulated and then inseminated. Collection may be surgical via a laparotomy or nonsurgical by flushing through the cervix. Recovered embryos have specific culture requirements. They are evaluated in terms of fertilization, possibly cleaved artificially to create clones, and washed to eliminate the possibility of transferring infection with the embryo. Long-term storage by freezing is a practicable procedure. The recipient needs to be in appropriate stage of uterine receptivity, effected by synchronizing the estrus cycle with that of the donor.
  • e. transplant see embryo transfer (above).

• embryocardia [em″bre-o-kahr′de- ] a clinical sign in which the heart sounds resemble those of the fetus, there being little difference in the quality of the first and second sounds.

• embryoctony [em″bre-ok′t -ne] destruction of the living embryo or fetus.

• embryogenesis [em″bre-o-jen′ -sis] the process of embryo formation. See also embryo.

• embryoid [em′bre-oid] resembling an embryo.

• embryological patterning [em″bre-ol-oj′ľ-k l] during embryonic growth the establishment of groups of cells in the proper relationship to each other and to surrounding tissues.

• embryologist an expert in embryology.

• embryology [em″bre-ol′ -je] the science of the development of the individual animal during the embryonic stage and, by extension, in several or even all preceding and subsequent stages of the life cycle.

• embryoma [em″bre-o′m ] a general term applied to neoplasms thought to be derived from embryonic cells or tissues, including dermoid cysts, teratomas, embryonal carcinomas.

• embryonal [em′bre-o″n l] emanating from or pertaining to embryo.

  • e. nephroma see nephroblastoma.

• embryonated a fertilized egg in which an embryo is developing; said of hens’ eggs commonly used for isolation and propagation of viruses.

• embryonic [em″bre-on′ik] emanating from or pertaining to embryo. See also embryo.

  • e. death see early embryonic mortality (below).
  • e. disk larger cells of the mammalian blastocyst that develop into the embryo.
  • early e. mortality death of the embryo, i.e., before it becomes a fetus; a principal cause of temporary infertility in farm livestock. Among causes are errors in timing of insemination, chromosomal defects, asynchronous development of the endometrium.
  • e. period see embryo.
  • e. regulation ability of embryonic tissues to recognize changes in their size and location and to make the necessary adjustments to form the disk-shaped assembly of appropriate structures.
  • e. stem cell pluripotent stem-cell lines derived from early embryos before formation of the tissue germ layers.
  • e. vesicle see chorionic vesicle.

• embryonization [em″bre-o′nľ-za′sh n] reversion of a tissue or cell to the embryonic form.

• embryonoid [em′bre-o-noid″] embryoid.

• embryopathy [em″bre-op′ -the] a morbid condition of the embryo or a disorder resulting from abnormal embryonic development, with consequent congenital anomalies.

• embryophore [em′bre-o-for] the thick layer of the tapeworm egg, which surrounds the oncosphere.

• embryoplastic [em″bre-o-plas′tik] pertaining to or concerned in formation of an embryo.

• embryotome [em′bre-o-tōm] see fetotome.

• embryotomy [em″bre-ot′o-me] fetotomy, dismemberment of the fetus in difficult labor in which a normal delivery is impossible.

• embryotoxicity [em″bre-o-tok-sis′ľ-te] being toxic to embryos.

• embryotoxin [em″bre-o-tok′sin] a substance poisonous to embryos.

• embryotroph [em′bre-o-trōf″] the total nutriment (histotroph and hemotroph) made available to the embryo.

• embryotrophy [em″bre-ot′r -fe] the nutrition of the early embryo.

• embryulcus a blunt hook for removal of the fetus from the uterus.

• EMC encephalomyocarditis.

• Emden an upright, white goose with orange beak and legs, blue eyes.

• emedullate [e-med′u-lāt] to remove bone marrow.

• emerald green cheap green pigment containing arsenic and capable of causing poisoning.

• emergency [e-mur′j n-se] a sudden and unexpected occurrence that requires urgent attention. Most veterinary practice is based on the need to take care of animal emergencies in medicine, surgery, and reproduction.

  • e. care delivery of urgent treatment to an animal, either as a temporary measure until full investigation and treatment is practical, or as a lifesaving measure. See also critical care.
  • e. slaughter a desirable procedure if animals are to be dealt with humanely and farmers protected against avoidable financial loss. Sheep and cattle burned in bush fires are a case in point. Emergency slaughter of animals with unspecified illness is a common source of food poisoning unless the animals are submitted to rigorous meat inspection.

• Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES) programs established by FAO to provide information, training and emergency assistance to prevent and control serious livestock diseases at their source. An example is the program for global eradication of rinderpest. EMPRES-i is a web-based application that facilitates access to regional and global disease information.

• emergent [e-mur′j nt] 1. coming out from a cavity or other part. 2. coming on suddenly.

  • e. disease a disease that is either new or is emerging after a period of absence.
  • e. treatment a new treatment with implication of increasing usage.

• emesis [em′ -sis] the act of vomiting. Also used as a word termination, as in hematemesis.

• emetic [ -met′ik] an agent that causes vomiting; used mostly in dogs and cats that have ingested a toxic substance.

  • e. factor an agent, probably deoxynivalenol (vomitoxi), produced by Fusarium spp. and found in moldy grain. Causes vomiting and food rejection in pigs and inappetance and malaise in horses. Called also vomitoxin.

• emetine [em′ -tēn] the principal alkaloid of ipecac; used as an antiamebic.

• emetocathartic [em″ -to-k -thahr′tik] 1. both emetic and cathartic. 2. an agent that has both emetic and cathartic effects (induces vomiting and fecal evacuation).

• Emex australis plant in the family Polygonaceae; contains sufficient oxalate to cause poisoning but field occurrences are rare. Called also spiny emex, double gee, Cape spinach, prickly jack.

• EMF 1. electromotive force. 2. electromagnetic field.

• EMG, EMyG electromyogram, electromyograph, electromyography.

• -emia word element. [Gr.] pertaining to the blood.

• emigration [em″ľ-gra′sh n] the escape of leukocytes through the walls of small blood vessels; diapedesis.

• eminence [em′ľ-n ns] a projection or boss.

  • iliopubic e. on the leading edge of the pubis; an attachment point for abdominal muscles.

• eminentia [em″ľ-nen′sh ] pl. eminentiae [L.] see eminence.

• emiocytosis a form of glandular secretion in which granules storing the secretory product are released through the plasma membrane into the extracellular space. Seen in insulin secretion by beta cells of the pancreas.

• emissarium a vein that connects an intracranial venous sinus with a vein outside the cranium.

• emissary [em′ľ-sar″e] affording an outlet, referring especially to the venous outlets from the dural sinuses through the skull.

• emission [e-mish′ n] a discharge.

• emmetropia [em″ -tro′pe-] proper coordination of the refractive system and the focal length of the eye so that the focused image falls exactly on the retina.

• Emmonsia [ě-mon′se- ] saprophytic soil fungal organisms, which when inhaled have been the cause of granulomatous inflammation of the lungs (adiaspiromycosis). Also referred to as Chysosporium. The main species are E. parva and E. crescens.

• EMO vaporizer Epstein–Macintosh–Oxford vaporizer, designed to deliver ether anesthesia, which is no longer used.

• emodepside an octadepsipeptide anthelmintic effective against gastrointestinal nematodes; used topically in cats and as an oral preparation in dogs. Semisynthetic derivative of the metabolite of the fungus Mycelia sterilia; part of the microflora found on the leaves of Camellia japonica.

• emodin [em′o-din] a purgative glycoside found in the plant Rhamnus.

• emollient [e-mol′e- nt] an agent that softens or soothes the skin or soothes an irritated internal surface.

• emotion [e-mo′sh n] activation and related behavior. Animals have emotions insofar as they are motivated to behave by what they perceive and much of the reaction is learned rather than intuitive. The reactions are based on rewarding and aversive properties of stimuli from the external environment. The center for the control of emotional behavior is the limbic system of the brain.

• emotional support animals companion animals of any type (dog, cat, pig, miniature horse, etc.) that provide comfort and support in forms of affection and companionship for an individual suffering from various mental and emotional conditions. They do not have to be professionally trained and, unlike service dogs, are not required to perform any specific tasks for a disability. They do not have the legal privileges, as do service dogs, to accompany its owner always and in all places. Some airlines and housing authorities may relax their rules on pets if the owner has a letter from a licensed doctor, psychiatrist, or other mental health professional, attesting the need for the emotional support of the companion animal. There are several registries on the web that provide for such attestation and provide emotional support dog vests for identification or tags. Registration is conducted under the honor system. Also known as comfort animals.

• emphysema [em″f -se′m] a pathological accumulation of gas (usually air) in tissues. The air may derive from a skin laceration and be drawn in by the movements of muscles. A discontinuity of the tracheal mucosa is a common cause, either by way of laceration or ulceration. Extension from a pulmonary lesion is also common. The syndrome resulting depends on the location of the air. See also pulmonary emphysema and subcutaneous emphysema (below).

  • acute bovine pulmonary e. see atypical interstitial pneumonia.
  • alveolar e. see pulmonary emphysema (below).
  • bullous e. emphysema in which bullae form in areas of lung tissue so that these areas do not contribute to respiration.
  • conjunctival e. may occur after head trauma that permits escape of air from the paranasal sinuses into the subconjunctival space.
  • fetal e. accumulation of gases in tissues of a dead fetus as a result of putrefaction. Complicates the management of dystocia.
  • functional alveolar e. reversible, uncomplicated bronchiolitis.
  • generalized e. widespread distribution of air, including subcutaneous tissues, seen with pneumomediastinum.
  • hypoplastic e. pulmonary emphysema due to a developmental abnormality, resulting in a reduced number of alveoli, which are abnormally large.
  • interlobular e. accumulation of air in the septa between lobules of the lungs. Often seen in cattle as a result of dyspnea.
  • interstitial e. see interlobular emphysema (above).
  • intestinal e. a condition marked by accumulation of gas under the tunica serosa of the intestine.
  • lobar e. emphysema involving less than all the lobes of the affected lung.
  • mediastinal e. see pneumomediastinum.
  • orbital e. may occur after trauma to the head that permits escape of air from the paranasal sinuses; appears as swelling with crepitus under the conjunctiva or periocular skin.
  • panacinar e., panlobular e. generalized obstructive emphysema affecting all lung segments, with atrophy and dilatation of the alveoli and destruction of the vascular bed.

    E-26.

    

    Diffuse pulmonary emphysema in a cat.

  • pulmonary e. and rupture of alveolar walls (alveolar emphysema) and in some cases escape of air into the interstitial spaces (interstitial emphysema). It is a common pathological finding in many diseases of the lung in all species, but also occurs independently, especially in horses, as a principal lesion in chronic obstructive pulmonary disease. The interstitial form is also a prominent feature of bovine atypical interstitial pneumonia. It is secondary to a primary condition in which air is more easily inspired than expired. It is characterized clinically by cough, dyspnea, forced expiratory effort and poor work tolerance. A double expiratory effort is a characteristic sign—hence broken wind.
  • subconjunctival e. see conjunctival emphysema (above).
  • subcutaneous e. air or gas in the subcutaneous tissues. The characteristic lesion is a soft, mobile swelling that crackles (crepitates) when palpated. There is no pain, nor heat, and no ill effects unless the pharyngeal area is sufficiently involved to cause asphyxia.
  • surgical e. subcutaneous emphysema following surgery.
  • unilateral e. emphysema affecting only one lung, frequently due to congenital defects in circulation.
  • vesicular e. see panacinar emphysema (above).

• emphysematous [em″f -sem′-t s] of the nature of or affectedwith emphysema.

  • e. gangrene see blackleg.

• empiricism [em-pir′ľ-siz- m] skill or knowledge based entirely on experience; compare with rationalism.

• EMPRES Emergency Prevention System for Trans-boundary Animal and Plant Pests and Diseases.

• emprosthotonos [em″pros-thot′ -n s] tetanic downward flexure of the head and tail and upward flexure of the back.

• empty said of a female of breeding age; nonpregnant. Called also open.

• emptying disorder see gastric emptying time.

• emptying time the time taken for stomach contents to be passed into the duodenum; influenced by gastric motility and activity of the pyloric sphincter.

• empyema [em″pi-e′m ] accumulation of pus in a body cavity, particularly the presence of a purulent exudate within the pleural cavity (pyothorax). It occurs as an occasional complication of pleuritis or some other respiratory disease. Signs include dyspnea, coughing, chest pain, malaise, and fever. Thoracentesis can confirm the diagnosis and determine the specific causative organism. Said also of nasal sinus, joint cavity, epidural space. See also guttural pouch empyema, pyothorax.

• empyesis [m″pi-e′sis] a pustular eruption.

• emu (Dromaius novaehollandiae) a large flightless bird, native to Australia; the second tallest bird after the ostrich, standing up to 6 ft high. They are farmed commercially for meat, leather, feathers, and oil. It appears with the kangaroo on the Australian coat of arms.

• emulgent [e-mul′j nt] an agent that effects a straining or purifying process.

• emulsifier [e-mul′sľ-fi″ r] a substance used to make an emulsion.

• emulsion [e-mul′sh n] a mixture of two immiscible liquids, one being dispersed throughout the other in small droplets; a colloid system in which both the dispersed phase and the dispersion medium are liquids. Margarine, cold cream, and various medicated ointments are emulsions. In some emulsions, the suspended particles tend to join together and settle out; hence, the container must be shaken each time the emulsion is used.

  • x-ray e. radiation-sensitive coating of an x-ray film consisting of a suspension of grains of silver halide in gelatin.

• emulsoid [e-mul′soid] a colloid system in which the dispersion medium is liquid, usually water, and the disperse phase consists of highly complex organic substances, such as starch or glue, which absorb much water, swell, and become distributed throughout the dispersion medium.

• emunctory [e-munk′t -re] 1. excretory or cleansing. 2. an excretory organ or duct.

• Emydidae the largest and most diverse family of turtles; includes box turtles and pond turtles, which accounts for the large number of species sold in the commercial pet trade. See also turtle.

• en- word element. [Gr.] meaning inward.

• en bloc resection see en bloc resection.

• enalapril [-nal′ -pril] an angiotensin converting enzyme (ACE) inhibitor, used in the management of heart failure to reduce systemic blood pressure and to attenuate up-regulation of the reninangiotensinaldosterone system.

• enalaprilat [-nal′ -pril-at″] the pharmacologically active product of hepatic hydrolysis of enalapril.

• enamel [-nam′ l] hardest tissue in the body (96% mineralized); white, compact; produced by ameloblasts; covering the dentin of the crown of a tooth; meeting the cementum that covers the dentin of the root at the cementoenamel junction in teeth of dogs, cats, and humans.

  • e. epithelium the inner (or internal) enamel epithelium enamel, representing a layer of columnar pre-ameloblasts on the rim nearest the dental papilla of the enamel organ in a developing tooth that secrete enamel matrix.
  • e. fracture fracture with loss of crown substance confined to the enamel.
  • e. hypomineralization inadequate mineralization of enamel matrix; often affecting several or all teeth; crowns of affected teeth are covered by soft enamel that may be worn rapidly.
  • e. hypoplasia inadequate deposition of enamel matrix, affecting one or several teeth and being focal or multifocal; crowns of affected teeth can have areas of normal enamel next to areas of hypoplastic or missing enamel.
  • e. infraction incomplete fracture (crack) of the enamel without loss of tooth substance.
  • inherited e. defect an inherited absence of enamel from all teeth combined with excessive flexibility of joints in Holstein–Friesian cattle. The teeth are pink and obviously deficient in substance. A defect in collagen formation is probable.
  • mottled e. dental fluorosis; defective enamel, with a chalky white appearance or brownish stain, caused by excessive amounts of fluorine in drinking water and food preparations during the period of enamel calcification.
  • e. organ aggregation of epithelial cells (inner enamel epithelium, outer enamel epithelium, stratum intermedium, and stellate reticulum) above a condensation of ectomesenchymal cells called the dental papilla; functions in the formation of enamel, initiation of dentin formation, establishment of the shape of a tooth’s crown, and establishment of the dentogingival junction.
  • e. points sharp projections of enamel at the junction of the buccal and occlusal surfaces of a tooth. Seen most commonly in horses.
  • e. rods progressively mineralized glycoproteinaceous tubules, the basic structural units of enamel; enamel is acellular and consists of interrod material and rods.

    E-27.

    

    Enamel hypoplasia.

    E-28.

    

    Enamel spot.

  • e. spot remnant of the enamel cup in the center of an incisor tooth table in a horse.

• enameloblastoma [-nam″l-o-blas-to′m] see ameloblastoma.

• enanthema [en″ n-the′m] an eruption upon a mucous surface.

• enantiomorph [en-an′te-o-morf″] one of a pair of isomeric substances, the molecular structures of which are mirror opposites of each other.

• enarthrosis [en″ahr-thro′sis] a joint in which the rounded head of one bone is received into a socket in another, permitting motion in three planes; called also ball-and-socket joint.

• encainide [en-ka′nīd] an antiarrhythmic drug that blocks Na+ conduction; No longer used in the treatment of ventricular arrhythmias because of the high risk of sudden death.

• encapsulation [n-kap″su-la′sh n] enclosure within a capsule.

• Encephalartos genus of African cycad plants in the family Zamiaceae. Meal made from seed contains cycad glycoside and causes liver, kidney, and heart damage. Includes E. hildebrandtii, E. laevifolius, E. lanatus, E. villosus.

• encephalic [en″s -fal′ik] 1. pertaining to the brain. 2. within the skull.

• encephalins [en-sef′ -linz] natural opiate hormones found in the central nervous system.

• encephalitides [en-sef″ -lit′ľ-dēz] plural of encephalitis.

• encephalitis [en-sef″ -li′tis] inflammation of the brain. Changes in vessel walls, as well as of nervous tissue, are almost a constant feature of encephalitis. There are many types of encephalitis, depending on the causative agent and the structures involved. Infectious causes include viruses (e.g., equine encephalomyelitis), bacteria, fungi (e.g., cryptococcosis), protozoa (e.g., toxoplasma encephalitis), and other organisms (e.g., amebae). In small animals, non-infectious causes are more common and include granulomatous meningoencephalomyelitis and nectrotizing meningoencephalitis (collectively referred to as meningoencephalitis of unknown etiology prior to histopathological diagnosis). Clinically, encephalitis is characterized by signs dictated by the region of the brain affected, with signs such as seizures, circling, and cortical blindness common when the prosencephalon is affected, and stupor, vestibular abnormalities, and cranial nerve deficits when the brainstem is affected. Commonly signs suggest more than one region of the brain is affected and are asymmetrical. Systemic evidence of illness (increased peripheral white blood cell counts, pyrexia) are variably present. Many encephalitides are accompanied by involvement of either the spinal cord and are more correctly classified as either meningoencephalitides or encephalomyelitides, respectively. See also encephalomyelitis. The etiologically or geographically specific diseases are listed under their specific titles. Human pathogens that sometimes infect animals include Central European, Far Eastern Russian tick-borne encephalitides, Omsk hemorrhagic fever, Kyasanur forest disease.

  • acute disseminated e. postinfection encephalitis.
  • arthropod-borne e. a group of viral encephalitides of animals. See Togaviridae, Flaviviridae.
  • canine distemper e. a demyelinating encephalitis that is a feature of infection by the canine distemper virus.
  • demyelinating e. seen in certain viral infections, e.g., canine distemper, caprine arthritis–encephalitis and visna of sheep.
  • Eastern equine e. (EEE) see Eastern equine encephalomyelitis.
  • equine herpesvirus e. see equine herpesvirus myeloencephalopathy.
  • granulomatous e. see granulomatous meningoencephalomyelitis.
  • histiocytic e. see granulomatous meningoencephalomyelitis.
  • Israeli turkey e. see Israeli turkey encephalomyelitis.
  • Japanese e. (JE) occurs in temperate and topical areas of Eastern and Southern Asia, where it is the major cause of encephalitis in humans. The virus is maintained in a zoonotic cycle between wading birds, pigs, and Culex spp. mosquitoes. There are high seroprevalence rates in many mammalian species, but clinical disease is largely restricted to horses and pigs. Manifest in horses by a wide variety of neurologic signs including incoordination, excitability, and blindness. Most cases recover. Vaccination of racehorses is mandatory in several Asian countries. The disease in pigs consists of encephalitis in young pigs, abortion, and stillbirth in sows and aspermia in boars. A disease notifiable to the OIE (see Table 20).
  • Murray Valley e. was evidence of clinically inapparent infection of horses in Australia but then associated with an outbreak of equine encephalitis in 2011 in southern Australia, in association with several other viruses.
  • necrotizing e. see necrotizing meningoencephalitis and meningoencephalitis of unknown etiology.
  • Nipah virus e. caused by a Henipavirus within the family Paramyxoviridae with severe disease in humans and swine. In humans, it produces encephalitis and respiratory disease with a high case fatality. In pigs, infection may be inapparent or produce respiratory disease, especially in younger pigs, and neurologic disease, abortion, or sudden death. Reservoir hosts are flying foxes (bats) belonging to the genus Pteropus, family Pteropodidae, which shed the virus, most often in urine. Transmission of virus may occur directly from reservoir hosts or from infected humans or pigs. The first occurrence was in Malaysian pig farmers in the late 1990s with spread to Singapore as a result of movement of pigs. Close contact with pigs and handling pig carcasses is a major risk factor for infection, and more than 1 million pigs were culled to minimize the risk of cross-species transmission. Classified as a biosafety level four pathogen due to high case fatality rate following human infection. A disease notifiable to the OIE (see Table 20).
  • non-suppurative e. inflammation of the brrain not characterized by accumulation of polymorphonuclear leucocytes. Gross changes are usually absent, and the histological features are focal gliosis and perivascular cuffing by mononuclear cells (predominantly lymphocytes). A feature of most examples of viral encephalitis.
  • old dog e. a chronic, progressive, sclerosing panencephalitis in mature dogs, caused by canine distemper virus; characterized by motor and mental deterioration, blindness, pacing, and circling.
  • Ontario e. see hemagglutinating encephalomyelitis virus disease of pigs.
  • paramyxovirus e. see porcine blue eye disease.
  • postinfection e. an acute disease of the central nervous system seen in patients convalescing from infectious, usually viral, diseases.
  • postvaccinal e. acute encephalitis sometimes occurring after vaccination, mediated by immune mechanisms.
  • Powassan e. a tick-borne flavivirus disease of humans with serological but no clinical evidence of infection in nearby goats.
  • Pug e. see necrotizing meningoencephalitis.
  • Ross River e. not a major veterinary pathogen, but this member of the family Togaviridae, genus Alphavirus has been isolated from horses in Australia, and there is serological evidence of infection. There is a temporal association with a generalized disease in horses, often including arthropathy, and the occurrence of specific antibody in serum.
  • Russian spring–summer e. a similar and probably identical disease to the flavivirus that causes louping ill of sheep, occurring in central Europe. It is a disease of humans occurring in epidemics related to the prevalence of vector ticks in forests where the disease is most common. Humans can also be infected orally from raw milk, usually from goats. Lesions are present in organs other than the brain. The severity varies from mild to fatal.
  • St. Louis e. an arthropod-borne flavivirus infection, first observed in 1932 in Illinois. It is a serious pathogen of humans, but does not cause disease in animals.
  • toxoplasma e. see toxoplasmosis.
  • West Nile e. see West Nile fever.
  • Western equine e. (WEE) see Western equine encephalomyelitis.

• encephalitis virus disease [en-sef″ -li′tis] of fish; see viral nervous necrosis.

• Encephalitozoon [en″s -fal″ľ-to-zo′on] a genus in the phylum Microsporidia, which are spore-forming unicellular parasites.

  • E. cuniculi occurs in rodents, dogs, primates, and humans. Has a similar physical appearance and pathogenetic effect to toxoplasmosis. Causes encephalitozoonosis.

• encephalitozoonosis [en″s -fal″ľ-to-zo″o-no′sis] a disease caused by the protozoa Encephalitozoon cuniculi in rabbits; occasionally in mice, rats, hamsters, and guinea pigs. The central nervous system, kidney and eye are predilection organs causing granulomatous meningoencephalitis, chronic interstitial nephritis, and phacoclastic uveitis. Dogs and cats may also be infected. Often referred to as microsporidiosis.

• encephal(o)- word element. [Gr.] pertaining to the brain.

• encephalocele [en-sef′ -lo-sēl″] hernial protrusion of brain substance through a congenital or traumatic opening of the skull.

• encephalocystocele [en-sef″ -lo-sis′to-sēl] hydroencephalocele.

• encephalogram [en-sef″ -lo-gram] recording obtained by encephalography.

• encephalography [en-sef″ -log′r -fe] radiography demonstrating the intracranial fluid-containing spaces after the withdrawal of cerebrospinal fluid and introduction of air or water-soluble contrast media. Called also pneumoencephalography, ventriculography, cerebral ventriculography. No longer in use.

• encephalolith [en-sef′ -lo-lith″] a brain calculus.

• encephalology the sum of knowledge regarding the brain, its functions and its diseases.

• encephaloma [en-sef″ -lo′m] 1. any swelling or tumor of the brain. 2. medullary carcinoma.

• encephalomalacia [en-sef″ -lo-m-la′sh] literally, softening of the brain. The term is used to include degenerative diseases and necrosis of the brain generally. Leukoencephalomalacia refers to the white matter, polioencephalomalacia to the gray matter. The syndrome associated with encephalomalacia is primarily one of loss of function related to the region of the brain affected. Signs may include somnolence, blindness, ataxia, head pressing, circling, and terminal coma.

  • degenerative e. includes nigropallidal encephalomalacia, leukoencephalomalacia.
  • focal symmetrical e. a subacute form of enterotoxemia due to Clostridium perfringens type D in sheep that are partly immune to the toxin. Clinical signs are the dummy syndrome of aimless wandering, head pressing, blindness, and incoordination. Most affected sheep die after an illness of about 7 days.
  • nigropallidal e. see nigropallidal encephalomalacia.

• encephalomeningitis [en-sef″ -lo-men″in-ji′tis] see meningoencephalitis; inflammation of the brain and meninges.

• encephalomeningocele [en-sef″ -lo-m -ning′go-sēl] meningocephalocele; protrusion of the brain and meninges through a defect in the skull.

• encephalomeningopathy [en-sef″ -lo-men″in-gop′ -the] meningoencephalopathy; disease involving the brain and meninges.

• encephalomere [en-sef′ -lo-mēr] one of the segments making up the embryonic brain.

• encephalometer [en-sef″ -lom′-t r] an instrument used in locating the cortical centers on the skull.

• encephalomyelitides plural of encephalomyelitis.

• encephalomyelitis [en-sef″ -lo-mi″ -li′tis] inflammation of both the brain (encephalitis) and spinal cord (myelitis). The causes and clinical signs are similar to those of encephalitis. The pathological lesions, however, include significant involvement of the spinal cord. Many of the causes are identical to the causes of encephalitis.

  • arthropod-borne e. a number of viral agents responsible for causing encephalomyelitis are transmitted by arthropods. See arbovirus.
  • avian e. caused by an enterovirus this disease affects young birds up to few weeks old. There is an obvious tremor of the neck, followed by weakness and incoordination and finally paralysis and death. Called epidemic tremor.
  • Eastern equine e. (EEE) a disease primarily of horses and humans, but also camelids, in the Americas. Caused by Eastern equine encephalitis virus, an Alphavirus (family Togaviridae) with two antigenic variants, North American and South American. Transmitted by mosquitoes. The horse is a terminal host and the reservoir of infection in birds and other native fauna. While many infections in horses and humans are subclinical, it is considered the most deadly of the mosquito-borne alphaviruses due to the high case fatality rate associated with apparent infections in horses and humans with many survivors exhibiting crippling neurologic sequelae. South American strains are less virulent, occasionally causing disease and death in horses, but human infections are rarely recognized. Clinical signs in horses include initial excitement, muscle tremor, walking in circles, followed by a paralytic phase including somnolence, staggering, dropping of the head, and finally recumbency. Prevention in horses is by vaccination. A disease notifiable to the OIE (see Table 20).
  • equine protozoal e. see equine protozoal myeloencephalitis.
  • equine viral e. see Eastern equine encephalomyelitis (above), Western equine encephalomyelitis (below) and Venezuelan equine encephalomyelitis (below). There are a number of other viruses that cause encephalitis in horses.
  • experimental allergic e. inoculation of animals with brain tissue in Freund’s complete adjuvant produces an autoimmune encephalomyelitis. Called also EAE.
  • granulomatous e. see granulomatous meningoencephalomyelitis.
  • hemagglutinating e. virus disease of pigs a disease of sucking pigs caused by a coronavirus characterized by the occurrence of two different clinical forms of the disease. They are probably the extremes of a clinical spectrum of one disease because both may be seen in the one outbreak in one piggery. The encephalitic form is characterized by incoordination, convulsions and death in 2–3 days. In the other form, the principal signs are vomiting, inability to drink, and severe dehydration and emaciation—hence vomiting and wasting disease. Called also Ontario encephalitis.
  • Israeli turkey e. nonsuppurative encephalomyelitis of turkeys caused by a flavivirus and carried by insects, probably mosquitoes. Manifested by a progressive paralysis.
  • mouse e. virus see Theiler’s disease.
  • Near Eastern equine e. the cause is a virus, antigenically identical with the Borna disease virus, which normally infects birds, but in its transport by a vector tick it infects horses. The disease is clinically indistinguishable from Borna disease.
  • North American equine e. Western and Eastern equine encephalomyelitis.
  • ovine e. see louping ill.
  • porcine viral e. caused by members of the genus, Teschovirus, family Picornaviridae. The virulence of the viruses and the severity of the diseases that they cause varies. Clinically the disease is characterized by a syndrome comprising hyperesthesia, paresis, and convulsions but the severity is very much less in older pigs than in baby pigs. Adult pigs are commonly infected but show no clinical signs. Also known as Teschen disease, Talfan disease, poliomyelitis suum.
  • postinfectious e. inflammation of the brain and spinal cord following vaccination or infection. Was commonly seen after the administration of earlier rabies vaccines containing brain tissue.
  • postvaccinal e. see postinfectious encephalomyelitis (above).
  • sporadic bovine e. caused by Chlamydia pecorum and characterized by inflammation of vessel walls, serous membranes, and synoviae, with incidental involvement of nervous tissue in some cases. Clinically there is high fever and weakness, circling, and knuckling in some. At necropsy there is fibrinous peritonitis, pleurisy, and pericarditis—hence serositis—as well as encephalomyelitis. Called also transmissible serositis, Buss disease, SBE.
  • Venezuelan equine e. (VEE) caused by an arthropod-borne alphavirus (family Togaviridae) with one virus, but six antigenically related subtypes, within which are variants. There are non-pathogenic and pathogenic strains. Non-pathogenic VEE viruses persist in sylvatic cycles in rodents associated with swamps, and transmitted by mosquitoes of the genus Culex. Horses and humans are accidental hosts. Pathogenic epizootic strains arise by mutation and horses develop a profound viremia and are amplifying hosts; all species of mosquitoes that feed on horses are thought to be capable of spreading the infection. Clinical signs in horses include fever, muscle fasciculation, severe depression, head pressing, incoordination, recumbency, opisthotonos, paddling, and death. There can be high case fatality. Infection of humans typically causes a “flu-like” illness that ranges from mild to severe, but neurologic involvement is rare. Prevention in horses is by vaccination. A disease notifiable to the OIE (see Table 20).
  • Western equine e. (WEE) an occasional disease in horses and humans. Caused by an Alphavirus (family Togaviridae) and likely arose as a recombinant of Eastern equine encepalomyelitis virus, Sindbis virus. Wild birds are the hosts and mosquitoes the vectors. Occurs primarily west of the Mississippi. Epidemics of WEE are uncommon, but sporadic individual cases are not. Clinical signs in horses include excitement, muscle tremor, walking in circles, followed by a paralytic phase including somnolence, staggering, dropping of the head, and finally recumbency. See also Eastern equine encephalomyelitis (above). A disease notifiable to the OIE (see Table 20).

• encephalomyeloneuropathy [en-sef″ -lo-mi″-lo-noo-rop′ -the] a disease involving the brain, spinal cord and nerves.

• encephalomyelopathy [en-sef″ -lo-mi″l-op′ -the] a disease involving the brain and spinal cord.

  E-29.

  

  Horse with mosquito-borne Western equine encephalomyelitis (WEE) displaying the typical stance. Courtesy of CDC/Mr. J. Bagby.

  E-30.

  

  Ewe with pregnancy toxemia encephalopathy, unaware of surroundings and not reactive to them, and with abnormal stance.

• encephalomyeloradiculitis [en-sef″ -lo-mi″-lo-r -dik″u-li′tis] inflammation of the brain, spinal cord and spinal nerve roots.

• encephalomyeloradiculopathy [en-sef″ -lo-mi″-lo-r-dik″u-lop′ -the] a disease involving the brain, spinal cord and spinal nerve roots.

• encephalomyocarditis (EMC) [en-sef- -lo-mi″o-kahr-di′tis] inflammation of the brain and cardiac muscle.

  • e. virus disease of pigs a sporadic disease of pigs caused by a picornavirus (genus Cardiovirus), which is primarily a pathogen of rodents but that infects other species including humans. Affected pigs are most commonly found dead of heart failure without having displayed clinical signs. Longer surviving pigs show tremor, incoordination, and dyspnea. There is a characteristic myocarditis evident at necropsy. Some strains are associated with reproductive failure in sows and increased neonatal mortality in piglets.

• encephalon [en-sef′ -lon] the brain; that part of the central nervous system contained within the carnium.

• enclitic having the planes of the fetal head inclined to those of the maternal pelvis.

• encephalopathy [en-sef″ -lop′ -the] any disease affecting the brain.

  • biliary e., bilirubin e. kernicterus.
  • feline ischemic e. an acute, ischemic cerebral necrosis in cats causing various degrees of cerebral dysfunction. Clinical signs relate to the region of the brain affected and may include depression, ataxia, circling, vestibular signs, behavioral changes, blindness, and seizures. Proposed to be due to migration of cuterebra larvae.

    E-31.

    

    Hepatic encephalopathy in a horse showing abnormal behavior and repeated yawning. McAuliffe, S. Knottenbelt and Pascoe’s Color Atlas of Diseases and Disorders of the Horse, 2nd ed. Elsevier Health Sciences, 2013.

  • hepatic e. severe hepatic insufficiency that may induce clinical signs of prosencephalic dysfunction. Signs may include hyperexcitability, tremor, compulsive walking, head pressing, seizures, and blindness, followed by coma and possibly death. The pathogenesis of this hepatic encephalopathy is the unknown, but proposed theories include the accumulation of ammonia, changes in neurotransmitter concentrations, the generation of endogenous benzodiazepines, and electrolyte and acid-base imbalances. A similar pathogenesis is hypothesized for the genesis of a cerebrotoxicant in companion animals with congenital defects in hepatic vasculature. See also portosystemic shunt, hepatitis. Note that similar signs, especially seizures, can develop in animals with portacaval shunts following ligation or coil placement, despite an absence of signs previously.
  • hypernatremic e. a severe hemorrhagic encephalopathy induced by the hyperosmolarity accompanying hypernatremia and dehydration.
  • hypoxic-ischemic e. see neonatal maladjustment syndrome.
  • lead e. brain disease caused by lead poisoning.
  • e.–microphthalmia syndrome an inherited disorder in Hereford cattle with ocular and neurological defects and muscular dystrophy. Affected calves are blind and unable to stand.
  • multifocal symmetrical myelinolytic e. a fatal disease of Limousin and Simmental calves, beginning at about a month of age with blindness and dysmetria (Limousins) or at 5–8 months of age with signs of ataxia and weight loss (Simmentals).
  • neonatal e. a developmental brain disease of neonatal Standard Poodle puppies characterized by extreme weakness, ataxia, seizures, and death within weeks; caused by a missense mutation in the canine ortholog of ATF2.
  • symmetrical multifocal e. inherited disease in two forms: Limousin form appears at about a month old with blindness, forelimb hypermetria, hyperesthesia, nystagmus, aggression, weight loss; Simmental form does not appear until 5–8 months, no blindness, hindquarters affected instead of forelimbs. Euthanasia inevitable in both forms.
  • portosystemic e. hepatic encephalopathy.
  • transmissible mink e. transmissible disease of mink that resembles scrapie in sheep. There is a very long incubation period, hyperirritability, biting, paralysis, coma, and death. The scrapie agent is believed to be the cause.

• encephalopuncture [en-sef″ -lo-pungk′ch r] surgical puncture of the brain.

• encephalopyosis [en-sef″ -lo-pi-o′sis] suppuration or abscess of the brain.

• encephalorrhagia [en-sef″ -lo-ra′j] hemorrhage within or from the brain.

• encephalosclerosis [en-sef″ -lo-skl -ro′sis] hardening of the brain.

• encephalosis [en-sef″ -lo′sis] any organic brain disease.

• encephalotomy [en-sef″ -lot′ -me] 1. incision into the brain. See also craniotomy (2). 2. dissection or anatomy of the brain.

• enchondral [en-kon′dr l] situated, formed or occurring within cartilage.

  • e. ossification see enchondral ossification.
  • retained e. cartilage cores see retained enchondral cartilage cores.

• enchondroma [en″kon-dro′m ] a benign growth of cartilaginous origin arising within the medullary cavity in the metaphyseal region of bone. May be solitary or multiple, which are referred to as enchondromatosis. They may be incidental findings or cause swelling and pain, or fracture due to thinning of cortical bone.

  E-32.

  

  Multiple enchondromatosis in a 9-month-old Chihuahua.

• enchondromatosis [en-kon″dro-m -to′sis] multiple enchondromas; rare in dogs. Called also dyschondroplasia and in humans, Ollier’s disease.

• enchondrosarcoma [en-kon″dro-sahr-ko′m ] central chondrosarcoma.

• Enchylaena tomentosa Australian plant in the family Chenopodiaceae. Contains high concentrations of soluble oxalate and may cause poisoning. Called also Barrier salt bush, ruby salt bush, berry cotton bush.

• enclave [en′klāv, ahn-klahv′] tissue detached from its normal connection and enclosed within another organ.

• encode [en′kōd] to code. See genetic code.

• encopresis [en-ko-pre′sis] incontinence of feces not due to anatomic defect or illness.

• encrustation scale. 1. the formation of a crust. 2. a crust, scab or scale.

• encysted [en-sist′ d] enclosed in a sac, bladder or cyst.

• end-artery an artery that supplies a territory of tissue without contributions from other arteries. They are often further classified into ‘anatomical end-arteries’ that remain strictly free from anastomoses with other arteries, and ‘physiological end-arteries’ that may retain a few anastomoses restricted to the capillary level. Occlusion or interruption of end arteries can lead to infarction. See infarction, collateral circulation.

• end-bulb [end′bulb] one of the small encapsulated bodies at the end of sensory nerve fibers in skin, mucous membranes, muscles and other areas. See bulboid corpuscle.

• end-feet button- or knob-like terminal enlargements of naked nerve fibers which end in a synapse with dendrites of another cell.

• END method the Exaltation of Newcastle Disease virus method; a Japanese technique for indirectly detecting the presence of classical swine fever (hog cholera) virus.

• end organ one of the larger, encapsulated endings of sensory nerves.

• end pieces the distal portion of the spermatozoon consisting of irregularly arranged microtubules.

• end-plate a flattened discoid expansion at the neuromuscular junction, where a myelinated motor nerve fiber joins a skeletal muscle fiber.

  • e.-p. potential created by acetylcholine causing depolarization of the muscle cell membrane.

• end-stage a pathologist’s term for any organ in the final stages of functional life. Said of kidney, liver, muscle, joint.

• end-tidal at the end of a respiratory cycle. Said of the carbon dioxide concentration in the airway, usually trachea.

  • e.-t. CO₂ (ETCO₂) concentration of CO₂ at the end of an expiration; demonstrated in a capnogram. Used as an indicator of arterial partial pressure of carbon dioxoide, a measure of respiratory function.

• end-to-end a pattern of anastomosis in which severed ends are matched and united, in contrast with other patterns such as end-to-side or side-to-side. Usually applied to anastomosis of the intestine.

• endadelphos [end″ -del′fos] a fetus in which a parasitic twin is enclosed within the body of the other twin (the autosite). Called also cryptodidymus.

• Endamoeba a genus of amebae parasitic in the intestines of invertebrates. They differ from Entamoeba spp. because they lack a central endosome.

• endangered species species of animals (and plants) whose existence on earth is threatened in the near future; the second most severe conservation status for wild populations in the International Union for Conservation of Nature (IUCN) Red List.

• endangiitis [en-an″je-i′tis] inflammation of the endangium.

• endangium tunica intima (inner coat) of a blood vessel.

• endaortitis [end″a-or-ti′tis] inflammation of the membrane lining the aorta.

• endarterectomy [end-ahr″t r-ek′t -me] excision of thickened atheromatous areas of the innermost coat of an artery.

  • carotid e. endarterectomy within an extracranial carotid artery, usually within the common carotid. See also carotid endarterectomy.

• endarterial [end″ahr-tēr′e- l] within an artery.

• endarteritis [end-ahr″t r-i′tis] inflammation of the innermost coat (tunica intima) of an artery.

  • e. obliterans a form in which the lumen of the smaller vessels becomes narrowed or obliterated as a result of proliferation of the tissue of the intimal layer.

• endaural [end-aw′r l] within the ear.

• endbrain [end′brān] see telencephalon.

• endectocides systemically administered parasiticides that remove nematodes and arthropods; includes ivermectin and milbemycin oxime.

• endemic [en-dem′ik] present in a predictable, continuous pattern in an animal community at all times; said of a disease that is clustered in space but not in time. See also enzootic.

• endemiology the science dealing with all the factors relating to the occurrence of endemic disease.

• endemoepidemic [en″d -mo-ep″ľ-dem′ik] endemic, but occasionally becoming epidemic.

• endergonic [end″ r-gon′ik] in chemistry, a chemical reaction in which the free energy change (ΔG) is positive and energy is absorbed; requiring the input of free energy.

• ending [end′ing] a termination, especially the peripheral termination of a nerve or nerve fiber.

• end(o)- word element. [Gr.] within, inward.

• endoaneurysmorrhaphy [en″do-an″u-riz-mor′ -fe] opening of an aneurysmal sac and suture of the orifices.

• endoangiitis [en″do-an-je-i′tis] endangiitis.

• endoarteritis [en″do-ahr″t r-i′tis] see endarteritis.

• endoblast [en′do-blast] endoderm.

• endobronchial [en″do-brong′ke- l] pertaining to or emanating from the lining of the bronchi.

  • e. intubation incorrect positioning of an endotracheal tube with the dorsal portion of the tube in a bronchus; a cause of inadequate delivery of gaseous anesthesia, hyperventilation, hypoxia and cyanosis.

• endobronchitis [en″do-brong-ki′tis] inflammation of the epithelial lining of the bronchi.

• endocardial [en″do-kahr′de- l] 1. situated or occurring within the heart. 2. pertaining to the endocardium.

  • e. cushions elevations on the atrioventricular canal of the embryonic heart which later help partition the heart. Defective development contributes to several cardiac anomalies, including ventricular septal defect and atrioventricularis communis.
  • e. fibroelastosis pallid thickening of the endocardium by collagen and elastic fibers in response to chronic overdistension of cardiac chambers, particularly in younger animals; Burmese cats are predisposed. It is a prominent feature of congenital heart conditions that produce ventricular overload.
  • e. fibrosis occurs with cardiac dilatation or hypertrophy. In cats, leads to restrictive cardiomyopathy.
  • e. splitting a complication of chronic valvular insufficiency and congestive cardiomyopathy in dogs. May be partial or full thickness; can occur on the interatrial septum, producing an acquired septal defect, or elsewhere causing hemopericardium.

    E-33.

    

    Endocardiosis of the left atrioventricular valve in a dog.

    E-34.

    

    Infective endocarditis. Vegetations are attached to the mitral and aortic valves and may be mobile or sessile.

  • e. tube formed from the cardiogenic plate in the developing embryo, this forms the primordium of the truncus arteriosus, the atrium and the ventricles; it is later invested by the myocardium.

• endocardiosis [en″do-kahr″de-o′sis] common cause of cardiac disease in the dog. Characterized by progressive myxomatous degeneration and nodular thickening of the free edges of the atrioventicular valves. Valve cusps can be distorted causing valvular incompetence. Leads to congestive heart failure. See chronic valvular heart disease.

• endocarditis [en″do-kahr-di′tis] proliferative inflammatory alterations of the endocardium, characterized by the presence of vegetations on the surface of the endocardium or in the endocardium itself, and most commonly involving a heart valve, but also affecting the inner lining of the cardiac chambers. Lesions on the valves may interfere with the ejection of blood from the heart by causing insufficiency or stenosis of the valves. Murmurs associated with the heart sounds are the major manifestation, and if interference with the blood flow is sufficiently severe, congestive heart failure develops. The further hazard with endocarditis, especially if it is bacterial in origin, is that of septic emboli in the lungs, kidneys, joints or in the other organs.

  • bacterial e. infectious endocarditis, acute or subacute, caused by various bacteria, including streptococci, staphylococci, enterococci, Bartonella spp. and Gram-negative bacilli. Of particular interest in animals is the predilection of Erysipelothrix rhusiopathiae to cause endocarditis, especially in pigs.
  • ductal e. due to thrombosis in a persistent ductus arteriosus with resulting mural inflammation.
  • infectious e., infective e. that due to infection with microorganisms, especially bacteria and fungi.
  • mural e. that affecting the lining of the walls of the heart chambers only.
  • nonbacterial thrombotic e. that in which the vegetations, single or multiple, consist of fibrin and other blood elements.
  • parietal e. mural endocarditis.
  • tuberculous e. that resulting from extension of a tuberculous infection from the pericardium and myocardium.
  • valvular e. that affecting the membrane over the heart valves only.
  • vegetative e. endocarditis, infectious or noninfectious, the characteristic lesions of which are vegetations or verrucae on the endocardium. Called also verrucous endocarditis.

• endocardium [en″do-kahr′de-um] the endothelial lining membrane of the cavities of the heart and the connective tissue bed on which it lies.

• endocervicitis [en″do-sur″vľ-si′tis] inflammation of the endocervix.

• endocervix [en″do-sur′viks] 1. the mucous membrane lining the canal of the cervix uteri. 2. the region of the opening of the cervix uteri into the uterine cavity.

• endochondral [en″do-kon′dr l] enchondral.

• endochondroma [en″do-kon-dro′m ] tumor arising from cartilage within the medullary cavity.

• endocolitis [en″do-ko-li′tis] inflammation of the mucous membrane of the colon.

• Endoconidium temulentum [en″do-k -nid′e-um] an imperfect fungus that grows on the grass Lolium temulentum or darnel grass and may be responsible for the grass’s toxic effects.

• endocranial [en″do-kra′ne- l] within the cranium.

• endocranitis [en ″do-kra-ni′tis] inflammation of endocranium.

• endocranium [en″do-kra′ne- m] the endosteal layer of the dura mater of the brain.

• endocrine [en′do-krīn, en′do-krin] 1. secreting internally, i.e., into the blood or lymph and not by way of ducts to any epithelial surface. 2. pertaining to internal secretions; hormonal.

  • e. cells are either gathered together in specific endocrine glands or scattered diffusely through other tissue, e.g., in the walls of the gastrointestinal tract and the pancreas in which the cells are clustered together into islands.
  • e. dermatosis skin changes accompanying many diseases of the endocrine glands such as hypothyroidism, hyperadrenocorticism, and hypopituitarism.
  • e. glands included are the pituitary, thyroid, parathyroid, and adrenal glands, gonads, pancreas and paraganglia.
  • e. system organs or groups of cells that secrete regulatory substances that are released directly into the circulation (hormone). The endocrine or hormonal system and the nervous system are the two major control systems of the body, and their functions are interrelated. Hormonal activity is mostly concerned with regulating metabolic activities by controlling the rates at which chemical reactions take place within cells, the transport of substances across the cell membrane, and activities related to growth and reproduction. The word hormone is applied to substances released by the endocrine glands that have physiological effects on target organs (which can be other endocrine glands) and tissues distant from the gland. There are, however, local hormones (autacoids) secreted at the site of the tissue being affected, for example, acetylcholine and serotonin.
  • e. tumor adenoma or carcinoma and can be functional (producing excess hormone) or non-functional. Typically derived from only one endocrine cell type, but may be derived from more than one type of cell capable of secreting more than one hormone.

• endocrinism endocrinopathy.

• endocrinologist [en″do-krľ-nol′ -jist] an individual skilled in endocrinology, and in the diagnosis and treatment of disorders of the glands of internal secretion, i.e. the endocrine glands.

• endocrinology [en″do-krľ-nol′ -je] study of the endocrine system.

• endocrinopathy [en″do-krľ-nop′ -the] any disease due to disorder of the endocrine system.

• endocrinotherapy [en″do-krľ″no-ther′ -pe] treatment of disease by the administration of hormone preparations; hormonotherapy.

• endocrinous of or pertaining to an internal secretion (hormone) or to a gland producing such a secretion, i.e., to an endocrine gland.

• endocystitis [en″do-sis-ti′tis] inflammation of the bladder mucosa.

• endocytosis [en″do-si-to′sis] the uptake by a cell of material from the environment by invagination of the plasma membrane; it includes both phagocytosis and pinocytosis.

  • receptor mediated e. uptake of materials bound to specific cell-surface receptors by invagination of the plasma membrane to form a small membrane-bounded vesicle; a mechanism for entry of viruses into cells.

• endoderm [en′do-d rm] the innermost of the three primitive germ layers of the embryo; from it are derived the epithelium of the pharynx, respiratory tract (except the nose), digestive tract, bladder, and urethra.

• endodermal [en″do-dur′m l] pertaining to or emanating from endoderm.

  • e. sinus tumor see yolk sac tumor.

• endodontia see endodontics.

• endodontic [en″do-don′tik] pertaining to or emanating from the pulp cavity of the tooth.

  • e. file an instrument used in the débridement of root canals.

• endodontics [en″do-don′tiks] a specialty in dentistry and oral surgery that is concerned with the prevention, diagnosis, and treatment of diseases of the pulp-dentin complex and their impact on associated tissues.

• endodontium [en″do-don′she- m] dental pulp.

• endodyogeny [en″do-di-oj′ -ne] asexual multiplication in protozoa in which two daughter cells are formed within the parent cell. Occurs, for example, in Toxoplasma and Sarcocystis spp.

• endoenteritis [en″do-en″t r-i′tis] inflammation of the intestinal mucosa.

• endogamy [en-dog′ -me] fertilization by union of separate cells having the same chromatin ancestry.

• endogenous [en-doj′ -n s] produced within or caused by factors within the organism.

  • e. feline oncornavirus see RD114 virus.
  • e. sarcoma virus see feline sarcoma virus.

• endointoxication [en″do-in-tok″sľ-ka′sh n] poisoning by an endogenous toxin.

• endolaryngeal [en″do-l -rin′je- l] situated on or occurring within the larynx.

• Endolimax [en″do-li′maks] a genus of amebae found in the colon of humans, other mammals, birds, amphibians and cockroaches; none of them appear to be pathogenic. Includes E. caviae (guinea pigs), E. nana (humans and monkeys), E. ratti (rats).

• endolymph [en′do-limf] the fluid within the membranous labyrinth of the ear.

• endolymphatic [en″do-lim-fat′ik] pertaining to or emanating from the endolymph.

  • e. duct connects the saccule of the membranous labyrinth of the internal ear to the endolymphatic sac.

• endometrial [en″do-me′tre- l] pertaining to or emanating from the endometrium.

  • e. biopsy punch biopsy specimens obtained in the mare and cow by passing the instrument through the cervix and controlling the site of the biopsy by a hand in the rectum.
  • e. cups round, raised structures in the endometrium of the pregnant mare. They are produced by trophoblastic cells from the chorionic girdles of the conceptus, but become detached from it. Their function is to produce equine chorionic gonadotropin (eCG), formerly PMSG.
  • e. curettage débridement of the endometrium by metal curette is not practiced in animals but a chemical equivalent, by the infusion of irritant substances, is used instead.
  • e. cyst in cows and ewes near caruncles; develop during uterine involution due to adhesions from the caruncle; no clinical importance. In mares, often due to impaired lymphatic drainage.
  • cystic e. hyperplasia pathological hyperplasia of endometrium, as distinct from the physiological state, due in most instances to excessive and prolonged estrogenic stimulation; characterized by thickening of the endometrium, development of mucus-filled glands and the accumulation of mucus in the lumen of the uterus. Associated with chronic cystic ovarian disease in cows. In ewes, it is usually due to prolonged low level intake of phyto-estrogens, e.g., on subterranean clover pasture. It may be a precursor of or associated with pyometra, especially in the dog where the hormonal cause is progesterone. See also pyometra.
  • e. folds in the mare these run the length of the uterus as observed by fiberscope or by ultrasonography.
  • e. glands provide uterine fluid (histotrophe) on which the developing fetus depends for subsistence during its first few days of existence.
  • e. hyperplasia with pyometra see cystic endometrial hyperplasia.
  • e. polyp found in the bitch and may cause prolapse of the affected horn with the polyp visible in the vagina.
  • e. regeneration postpartum return to normal of the endometrium, e.g., in cows by the sloughing of superficial layers of caruncles.

• endometriosis [en″do-me″tre-o′sis] a condition unique to menstrual animals in which tissue more or less perfectly resembling the uterine mucous membrane occurs aberrantly in various locations in the pelvic cavity. See also uterine adenomyosis.

• endometritis [en″do-me-tri′tis] inflammation of the endometrium. See also metritis.

  • hyperplastic e. see pyometra.
  • puerperal e. endometritis following parturition.
  • purulent e. characterized by a small accumulation of pus in the uterus and a discharge, which may be intermittent, of thick pus from the vulva.
  • syncytial e. a benign tumor-like lesion with infiltration of the uterine wall by large syncytial trophoblastic cells.
  • tuberculous e. inflammation of the endometrium, usually also involving the uterine tubes, due to infection by Mycobacterium bovis, with the presence of tubercles. subclinical e. inflammation of the endometrium in the absence of externally visible or macroscopic signs.

• endometrium [en″do-me′tre- m] the mucous membrane lining the uterus.

• endomitosis [en″do-mi-to′sis] mitosis taking place without dissolution of the nuclear membrane, and not followed by cytoplasmic division, resulting in doubling of the number of chromosomes within the nucleus.

• endomyocardial fibrosis [en ″do-mi″o-kahr′de- l] see restrictive cardiomyopathy.

• endomyocarditis [en″do-mi″o-kahr-di′tis] inflammation of the endocardium and myocardium.

• endomysium [en″do-mis′e- m] the sheath of delicate reticular fibrils that surrounds each muscle fiber.

• endoneuritis [en″do-n $\stackrel{⌣}{o}$ $\stackrel{⌣}{o}$ -ri′tis] inflammation of the endoneurium.

• endoneurium [en″do-noor′e-um] the interstitial connective tissue in a peripheral nerve, separating individual nerve fibers.

• endonuclease [en″do-noo′kle-ās] a nuclease that cleaves internal bonds of polynucleotides.

  • restriction e. see restriction endonuclease.
  • phosphate yielding e’s. a class of ribonuclease involved in the usually fairly rapid turnover of RNA in the cell that degrades RNA by cleavage of the phosphodiester bonds within the molecule.

• endoparasite [en″do-par′ -sīt] a parasite that lives within the body of the host.

• endopelvic [en″do-pel′vik] within the pelvis.

• endopeptidase [en″do-pep′tľ-dās] a peptidase capable of acting on any non-terminal peptide linkage in a peptide chain.

• endopericarditis [en″do-per″ľ-kahr-di′tis] inflammation of the endocardium and pericardium.

• endoperimyocarditis [en″do-per″ľ-mi″o-kahr-di′tis] inflammation of the endocardium, pericardium and myocardium.

• endoperitonitis [en″do-per″ľ-to-ni′tis] inflammation of the serous lining of the peritoneal cavity.

• endophlebitis [en″do-fl -bi′tis] inflammation of the intima of a vein.

• endophthalmitis [en″dof-th l-mi′tis] inflammation (usually purulent) within the ocular cavities (anterior, posterior, and vitreous chambers) as a result of inflammation of the surrounding ocular tunics; frequently occurs as a result of a penetrating injury or septicemia; compare with panophthalmitis.

  • lens-induced e. see phacoanaphylactic endophthalmitis (see below).
  • nonsuppurative e. may be caused by trauma to the eye, or secondary to severe corneal inflammation.
  • phacoanaphylactic e. hypersensitivity to lens material. Called also lens-induced endophthalmitis.
  • suppurative e. caused by foreign bodies or infectious agents, which may be associated with systemic infection.

• endophyte [en′do-fīt] microbes, principally fungi of the Neotyphodium/Epichloe complex, living within plants in a mutualistic symbiotic relation. Transmission of Neotyphodium endophytes is asexual, they are exclusively transmitted vertically from host plants to seeds. Transmission of Epichloe endophytes can be both horizontal and vertical as some are transmitted by sexual spores. Endophytes, especially Neotyphodium endophytes in grasses, and their bioactive alkaloids, confer benefits to the grass that include increased resistance to environomental stresses and protection against insect herbivory. In agriculture and veterinary medicine endophytes have great interest due to the opposing effects of pasture protection against insect herbivory (peramine, lolines, ergopeptines) and concomitant toxicity, to stock (ergovaline, lolitrem B).

• endophytic [en″do-fit′ik] 1. pertaining to an endophyte. 2. growing inward; proliferating on the interior of an organ or structure.

  • e. fungus fungal species living as symbionts within the tissues of pasture grasses including Epichloë (Neotyphodium, Acremonium) spp. in Festuca and Lolium spp.

• endoplasm [en′do-plaz″ m] central cytoplasm, full of organelles.

• endoplasmic [en″do-plas′mik] pertaining to or arising from endoplasm.

  • e. ribosomes small, cytoplasmic granules consisting of approximately 60% RNA and 40% protein.

• endopolygeny asexual reproduction in protozoa in which new progeny are produced by budding within the parental cell.

• endoreduplication [en″do-re-doo″plľ-ka′sh n] replication of chromosomes without subsequent cell division that results in nuclear polyploidy.

• endorphin [en-dor′fin, en′dor-fin] one of a group of opiate-like peptides produced naturally by the body at neural synapses at various points in the central nervous system pathways where they modulate the transmission of pain perceptions. The term endorphin was coined by combining the words endogenous and morphine. Like morphine, endorphins raise the pain threshold and produce sedation and euphoria; the effects are blocked by naloxone, a narcotic antagonist.

• endosalpingitis [en″do-sal″pin-ji′tis] inflammation of the endosalpinx.

• endosalpingoma [en″do-sal″pin-go′m ] adenomyoma of the uterine tube.

• endosalpinx [en″do-sal′pinks] the mucous membrane lining the oviduct (uterine tube).

• endoscope [en′do-skōp] to, ‘look inside’, an instrument used for direct visual examination of the interior of hollow organs or body cavities. Specially designed endoscopes are used for such examinations as arthroscopy, bronchoscopy, cystoscopy, gastroscopy, hysteroscopy, and laparoscopy. Although the design of an endoscope may vary according to its specific use, endoscopes are either of a ‘rigid’ or ‘flexible’ construction. Rigid endoscopes use a series of glass lenses arranged in a linear sequence within a straight metal or rigid fiber tube that permits viewing at a specified angle (e.g., 15 degrees from the central axis); the field of view is therefore limited by the angle and position of the inflexible endoscope and the dimensions of the structure under examination. Flexible endoscopes all use fiberoptics or other advanced technologies for the transmission of light from the light source to the tip of the endoscope. Transmission of the image to the viewer is either via a fiberoptic image bundle to an eyepiece (fiberscope) or via an electrical signal from a sensor (chip) at the tip of the endoscope directly to a video processor. Each type of endoscope has a light source, power cord, and power source. Accessories that might be used with an endoscope for diagnostic or therapeutic purposes include suction tip, tubes, and suction pump for delivery and removal of fluid via the air/water portal; brush for collection of surface material for cytologic examination; forceps for removal of biopsy tissue or a foreign body; electrode tip for cauterization; and laser fiber for performing endoscopic laser surgery.

  E-35.

  

  Storz veterinary small animal endoscope.

  • flexible e. a type of endoscope that has a relatively long, narrow, and flexible shaft, with manual controls that enable the operator to direct the orientation of the flexible tip; these features allow the thorough examination of irregularly shaped, tortuous organs, such as the intestine, and of cavernous structures such as the stomach and the urinary bladder, as the operator can safely advance, retract, redirect, and even turn the flexible endoscope back on itself within the hollow organ.
  • rigid e. a type of endoscope that has a narrow but relatively short and inflexible shaft; available in a variety of sizes (diameters, lengths) and viewing angles, rigid endoscopes are useful for a number of minimally invasive surgical procedures, either via a natural orifice, such as cystoscopy, or via a surgically created portal, such as laparoscopy.
  • semi-rigid e. a subclass of narrow, rigid endoscopes constructed of a fused silica bundle; useful for examination of areas otherwise inaccessible with standard lensed endoscopes or flexible fiberoptic endoscopes.

• endoscopy [en-dos′k -pe] direct visual examination of interior structures of the body with an endoscope.

• endosepsis [en″do-sep′sis] septicemia originating from causes inside the body.

• endoskeleton [en″do-skel′ -ton] the cartilaginous and bony skeleton of the body, exclusive of that part of the skeleton of dermal origin. See also exoskeleton.

• endosmosis [en″dos-mo′sis] inward osmosis; inward passage of liquid through a membrane of a cell or cavity, by which one fluid passes through a septum into a cavity that contains fluid of a different density.

• endosome [en′do-sōm] an intracellular vesicle formed from the cell membrane which is involved in intracellular transport.

• endosteal [en-dos′te- l] 1. pertaining to the endosteum. 2. occurring or located within a bone.

  • e. lining cells cover the internal surfaces of the compact bone, trabecular bone and osteonal canals.

• endosteitis [en-dos″te-i′tis] inflammation of the endosteum.

• endosteoma [en-dos″te-o′m ] a tumor in the medullary cavity of a bone.

• endosteum [en-dos′te- m] the tissue lining the medullary cavity of a bone.

  • cortical e. endosteal lining to cortical bone; delimits the marrow cavity.
  • osteonal e. endosteal lining of the osteonal canals.
  • trabecular e. the endosteum that coats the surfaces of the trabeculae.

• endostoma [en″dos-to′m ] see endosteoma.

• endostoses bony outgrowths on the medullary surface of long bones. Called also enostosis.

• endosulfan see chlorinated hydrocarbons.

• endosurgery [en′do-sur″j r-e] the use of endoscopy to perform minimally invasive surgical procedures.

• endotendineum [en″do-t n-din′e- m] the delicate connective tissue separating the secondary bundles (fascicles) of a tendon.

• endotendon, endotenon [en″do-ten′don, en″do-ten′on] the synovial connective tissue sleeve that covers the surface of certain tendons and that is separated from an outer exotendon by a slender synovial-fluid filled cavity.

• endothelial [en″do-the′le- l] pertaining to or made up of endothelium.

  • e. tissue special connective tissue lining blood and lymph spaces.
  • e. tumors see hemangioma and hemangiosarcoma.

• endothelin [en″do-the′lin] see endothelium-derived constricting factor.

• endotheliochorial [en″do-the″le-o-kor′e- l] see placenta.

• endotheliocyte a large mononuclear phagocytic cell of the circulating blood and tissues. Called also endothelial leukocyte.

• endothelioid [en″do-the′le-oid] resembling endothelium.

• endothelioma [en″do-the″le-o′m ] a tumor arising from the endothelial lining of blood vessels.

• endotheliosis [en″do-the″le-o′sis] proliferation of endothelial elements.

• endothelium [en″do-the′le- m] pl. endothelia [Gr.] the layer of epithelial cells that lines the cavities of the heart and of the blood and lymph vessels, sometimes applied to other internal epithelial surfaces.

  • corneal e. lines the inner surface of the cornea, between the corneal stroma and aqueous humor; called also the posterior epithelium.

• endothelium-derived derived from endothelium.

  • e.-d. vasoactive substances substances produced by or released from endothelial cells that regulate vascular smooth muscle or other regulatory mechanism; include prostacyclin and other prostanoids, nitric oxide, and other relaxing or constricting factors.
  • e.-d. constricting factor vasoconstrictive peptides isolated from vascular endothelial cells that are actively vasoconstrictive; endothelin (ET) is the most active of them.
  • e.-d. relaxing factor several are known; nitric oxide is one of the chief mediators, probably derived from l-arginine.

• endothermic [en″do-thur′mik] 1. “warm blooded”; capable of maintaining body temperature, independent of the environment. Includes mammals and birds. 2. pertaining to endothermy.

• endothermy [en″do-thur′me] see diathermy.

• endothrix [en′do-thriks] a dermatophyte whose growth and spore production are confined chiefly within the shaft of a hair.

• endotoxemia [en″do-tok-se′me- ] the presence of endotoxin in the blood.

• endotoxic [en″do-tok′sik] pertaining to or possessing endotoxin.

  • e. shock see toxemic shock.

• endotoxin [en′do-tok″sin] a heat-stable toxin not secreted by intact gram-negative bacterial cells. It is the lipopolysaccharide (LPS) of gram-negative outer membranes. Also called O antigen. It is pyrogenic and increases capillary permeability through stimulation of tumor necrosis factor release.

• endotracheal [en″do-tra′ke- l] within the trachea.

  • Cole-pattern e. tube one with a tapered shape with no cuff; designed to be fitted with a wider shoulder at the larynx and narrow end in the trachea. Useful for birds and reptiles.
  • e. intubation an airway tube inserted in the trachea during endotracheal intubation to assure patency of the upper airway by allowing for maintenance of an adequate air passage. In animals, endotracheal intubation is usually accomplished through the mouth using an orotracheal tube.
  • nasal e. tube an endotracheal tube designed to be passed through the nasal cavity into the trachea. It usually has a thin wall.
  • reinforced e. tube a spiral wire or nylon strip is incorporated into the wall to reduce the risk of collapse or kinking.
  • e. tube (ETT) various types of endotracheal tubes are available. The tubes are almost always ‘cuffed’ to allow for their use with a mechanical ventilator. The cuff is a rubber balloon-like device that fits over the lower end of the tube. It is attached to a narrow tube that extends outside the body and allows for inflation of the cuff. Once the cuff is inflated there is no flow of air through the trachea other than that going through the endotracheal tube.

• endoturbinates [en″do-tur′bľ-nāts] the larger of the ethmoturbinalia that interleave with ectoturbinates in the caudal part of the nasal cavity and that are most complicated in animals with an acute sense of smell such as dogs.

• endovasculitis [en″do-vas″ku-li′tis] see endangiitis.

• endrin [en′drin] see chlorinated hydrocarbons.

• endurance rides equine performance tests requiring contestants to complete a course of 80–150 km in 1–2 days. They create special problems in equine sports medicine. These include the exhausted horse syndrome, evidence of impending pulmonary edema, heat exhaustion, exertional rhabdomyolysis, and a variety of disturbances of acid–base balance. The problem for the veterinarian is to decide whether horses should be allowed to continue in the contest. See also exhaustion syndrome.

  E-36.

  

  Endotracheal tube type, material, and size comparison. A, Cuffed 11-mm, silicone rubber Murphy tube. B, 2.5-mm Cole tube. C, Cuffed 8-mm polyvinyl chloride (PVC) Murphy tube. D, Cuffed 4-mm red rubber Murphy tube. E, Uncuffed 2 mm PVC Murphy tube.

• Endymion nonscriptus see Hyacinthoides non-scripta.

• enema [en′ -m] 1. introduction of fluid into the rectum. 2. a solution introduced into the rectum to promote evacuation of feces or as a means of administering nutrient or medicinal substances, or opaque material in radiological examination of the lower intestinal tract. See also barium study.

• enemata plural of enema.

• energy [en′ r-je] power that may be translated into motion, overcoming resistance, or effecting physical change; the ability to do work. Energy assumes several forms; it may be thermal (in the form of heat), electrical, mechanical, chemical, radiant, or kinetic. In doing work, the energy is changed from one form to another or to several forms. In these changes some of the energy is ‘lost’ in the sense that it cannot be recaptured and used again. Usually there is loss in the form of heat, which escapes or is dissipated unused. All energy changes give off a certain amount of the energy as heat. All activities of the body require energy, and all needs are met by the consumption of food containing energy in chemical form. The animal diet comprises three main sources of energy: carbohydrates, proteins and fats. Carbohydrates most readily provide the energy needed to activate muscles; fats are stored in adipose tissue and provide large amounts of energy when released and broken down in tissues; excess amino acids resulting from the breakdown of proteins during digestion that are not needed to build and maintain body tissues are also used to generate energy. The body derives energy from food molecules by the process of catabolism. See also adenosine.

  • dietary e. the total energy intake in the diet is the gross energy. Digestible energy is gross energy less fecal energy. Metabolizable energy is digestible energy less that lost in fermentation in the gut, energy lost in urine. Net energy is metabolizable energy less energy used in specific dynamic action response. Expressed as joules, calories or occasionally therms (1 calorie = 4.18 joule).
  • e. balance is the difference between energy intake and energy expenditure.
  • e. density see caloric density.
  • e. expenditure under normal conditions, consists of three elements: basal metabolism, postprandial thermogenesis, and physical activity.
  • e. feeds feeds with a high carbohydrate content and low fiber (<18%) and protein (<20%) contents.
  • free e. the energy equal to the maximum amount of work that can be obtained from a process occurring under conditions of fixed temperature and pressure.
  • gross e. total energy of a feed as measured by direct calorimetry.
  • nuclear e. energy that can be liberated by changes in the nucleus of an atom (as by fission of a heavy nucleus or by fusion of light nuclei into heavier ones with accompanying loss of mass).
  • nutritional e. deficiency causes loss of body weight, milk, egg, and wool production. Continued for long periods or severe restriction causes particular metabolic upsets in pregnant and lactating ewes and cows—see pregnancy toxemia, ketosis (2); in neonates, hypoglycemia. In others causes emaciation, inanition, starvation.
  • e. production production of ATP via oxidative phosphorylation or substrate-level phosphorylation.
  • e. requirements generally vary between species and particularly between individuals. They are determined by many factors, especially age, level of activity, physiological status and body size, specifically body surface area. The basal energy requirement (BER) is the level required by a healthy animal at complete rest in a neutral environmental temperature. It can be calculated by using several formulae, based on body weight or body surface area, which is then used in the further calculation of the maintenance energy requirement (MER) which takes into account the individual animal’s level of activity or disease status.
  • e. reserves energy stored in the body in the form of reduced carbon in compounds such glycogen (storage form of glucose) in the liver and muscle, as fatty acids in triacylglycerols in adipose tissue, and amino acids in protein. Energy is released when required, ultimately in the form of ATP on oxidation of the carbon.
  • e. transfer conversion of energy from one form usually chemical in the form of ATP to another usually chemical, but can be electrical, mechanical, or heat energy. In biochemistry, this concept generally refers to the transfer of groups from compounds that contain energy-rich bonds to compounds that have relatively energy-poor bonding characteristics via thermodynamically permissible enzymatic reactions. This principle is a major premise of the interaction between energy-producing and energyutilizing metabolic pathways in living cells.

• enervation [en″ r-va′sh n] 1. lack of nervous energy. 2. removal of a nerve or a section of a nerve.

• enflagellation [en-flaj″ -la′sh n] the formation of flagella; flagellation.

• enflurane [en′floo-rān] an isomer of the inhalant anesthetic isoflurane, approved for general anesthesia in animals but no longer in common use.

• ENG enzootic nasal granuloma.

• engastrius [en-gas′tre- s] conjoined twins in which one fetus is contained within the abdomen of the other.

• engine oil [en′jin] a cause of poisoning. See sump oil.

• English bobtail Old English sheepdog.

• English bulldog see Bulldog.

• English coach dog see Dalmatian.

• English cocker spaniel see Cocker spaniel.

• English coonhound see American English coonhound.

• English foxhound see Foxhound.

• English Game a long-legged, long-necked meat fowl with a wide, shallow body, long, muscular legs, and muscular wings. Multicolored, mostly red, brown and white; originated from fighting birds.

• English ivy see Hedera helix.

• English Leicester see Leicester.

• English longwool a class of sheep; includes Romney Marsh, Leicester, Lincoln (Lincoln longwool) and Border Leicester. Called also British longwool.

• English pointer see Pointer.

• English setter a medium-weight, tall, lean, deep-chested bird dog with a long, silky coat that is most profuse under the neck, trunk, tail, and behind the legs. The coat is basically white with black, liver, lemon, or orange spots and flecks (belton markings). The breed is predisposed to neuronal ceroid lipofuscinosis (juvenile amaurotic familial idiocy), deafness, entropion and progressive retinal atrophy.

• English spot a breed of medium-sized rabbits with a white coat and distinctive colored markings on the face, ears, and down the back in a herringbone pattern with a chain of spots on either side.

• English springer spaniel a medium-sized (40–50 lb), compact dog with floppy ears, short, docked tail, and a long, flat, silky coat in brown (liver) or black and white, blue or liver roan, or tricolor, that is most profuse under the neck and body, and behind the legs. The breed is affected by an inherited storage disease (fucosidosis), cutaneous asthenia, factor XI deficiency, retinal dysplasia and cataracts.

• English toy spaniel a small, compact dog with domed head, snub nose, pendulous ears and long, silky, wavy coat; four solid or broken-colored varieties are recognized: black and tan, ruby (rich chestnut red), Blenheim (white with chestnut red patches, one of which must be in a white blaze in the center of the skull and called the ‘lozenge’, ‘Blenheim’ spot, or ‘kissing spot’), and tricolor (called Prince Charles in the United States) (white with black patches and tan markings). Similar to, but smaller than, the Cavalier King Charles spaniel. In the UK and Australia, the breed is called the King Charles spaniel.

• English toy terrier the toy variety of the Manchester terrier, recognized in the UK as a separate breed.

• engorgement [en-gorj′m nt] distention.

  • carbohydrate e. see carbohydrate engorgement.
  • equine wheat e. see carbohydrate engorgement.
  • vascular e. local congestion; distention with fluids; hyperemia.

• enhancement [en-hans′m nt] immunologically speaking, ways of increasing the level of an immune response. Immunoenhancement.

  E-37.

  

  Enophthalmos in both eyes of a dog resulting from emaciation.

  • tumor e. successful establishment and prolongation of survival time of a transplanted tumor allograft, as a result of binding of specific antibody that acts to mask tumor specific antigens on the surface of the tumor cells.

• enhancer [en-hans′ r] see enhancer sequence.

• enilconazole a broad-spectrum imidazole antifungal agent particularly useful in the treatment of canine nasal aspergillosis.

• enkatarrhaphy the operation of burying a structure by suturing together the sides of tissues adjacent to it.

• enkephalin [en-kef′ -lin] either of two naturally occurring pentapeptides (methionine enkephalin and leucine enkephalin) isolated from the brain, which have potent opiate-like effects and serve as neurotransmitters. They are classified as endorphins.

• enol [e′nol] one of two tautomeric forms of a substance, the other being the keto form; the enol is formed from the keto by migration of hydrogen from the adjacent carbon atom to the carbonyl group.

• enolase [e′no-lās] an enzyme in glycolytic systems that changes phosphoglyceric acid into phosphoenolpyruvic acid.

• enophthalmos [en″of-thal′mos] a backward displacement of the globe into the orbit; may be active due to contraction of the retractor bulbi (in most veterinary species) or passive due to loss of orbital contents.

• enostosis [en″os-to′sis] a bony growth within a bone cavity or on the internal surface of the bone cortex. See also panosteitis.

• enstrophe [en′stro-fe] inversion; especially of the margin of the eyelids; entropion.

• enoxacin [ě-nok′s -sin] a broad spectrum fluoroquinolone antibiotic, similar to ciprofloxacin.

• enoxaparin [e-nok″s -par′in] a low-molecular-weight (LMW) heparin used as an antithrombotic agent.

• enoxolone see glycyrrhetinic acid.

• enrobing the application of liquid or dry coatings to the external surface of dry, extruded pet foods as the final step prior to packaging. Coatings are typically in the form of fat, which diminishes starch gelatinization, and/or flavor enhancers which enhance palatability.

• enrofloxacin [en″ro-flok′s -sin] a fluoroquinolone antibiotic, similar to ciprofloxacin, useful against a wide spectrum of aerobic bacteria, but particularly gram-negative bacteria and mycoplasma. Marketed for veterinary use as Baytril®. Can cause retinal toxicity in cats.

• ENS enteric nervous system.

• ensiform [en′sľ-form] sword-shaped; xiphoid.

  • e. cartilage, e. process the xiphoid cartilage.

• ensilage see silage.

• ensiled pertaining to or emanating from ensilage.

• ensomphalus [n-som′f-l s] conjoined twins with blended bodies, two separate navels and two umbilical cords.

• ENT ear, nose and throat.

• entactin [en-tak′tin] a glycoprotein that is an integral component of the basement membrane and contributes to the cell-to-basal membrane and lamina-to-matrix interfaces. Called also Nidogen-1.

• entad [en′tad] toward a center; inwardly.

• ental [en′t l] inner; central.

• entamebiasis infection by Entamoeba spp. Occurs in most animal species but clinical illness is evident only in humans in the form of amebic dysentery caused by E. histolytica.

• Entamoeba [en″t -me′b] a genus of amebae parasitic in the intestines of vertebrates. Member of the family Endamoebidae.

  • E. bovis found in cattle; nonpathogenic.
  • E. bubalis an ameba with a single nucleus in the cysts in its trophozoite.
  • E. canibuccalis (syn. E. gingivalis) in the mouth of cats, dogs, humans and primates; nonpathogenic.
  • E. caviae found in guinea pigs; nonpathogenic.
  • E. coli a nonpathogenic form found in the intestinal tract of humans. Its importance is that it may be confused with the pathogenic E. histolytica.
  • E. cuniculi found in large bowel of rabbits.
  • E. equi found in horses.
  • E. equibuccalis nonpathogenic; found in the mouths of horses.
  • E. gedoelsti found in horse large intestine; nonpathogenic.
  • E. hartmanni found in large intestine of humans and the colons of dogs; nonpathogenic.
  • E. histolytica a species causing amebic dysentery and abscess of the liver in humans. Found also in monkey, dog, cat, rat, pig.
  • E. invadens cause of entamebiasis in reptiles. See amebiasis.
  • E. moshkovskii found in sewage. Resembles E. histolytica.
  • E. muris found in large intestine of rats and mice; nonpathogenic.
  • E. ovis found in sheep.
  • E. ranarum found in tadpoles.
  • E. suigingivalis found in the mouths of pigs.
  • E. suis found in swine.
  • E. wenyoni an entameba with eight-nucleated cysts in the trophozoite.

• Entandrophragma cylindricum African tree in the family Meliaceae whose wood shavings, when used as bedding, have caused balanoposthitis in rams. Sawdust from this tree, used as litter for chickens, has caused hyperkeratosis, weight loss, nervous signs, and collapse. Called also aboudikro, redwood, sapele.

• entasia a constrictive spasm; tonic spasm.

• ENTEC enterotoxigenic Escherichia coli. More commonly abbreviated as ETEC.

• enteque seco [en-ta′ka] [Span.] see enzootic calcinosis.

• enteral [en′t r- l] within, by way of, or pertaining to the intestine.

  • e. feeding delivery of nutrients directly into the stomach, duodenum, or jejunum. Called also enteral nutrition.
  • e. nutrition see enteral feeding (above).
  • e. tube the feeding tube positioned in the alimentary tract for administration of nutrients. See also enterostomy tube.

• enteralgia [en″t r-al′j] pain in the intestine. Called also colic.

• enterectomy [en″t r-ek′t -me] excision of a portion of the intestine.

• enterelcosis ulceration of the intestine.

• enteric [en-ter′ik] pertaining to the small intestine.

  • e. bacteria straight gram-negative rods, members of the family Enterobacteriaceae.
  • e.-coated designating a special coating applied to tablets or capsules that prevents release and absorption of their contents until they reach the intestine.
  • e. fever see salmonellosis.
  • e. protein loss see protein-losing enteropathy.
  • e. red mouth disease caused by Yersinia ruckeri. Also called red mouth disease.

• enteritis [en″t r-i′tis] inflammation of the intestinal mucosa resulting in clinical signs of diarrhea, sometimes dysentery, abdominal pain, and dehydration and electrolyte loss and imbalance. In more severe cases, there is much mucus in the feces, and in the worst ones, there are shreds or even sheets of exfoliated mucosa. Gastritis is commonly an accompanying lesion. Vomiting may be a concurrent sign in monogastric animals. The causes are many and include bacteria, viruses, chemicals, damaged feedstuffs, and nematode parasites and protozoa. Descriptions of those diseases will be found under the headings of their causative agents, e.g., rotavirus, coronavirus, enterovirus, Salmonella. There is a further list of diseases in which diarrhea is the cardinal sign but in which there are no lesions of enteritis. These are the enteropathies. See also enteropathy.

  • canine viral e. common causes in dogs are canine parvoviruses, coronavirus and rotavirus. Other viruses isolated from dogs with enteritis but of unknown clinical significance are canine astrovirus, kobuvirus, circovirus, and several members of the family caliciviridae.
  • equine chronic eosinophilic e. an eosinophilic intestinal condition in the horse, without known causes for eosinophilia, that is part of the inflammatory bowel disease complex that includes idiopathic focal eosinophilic enteritis (below). This disease is a multisystemic epitheliotropic syndrome including eosinophilic pancreatitis, dermatitis, and eosinophilic enteritis.
  • feline e. see feline panleukopenia.
  • granulomatous e. horses with this disease continue to lose condition over a long period and most have diarrhea and edema. There is a hypoproteinemia and protein loss in the feces. In dogs, the changes are similar, but may be segmental and can be the cause of partial obstruction.
  • hemocytic e. enteritis of shrimps associated with blooms of some blue-green algae.
  • idiopathic focal eosinophilic e. a rare diffuse eosinophilic enteritis without a known cause, but believed to be a distinct entity represented by an accumulation of leucocytes in the submucosa and muscularis, with dominance of eosinophils. Clinical signs may include weight loss, hypoalbuminemia and diarrhea, consistent with diffuse infiltrative intestinal disease. A cause of intestinal obstruction.
  • lymphocytic–plasmacytic e. infiltration of the lamina propria with lymphocytes and plasma cells can be a nonspecific response to chronic inflammation, but is classified by some as a primary, immune-mediated disease of the intestine causing malabsorption, chronic watery diarrhea and sometimes a protein-losing enteropathy.
  • mink e. see mink enteritis.
  • necrotic e. see necrotic enteritis.
  • parvoviral e. see canine parvovirus.
  • phlegmonous e. a condition with clinical signs resembling those of peritonitis, which may be secondary to other intestinal diseases, e.g., chronic obstruction, strangulated hernia, carcinoma.
  • proximal e. duodenitis.
  • regional e. inflammation of the terminal portion of the ileum. See also terminal ileitis, Crohn’s disease and porcine proliferative enteropathy.
  • turkey hemorrhagic e. see turkey hemorrhagic enteritis.
  • ulcerative e. an acute disease of chickens, poults, and game birds caused by Clostridium colinum. It is characterized by rapid spread of an acute symptomless disease. Quail show watery white droppings. Lesions include hemorrhagic enteritis in acute cases with ulceration the major finding in subacute cases. The morbidity in quail may be 100%, in chickens it is nearer 10%. Called also quail disease.

• enter(o)- word element. [Gr.] pertaining to the intestine.

• enteroaggregative [en″t r-o-ag′r -ga″tiv] adhering to or forming colonies on intestinal mucosa.

  • e. Escherichia coliE. coli have fimbrial adherence to intestinal mucosa. Subsequent production of mucus by the bacteria and the host cell forms a biofilm on the surface of the enterocytes with release of toxins and elicitation of an inflammatory response and diarrhea.

• enteroanastomosis [en″t r-o- -nas″to-mo′sis] see enteroenterostomy.

• Enterobacter [en″t r-o-bak′t r] a genus of lactose-fermenting, gram-negative rod-shaped bacteria in the family Enterobacteriaceae. Found chiefly in the environment in water and soil, but are common invaders of tissues in contaminated wounds of animals and in opportunistic infections such as cystitis and pyelonephritis in cattle. E. aerogenes (previously Klebsiella mobilis) is now classified as Klebsiella aerogenes.

  • E. cloacae occasionally isolated from dogs and cats with septicemia.

• Enterobacteriaceae [en″t r-o-bak-te″re-a′se-e] a family of gram-negative, rod-shaped bacteria (order Eubacteriales) occurring as plant or animal parasites or as saprophytes. Includes the lactose-fermenting genera of Escherichia, Enterobacter, Serratia and Klebsiella, and the non-lactose fermenters of pathogenic significance, Salmonella, Proteus, and Yersinia.

• enterobiasis [en″ter-o-bi′ -sis] infection with nematodes of the genus Enterobius, especially E. vermicularis. A disease of humans that also occurs in primates, causing perianal irritation and aggressive behavior.

• Enterobius [en″t r-o′be- s] a genus of nematodes of the family Oxyuridae. Includes E. vermicularis, the human pinworm; causes enterobiasis.

• enterocele [en′t r-o-sēl″] 1. intestinal hernia. 2. the body cavity formed by outpouchings from the archenteron.

• enterocrinin a hormone found in the canine small intestine and may stimulate intestinal juice secretion.

• enterocentesis [en″t r-o-sen-te′sis] surgical puncture of the intestine, usually with a needle and syringe in order to collect a sample of intestinal contents.

• enteroception [en″t r-o-sep′sh n] reception of sensory stimuli in the walls of hollow internal organs.

• enterochromaffin [en″t r-o-kro′m -fin] pertaining to intestine and chromaffin.

  • e. cells epithelial cells of the intestinal mucosa that stain with chromium salts; they usually contain serotonin.
  • e. tumor see carcinoid.

• enteroclysis [en″t r-ok′lľ-sis] the injection of liquids into the intestine.

• enterococci gram-positive bacteria in the genus Enterococcus.

• Enterococcus [en″t r-o-kok′ s] a genus of Gram-positive coccoid bacteria characterized by a capacity to grow in the presence of bile salts. Commonly intestinal in origin and previously classified as streptococci, mostly of Lancefield Group D. E. durans (previously Streptococcus durans), E. faecalis (previously S. faecalis). and E. faecium (previously S. faecium) are a cause of avian streptococcosis. E. faecalis has also been associated with amyloid arthropathy in chickens. Mostly they are found in the feces of animals and may be involved in opportunistic infections. E. avium (previously S. avium) is of unknown pathogenicity. Of particular significance as multi-resistant opportunisitic pathogens of humans.

  • E. cecorum causes arthritis and osteomyelitis of the spine and hip in male broilers.
  • E. hirae a cause of outbreaks of septicemia and endocarditis in broiler chickens E. seriolicida an important pathogen of Japanese yellowtail and rainbow trout. Now classified as Lactococcus garvieae.

• enterocolectomy [en″t r-o-ko-lek′t -me] resection of part of the intestine, including the ileum, cecum and colon.

• enterocolitis [en″t r-o-ko-li′tis] inflammation of the small intestine and colon. Classifications include eosinophilic, granulomatous, hemorrhagic, plasmacytic, pseudomembranous, ulcerative.

  E-38.

  

  Tall columnar enterocytes lining the villus and being produced in the crypts in the small intestine.

  • antibiotic-associated e. see antibiotic-associated colitis.
  • hemorrhagic e. enterocolitis characterized by hemorrhagic breakdown of the intestinal mucosa, with inflammatory cell infiltration.
  • protothecal e. caused by oral infection with Prototheca spp. may cause chronic intractable diarrhea, with or without dysentery; necropsy lesions include ulcerative and hemorrhagic colitis.
  • pseudomembranous e. an acute inflammation of the bowel mucosa, with the formation of pseudomembranous plaques, usually associated with antimicrobial therapy.
  • ulcerative e. ulcers of the enteric mucosa resulting from bacterial or fungal infection of pre-existing erosions; can also result from tannin poisoning as in horses which consume foliage of oak trees.

• enterocolostomy [en″t r-o-k-los′t -me] surgical anastomosis of the small intestine to the colon.

• enterocutaneous [en″t r-o-ku-ta′ne- s] pertaining to or communicating with the intestine and the skin, or surface of the body.

• enterocyst [en′t r-o-sist″] a cyst proceeding from subperitoneal tissue.

• enterocystocele [en″t r-o-sis′to-sēl] hernia of the bladder and intestine.

• enterocystoma [en″t r-o-sis-to′m] see vitelline cyst.

• enterogastrone [en″t r-o-gas′trōn] an uncharacterized hormone of the duodenum which has been suggested to mediate the humoral inhibition of gastric secretion and motility produced by ingestion of fat. Called also anthelone E.

• enterocyte [en′t r-o-sīt″] the predominant cells in the small intestinal mucosa. They are tall columnar cells and responsible for the final digestion and absorption of nutrients, electrolytes and water.

• Enterocytozoon [en″t r-o-si″to-zo′ n] a genus in the phylum Microsporidia; includes E. bieneusi, a cause of microsporidiosis.

• enterodynia [en″t r-o-din′e-] pain in the intestine.

• enteroendocrine [en″t r-o-en′do-krin] pertaining to intestinal hormones.

  • e. cells cells of the intestinal mucosa that produce hormones such as secretin and cholecystokinin.

• enteroenteropexy [en″t r-o-en′t r-o-pek″se] see bowel plication.

• enteroenterostomy [en″t r-o-en″tr-os′t -me] surgical anastomosis between two segments of the intestine.

• enteroepiplocele [en″t r-o- -pip′lo-sēl] hernia of the intestine and omentum.

• enterogastritis [en″t r-o-gas-tri′tis] inflammation of the small intestine and stomach.

• enterogenous [en″t r-oj′-n s] 1. arising from the primitive foregut. 2. originating within the small intestine.

• enteroglucagon [en″t r-o-gloo′k -gon] a peptide hormone secreted by gastrointestinal mucosal cells; functions include inhibiting gastric acid secretion, regulation of insulin and glycemic control.

• enterogram [en′t r-o-gram″] an instrumental tracing of the movements of the intestine.

• enterohemorrhagic [en″t r-o-hem″ -raj′ik] causing bloody diarrhea.

  • e. Escherichia coli (EHEC)E. coli induce the attaching and effacing lesion, but in the colon and induce diarrhea by the production of Shiga toxin (Stx).

• enterohepatic [en″t r-o-h -pat′ik] pertaining to the liver and the intestine.

  • e. circulation see enterohepatic circulation.

• enterohepatitis [en″t r-o-hep″ -ti′tis] inflammation of the intestine and liver.

  • infectious e. a disease of poultry. See histomoniasis.

• enterohepatocele [en″t r-o-hep′ -to-sēl″] an umbilical hernia containing intestine and liver.

• enterohydrocele [en″t r-o-hi′dro-sēl] hernia with hydrocele.

  E-39.

  

  Enterolith from a horse.

• enteroinsular axis the relationship between insulin secretion and the entrance of a glucose load into the intestine. The response to a glucose meal taken orally is much greater than if the glucose is given intravenously.

• enteroinvasive [en″t r-o-in-va′siv] invading the intestinal mucosa.

  • e. Escherichia coliE. coli invade colonic epithelial cells to produce colonic cell damage and diarrhea.

• enterokinase [en″t r-o-ki′nās] the intestinal hormone that activates trypsinogen into becoming active trypsin.

• enterokinesia [en″t r-o-kľ-ne′zh] peristalsis.

• enterokinetic [en″t r-o-kľ-net′ik] pertaining to or stimulating peristalsis.

• enterolike viruses see infectious stunting syndrome.

• enterolith [en′t r-o-lith″] a concretion or calculus in the intestine; can cause intraluminal obstruction of the transverse or small colon in horses. The enteroliths are smooth, lamellated objects consisting of ammonium magnesium phosphate and occur in mature animals. See also fecalith.

• Enterolobium Central American genus of plants in the family Mimosaceae. Includes E. cyclocarpum (elephant-ear tree, conocaste tree), E. contortisiliquum (timbauba), E. gummiferum (tamboril da campo), E. timbouva (orelha de preto, timbora); no specific toxin identified, but associated with hepatogenous photosensitization and in some cases, abortion.

• enterolysis [en″t r-ol′ -sis] surgical separation of intestinal adhesions.

• enteromegaly [en″t r-o-meg′ -le] enlargement of the intestines.

• enteromerocele [en″t r-o-me′ro-sēl] femoral hernia.

• Enteromonas [en″t r-o-mo′n s] a genus of the family Monocercomonadidae of protozoa. None appears to have pathogenic effects.

  • E. caviae found in the cecum of the guinea pig.
  • E. hominis found in the cecum of humans, primates, and rodents.
  • E. suis found in the cecum of pigs.

• enteromycosis [en″t r-o-mi-ko′sis] fungal disease of the intestine.

• enteron the gut or alimentary canal; usually used in medicine with specific reference to the small intestine.

• enteroparesis [en″t r-o-p -re′sis] relaxation of the intestine resulting in dilatation.

• enteropathogen [en″t r-o-path′o-j n] a microorganism with pathogenicity for the intestine. Includes enterobacteria, corynebacteria, Mycobacterium avium subspecies paratuberculosis, Brachyspira species, Lawsonia intracellularis, campylobacters, clostridia, coronaviruses, rotaviruses, toroviruses, caliciviruses, astroviruses, noroviruses, canine parvovirus, rinderpest virus, malignant catarrhal fever virus, coccidia, cryptosporidia.

• enteropathogenesis [en″t r-o-path″o-jen′ -sis] the production of disease or disorder of the intestine.

• enteropathogenic [en ″t r-o-path″o-jen′ik] having pathogenicity for the intestine.

  • e. Escherichia coli strains of E. coli that adhere to small bowel enterocytes and destroy normal microvillar architecture, resulting in characteristic attaching and effacing lesions, accompanied by an inflammatory response and diarrhea. Called also attaching and effacing E. coli.

• enteropathy [en″t r-op′ -the] any disease of the intestine. Includes enteritis plus those diseases in which there is no physical lesion of enteritis but in which there is severe diarrhea.

  • antibiotic-responsive e. see antibiotic-responsive diarrhea.
  • Basenji e. a severe hereditary lymphocytic-plasmacytic gastroenteropathy in Basenjis characterized by gastric mucosal thickening, chronic vomiting and small intestinal diarrhea. A progressive protein-losing enteropathy (see below) is common and often refractory to treatment, leading to death.
  • chronic e (CE). a group of intestinal diseases in dogs and cats characterized by chronic gastrointestinal signs, variable type of inflammatory infiltrate on histology and no identifiable cause; encompasses food-responsive, antibiotic-responsive and steroid- or immunosuppressive-responsive enteropathies. Immunosuppressive-responsive enteropathy has been equated with idiopathic inflammatory bowel disease.
  • cystic mucinous e. see lymphocytic–plasmacytic enteritis.
  • equine proliferative e. a disease of weaned foals presenting with lethargy, weight loss, a varying degree of fever, inappetance, a potbellied appearance with a rough coat, colic, diarrhea, and ventral edema associated with a pronounced hypoproteinemia. The disease is a protein losing enteropathy associated with a proliferation of crypt epithelial cells in the terminal small intestine and thickening of the intestine at this site. The causative agent, Lawsonia intracellularis, is present in proliferating cells. The disease responds to a long treatment course with erythromycin and rifampicin or tetracyclines.
  • food-responsive e. chronic enteropathy of unknown cause that is completely responsive to a change in diet.
  • gluten-sensitive e. a hereditary sensitivity to gluten, seen in Irish set-ters and suspected in soft-coated wheaten terriers. There is chronic, intermittent diarrhea and poor growth from a young age, all of which resolve when a gluten-free diet is fed. The condition resembles celiac disease of humans, but the pathogenesis differs.
  • immunosuppressive-responsive enteropathy chronic enteropathy of unknown cause that is only responsive to treatment with immunosuppressive drugs. Called also steroid-responsive enteropathy. See also inflammatory bowel disease.
  • mucoid e. a secretory diarrhea of rabbits, of unknown cause; characterized by occurrence of mucoid diarrhea, abdominal distention, cecal impaction, constipation, depression, and hypothermia in rabbits of weaning age and older.
  • mycotic e. one caused by a fungal agent; see histoplasmosis, phycomycosis, candidiasis.
  • porcine proliferative e. a disease of recently weaned pigs characterized by diarrhea, anorexia, weight loss, a clinical course of a few weeks, and recovery in most cases. One of the common causes of failure to grow, weight variation in batches of pigs, and delay to market. The diagnostic feature at postmortem is the thickening of the wall of the ileum due to proliferation of intestinal epithelial crypt cells. Lawsonia intracellularis is the causative agent. There is an etiological and pathological relationship between porcine proliferative enteropathy, necrotic enteritis, regional enteritis, and proliferative hemorrhagic enteropathy. In some outbreaks, inflammation and necrosis, and an accompanying infection with Salmonella spp., can result in necrotic enteritis and regional ileitis with intestinal perforation, diarrhea, severe weight loss, and death. Occurs also in recently weaned gilts and young boars but at that age it is usually manifest as a hemorrhagic enteropathy.
  • proliferative hemorrhagic e. a disease, usually of replacement gilts and boars, characterized by anemia and bloody diarrhea, a short clinical course and a proliferative, hemorrhagic lesion in the terminal ileum, and a high death rate. The underlying intestinal abnormality is porcine proliferative enteropathy caused by Lawsonia intracellularis. The later age of onset is believed to occur because of suppression of infection by antibiotic use during the growing period, but the reason for the hemorrhagic complication is not known.
  • protein-losing e. (PLE) a nonspecific term referring to conditions associated with excessive and non-selective loss of plasma proteins into the intestinal lumen; characterized by low total serum protein concentrations. Associated with a variety of systemic and bowel disorders, including congestive heart failure, gastric ulceration, gastric tumors, intestinal mucosal ulceration, inflammatory bowel disease, lymphangectasia, intestinal parasitic infestations, bacterial-induced lesions such as in Johne’s disease, and the proliferative enteropathies.

    E-40.

    

    Thickened wall of the jejunum in porcine proliferative enteropathy.

  • rabbit e. complex term used to designate a number of poorly defined diarrheal conditions of rabbits; includes mucoid enteropathy and nonspecific enteropathy.
  • steroid-responsive e. see immunosuppressive-responsive enteropathy (above).
  • wheat-sensitive e. see gluten-sensitive enteropathy (above).

• enteropeptidase [en″t r-o-pep′tľ-dās] an enzyme of the intestinal juice which activates the proteolytic enzyme of the pancreatic juice by converting trypsinogen into trypsin.

• enteropexy [en′t r-o-pek″se] surgical fixation of the intestine to the abdominal wall.

• enteroplasty [en′t r-o-plas″te] plastic repair of the intestine.

• enteroplegia [en′t r-o-ple′j] see paralytic ileus.

• enteroplication [en″t r-o-plľ-ka′sh n] surgical procedure for treatment of intussusception and prevention of obstructive adhesions following abdominal surgery; adjacent loops of intestine are sutured to each other.

• enteropooling [en″t r-o-pōōl′ing] increased fluids and electrolytes within the lumen of the intestines.

• enterorrhagia [en″t r-o-ra′j] intestinal hemorrhage.

• enterorrhaphy [en″t r-or′ -fe] suture of the intestine.

• enterorrhexis [en″t r-o-rek′sis] rupture of the intestine.

• enteroscopy [en′t r-o-skōp] examination of the inside (luminal aspect) of the intestinal tract using an instrument (usually a flexible endoscope).

• enterosepsis [en″t r-o-sep′sis] sepsis developed from the intestinal contents.

• enterospasm [en′t r-o-spaz″ m] intestinal colic.

• enterostasis [en″t r-o-sta′sis] intestinal stasis.

• enterostenosis [en″t r-o-st -no′sis] narrowing or stricture of the intestine.

• enterostomal [en″t r-o-sto′m l] relating to or having undergone an enterostomy.

• enterostomy [en″t r-os′t -me] the artificial formation of a permanent opening into the intestine through the abdominal wall. See also colostomy, ileostomy, duodenostomy, jejunostomy.

  • e. tube one introduced through a surgical opening in the small intestine (duodenostomy or jejunostomy). May be for purposes of introducing food past the pylorus, or for collection of intestinal contents.

• enterosystemic [en″t r-o-sis-tem′ik] the relationship between the intestine and the systemic circulation.

  • e. fluid cycle the net movement of fluid into and out of the gut lumen every 24 hours. The volume of the exchange is large and a temporary suspension of it can cause fatal dehydration in a horse in 24 hours. The volume depends very much on the diet, being much larger on a high-fiber diet such as in herbivores.

• enterotomy [en″t r-ot′ -me] incision of the intestine.

• enterotoxemia [en″t r-o-tok-se′me-] a condition characterized by the presence in the blood of toxins produced in the intestines.

  • Clostridium perfringens e. all of the types of C. perfringens cause profound enteroxemia with sudden death as the principal manifestation. The postmortem lesions in type D (pulpy kidney disease) enterotoxemia are minimal especially if the course is short. In types A, B, C, and E, there is a severe enteritis with diarrhea and dysentery. The diseases are most common in young rapidly growing ruminants but foals and piglets are sometimes affected.
  • coliform e. see Escherichia coli enterotoxemia (below).

    E-41.

    

    Enterotoxemia (necrotic enteritis) caused by Clostridium perfringens type C. Courtesy of J.T. Done.

  • Escherichia coli e. calves with an enteric infection with the relevant serotype of E. coli show sudden collapse, subnormal temperature, coma, slow irregular heart rate, collapse of veins, and pale mucosae. The course is short and affected calves die within 2–6 hours. Postmortem lesions are limited to flaccidity of the intestines and the presence of thin, yellow contents.
  • hemolytic e. a little reported disease recorded mostly in Australia in sheep, cattle and foals; a highly fatal hemolytic anemia associated with a heavy population of Clostridium perfringens type A in the intestines.

• enterotoxemic jaundice an acute disease of lambs reported in the Western US in which there is hemoglobinuria, anemia, and jaundice. It is caused by Clostridium perfringens type A, alpha toxin. Called also yellow lamb disease.

• enterotoxic [en′t r-o-tok″sin] of the nature of or pertaining to enterotoxin.

  • e. bacteria bacteria capable of producing enterotoxins.

• enterotoxicosis [en″t r-o-tok″sľ-ko′sis] intoxication by enterotoxins.

• enterotoxigenic [en″t r-o-tok″sľ-jen′ik] producing, produced by, or pertaining to production of enterotoxin. Said particularly of specific strains of Escherichia coli.

  • e. colibacillosis diarrheal disease caused by enterotoxigenic E. coli; especially seen in young animals.
  • e. Escherichia coliE. coli that adhere to small intestinal enterocytes and induce watery diarrhea by the secretion of heat-labile (LT) and/or heat-stable (ST) enterotoxins.

• enterotoxin [en″t r-o-tok′sin] 1. a toxin specific for the cells of the intestinal mucosa. 2. a toxin arising in the intestine.

• enterotoxism [en″t r-o-tok′siz- m] autointoxication of enteric origin.

• enterotropic [en″t r-o-tro′pik] affecting the intestines.

• enterovaginal [en″t r-o-vaj′ľ-n l] pertaining to or communicating with the intestine and the vagina, as an enterovaginal fistula.

• enterovenous [en″t r-o-ve′n s] communicating between the intestinal lumen and the lumen of a vein.

• enterovesical [en″t r-o-ves′ľ-k l] pertaining to or communicating with the intestine and urinary bladder.

• Enterovirus [en′t r-o-vi″r s] a genus of the family Picornaviridae. The genus includes the important animal pathogens of porcine encephalomyelitis (Teschen disease), possibly SMEDI disease (see porcine parvovirus), avian encephalomyelitis (epidemic tremor), duckling hepatitis, turkey hepatitis. Equine and bovine enteroviruses of doubtful pathogenicity have also been isolated. Human enteroviruses, e.g., Coxsackie virus, ECHO virus, are also isolated occasionally from animals without appearing to cause disease.

• enterovirus [en′t r-o-vi″r s] a virus in the genus Enterovirus of the family Picornaviridae.

  • e. encephalitis several porcine enteroviruses cause highly transmissible encephalitides. See also porcine viral encephalomyelitis (Teschen disease, Talfan disease, poliomyelitis suum).

• enterozoon an animal parasite in the intestines.

• enterprise a definable system that produces a commodity or groups of related commodities. On a farm, there may be only one or several, e.g., grass seed production, lamb production, fat sheep sales, wool production, wheat production.

• enthalpy [en′th l-pe] the heat content of a biochemical system.

• enthesis [en-the′sis] 1. the use of artificial material in the replacement or repair of a defect or deformity of the body. 2. the site of attachment of a muscle or ligament to bone.

• enthesopathy [en″th -sop′ -the] disorder involving the attachment of a tendon or ligament to a bone. Called also enthesitis.

• enthesophyte, enthesiophyte mineralisation of a muscle attach-ment, tendon, joint capsule, or ligament at the point of its insertion into the bone.

• enthetobiosis [en-thet″o-bi-o′sis] a term suggested to denote the dependency of an organism on a mechanical device implanted within the body, for example, dependency of a patient on an electronic cardiac pacemaker to regulate the heartbeat. The organism critically dependent on the device. Called also epenthetobiosis.

• entire [en-tīr′] a term used in reference to an uncastrated animal, male or female.

• Entlebucher mountain dog the smallest (45–65 lb) of the Swiss mountain dogs (Sennenhund) with a short coat in the typical tricolors.

• ent(o)- word element. [Gr.] within, inner.

• entoblast [en′to-blast] endoderm.

• entocele an internal hernia.

• entochoroidea [en″to-ko-roid′e- ] the inner layer of the choroid of the eye.

• entoderm [en′to-d rm] endoderm.

• entoectad [en″to-ek′tad] from within outward.

• entomere [en′to-mēr] a blastomere normally destined to become endoderm.

• entomology [en″to-mol′ -je] that branch of biology concerned with the study of insects.

• Entomophthora coronata [en″to-mof′th -r] Now known as Conidiobolus coronatus. See swamp cancer.

• entomophthoromycosis [en ″t -mof″th -ro-mi-ko′sis] infection caused by Entomophthora spp. See swamp cancer.

• Entomopoxvirinae subfamily in the order Poxvirales that includes insect poxviruses.

• entomopoxvirus a group of poxviruses recovered from insects.

• entrainement [en-trān′m nt] the phenomenon in which a species of bacteria growing close to another may acquire some of the characteristics of the second species. See also recombination.

• Entonyssus an entonyssid mite of snakes.

• Entophionyssus a mite of snakes; see Ophionyssus.

• entopic [en-top′ik] occurring in the proper place, as opposed to ectopic.

• entoptic [en-top′tik] originating within the eye.

• entoptoscopy [en″top-tos′ko-pe] inspection of the interior of the eye.

• entoretina [en″to-ret′ľ-n ] the nervous or inner layer of the retina.

• entotic situated in or originating within the ear.

• entozoon [en″to-zo′on] an internal animal parasite.

• entraining [en-trān′ing] loading horses, cattle or any other livestock onto a train.

• entrapment [en-trap′ment] the state of being trapped.

  • bowel e. part of large or small intestine is ensnared in adhesions, foramina such as the epiploic foramen, intraabdominal ligaments such as the nephrosplenic ligament, or hernias. Obstruction to aboral movement of ingesta occurs, with or without compromise of the blood supply to the incarcerated loop.
  • epiglottic e. see epiglottic entrapment.

• Entrefino Spanish meat and medium wool sheep, white, polled; includes many Spanish breeds. It is a class of sheep rather than a single breed.

• entropion [en-tro′pe-on] inversion, or turning inward, as of the margin of an eyelid.

  • anatomic e. see conformational entropion (below).
  • cicatricial e. caused by scarring of the eyelid or conjunctiva following surgery, injury, or inflammation.
  • conformational e. seen as a presumed inherited feature in many species; especially common in some dog breeds, including Shar peis, Chow Chows, and St. Bernards. Called also anatomic entropion. May be congenital or occur during cranial maturation.
  • inherited congenital e. occurs in sheep, cattle, miniature pigs, and some breeds of dogs.

    E-42.

    

    Entropion of the lower eyelid of the left eye of a dog.with consequent epiphora, moist blepharitis, and conjunctival hyperemia.

    E-43.

    

    Inherited congenital entropion in a Suffolk lamb involving the lower eyelid and resulting in conjunctivitis and purulent ocular discharge.

  • lateral e. entropion of the lateral canthus and lateral ends of the upper and lower eyelids. Seen most commonly in broad-skulled dogs such as Rottweilers, Chow chows, retrievers, etc. May be caused by inadequate function of the retractor anguli oculi muscle or an inverting force from the lateral canthal ligament.
  • medial e. entropion of the medial aspect of the lower eyelid; seen most often in brachycephalic dogs.
  • neonatal e. usually temporary entropion seen in newborn animals, especially foals, lambs, and calves. Often due to a lack of orbital fat or dehydration. Self-limiting as these conditions resolve although temporary surgical correction may be required.
  • spastic e. due to spasm of the orbicularis oculi muscle in response to ocular pain (ulcerative keratitis, ectopic cilia, foreign bodies or keratoconjunctivitis sicca). Usually temporary and resolves with resolution of the source of pain. However, if chronic, can become permanent due to shortening of the orbicularis oculi muscle.
  • uveal e., e. uveae inversion of the pupillary border sometimes with adherence to the anterior lens capsule (posterior synechia). A sign of (usually chronic) uveitis.

• entropy [en′tro-pe] 1. in thermodynamics, a measure of the part of the internal energy of a system that is unavailable to do work. In any spontaneous process, such as the flow of heat from a hot region to a cold region, entropy always increases. 2. in information theory, the negative of information, a measure of the disorder or randomness in a physical system. The theory of statistical mechanics proves that this concept is equivalent to entropy as defined in thermodynamics.

• enucleate [e-noo′kle-āt] to remove whole and clean, as the eye from its socket.

• enucleation [e-noo″kle-a′sh n] removal of an organ or other mass intact from its supporting tissues, as of the eye from the orbit.

  • transconjunctival e. surgical method of globe removal with initial incisions through the perilimbal conjunctiva.
  • transpalpebral e. surgical removal of the globe with initial incisions made through the eyelid skin just outside the eyelid margins.

• enuresis [en″u-re′sis] see incontinence.

• env gene a gene that encodes a protein precursor for the envelope proteins, found in the retroviral genome.

• envelope [en′v -lōp] an encompassing structure or membrane. In virology, a lipid bilayer with glycoprotein spikes surrounding the nucleocapsid and usually furnished, at least partially, by the host cell. In bacteriology, the cell wall and the plasma membrane considered together.

  • nuclear e. the condensed double layer of lipids and proteins enclosing the cell nucleus and separating it from the cytoplasm; its two concentric membranes, inner and outer, are separated by a perinuclear space.

• envenomation [en-ven″o-ma′sh n] the poisonous effects caused by the bites, stings or effluvia of insects and other arthropods, or the bites of snakes.

• environment [en-vi′ron-m nt] the sum total of all the conditions and elements that make up the surroundings and influence the development of an animal. The environment of animals is often assumed to comprise only physical, chemical, and biological factors but society is gradually coming to appreciate that there is also an emotional and psychological side to the life of all animals.

  • external e. environment outside the animal; includes ambient temperature, wind chill factor, bedding adequacy, stall space, feed, and water supply.
  • indoor e. the physical, social, and psychological environment within a human dwelling that can influence the health of a companion animal.

• environmental [en-vi″ron-m nt′- l] pertaining to or emanating from the environment.

  • e. injuries include burns, electrical injuries, frostbite, heat stroke.
  • e. melanosis see acquired melanosis.
  • permanent e. factors factors that affect all measures of performance equally and through the patient’s lifetime, e.g., fulltime at pasture, tropical climate.
  • e. pollution the presence of offensive, but not necessarily poisonous, matter in the environment. For example, pollution may be by specific organic or inorganic chemicals, by physical agents such as dust, volcanic fallout, smoke, automobile fumes, radioactive material, and animal feces and urine. Each of these items and noise pollution is dealt with under specific headings.
  • e. stress see stress (2).
  • temporary e. factors risk factors that may vary widely, e.g., nutrition, pregnancy status, disease.

• Environmental Systems Research Institute (ESRI) world’s leading developer of geographic information systems software, ArcGIS, used by the majority of governmental veterinary and regulatory bodies. Can be server based or operate on personal desk top computers. Main components are ArcView, which is a program for viewing spatial data, creating layered maps, and performing basic spatial analysis, ArcEditor (ArcGIS for Desktop Standard), a program with more advanced tools than ArcView (ArcGIS for Desktop Basic), and ArcInfo (ArcGIS for Desktop Advanced), a program that allows data manipulation, editing, and analysis.

• enzootic [en″zo-ot′ik] peculiar to or present constantly in a location. See also endemic.

  • e. abortion of ewes late abortion in ewes caused by Chlamydia abortus introduced to a flock by carrier sheep. In many countries, one of the most common causes of abortion. Characterized by late-term abortions, stillbirths, and the birth of weak lambs. Infection occurs by ingestion and the major source is the placenta and uterine discharge of aborting ewes and the associated contaminated pasture. Infected animals abort, or give birth to weak neonates, at the next pregnancy following infection, as the result of a placentitis. A disease notifiable to the OIE (see Table 20).
  • e. arthrogryposis/hydranencephaly infection of the pregnant cow, ewe, or goat doe with Akabane virus causes congenital defects of the nervous system of the fetus.
  • e. ataxia a disease of unweaned lambs caused by a nutritional deficiency of copper (see copper Cu) and characterized by an absence of myelin in tissues of the central nervous system, and a clinical picture of incoordination and terminally recumbency and death from starvation. Called also Gingin rickets, renguera, swayback, lamkruis.
  • e. balanoposthitis an endemic inflammation of the prepuce and penis of castrated male sheep. It is caused by Corynebacterium renale but the clinical disease appears only when there is lush pasture and a consequent high alkalinization of the urine, and also a high intake of estrogens from the pasture. There is a concurrent vulvitis in ewes and bulls may be affected. There is swelling, scabby ulceration, and inflammation of the exterior and the interior of the prepuce and the glans penis. Affected wethers dribble urine, show pain at the site, and may become flyblown. Called also pizzle rot, sheath rot.
  • e. bovine adenomatosis see atypical interstitial pneumonia.
  • e. bovine arthrogryposis see Akabane virus disease.
  • e. bovine leukosis see bovine viral leukosis.
  • e. calcinosis a poisoning by the plant Solanum glaucophyllum (S. malacoxylon) causes a significant increase in calcium absorption and deposition in tissues. The characteristic clinical signs are stiffness of the limbs and the back, and unwillingness to stand up if lying down, or to lie down if standing up. Identical diseases are caused by the plants Trisetum flavescens, Stenotaphrum secundatum, Nierembergia veitchii, Solanum linneaneum, S. torvum, S. erianthum, and Cestrum diurnum. Called also enteque seco, Manchester wasting disease, Naalehu disease, espichamento.
  • e. equine ataxia see enzootic equine incoordination (below).
  • e. equine incoordination now archaic term referring to clinical syndrome of ataxia in horses. Called also wobbler syndrome.
  • e. ethmoidal tumor this carcinoma has been a problem in cattle in South America, but has also occurred in Sweden and Asia. Occurs as multiple cases over several years on some farms. Epistaxis and nasal obstruction are the important findings. The paranasal sinuses may also be invaded.

    E-44.

    

    Leg of lamb that died from enzootic muscular dystrophy (white muscle disease) showing the characteristic change in muscle color that gives this disease this colloquial name.

  • e. hematuria a disease characterized by hemangiomatous lesions in the bladder of cattle, causing the intermittent passage of heavily blood-stained urine. The blood loss may be sufficiently severe to cause a fatal hemorrhagic anemia. Caused by chronic intake of ptaquiloside from Pteridium spp., Cheilanthes sieberi, Onychium contiguum; most cases are obviously related to the long-term ingestion of bracken. See also pteridium aquilinum.
  • e. icterus a syndrome that includes the hepatopathies of grazing animals. Includes facial eczema, toxemic jaundice and toxipathic hepatitis.
  • e. intestinal adenocarcinoma a disease of sheep in New Zealand, Iceland, Norway and of cows in New Zealand. Possibly associated with grazing bracken fern and ingestion of ptaquilosde.
  • e. marasmus see cobalt nutritional deficiency.
  • e. muscular dystrophy a disease that is due to a nutritional deficiency of vitamin E or selenium and occurs in calves, lambs, and foals. There is a sudden onset, commonly after exercise. The calf may drop dead or show dyspnea, a frothy nasal discharge, and a rapid and irregular heartbeat, all signs of acute heart failure. Less acute cases show recumbency with inability to rise and increased respiratory rate. Less severe cases still are able to stand and walk but are weak and dyspneic. Although the pathogenesis is an acute myopathy, there is no myoglobinuria except in unusual circumstances in yearling male cattle. Called also white muscle disease.
  • e. nasal granuloma a form of chronic nasal obstruction that occurs most commonly in dairy cows of the Channel Islands breeds. The disease is a chronic dyspnea with stertorous breathing due to partial obstruction of both nasal cavities by eosinophilic granulomas about 4 mm in diameter on the mucosa just inside the nostril. The disease is thought to have an allergic origin. Called also allergic rhinitis, atopic rhinitis. See also caprine enzootic nasal granuloma.
  • e. nasal tumor see enzootic nasal adenocarcinoma.
  • e. nasal adenocarcinoma contagious neoplasm of the ethmoidal turbinates with sporadic occurrence in sheep and goats. May be clustered in some farms, associated with closely related but different retroviruses, both of which have close homology to the jaagsiekte retrovirus. Disease of young adults manifest with seromucous and seropurulent nasal discharge, sneezing, stertorous respiration, facial deformity in some, progressive weight loss, and death in 3–6 months. Called also enzootic nasal tumor.
  • e. nodular thelitis of alpine cows in Switzerland; characterized by nodular lesions in the teat wall. See enzootic abortion of ewes (above).
  • e. pneumonia a group of pneumonic diseases that affect young animals. They are principally of viral origin, although mycoplasmas also play a part, and are only mildly pathogenic unless secondary bacterial invasion intervenes. In calves parainfluenza-3 virus, respiratory syncytial virus, adenovirus, bovine herpesvirus 1, rhinovirus, reovirus and mycoplasmas and Chlamydia are causes. In lambs the list of causes is the same. In pigs there is only one agent, Mycoplasma hyopneumoniae (syn. M. suipneumoniae). The importance of these diseases is not the wastage that they cause in their own right, although there is sometimes a significant loss of productivity and occasional cases of severe illness and even death, but the losses that occur when lethal bacterial pneumonia supervenes.
  • e. posthitis see enzootic balanoposthitis (above).
  • e. staphylococcosis a septicemia of lambs caused by Staphylococcus aureus; the spread of the disease is facilitated in some way by tick bites. The lambs are affected soon after birth and die quickly of septicemia or develop arthritis and meningitis later. Called also tick pyemia.

• enzootische herztod see porcine stress syndrome.

• enzygotic [en″zi-got′ik] developed from one zygote.

• enzymatic [en″zi-mat′ik] of, relating to, caused by, or of the nature of an enzyme.

• enzyme [en′zīm] any protein that acts as a catalyst, increasing the rate at which a chemical reaction occurs. The animal body probably contains about 10,000 different enzymes. At body temperature, very few biochemical reactions proceed at a significant rate without the presence of an enzyme. Like all catalysts, an enzyme does not control the direction of the reaction; it increases the rates of the forward and reverse reactions proportionally.

  • activating e. one that activates a given amino acid by attaching it to the corresponding transfer ribonucleic acid.
  • e. assays several enzymes are important in clinical pathology. Enzymes characteristic of a tissue are released into the blood when the tissue is damaged, and enzyme concentrations in the blood can aid in the diagnosis or monitoring of specific diseases. Lipase and amylase concentrations are useful in pancreatic diseases; alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in liver diseases; and lactate dehydrogenase (LD), AST, and creatine kinase (CK) in muscle disease. ALP is also released in bone diseases. Many enzymes have different forms (isoenzymes) in different organs. The isoenzymes can be separated by electrophoresis in order to determine the origin of the enzyme. Isoenzymes of LD, CK, and ALP have the most clinical utility.
  • brancher e., branching e. amylo-(1,4→1,6)-transglycosylase; important in the synthesis of the branched glycogen molecule. Absence of the enzyme causes an increase in the length of the glucose chains and a decrease in the number of branch points in the glycogen molecules.
  • congenital e. deficiency in humans hundreds of genetic diseases that result from deficiency of a single enzyme are now known. Many of these diseases fall into two large classes. The aminoacidopathies, e.g., phenylketonuria (PKU), result from deficiency of an enzyme in the major pathway for the metabolism of a specific amino acid. The amino acid accumulates in the blood, and it or its metabolites are excreted in the urine. The lysomal storage diseases, e.g., gangliosidosis, mannosidosis, result from deficiency of a lysomal enzyme and the accumulation of the substance degraded by that enzyme in lysosomes of cells throughout the body. The stored material is usually a complex substance, such as glycogen, a sphingolipid, or a mucopolysaccharide. Many similar diseases are now identified in animals and are to be found under the specific name of each disease.
  • constitutive e. one produced by a microorganism regardless of the presence or absence of the specific substrate acted upon.
  • core e. the smallest aggregate of an enzyme’s subunits that has enzymatic activity.
  • debrancher e., debranching e. dextrin-1,6-glucosidase: an enzyme that acts to move glucose residues of the glycogen molecule, and is important in glycogenolysis.
  • induced e., inducible e. one whose production requires or is stimulated by a specific small molecule, the inducer, typically a substrate of the enzyme or a compound structurally related to it.
  • e. induction increase in the activity of an enzyme caused by an inducer. For example, the effect some compounds such as phenobarbitone and phenytoin have in increasing the activity of microsomal hepatic enzymes. This may cause alterations in the metabolism of concurrently administered drugs.
  • microsomal e’s those associated with the endoplasmic reticulum of cells.
  • proteolytic e. one that catalyzes the hydrolysis of proteins and various split products of proteins, the final product being small peptides and amino acids.
  • repressible e. one whose rate of production is decreased as the concentration of certain metabolites is increased.
  • respiratory e’s enzymes of the mitochondria, e.g., cytochrome oxidase, which are involved in the respiratory chain.
  • restriction e’s see restriction endonuclease.

• enzyme-linked immunoabsorbent assay see ELISA.

• enzymology [en″zi-mol′ -je] the study of enzymes and enzymatic action.

• enzymopathy [en″zi-mop′ -the] an inborn error of metabolism consisting of defective or absent enzymes, as in the glycogenoses or the mucopolysaccharidoses.

  E-45.

  

  Canine (C), feline (F), equine (E), and bovine (B) eosinophils that demonstrate the variable size, shape, and color of granules in different species.

• EOD abbreviation for every other day, usually with respect to intervals of administration of medication or other interventions; used in medical records.

• EOG electro-olfactogram.

• Eohippus ‘dawn horse’. See Hyracotherium.

• Eolophus roseicapilla see galah Eomenacanthus see Menacanthus.

• EOSCC equine ocular squamous cell carcinoma.

• eosin [e′o-sin] any of a class of rose-colored stains or dyes, all being bromine derivatives of fluorescein; eosin Y, the sodium salt of tetrabro-mofluorescein, is much used in histological and laboratory procedures. See also hematoxylin and eosin stain.

• eosinopenia [e″o-sin-o-pe′ne- ] abnormal deficiency of eosinophils in the blood. Commonly associated with stress or the administration of corticosteroids.

• eosinophil [e″o-sin′o-fil] a circulating blood cell readily stained by eosin; specifically, a granular leukocyte with a nucleus that usually has two lobes connected by a thread of chromatin, and cytoplasm containing coarse, round or rod-shaped, eosinophilic granules (lysosomes) of uniform size. The size, number and staining characteristics of granules varies between species.

• eosinophilia [e″o-sin″o-fil′e- ] the formation and accumulation of an abnormally large number of eosinophils in the blood.

• eosinophilic [e″o-sin″o-fil′ik] staining readily with eosin; pertaining to eosinophils or to eosinophilia.

  • canine e. granuloma proliferative nodules or plaques that occur on skin or oral mucosa of dogs. Usually not pruritic, but oral lesions can cause some difficulties in eating. Siberian huskies and Cavalier King charles spaniels appear to be predisposed. The cause is unknown, but a hypersensitivity reaction is suspected. See also feline eosinophilic granuloma complex (below), and equine nodular collagenolytic granuloma.
  • cartilaginous e. streaks streaks of eosinophilic matrix in cartilage. Some are normal zones of development, others represent areas of matrix degeneration and osteochondrosis.
  • e. chemotactic factor a primary mediator of type I anaphylactic hypersensitivity, it is an acidic peptide (molecular weight 500) released by mast cells, which attracts eosinophils to areas where it is present.
  • equine e. chronic dermatitis see multicentric eosinophilic epitheliotrophic disease (below).
  • equine multisystemic e. epitheliotropic syndrome disease characterized by eosinophilic infiltrates and the formation of eosinophilic granulomas in different organs, including the pancreas, salivary glands, gastrointestinal tract, biliary and bronchial epithelium, and skin, and the lack of peripheral eosinophilia. Horses usually present with weight loss; other clinical signs vary according to the organs affected.
  • feline e. granuloma complex a reaction pattern in cats that includes eosinophilic ulcer, eosinophilic plaque, and eosinophilic or linear granuloma because of similarities in histopathology, clinical course, and occasionally simultaneous occurrence in the cat. Treatment can be difficult and only symptomatic unless the inciting cause can be identified.
  • e. intestinal granuloma see Angiostrongylus costaricensis.
  • e. lung disease see eosinophilic bronchopneumopathy (PIE).
  • e. meningitis see Angiostrongylus cantonensis, A. costaricensis.

    E-46.

    

    Eosinophilic ulcer (bilateral) on the upper lip margins and an eosinophilic granuloma on the chin of a cat.

    E-47.

    

    Eosinophilic plaque on the abdomen of a cat.

    E-48.

    

    Bilateral eosinophilic ulcer in a cat.

  • e. meningoencephalitis see sodium chloride poisoning, Angiostrongylus cantonensis.
  • multicentric eosinophilic epitheliotrophic disease (MEED) rare disease of horses typically presented for evaluation of exfoliative dermatitis and weight loss; characterized by eosinophilic and lymphoplasmacytic infiltrates along with eosinophilic granulomas in multiple epithelial tissues, including skin, gastrointestinal tract, pancreas, liver, and lung. Called also eosinophilic granulomatosis, equine esoinophilic chronic dermatitis.
  • e. myocarditis in cattle may be observed in normal animals at slaughter. Histologically there is a predominant eosinophil invasion of the heart muscle. May be accompanied by similar lesions in skeletal muscles.
  • e. plaque well-defined, raised, ulcerated, and extremely pruritic lesions that occur on the skin of cats, usually on the abdomen or hindlegs. There are large numbers of eosinophils present in the dermis and sometimes peripheral blood. See also eosinophilic granuloma complex (above), eosinophilic linear granuloma of cats.
  • e. pneumonia see eosinophilic bronchopneumopathy (PIE).
  • e. pneumonitis see eosinophilic pneumonitis.
  • e. ulcer a well-defined ulceration, usually on the upper lip of cats, usually overlying the canine tooth, which is shallow initially but can become extremely erosive and sometimes neoplastic. Generally not painful or pruritic, but mildly irritating to the cat causing frequent licking. Called also indolent ulcer, rodent ulcer. See also feline eosinophilic granuloma complex (above).

• eosinopoiesis formation of eosinophils.

• Epagneul Breton see Brittany.

• epallobiosis [ p-al″o-bi-o′sis] dependency on an external life-support system, as on an extracorporeal circulatory support unit or hemodialyzer. See hemodialysis.

• epaxial [p-ak′se- l] situated above or upon an axis.

• EPD expected progeny difference.

• EPE equine pituitary extract.

• EPEC enteropathogenic Escherichia coli.

  E-49.

  

  Superficial pyoderma showing epidermal collarettes.

• ependyma the cells lining the cerebral ventricles and the central canal of the spinal cord; principal source of cerebrospinal fluid, mostly from where the ependyma covers the choroid plexuses.

• ependymal [-pen′d-m l] emanating from or pertaining to ependyma.

  • e. cells squamous-to-columnar cell lining of the spinal central canal and the four ventricles of the brain; supports the choroid plexuses.

• ependymitis [-pen″d-mi′t s] inflammation of the ependyma.

• ependymoma [-pen″d-mo′m] fleshy masses protruding into the third ventricles, the central canal in the medullary region or the central spinal canal; arise from the ependyma.

• epenthetobiosis see enthetobiosis.

• Eperythrozoon [ep″ -rith″ro-zo′on] a group of bacteria that parasitize erythrocytes and now recognized to be within the genus Mycoplasma.

  • E. coccoides see Mycoplasma coccoides.
  • E. felis see Mycoplasma haemofelis.
  • E. ovis see Mycoplasma ovis.
  • E. parvumseeMycoplasmaparvum.
  • E. suis see Mycoplasma suis.
  • E. wenyoni see Mycoplasma wenyoni.

• eperythrozoonosis [ep″ -rith″ro-zo″o-no′sis] infection with hemophilic mycoplasmas previously grouped in the genus Eperythrozoon. The infection is mostly innocuous but in times of stress, e.g., in the presence of another disease, it may cause an acute anemia with fever. There is no hemoglobinuria. The bacteria are spread by insects and the disease may be seasonal as a result. In many cases the disease is a subacute one with illthrift as the main presenting sign.

• EPF early pregnancy factor.

• EPH early pregnancy hormone.

• ephapse [ -faps′] a point of lateral contact (other than a synapse) between nerve fibers across which impulses are conducted directly through the nerve membranes.

• ephebogenesis the bodily changes occurring at sexual maturity.

• Ephedra [-fed′r] plant genus in the family Ephedraceae, species of which are used as herbal remedies or as sources of ePHEDrine; herbal preparations of these have poisoned dogs. Includes E. equisetina, E. distachya (E. gerardiana), E. intermedia, E. sinica (ma huang, Chinese ephedra), E. viridis (desert tea), E. shennungiana, E. nevadensis, E. trifurca (Mormon tea).

• ephedrine [-fed′rin, ef′ -drin] an adrenergic alkaloid obtained from several species of the shrub Ephedra or produced synthetically; used as the hydrochloride as a bronchodilator, antiallergic, central nervous system stimulant, mydriatic, pressor agent, and for stimulation of the α-adrenergic receptors in the treatment of certain types of urinary incontinence.

• ephemeral fever [-fem′r- l] an infectious disease of cattle in Africa, Asia, Middle East and Australia. Caused by an arthropod-borne Rhabdovirus of the genus Ephemerovirus, and is characterized by inflammation of mesodermal tissues. Clinically there is fever, in milking cows a profound fall in production, muscle stiffness and shivering, lameness, enlargement of lymph nodes, and recumbency. The disease is a nonfatal one and has an average course of 3 days—hence 3-day fever. The virus is transmitted by insect vectors, e.g., the sandfly, Ceratopogonidae spp. Called also 3-day sickness.

• Ephemerovirus [e-fem′ r-o-vi″r s] a genus in the family Rhabdoviridae; includes bovine ephemeral fever virus.

• EPI exocrine pancreatic insufficiency.

• epi- word element. [Gr.] upon, above, beside.

• epibiotic fouling fouling of external surfaces of mainly shellfish but sometimes finfish, with living organisms, principally protozoa of the genera Zoothanium, Epistilis, Vorticella.

• epiblast [ep′ľ-blast] layer of cells roofing over the blastocoel in the avian embryo.

• epibulbar [ep″ľ-bul′b r] situated upon the eye.

• epicardia [ep″ľ-kahr′de- ] the abdominal portion of the esophagus, extending from the esophageal hiatus to the cardia, the upper orifice of the stomach.

• Epichloë typhina fungus found on tall fescue grass and possibly implicated in causing poisoning. See also Festuca.

• epicardial [ep″ľ-kahr′de- l] pertaining to the visceral pericardium (epicardium) or to the epicardia.

  • e. receptors receptors in the left ventricle adapted to respond to stretch and chemical stimulants.

• epicardium [ep″ľ-kahr′de-um] the inner layer of the serous pericardium, which is in intimate contact with the heart.

• Epicauta vittata [ep″ľ-kaw′t ] an insect that may infest hay and when ingested cause colic, frequent urination, hematuria, weakness, and death in horses. Contains the vesicant substance cantharidin. Called also blister beetle.

• epiceras, epikeras a thin layer of skin covering the junction between the base of a horn and the surrounding skin, similar to the periople of the hoof.

• Epichloë a genus of endophytic fungi in the phylum Ascomycota with species symbiotic in Lolium perenne and Festuca arundinacea (Schedonorus arundina). Previously classified as Acremonium spp. and more recently Neotyphodium spp. Now assigned to the genus Epichloë from the genus Neotyphodium. Produce toxic lolitrems and ergot alkaloids, respectively. Unspecified species have been reported as a cause of eumycotic mycetoma and systemic mycosis in dogs, but these may now be classified as within the genus Epichloë.

  • E. chisosa inhabits Stipa robusta and produces lysergic acid amide, isolysergic acid amide, and ergonovine that cause deep somnolence in horses and cattle. Previously called Acremonium chisosum and Neotyphodium chisosum.
  • E. coenophialum inhabits Festuca arundinacea and F. elatior and produces ergot alkaloids, principally ergovaline, that cause fescue toxicosis. Previously called Acremonium coenophialum and Neotyphodium coenophialum. See also Festuca.
  • E. lolii (now proposed as Epichloë festucae var. lolii) inhabits Lolium perenne and produces lolitrems, principally lolitrem B, that cause perennial ryegrass staggers. Previously called Acremonium lolii and Neotyphodium lolii.

• epichorion [ep″ľ-kor′e-on] the portion of the uterine mucosa enclosing the implanted conceptus.

• epicillin [ep-ľ-sil′in] an aminopenicillin antibiotic.

• epicondyle [ep″ľ-kon′dīl] an eminence upon a bone, above its condyle, as in the distal extremity of the humerus and femur.

• epicondylitis [ep″ľ-kon″d -li′tis] inflammation of an epicondyle or of tissues adjoining the humeral epicondyle.

• epicranium [ep″ľ-kra′ne- m] the muscle, aponeurosis and skin covering the cranium.

• epicritic [ep″ľ-krit′ik] determining accurately; said of cutaneous nerve fibers sensitive to fine variations of touch or temperature.

• epicyte [ep′ľ-sīt] cell membrane. The cell cortex of eugregarines.

• epidemic [ep″ľ-dem′ik] a level of disease occurrence in an animal population which is significantly greater than usual; only occasionally present in the population, widely diffused and rapidly spreading. The disease is clustered in space and time. The word has common usage in veterinary science in preference to the more accurate, epizootic.

  • common source e. see point epidemic (below).
  • e. curve see epidemic curve.
  • e. diarrhea of infant mice (EDIM) see murine epizootic diarrhea.
  • e. hyperthermia poisoning by Neotyphodium (Acremonium) coenophialum; called also fescue summer toxicosis.
  • multiple event e. when the epidemic begins at about the same time in a number of places, e.g., when a poisoned batch of feed is supplied to a number of farms.
  • point e. when the epidemic begins at one central point, with a large number of animals coming in contact with the source over a short time; a very rapid form of spread with a number of cases presenting with the same stage of the disease at the one time, indicating the single source of the pathogen.
  • propagated e., propagative e., propagating e. outbreaks in which the disease propagates in one or more initial cases and then spreads to others, a relatively slow method of spread.
  • e. tremor see avian encephalomyelitis.

• epidemicity [ep″ľ-d -mis′ľ-te] the quality of being widely diffused and rapidly spreading throughout a population.

• epidemiogenesis the escalation of a communicable disease to epidemic proportions.

• epidemiological emanating from or pertaining to epidemiology.

  • e. associations the associative relationships between the frequency of occurrence of a disease and its determinants, its predisposing and precipitating causes.
  • e. intelligence all of the epidemiological information about a disease occurrence. Includes information gathering over a short period at the time of an outbreak and the more prolonged follow-up of surveillance afterwards.
  • e. techniques include case-control study, clinical trials, cohort studies.

• epidemiologist [ep″ľ-de″me-ol′o-jist] an expert in epidemiology.

  • clinical e. an epidemiologist who sees patients and herds in a clinical capacity but with an epidemiological viewpoint. An investigator of clinical problems affecting populations.

• epidemiology [ep″ľ-de″me-ol′ -je] 1. the study of the relationships of various factors determining the frequency and distribution of diseases in a community. 2. the field of veterinary medicine dealing with the determination of specific causes of localized outbreaks of infection, toxic poisoning, or other disease of recognized etiology. 3. the field of veterinary medicine dealing with the investigation and establishment of risk factors for disease and production problems of unknown or undetermined cause. 4. the study of disease in communities. 5. called also epizootiology.

  • analytical e. statistical analysis of epidemiological data in an attempt to establish relationships between causative factors and incidence of disease.
  • clinical e. the application by a veterinarian who provides direct patient care of epidemiological methods to the study of diagnosis and therapeutics in order to promote efficiency in clinical care.
  • descriptive e. information about the occurrence of a disease, some of it mathematical, but with no attempt to establish relationships between cause and effect.
  • experimental e. prospective population experiments designed to test epidemiological hypotheses, and usually attempt to relate the postulated cause to the observed effect. Trials of new anthelmintics are an example.
  • geographic e. the effect of climate, terrain, population of humans and animals, industrial enterprises on animal disease. Includes the zoogeography of the subject species itself, plus that of carrier species, and vectors and intermediate hosts, especially mobile ones such as insects. The distribution and concentration of poisonous plants and the use of specific management techniques which put the animals at greater risk are also important.
  • gum-boots e. see shoe-leather epidemiology (below).
  • landscape e. epidemiology of a disease in relation to the entire ecosystem under study.
  • observational e. based on clinical and field observations, not on experiments.
  • quantitative e. that branch of epidemiological studies that concentrates on quantitative methods.
  • shoe-leather e. epidemiology conducted as a field study. Called also gum-boots epidemiology.
  • theoretical e. the use of mathematical models to explain and examine aspects of epidemiology, e.g., computer simulation models of outbreaks.

• epidermal [ep″ľ-dur′m l] pertaining to or emanating from epidermis.

  • e. appendage see hair, claw, hoof, horn, chestnut (1), ergot², dewclaw, comb, wattle, spur (3), pad, footpad, beak, frontal process, feather (1), cere, scale, fin, antler, bristle (1), wool, mohair, cashmere, Angora.
  • e. clefts slit-like discontinuities in the epidermis that do not contain fluid.
  • e. collarette a secondary skin lesions, characterized by a circular rim of loose keratin flakes or peeling keratin; may represent the margins of an earlier bulla, vesicle or pustule. Characteristic of bullous pemphigoid.
  • e. crust a consolidated mass of cellular debris, dried exudate, serum, hair, epidermophytic hyphae. Usually is dry and crumbly but in parakeratosis may have a greasy feel about it.
  • e. cyst, epidermoid cyst an intradermal or subcutaneous cyst containing keratinizing squamous epithelium. It arises from occluded hair follicles. Called also infundibular cyst, wen.
  • e. dysplasia a severe disorder of keratinization. In West Highland white terriers, it is a familial skin disease characterized by marked erythema, seborrhea, pruritus, alopecia, and lichenification from an early age. Infection by Malassezia spp. is a common feature. That it is sometimes called ‘armadillo disease’ is an indication of the severity and extent to which this disease can progress. See also inherited epidermal dysplasia of calves (below).
  • e. growth factor a potent growth factor for both epithelial and fibroblast cells.
  • inherited e. dysplasia of calves an hereditary disease of calves appearing at 1–2 months of age and characterized by alopecia, cracking, and ulceration of skin in the axillae, flanks, and at the limb joints. There is also emaciation, failure of horns to grow, elongation of the feet, and hypersalivation. The calves are not viable. Called also baldy calves.
  • e. lacunae see epidermal clefts (above).
  • e. laminae structures formed of epidermal pegs; part of the interdigitating structure between the dermis and the epidermis. Called also epidermal ridges.
  • e. limbi the layer of soft, light-colored horn that covers the outer side of the coronary border and merges with the horn of the hoof.
  • e.-melanin unit a melanocyte and adjacent keratinocytes.
  • e. necrolysis see toxic epidermal necrolysis.
  • e. nibbles focal areas of epidermal edema, eosinophils, and necrosis; suggestive of ectoparasite injury to the skin.
  • e. papilla a knob-like projection of the epidermis into the dermis; a touch receptor. Called also tylotrich pad and haarscheiben.
  • e. pegs see rete pegs.
  • e. renewal time see keratinocyte transit time.
  • e. ridge see rete ridge.

• epidermis [ep″ľ-dur′mis] the outermost and nonvascular layer of the skin, derived from the embryonic ectoderm, the thickness varying between species and in different locations on the body. There are generally five layers, from within outward: (1) basal layer (stratum basale), composed of columnar cells arranged perpendicularly; (2) prickle-cell or spinous layer (stratum spinosum), composed of flattened polyhedral cells with short processes or spines; (3) granular layer (stratum granulosum), composed of flattened granular cells; (4) clear layer (stratum lucidum), composed of several layers of clear, transparent cells in which the nuclei are indistinct or absent; and (5) horny layer (stratum corneum), composed of flattened, cornified, non-nucleated cells. The clear layer is only present in certain areas such as the footpads of dogs and cats and the planum nasale.

  • limbic e. transitional epithelium between limb skin and hoof horn; covers the limbic corium.
  • perioplic e. see limbic epidermis (above).
  • tubular e. covering of the corium of the hoof coronet; produces the tubular horn of the hoof wall.

• epidermitis [ep″ľ-d r-mi′tis] inflammation of the epidermis.

  • peracute e. see exudative epidermitis.

• epidermoid [ep″ľ-dur′moid] 1. resembling the epidermis. 2. any tumor occurring at a noncutaneous site and formed by inclusion of epidermal cells.

  • e. carcinoma see squamous cell carcinoma.
  • e. cysts occur in dogs and humans and represent sections of epidermal tissue isolated during the closure of the neural tube.

• epidermoidoma [ep″ľ-dur″moi-do′m ] a cerebral or meningeal tumor formed by inclusion of ectodermal elements at the time of closure of the neural groove.

• epidermolysis [ep″ľ-d r-mol′ -sis] skin condition that leads to the formation of vesicles and bullae, either spontaneously or via trauma.

  • e. bullosa a group of hereditary mechanobullous diseases of humans, Collie dogs, Shetland sheepdogs, Suffolk, South Dorset Down and Scottish blackface sheep, Simmental and Brangus calves, Belgian horses and Quarterhorses. Characterized by the formation of epidermal bullae, which can be severe, particularly on areas of pressure or trauma and in sheep in the mouth and on woolless skin. There may be shedding of hooves and horns. Called also red foot disease. See also congenital bovine epidermolysis and junctional epidermolysis bullosa (below).
  • congenital bovine e. ulcers on lips, gums, tongue, muzzle and limb extremities at birth; skin lesions may be local alopecia without ulceration; resembles epidermolysus bullosa simplex in humans; an autosomal dominant recorded in Simmentals and an autosomal recessive in Vorderwald cattle.
  • junctional e. bullosa a fatal disease inherited as an autosomal recessive in Belgian draft horse foals and other breeds with the LAMC2 mutation where a cytosine insertion creates a premature stop codon. Foals develop erosions of the skin and mucous membranes in the first few days of life and extensive erosions may be present at mucocutaneous junctions of the mouth, rectum, and vulva, and along the coronary bands. Lesions are common over bony prominences and the erosions progress to deeper ulcerative lesions often with complete loss of the epidermis of the distal extremities. The central incisors and premolars are present birth, and there is enamel hypoplasia with pits and serrated edges on the teeth. Called also equine epitheliogenesis imperfecta neonatorum, hereditary junctional mechanobullous disease.

• epidermomycosis [ep″ľ-dur″mo-mi-ko′sis] see dermatophytosis.

• epidermophytid [ep″ľ-d r-mof′ -tid] dermatophytid.

• epidermophytin a filtrate of Epidermophyton spp. cultures that induces a hypersensitivity reaction of the tuberculin type when used in humans.

• Epidermophyton a genus of dermatophytic fungi. E. floccosum is a common cause of fungal skin and nail infections in humans; rare in animals.

• epidermophytosis [ep″ľ-dur″mo-fi-to′sis] dermatophytosis.

• epidermopoiesis formation of the epidermis.

• Epidermoptes a genus of parasitic mites of the family Epidermoptidae. Includes E. bifurcatus (E. bifurcata), E. bilobatus; found on the skin of birds; capable of causing allergy in humans. May coexist with fungal infections, e.g., Lophophyton spp.

• epidermotropic predilection for epidermis.

• epididymal [ep″ľ-did′ -m l] emanating from or pertaining to the epididymis.

  • e. inflammation see epididymitis.
  • e. segmental aplasia a defect in mesonephric development in which part of the epididymis is missing. A cause of infertility in male animals manifested by azoospermia in bilaterally affected animals. Usually unilateral in bulls and rams and probably inherited. Associated with the polled character in male goats and causes spermatostasis.
  • e. sperm granulomas see sperm granuloma.
  • e. stagnation a condition in stallions in which peak fertility is maintained only by frequent ejaculation. Spermatozoa are usually retained in the ampullae of the vas deferens. See also plugged ampullae syndrome.

• epididymectomy [ep″ľ-did″ -mek′t -me] excision of the epididymis. A surgical procedure done to prepare teaser rams or bucks by removing the tail of the epididymis and rendering them sterile. Called also epididymal caudectomy or caudal epididymectomy.

• epididymis [ep″ľ-did′ -mis] pl. epididymides [Gr.] an elongated, cord-like structure along the attached border of the testis, whose coiled duct provides for the storage, transport and maturation of spermatozoa.

• epididymitis [ep″ľ-did″ -mi′tis] inflammation of the epididymis. Nonspecific epididymitis may result from an infection in the urinary tract, especially in the prostate. Rarely it may be traced to an infection elsewhere in the body. Specific epididymitides are those caused by Actinobacillus seminis and by Brucella ovis, both in rams, by B. canis in dogs, and the virus of epivag, bovine viral epididymitis, and vaginitis in bulls.

• epididymitis–orchitis [ep″ľ-did″ -mi′tis-or-ki′tis] see epididymo-orchitis.

• epididymitis-vaginitis [ep″ľ-did″ -mi′tis-vaj″ľ-ni′tis] inflammation of the epididymis and the tunica vaginalis. Also applied to a syndrome described in east Africa where bulls displayed epididymits and cows had vaginitis, colloquially called ‘Epivag’.

• epididymo–orchitis inflammation of the epididymis and testis.

• epididymotomy [ep″ľ-did″ -mot′ -me] incision of the epididymis.

• epididymovasostomy [ep″ľ-did″ -mo-v-sos′t -me] surgical anastomosis of the epididymis to the ductus deferens.

• epidural [ep″ľ-doo′r l] pertaining to or emanating from the dura mater.

  • e. abscess see brain abscess, spinal abscess.
  • e. anesthesia see epidural anesthesia.

• epidurography [ep″ľ-doo-rog′r -fe] imaging of the spine after a contrast medium has been injected into the epidural space.

• epigamic attracting the opposite sex.

  E-50.

  

  Lateral view of the right canine testis and epididymis with the head (H), body (B), and tail (T) of the epididymis.

  E-51.

  

  The anatomy of the pharynx and larynx in a dog: P, palate; T, tongue; E, epiglottis, which in this view is covering the glottis.

  • e. display courtship displays, for example, display of tail feathers by the male peacock.

• epigastralgia [ep″ľ-g s-tral′j] pain in the epigastrium.

• epigastrium [ep″ľ-gas′tre- m] the cranial and middle region of the abdomen, located within the sternal angle.

• epigenetic [ep″ľ-j -net′ik] changes in phenotype or gene expression caused by mechanisms that are independent of changes in the DNA sequence or the influence of DNA-binding regulatory proteins, that may remain through many cell divisions and may be transferred vertically to progeny. Methylation of cytosines in the DNA sequence is an underlying mechanism and epigenetic changes influence cell differentiation such that totipotent stem cells become various pluripotent cell lineages in the embryo, which in turn become the cells that form the different cells and tissues of the body.

• epiglottic [ep″ľ-glot′ik] pertaining to or emanating from the epiglottis.

  • e. cartilage the leaf-shaped cartilage attached to the thyroid cartilage of the larynx by the thyroepiglottic ligament; it is the structural basis of the epiglottis composed of elastic cartilage and covered in mucous membrane and forms a lid to the laryngeal entrance during swallowing.
  • e. cysts see pharyngeal cyst.
  • e. entrapment the epiglottis is trapped by the arytenoepiglottic fold and fails to function normally. Affected horses show exercise intolerance, noisy breathing, coughing, and a characteristic appearance of the laryngeal opening viewed through a fiberscope.
  • e. hypoplasia a smaller than normal epiglottis is often associated with dorsal displacement of the soft palate in horses, resulting in respiratory embarrassment during exercise.

• epiglottis [ep″ľ-glot′is] the lid-like elastic cartilaginous structure guarding the entrance to the larynx (the aditus laryngis). The muscular action of swallowing involves sequential contraction of the pharyngeal constrictors and retraction of the tongue against the epiglottis, which folds over the entrance to the larynx (aditus laryngis) forming a seal with adjacent laryngeal components. This prevents food and drink from entering the larynx and trachea, directing it instead into the esophagus.

• epihyoid [ep″ľ-hi′oid] middle of the chain of hyoid bones; it articulates with the stylohyoid and the ceratohyoid.

• epikeras see epiceras.

• epilate [ep′ľ-lāt] to remove hair, particularly cilia. See cryoepilation, electroepilation.

• epilemma [ep″ľ-lem′ ] endoneurium.

• epilepsy [ep′ľ-lep″se] recurrent seizures. Idiopathic epilepsy exists when seizures occur with no obvious identifiable cause (presumed to be either genetic in origin or of unknown cause). Structural epilepsy is caused by a lesion within the prosencephalon, such as a brain tumor, injury to the brain at birth, a wound, or blow to the head, inflammation or a vascular cause such as infarction. Previously the term reactive epilepsy has been used to describe seizures that occur as a result of disease in other parts of the body that has secondary effects on the brain, e.g., hepatic encephalopathy, electrolyte disturbances. This has now been replaced by the term reactive seizures.

  • autonomic e. see visceral epilepsy (below).
  • cryptogenic e. an underlying cause is suspected but cannot be proven. In dogs, this term is most commonly applied to cases that present with seizures in patients outside the usual age range for idiopathic epilepsy. This has now been replaced with the rather tautological idiopathic epilepsy of unknown cause.
  • idiopathic e. recurrent seizures for which no cause can be identified during life and for which no lesions are demonstrable at autopsy. The diagnosis is made by ruling out all extracranial and other intracranial causes. Among the domestic species, idiopathic epilepsy has been reported in dogs, cats, cattle, and horses. In dogs, this disorder occurs most frequently in certain breeds, particularly German shepherd dogs, miniature poodles, Keeshonds, Tervuren shepherds, and Beagles, in which it is regarded as an inherited trait. Generalized seizures begin occurring at a young age, typically from 6 months to 5 years; the affected dog is otherwise normal. This has been subdivided into ‘genetic’, ‘presumed genetic’, and ‘unknown cause’ subtypes. In affected cattle, seizures occur from 2–3 months of age. A form of idiopathic epilepsy has been recorded in horses.
  • Jacksonian e. see jacksonian seizures.
  • myoclonic e. see glycoproteinosis.
  • reactive e. caused by disease out with the brain, e.g., hepatic insufficiency, electrolyte disturbances. The term has been reclassified more simply as reactive seizures.
  • secondary e. caused by a lesion within the brain.
  • visceral e. a term used to describe a syndrome of hypersalivation, vomiting, retching and apparent abdominal pain in dogs that occurs paroxysmally and is responsive to anticonvulsant medication, usually with phenobarbitone. It is presumed that visceral epilepsy is a form of epilepsy in which the seizures are focal and cause autonomic signs only, but this is very difficult to prove. Called also autonomic epilepsy.

• epileptic [ep″ľ-lep′tik] 1. pertaining to or affected with epilepsy. 2. a patient affected with epilepsy.

  • e. seizure a seizure occurring as part of epilepsy.

• epileptiform [ep″ľ-lep′tľ-form] 1. resembling epilepsy or its manifestations. 2. occurring in severe or sudden paroxysms.

• epileptogenic [ep″ľ-lep-to-jen′ik] causing an epileptic seizure, e.g., an epileptogenic scar in the cerebral cortex, or more significantly in the cerebrum and its proximate meningeal tissue.

• epileptoid [ep″ľ-lep′toid] see epileptiform.

• epimastigote [ep″ľ-mas′tľ-gōt] a developmental stage in trypanosomes. The undulating membrane is shortened, and the axoneme and the kinetoplast are anterior to the nucleus; in the previous stage, they are near the tail and behind the nucleus. This stage occurs usually in the arthropod host. Called also crithidial stage.

• epimer [ep′ľ-m r] one of two or more isomers that differ only in the configuration about one carbon atom.

• epimerase [-pim′ -rās] an isomerase that catalyzes the inversion of asymmetric groups in substrates (epimers) having more than one center of asymmetry.

• epimere [ep′ľ-mēr] the dorsal portion of a somite, from which is formed muscles innervated by the dorsal ramus of a spinal nerve.

• epimerite an organelle of certain protozoa by which they attach themselves to epithelial cells.

• epimerization [-pim″r-ľ-za′sh n] the changing of one epimeric form of a compound into another, as by enzymatic action.

• epimorphosis [ep″ľ-mor-fo′sis] the regeneration of a piece of an organism by proliferation at the cut surface.

• epimyocardial receptors [ep″ľ-mi″o-kahr′de- l] pressure receptors in the left ventricle concerned with regulation of the blood volume.

• epimysial sheath see epimysium.

  E-52.

  

  Epiphora in a dog. Tears have stained the facial hairs brown.

• epimysium [ep″ľ-mis′e- m] the fibrous sheath around an entire skeletal muscle.

• epinephrectomy see adrenalectomy.

• epinephrine [ep″ľ-nef′rin] a hormone produced by the medulla of the adrenal glands. Its function is to aid in the regulation of the sympathetic branch of the autonomic nervous system. Concentrations increase in blood during exercise, exertion, or fear. Epinephrine is a powerful vasopressor that increases blood pressure, heart rate and cardiac output. It also increases glycogenolysis and the release of glucose from the liver. Called also adrenaline.

• epineural [ep″ľ-noo′r l] situated upon a neural arch.

  • e. capping the surgical procedure of folding the epineurium over the proximal end of a transected nerve and suturing it in place helps to prevent the development of painful neuroma.

• epineurium [ep″ľ-noor′e-um] the sheath of a peripheral nerve.

• epiphora [-pif′-r] an abnormal overflow of tears down the face, due to excess production (secondary to painful ocular conditions) or reduced outflow through the nasolacrimal duct. Called (rarely) illacrimation.

• epiphyseal [ep″ľ-fiz′e- l] emanating from or pertaining to the epiphysis.

  • e. aseptic necrosis caused by (1) idiopathic primary necrosis of the epiphysis in growing small-breed dogs (Legg-Calvé-Perthes disease); (2) fracture of the femoral neck; or (3) epiphyseal slippage, particularly of the femoral head in young dogs, cats, pigs, calves, and foals. The disease has a characteristic radiographic appearance.
  • e. cartilage it is located between the metaphyseal part of the diaphysis of long bones; growth at the cartilage is responsible for continuing growth in length of the bone; when growth ceases, the cartilage disappears and is succeeded by an epiphyseal scar. Called also growth plate, physis.
  • e. detachment see epiphysiolysis.
  • e. dysplasia an inherited defect of dogs characterized by very short limbs and early degenerative arthropathy, also called chondrodystrophia fetalis and pseudoachondrodysplasia of Miniature poodles and Scottish deerhounds. A similar histological lesion occurs in multiple epiphyseal dysplasia in Beagles.
  • e. fracture one involving the epiphysis; known as Salter type I in the Salter classification.
  • e. plate the thin plate of cartilage between the epiphysis and the shaft of a long bone; it is the site of growth in length and is obliterated by epiphyseal closure. Called also growth plate, physis.
  • e. scar on radiographs, the radiodense band seen at the junction of the epiphysis and metaphysis, which represents the closed physis.

• epiphysiolysis [ep″ľ-fiz″e-ol′ -sis] separation of the epiphysis from the diaphysis of a bone. It is a traumatic lesion originating from a defect in the growth plate, often osteochondrosis.

  • femoral head e. disease of 5- to 12-month-old pigs, characterized by hindlimb lameness followed in a few days by inability to stand on the hindlimbs.

    E-53.

    

    Epiphyseal (growth) plates. Radiograph of young cat pelvis and femurs. The epiphyseal plates appear dark because they are made up largely of cartilage, which is relatively transparent to x-rays.

• epiphysis [-pif′ -sis] pl. epiphyses [Gr.] 1. the end of a long bone, usually wider than the shaft, and either entirely cartilaginous or separated from the shaft by a cartilaginous disk. 2. part of a bone formed from a secondary center of ossification, commonly found at the ends of long bones, on the margins of flat bones, and at tubercles and processes; during the period of growth epiphyses are separated from the main portion of the bone by cartilage.

  E-54.

  

  Epiphysitis in a calf caused by copper deficiency. Arrow identifies enlargement of the distal tibial epiphysis.

  E-55.

  

  Congestion of the episclera associated with glaucoma in a dog.

  • e. cerebri pineal body.

• epiphysitis [-pif″ -si′tis] inflammation of the epiphysis. Clinically a lesion at the epiphyses of long bones characterized by one or more of enlargement of the epiphysis, lameness, pain response on palpation, and increased warmth. See also osteodystrophy, physeal dysplasia, physitis.

• epipial [ep″ľ-pi′ l] situated upon the pia mater.

• epiplocele [ -pip′lo-sēl] see omental hernia.

• epiploenterocele [-pip″lo-en′t r-o-sēl] a hernia containing intestine and omentum.

• epiplomerocele a femoral hernia containing omentum.

• epiplomphalocele an umbilical hernia containing omentum.

• epiploon pl. epiploa [Gr.] the greater omentum.

• Epipremnum pinnatum plant in family Araceae; contains calcium oxalate raphide crystals; causes stomatitis, salivation. Called also Scindapsus aureus, devil’s ivy, money plant.

• epirubicin [ep″ľ-roo′bľ-sin] an anthracycline antibiotic similar to doxorubicin, used as an antineoplastic agent.

• episclera [ep″ľ-skler′ ] the loose, highly vascular connective tissue on the surface of the sclera; blends with Tenon’s capsule.

• episcleral [ep″ľ-skler′ l] 1. overlying the sclera. 2. pertaining to the episclera.

  • e. space narrow space between the deep muscular fascia and the eye.

• episcleritis [ep″ľ-skl -ri′tis] inflammation of the episclera; typically the adjacent tissues such as sclera, cornea, and conjunctiva are also involved and so the term episclerokeratoconjuncitivitis is sometimes used.

  • nodular granulomatous e. a form of episcleritis characterized by firm, usually painless, nodular non-neoplastic swelling(s) under the conjunctiva at the corneoscleral junction of the eye in dogs. Histology reveals histiocytes, fibroplasia, and lymphoplasmacytic inflammation. Called also nodular fasciitis, Collie granuloma, and proliferative keratoconjunctivitis.

• episclerokeratoconjunctivitis [ep″ľ-skl -ro-ker″-to-k n-junk″tľ-vi′tis] see episcleritis.

• episioperineoplasty [ -piz″e-o-per″ľ-ne′o-plas″te] plastic repair of the vulva and perineum.

• episioperineorrhaphy [-piz″e-o-per″ľ-ne-or′ -fe] surgical closure of the vulva and perineum.

• episioplasty [ -piz′e-o-plas″te] plastic repair of the vulva.

• episiorrhaphy [-piz″e-or′ -fe] 1. suture of the labia majora. 2. suture of a lacerated perineum.

• episiostenosis [-piz″e-o-st -no′sis] narrowing of the vulvar orifice.

• episiotomy [ -piz″e-ot′o-me] surgical incision into the perineum and vagina for obstetrical purposes.

• episode [ep′ľ-sōd] a noteworthy happening occurring in the course of a continuous series of events.

• episodic sporadic; occurring in episodes.

  • e. dyscontrol syndrome see rage syndrome.
  • e. falling a neurological disorder described in Cavalier King Charles spaniels in which affected dogs, starting at an early age, experience episodes of extensor rigidity, possibly brought on by exercise or stress. Also known as paroxysmal exercise-induced dystonia or dyskinesia. The syndrome is caused by a mutation in the BCAN gene, and genetic testing is available.
  • e. muscular weakness see hyperkalemic periodic paralysis. episodic weakness.

• episome any accessory extrachromosomal replicating genetic element that can exist either autonomously or integrated with the chromosome. See also plasmid.

• epispadias [ep″ľ-spa′de- s] a congenital malformation with absence of the upper (dorsal) wall of the urethra, occurring in both sexes, but more commonly in the male, the urethral opening being located anywhere on the dorsum of the penis.

• episplenitis [ep″ľ-spl -ni′tis] inflammation of the capsule of the spleen.

• epistasis [-pis′t -sis] when the effect of one gene or locus is dependent on the presence of one or more modifier genes or loci, typically arising because of interactions between gene products. One example is the yellow coat color locus in Labrador retriever dogs, which is epistatic to the black/brown locus; if a dog has the genotype for yellow at that gene, it will not express either black or brown from the other gene, regardless of what genotype is present at that locus.

• epistatic deviation [ep″ľ-stat′ik] deviation from normal additive gene action due to epistasis.

  E-56.

  

  Epistaxis in a horse.

• epistaxis [ep″ľ-stak′sis] bleeding from the nose. This is usually from damaged vessels in the nasal mucosa but can also be due to an increased fragility of capillaries or bleeding tendencies, particularly thrombocytopenia. Injury may be due to erosion or ulceration of the mucosa by a systemic disease, e.g., glanders in the horse, or by a local disease of the mucosa, e.g., allergic rhinitis, trauma to the face or to the head generally, in which case the bleeding is likely to be due to a serious lesion, or to foreign bodies up the nose, a common cause. Bleeding from the nose originating from sites other than the nasal mucosa is a common and serious occurrence in all species but particularly in the horse because of its implication for safety while racing. When the bleeding in the horse occurs at rest the origin is commonly from the guttural pouch and due to mycotic erosion of the internal carotid artery, maxillary or external carotid arteries. See also exercise-induced pulmonary hemorrhage, guttural pouch mycosis, pulmonary hemorrhage, vena caval thrombosis, cranial vena caval thrombosis.

• episternal [ep″ľ-stur′n l] 1. situated on or over the sternum. 2. pertaining to the episternum.

• episternum [ep″ľ-stur′n m] the manubrium, or cranial segment of the sternum.

• epistropheus [ep″ľ-stro′fe- s] see axis (2).

• Epistylis a genus of ciliated protozoan parasites in the phylum Ciliophora. Found commonly on the skin of freshwater fish; usually nonpathogenic.

• epitendineum [ep″ľ-t n-din′e- m] the fibrous sheath covering a tendon.

• epitenon [ep″ľ-te′non] outer or parietal layers of tendons.

• epithalamus [ep″ľ-thal′ -m s] the part of the diencephalon just superior and posterior to the thalamus, comprising the pineal body and adjacent structures; considered by some to include the stria medullaris.

• epithelial [ep″ľ-the′le- l] pertaining to or composed of epithelium.

  • e. root sheath a fold of gingival epithelium that grows down into the dental alveolus and surrounds the tooth root.
  • e. tissue a general name for tissues not derived from the mesoderm.

• epithelialization [ep″ľ-the″le- l-ľ-za′sh n] healing by the growth of epithelium over a denuded surface. See also pulmonary epithelialization.

  • adnexal e. partial-thickness loss of epidermis can be re-epithelialized by epithelial cells from the remaining portions of adnexal structures.

• epithelialize [ep″ľ-the′le- l-īz″] to cover with epithelium.

• epitheliitis [ep″ľ-the″le-i′tis] inflammation of the epithelium.

• epitheliochorial [ep″ľ-the″le-o-kor′e- l] see placenta.

• epitheliocystis [ep″ľ-the″le-o-sis′tis] disease of aquarium, aquaculture, and wild marine and fresh water fish caused by a Chlamydia or Chlamydia-like organism and characterized by small vesicles in the epidermal cells of the gills and skin.

• epitheliogenesis [ep″ľ-the″le-o-jen′ -sis] development of the epithelium.

  • equine e. imperfecta neonatorum see junctional epidermolysis bullosa.
  • e. imperfecta congenital absence of the skin and commonly also the mucosae; an inherited defect in most animal species. It is incompatible with life. Called also aplasia cutis.
  • e. imperfecta linguae bovis see smooth tongue.

• epithelioid [ep″ľ-the′le-oid] resembling epithelium.

  • e. cells histiocytes with elongated or oval vesicular nuclei and finely granular eosinophilic cytoplasm; seen in epithelioid sarcoma.

• epitheliolysis [ep″ľ-the″le-ol′ -sis] destruction of epithelial tissue.

• epithelioma [ep″ľ-the″le-o′m ] outdated and inaccurate term applied to any tumor derived from epithelium.

  • e. adenoides cysticum see trichoepithelioma.
  • basal cell e. see basal cell tumors.
  • benign calcifying e. see pilomatrixoma.
  • intracutaneous cornifying e. a benign skin tumor of hair follicle origin in dogs that consists of a keratin-filled cyst, usually opening to the surface of the skin through a pore. Occasionally, and particularly in some breeds, tumors may be multiple or recurring. Called also keratoacanthoma, infundibular keratinizing acanthoma.
  • e. of Malherbe see pilomatrixoma.
  • necrotizing e., necrotizing calcifying e. see pilomatrixoma.
  • sebaceous e. a low-grade malignant tumor of sebaceous glands that is comprised of irregular nodules of epithelial reserve cells with small areas of, or individual cells with, sebaceous differentiation.

• epithelion [ep″ľ-the′le- n] see epidermal membrane.

• epitheliosis [ep″ľ-the-le-o′sis] proliferation of conjunctival epithelium, forming trachoma-like granules.

  • bovine e. see malignant catarrhal fever.

• epitheliotropic [ep″ľ-the-le-o-tro′pik] having a special affinity for epithelial cells.

  • equine multisystemic eosinophilic e. syndrome see equine multisystemic eosinophilic epitheliotropic syndrome.
  • e. lymphoma see lymphoma.

• epithelium [ep″ľ-the′le- m] pl. epithelia [Gr.] the cellular covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances. Epithelium is classified into types on the basis of the number of layers deep and the shape of the superficial cells. Standard classifications include ciliated (cilia attached), columnar (taller than wide), cuboidal (same height as width), pseudostratified (single layer but because of varying cell height appears to be more than one), simple (one cell layer), squamous (flattened, plate-like cells), stratified (more than one layer), transitional (variable number of layers apparent). Other types are listed below.

  • corneal e. epithelium on the anterior (outer) surface of the cornea.
  • germinal e. thickened peritoneal epithelium covering the gonad from earliest development; formerly thought to give rise to germ cells.

    E-57.

    

    Adaptive changes in epithelium.

  • glandular e. that composed of secreting cells.
  • iris e. epithelium on the posterior surface of the iris.
  • lens e. cuboidal epithelium occurring immediately under the anterior lens capsule.
  • pigmentary e., pigmented e. that made of cells containing granules of pigment.
  • retinal pigment e. see retinal pigment epithelium.
  • sense e., sensory e. see neuroepithelium (1).

• epithelization [ep″ľ-the″lľ-za′sh n] epithelialization.

• epitonic [ep″ľ-ton′ik] abnormally tense or tonic.

• epitope [ep′ľ-tōp] see antigenic determinant.

  • continuous e. contiguous amino acid sequences in a linear array. Called also linear epitope.
  • discontinuous e. one in which amino acids are in close proximity in the folded protein, but distant when unfolded. Called also conformational epitope.

• epitrichial gland see sweat glands.

• epitrichium [ep″ľ-trik′e- m] periderm.

• epitympanic [ep″ľ-tim-pan′ik] emanating from or pertaining to the eardrum or the part of the adjacent tympanic cavity.

  • e. recess see attic.

• epitympanum [ep″ľ-tim′p -n m] the upper part of the tympanic cavity.

• epivag [ep′ľ-vag] an incompletely defined venereal disease of cattle, probably caused by a herpesvirus. Cows develop a profuse purulent vaginal discharge with spread of the infection to the uterus and rendering many cows sterile because of damage to the fallopian tube and bursa. Initially in bulls, there is swelling followed by fibrosis of the epididymis; associated lesions include abscess formation, ampullitis, vesicular adenitis (seminal vesiculitis), and degeneration of the testicles. Recorded only in Africa.

• epivaginitis [ep″ľ-vaj-ľ-ni′tis] see epivag.

• epizoic [ep″ľ-zo′ik] pertaining to or caused by an epizoon.

• epizoon [ep″ľ-zo′on] pl. epizoa [Gr.] an external animal parasite.

• epizootic [ep″ľ-zo-ot′ik] a disease that attacks many subjects in a region at the same time but is only occasionally present in the population; when it occurs, it is widely diffused and rapidly spreading. The rarely used equivalent of epidemic in veterinary medicine.

  • e. catarrhal enteritis (ECE) a highly contagious coronaviral enteritis in ferrets which may be mild to severe. There is profuse, bright green diarrhea. Called also green slime disease.
  • e. bovine infertility see bovine genital campylobacteriosis.
  • e. cellulitis see equine viral rhinopneumonitis.
  • e. cellulitis-pinkeye see equine viral arteritis.
  • e. chlamydiosis a disease of rabbits, hares, deer mice, squirrels, and muskrats caused by Chlamydia psittaci M56 serovar and characterized by septicemia, fever, diarrhea.
  • e. diarrhea of infant mice see murine epizootic diarrhea.
  • e. hematopoietic necrosis a systemic iridoviral disease of fish endemic in Australian redfin perch and rainbow trout and occasionally reported in other countries; characterized by massive moralities in juvenile perch and lower moralities in trout. May have originated in amphibians. A disease notifiable to the OIE (see Table 20).
  • e. hemorrhagic disease a disease clinically similar to bluetongue of sheep that periodically causes very heavy mortalities in wild ruminants, particularly white-tailed deer in North America. Infection also occurs in cattle, sometimes subclinically. Caused by either epizootic hemorrhagic disease virus (EHDV) or bluetongue virus (BTV); Orbiviruses that are related, but genetically distinct. Transmitted by biological vectors, usually biting midges of the genus Culicoides. A disease notifiable to the OIE (see Table 20).
  • e. hemorrhagic septicemia see hemorrhagic septicemia.
  • e. lymphangitis a chronic, contagious disease of horses caused by Histoplasma capsulatum var farciminosum (or Blastomyces, Cryptococcus, Saccharomyces, Zymonema). It is characterized by suppurative lymphangitis, lymphadenitis, and cutaneous ulcers. Lesions may also occur on the muzzle and nasal mucosa, in the eye causing keratitis, and also in the lungs causing pneumonia. The disease is an important one on its own account, but it also has importance because of its similarity to glanders. Called also pseudoglanders.
  • e. pneumoenteritis see chronic respiratory disease. Called also CRD.
  • e. ulcerative syndrome (EUS) important cause of loss in ornamental fish and foodfish; a small area of reddening spreads to become extensive ulceration with the loss of fins, tail, jaw, and ultimately penetration of the abdominal wall. There may also be cloudiness of the corneas. Caused by the pathogenic fungus Aphanomyces invadans. Called also Bundaberg disease, red spot disease. A disease notifiable to the OIE (see Table 20).

• epizootic ulcerative syndrome see Aphanomyces.

• epizootiology [ep″ľ-zo-ot″e-ol′ -je] with reference to animal diseases is the rarely used, etymologically proper, equivalent of epidemiology.

• EPM equine protozoal myeloencephalitis.

• EPN ethyl p-nitrophenyl benzenethiophosphanate; a nonsystemic organophosphorus insecticide and acaricide.

• EPO see erythropoietin.

• Epomidiostomum a genus of nematodes in the strongyloid family Amidostomidae. The worms cause hemorrhage and necrosis in the proventriculus and the stomach and gizzard. Includes, in geese, ducks, and swans, E. crispinum, E. skrjabini, E. uncinatum, and E. vogelsangi.

• eponychium [ep″o-nik′e- m] 1. the narrow band of epidermis extending from the claw wall onto the claw surface; commonly called cuticle. 2. the horny fetal epidermis at the site of the future claw.

• eponym a name or phrase formed from or including a person’s name, e.g., Theiler’s disease, Cowper’s gland, Aschheim–Zondek test.

• epoöphoron [ep″o-of′ -r n] a vestigial structure associated with the ovary; originates from the cranial mesonephric tubules and cysts of it may resemble ovarian cysts.

• epoprostenol [e″po-pros′t -nol] see prostacyclin.

• epornithic an epidemic in a population of birds.

• epornithology [ep-or″nľ-thol′ -je] the study of avian epidemics; study of diseases of birds that occur in a community sporadically but with high morbidity.

• epostane an antiprogesterone agent used to terminate pregnancy in dogs and to induce farrowing in sows.

• epoxide [ -pok′sīd] any compound containing a three-membered ring of two carbon atoms and one oxygen atom, e.g., oxirane.

• epoxy [ -pok′se] 1. containing one atom of oxygen bound to two different carbon atoms. 2. a resin composed of epoxy polymers and characterized by adhesiveness, flexibility and resistance to chemical actions.

• epoxyscillirosidin toxic cardio-active bufadienolide in Moraea glauca that acts by inhibition of cardiac Na,K-ATPase.

• eprinomectin an avermectin effective against nematodes and used as a pour-on for the control of ectoparasites.

• epsilon [ep′si-lon] the fifth letter of the Greek alphabet, Ε or ε.

• Epsilonproteobacteria a class of Gram-negative bacteria in the phylum Proteobacteria that contains the families Helicobacteraceae and Campylobacteraceae.

• Epsilonretrovirus [ep′stīn bahr′] a genus of the family Retroviridae. Viruses infect fish and include walleye dermal sarcoma virus and walleye epidermal hyperplasia virus 1 and 2.

• epsiprantel a cesticide, similar to praziquantel used for treatment of tapeworms in dogs and cats.

• Epsom salt magnesium sulfate, an osmotic laxative/cathartic; also used topically as a drawing agent to accelerate the maturation of foot abscesses in horses.

• EPSP excitatory postsynaptic potential.

• Epstein–Barr virus see Burkitt’s lymphoma.

• EPTCS-ethyldipropylthiocarbamate; a thiocarbamate non-cholinesterase inhibiting herbicide.

• epulides [ -pu′lľ-dēz] see epulis.

• epulis [ -pu′lis] pl. epulides [Gr.] a benign tumor of mixed cell origin arising in the vicinity of the periodontal membrane. May be due to chronic irritation or to true neoplasia.

  E-58.

  

  Periodontal fibromatous epulis in a dog.

  • acanthomatous e. a locally invasive, sometimes recurrent, tumor of the gums of dogs and sometimes cats. Called also oral adamantinoma.
  • giant-cell e. see periodontal fibromatous epulis (below).
  • ossifying e. has a greater abundance of hard tissue, osteoid, bone, and cementum than fibromatous epulides.
  • periodontal fibromatous e. firm, nodular benign structures on the lingual or labial gum margins, resembling normal gingiva in color and texture. Common in dogs, particularly the brachycephalic breeds. Considered by some to be hyperplastic rather than neoplastic. Called also giant-cell epulis.

• epulosis [ep″u-lo′sis] a scarring over; cicatrization.

• Eq equivalent; see chemical equivalent.

• equatorial [e″kw -tor′e- l] the circle that divides the spherical object into equal halves.

  • e. region the middle piece; said of spindle muscle fibers.

• equestrian a rider of horses.

• equid see Equidae.

• Equidae [ek′wľ-de] a family of mammals, members of which have a single functional digit, although the second and third digits persist as splint bones. Includes horses, wild horses, asses (donkeys), and zebras. Quaggas were a member of the family but are now extinct. See also Equus.

• equilenin one of several estrogens produced by the pregnant mare which are unique to Equidae. Has unsaturated B ring.

• equilibration [e-kwil″ľ-bra′sh n] the achievement of a balance between opposing elements or forces.

• equilibrium [e″kwľ-lib′re- m] a state of balance between opposing forces or influences. In the body, equilibrium may be chemical or physical. A state of chemical equilibrium is reached when the body tissues contain the proper proportions of various salts and water. See also acid–base balance and fluid balance. Physical equilibrium, such as the state of balance required for walking or standing, is achieved by a very complex interplay of opposing sets of muscles. The labyrinth of the inner ear contains the semicircular canals, or organs of balance, and relays to the brain information about the body’s position and also the direction of body motions. Genetic equilibrium is achieved when the allelic frequencies do not change from generation to generation.

  • e. dialysis a technique for determining the affinity of an antibody for an antigen.
  • e. disturbances see posture, posture balance.
  • dynamic e. the condition of balance between varying, shifting and opposing forces that is characteristic of living processes.

• equilin [ek′wil-in] one of several estrogens produced by the pregnant mare that are unique to Equidae. They have unsaturated B rings.

• equine [e′kwīn] pertaining to, characteristic of, or derived from member of the genus Equu.

  • e. abortion infectious causes include equine herpesvirus 1, equine viral arteritis, bacterial placentitis, Salmonella abortus-equi. See also equine viral abortion.
  • acute e. respiratory syndrome see Hendra virus disease.
  • e. adenovirus see equine adenovirus (types 1 and 2).
  • e. alphaherpesvirus see Herpesviridae.
  • e. ammonitis and fetal loss syndrome abortion in mares in South Eastern Australia. Clinically similar to mare reproductive loss syndrome in North America. Suspected to be associated with ingestion or contact with processionary caterpillars (Ochrogaster lunifer). See mare reproductive loss syndrome.
  • e. arteritis see equine viral arteritis (below).
  • e. asthma syndrome non-infectious respiratory disease of horses characterized by airway hyperresponsiveness and inflammation. Likely immune mediated. Comprised of a range of clinical presentations from inflammatory airway disease (IAD) to recurrent airway obstruction (RAO). A particular manifestation is summer pasture associated RAO of horses in the southern US.
  • e. atypical myopathy see myopathy.
  • e. babesiosis see babesiosis.
  • e. biliary fever see babesiosis.
  • e. blastomycosis see epizootic lymphangitis.
  • e. chorionic gonadatropin (eCG) see pregnant mare serum gonadatropin.
  • e. coital exanthema see equine coital exanthema.
  • e. colic see equine colic.
  • contagious e. metritis called also CEM; see contagious equine metritis.
  • e. Cushing’s disease see equine pituitary pars intermedia dysfunction (below).
  • e. degenerative myeloencephalopathy (EDM) see myeloencephalopathy.
  • e. duodenitis-proximal jejunitis syndrome of small intestinal ileus characterized by rapid onset of abdominal pain and copious nasogastric reflux in horses. Unknown etiology. Lesions in duodenum and proximal jejunum.
  • e. ehrlichial colitis see equine neorickettsiosis.
  • e. ehrlichiosis see equine granulocytic anaplasmosis.
  • e. encephalitis see Borna disease, equine viral myeloencephalitis, equine herpesvirus 1, West Nile virus, equine protozoal encephalomyelitis, rabies.
  • e. encephalosis insect-borne orbivirus that is transmitted by a variety of Culicoides spp. Seven serotypes of equine encephalosis virus infect equids of southern Africa including Kenya, Botswana, and South Africa. Clinical signs include fever, lassitude, edema of the lips, acute neurologic disease, enteritis, and abortion. Serological surveys suggest that most infections are subclinical.
  • e. eosinophilic granuloma see equine nodular collagenolytic granuloma (below).
  • e. epidemic cough see equine influenza (below).
  • e. farcy see glanders.
  • e. grass sickness see grass sickness.
  • e. Hendra virus disease see Hendra virus disease.
  • e. henipavirus a virus in the family Paramyxoviridae, genus Henipavirus that causes fatal illness in horses and humans following ‘natural’ infection and of guinea pigs and cats following experimental inoculation. Previously called equine morbillivirus. See also Hendra virus disease.
  • e. herpesvirus 1 (EHV1) the major cause of equine viral abortion (see also equine viral abortion) and a myeloencephalopathy. The latter is characterized by nervous signs varying from mild ataxia to enforced recumbency. Also causes respiratory disease (rhinopneumonitis), but the distinctly different equine herpesvirus 4, is more commonly identified as the cause of rhinopneumonitis and rarely abortion. The disease may be a transitory incoordination or a permanent recumbency necessitating euthanasia. When infection of the fetus occurs in the last week or so of pregnancy, perinatal death of the foal in the first few days of life can occur that is characterized by generalized viremia and pathology similar to that found in EHV1 aborted fetuses.
  • e. herpesvirus 2 (EHV2) a common infection of horses, often asymptomatic but also associated with a variety of signs including pharyngitis, malaise and coughing, The virus is a member of the subfamily Gammaherpesvirinae, genus Percavirus. Formerly called equine cytomegalovirus or slowly growing equine herpesvirus.
  • e. herpesvirus 3 (EHV3) see equine coital exanthema.
  • e. herpesvirus 4 (EHV4) a major cause of equine viral rhinopneumonitis (below).
  • e. herpesvirus 5 (EHV5) a common infection of horses, often asymptomatic but also associated with a variety of signs including pharyngitis, malaise, coughing, and equine multinodular pulmonary fibrosis. The virus is classified in the subfamily Gammaherpesvirinae, genus Percavirus; distinctly different from EHV2.
  • e. histoplasmosis see epizootic lymphangitis.
  • e. infectious anemia (EIA) is caused by a non-oncogenic retrovirus in the subfamily Lentivirinae. After an initial acute attack of fever, weakness to the point of incoordination, jaundice, petechiation of the mucosae and conjunctivae, and ventral edema, there are alternating periods of normality and illness that may continue for many years. During ensuing attacks, there is a gradual development of anemia, emaciation, and cardiac insufficiency. The disease is contagious to all members of the family Equidae and is spread by biting flies and mosquitoes. Spread by veterinary equipment has occurred frequently in the past. A disease notifiable to the OIE (see Table 20). Called also swamp fever.
  • infectious e. bronchitis see equine influenza (below).
  • e. inflammatory airway disease non-infectious disease of predominantly young horses characterized by excessive accumulation of mucus in the lower airways including trachea. Increased concentration of inflammatory cells in tracheal aspirates or bronchoalveolar lavage fluid. See equine asthma (above).
  • e. influenza a globally occurring infectious disease of the upper respiratory tract of horses of all ages and caused by members of the family Orthomyxoviridae, genus A. The identified viruses are influenza A/Equi Prague/56 (H7N7) and A/Equi-2/Miami/63 (H3N8). The clinical signs typical of the infection are a minor fever and a persistent, long-term cough that prevents the horse being exercised. Droplet infection is highly effective, and the disease has the capacity to reach epidemic proportions quickly and disrupt racing and other equine activities. The course is about 3 weeks, and there are usually no serious sequelae if the horse is cared for properly. Formerly called with some uncertainty also equine infectious bronchitis, Hoppengarten cough, laryngotracheobronchitis, shipping fever. Effective inactivated vaccines are available, although the duration of protective immunity to infection is short. The viruses do not show the same degree of antigenic change (drift and shift) evident in human influenza A viruses. A disease notifiable to the OIE (see Table 20).
  • e. laryngeal hemiplegia see laryngeal hemiplegia.
  • e. linear keratosis vertical linear areas of alopecia, scaling, and crust formation on the sides of the neck, shoulder, and chest.
  • e. lipidemia see equine hyperlipemia.
  • e. metabolic syndrome disease of equids characterized by regional adiposity or generalize obesity, fasting hyperinsulinemia, hypertriglyceridemia, insulin resistance, and predisposition to laminitis. Insulin resistance is the underlying abnormality. Breed predisposition with ponies at particular risk. No effective treatment apart from restoration of optimal body weight.
  • e. morbillivirus see equine henipavirus (above).
  • e. motor neurone disease neurodegenerative disease of horses associated with abnormally low intake of vitamin E. Characterized by muscle atrophy, weakness, fasciculations, and increased recumbency.
  • e. multinodular pulmonary fibrosis see equine multinodular pulmonary fibrosis.
  • e. neorickettsiosis acute systemic disease of horses frequently manifest as enterocolitis. Clinically characterized by fever, depression, anorexia, diarrhea, colic, and laminitis. Infectious and non-contagious, associated with infection by Neorickettsia risticii. Also known as Potomac horse Fever, equine ehrlichial colitis, and equine monocytic ehrlichiosis.
  • e. nodular collagenolytic granuloma firm subcutaneous nodules 0.5–5 mm diameter on the side of the neck, withers, and back. They are eosinophilic granulomas and the cause is not known.
  • e. papular dermatitis a transient skin disease of horses that may be caused by a virus. Begins with 0.25- to -1-inch-diameter papules that subsequently crust over and then become alopecic. A number of horses are likely to be affected at the one time, and an insect vector trans-mission is suspected.
  • e. parainfluenza 3 see Parainfluenzavirus 3.
  • e. pituitary pars intermedia dysfunction (PPID) slowly progressive neurodegenerative disease of older equids characterized by nonmalignant hypertrophy of melanotropes of the pars intermedia of the pituitary gland secondary to degeneration of periventricular hypophyseal neurones. Clinically evident as hirsutism, laminitis, polyuria, and polydypsia. See also Cushing’s syndrome.
  • e. plague see African horse sickness.
  • e. polysaccharide storage myopathy glycogen storage myopathy most commonly seen in draft, warm-blood – and Quarter Horse–related breeds. Clinically can present as exertional rhabdomyolysis, weakness, and muscle atrophy. Characteristic PAS-positive inclusions in myocytes on histopathology.
  • e. proliferative enteropathy see equine proliferative enteropathy.
  • e. protozoal myeloencephalitis see equine protozoal myeloencephalitis.
  • e. recurrent ophthalmia see equine recurrent uveitis.
  • e. reovirus a member of the genus Orthoreovirus; uncommonly reported as a cause of upper respiratory tract disease in young horses.

    E-59.

    

    Verrucose sarcoid in a horse.

    E-60.

    

    Conjunctivitis in equine viral arteritis.

  • e. rhinopneumonitis see equine viral rhinopneumonitis (below).
  • e. rhinitis A virus member of the genus Aphthovirus, family Picornaviridae that causes an upper respiratory tract infection in horses with laryngitis and a copious sometimes mucopurulent nasal discharge accompanied by viremia; formerly called equine rhinovirus 1.
  • e. rhinitis B viruses members of the genus Erbovirus, family Picornaviridae that cause upper respiratory tract infections in horses; formerly called equine rhinoviruses 2 and 3.
  • e. sarcoid a locally aggressive, non-regressing, fibroblastic skin tumor common in horses, donkeys, and mules and associated with bovine papillomavirus BPV-1, -2, and BPV-13. Single or multiple lesions that are hairless fibroid tumor masses that frequently ulcerate, look like large warts, often recur after excision, and occur most commonly on the lower legs but can occur on any part of the body. Rarely reported in cats. See also sarcoid.
  • e. sensory ataxia see equine cervical vertebral compressive myelopathy.
  • e. serum hepatitis acute liver disease in horses. See postvaccinal hepatitis. Now associated with infection by equine parvovirus-hepatitis.
  • e. spinal ataxia see equine protozoal myeloencephalitis.
  • e. sports medicine all aspects of equine medicine that touch on quality of performance by show, event, or racing horses; particular attention paid to diseases of the respiratory, cardiovascular, and musculoskeletal systems.
  • e. staphylococcal dermatitis a contagious but low prevalence equine dermatitis from which Staphylococcus aureus can be isolated regularly. Small, painful nodules appear under the harness; subsequently become pustular and rupture. Called also saddle scab, tail pyoderma.
  • e. sternal granuloma see breast boil.
  • e. tropical lichen see equine allergic dermatitis.
  • e. viral abortion see equine herpesvirus 1 (above).
  • e. viral arteritis (EVA) is caused by a member of the family Arteriviridae, genus Arterivirus. Infection is commonly asymptomatic but clinical signs after an incubation period of 3–14 days include coughing, fever, leukopenia, depression, excessive lacrimation, anorexia, conjunctivitis, rhinitis, and nasal discharge. There may be edema around the eyes, lower abdomen, scrotum, and lower limbs, and abortion. The virus is transmitted horizontally by semen from carrier stallions. A disease notifiable to the OIE (see Table 20).
  • e. viral encephalomyelitis see equine viral encephalomyelitis.
  • e. viral rhinopneumonitis (EVR) predominantly caused by equine herpesvirus 4 (EHV4) but also by EHV1. Occasionally EHV4 causes abortion, but EHV1 is the predominant cause of abortion. The rhinopneumonitis is manifested by a cough, serous nasal discharge, mild conjunctivitis, and fever. Abortion, when it occurs, does so in the last few months of pregnancy, and the mare is not systemically ill at that time. A disease notifiable to the OIE (see Table 20).
  • e. zygomycosis see swamp cancer.

• equine cervical vertebral compressive myelopathy disease caused by extradural compression of the cervical spinal cord in horses. Clinical signs of bilaterally symmetrical ataxia, usually more severe in the hind limbs. Predominantly a disease of young male Thoroughbreds and other large breeds.

• equine metabolic syndrome disease of equids characterized by regional adiposity or generalize obesity, fasting hyperinsulinemia, hypertriglyceridemia, insulin resistance, and predisposition to laminitis. Insulin resistance is the underlying abnormality. Breed predisposition with ponies at particular risk. No effective treatment apart from restoration of optimal body weight.

• equine neorickettsiosis acute systemic disease of horses frequently manifest as enterocolitis. Clinically characterized by fever, depression, anorexia, diarrhea, colic, and laminitis. Infectious and non-contagious, associated with infection by Neorickettsia risticii. Also known as Potomac horse fever, equine ehrlichial colitis, and equine monocytic ehrlichiosis.

• Equinia a genus of tapeworms of the family Anoplocephalidae found in the small intestine of horses; with a single species E. mamillana. Formerly known as Paranoplocephala m. or Anoplocephaloides m.

• equinovarus [e-kwi″no-va′r s] talipes equinovarus; a foot deformity in which the heel is turned inward and the foot is plantar flexed.

• equipotential [e″kwľ-po-ten′sh l] having similar and equal power or capability.

• equipotentiality [e″kwľ-po-ten″she-al′ľ-te] the quality or state of having similar and equal power; the capacity for developing in the same way and to the same extent.

• Equisetum [ek″wľ-se′t m] genus of the fern ally family Equisetaceae. These plants have a high content of thiaminase, and horses that eat a lot of them, usually in their hay, develop thiamine deficiency. This is characterized by incoordination, falling, bradycardia, and severe cardiac irregularity. Response to treatment with thiamine is rapid and complete. Includes E. arvense, E. fluviatile, E. hyemale, E. laevigatum, E. limosum, E. palustre, E. ramosissimum. Called also horsetails, marestails, scouring rush.

• equitation [ek″wľ-ta′sh n] the art of horsemanship.

• Equithesin trade name for a mixture of chloral hydrate, magnesium sulfate, and pentobarbital used as an anesthetic, especially for horses. Historical use as an equine anesthetic.

• equivalency [e-kwiv′ -len-se] 1. the combining power of an electrolyte. See also equivalent. 2. comparison of two drugs that have similar efficacy.

• equivalent [e-kwiv′ -lent] 1. of equal force, power, value, etc. 2. something that has equivalent properties.

  • chemical e. (Eq) that weight in grams of a substance that will produce or react with 1 mole of hydrogen ion or 1 mole of electrons. The concentrations of electrolytes are often specified in milliequivalents per liter (mEq/L).
  • epilepsy e. any disturbance, mental or physical, that may take the place of an epileptic seizure.
  • temperature e. see Table 3.

• equol a metabolite of the phytoestrogen daidzein; an isoflavan.

• Equus a genus in the family Equidae. Includes horses, zebras, and donkeys or asses. Includes E. asinus (donkey), E. burchelli (common zebra), E. caballus (the modern horse), E. grevyi (Grevyi’s zebra), E. hemionus (Asian wild ass), E. kiang (Tibetan wild ass), E. przewalskii (Przewalski’s horse), E. zebra (zebra).

• equus [ek′w s] the final stage of the evolution of the horse. The evolution appears to have been direct beginning with Hyracotherium, through Miohippus and Merychippus to Pliohippus and finally to Equus.

• Er chemical symbol, erbium.

• ER bodies erythrocyte refractile bodies; see Heinz body.

• eradication extermination of an infectious agent so that no further cases of the related disease can occur.

  • virtual e. reduction of the frequency of occurrence of a disease to an arbitrary level that is considered to be not a threat to the animal population at risk.

• erasion removal by scraping or curettage.

• Erb–Goldflam disease [erb′ gōlt′flahm] see myasthenia gravis.

• erbium (Er) [ur′be- m] a chemical element, atomic number 68, atomic weight 167.26.

• Erbovirus a genus in the family Picornaviridae; includes equine rhinitis B viruses.

• Erechtites see Senecio.

• erectile [ -rek′tīl] capable of erection.

  • e. tissue spongy tissue that expands and becomes firm when filled with blood, e.g., corpus cavernosum of the penis.

• erection [-rek′sh n] the condition of becoming rigid and elevated, as erectile tissue when filled with blood; applied especially to the swelling and rigidity that occur in the penis as a result of sexual or other types of stimulation. Impulses received by the nervous system stimulate a flow of blood from the arteries leading to the penis, where the erectile tissue fills with blood, and the penis becomes firm and erect. Erection makes possible the transmission of semen into the body of the female. See reproduction.

  • persistent e. see priapism.

• erector [-rek′t r] [L.] a structure that erects, as a muscle that holds up or raises a part.

• Eremophila an Australian plant genus of the Myoporaceae family; E. maculata (native fuchsia) can cause cyanide poisoning. E. deserti (Myoporum deserti, Ellangowan poison bush; carrot bush) contains furanosesquiterpenes and causes acute liver necrosis.

• erethism excessive irritability or sensitivity to stimulation.

• erethisophrenia exaggerated mental excitability.

• ERG electroretinogram.

• erg [urg] a unit of work or energy, equivalent to 1.0 × 10⁻⁷ joules, to 2.4 × 10⁻⁸ calories, or to 0.624 × 10¹² electron volts.

• erg- word element. [Gr.] work, energy.

• ergasia [r-ga′zh] any mentally integrated function, activity, reaction, or attitude of an individual.

• ergocalciferol [ur ″go-kal-sif′ r-ol] vitamin D2; an oil-soluble vitamin used in the treatment and prevention of rickets, a skeletal disease caused predominantly by vitamin D deficiency. See also vitamin D.

• ergograph [ur′go-graf] an instrument for measuring work done in muscular action.

• ergometrine [ur″go-met′rin] see ergonovine.

• ergonomics [ur″go-nom′iks] the science of relating the physiological and anatomical characteristics of the working or racing animal to the physical aspects of its working environment.

• ergonovine [ur″go-no′vin] one of the alkaloids from ergot ¹ or produced synthetically, used as an oxytocic.

• ergosterol [r-gos′t -rol″] a sterol occurring in the cell wall of fungi; a provitamin, which on ultraviolet irradiation, becomes a potent antirachitic substance, vitamin D₂ (ergocalciferol).

• ergot¹ the dried sclerotia of the fungi Claviceps spp. parasitic on grass seed heads.

  • e. alkaloids clavine alkaloids, lysergic acid and its amides, and ergot peptide alkaloids (ergotamine, ergosine, ergocristine, etc.).
  • bulrush millet e.Claviceps fusiformis parasitizes bulrush millet (Pennisetum glaucum) and causes agalactia and piglet loss in sows. Called also munga ergot.
  • munga e. the seed of the bullrush millet, Pennisetum typhoides, which may be infested with Claviceps fusiformis.
  • paspalum e.Claviceps paspali is an ergot fungus that parasitizes Paspalum spp. animals eating the infected plants are poisoned; the clinical syndrome consisting of gross incoordination is indistinguishable from cerebellar ataxia. Recovery is quick and complete if the animals are removed from the contaminated pasture.
  • rye e.Claviceps purpurea, the ergot of rye, infests cereal rye, and other grasses including Lolium spp. It contains a number of alkaloids one of which, ergonovine (ergometrine), is extracted and used pharmaceutically as an oxytocin. Livestock and humans fed on contaminated grain or seed from affected crops develop chronic ergotism.

    E-61.

    

    Peripheral necrosis, edema and hemorrhage in a bovid caused by ergot alkaloids found present in feed pellets fed to this heifer.

    E-62.

    

    Ergot in horses.

• ergot² [ur′got] the small mass of horn in a small bunch of hair on the palmar or plantar aspects of the fetlock of the horse. Regarded as the vestige of the metacarpal or metatarsal pads. See also chestnut.

  • e. ligament shimmering band of connective tissue connecting the fetlock ergot to the distal parts of the pastern in the horse. It is easily confused with the digital nerves during neurectomy.

• ergotamine [r-got′ -min] an alkaloid derived from rye ergot; the tartrate is used as an oxytocic.

• ergotherapy [ur″go-ther′ -pe] treatment of disease by physical effort.

• ergothioneine [ur″go-thi″o-ne′in] a sulfur-containing base, present in significant quantities in the semen of the boar and the stallion, which is thought to protect spermatozoa against oxidizing agents. In other species, this role is played by ascorbic acid.

• ergotism [ur′go-tiz- m] toxicity caused by ergot alkaloids in feeds that may be from Claviceps spp. or from endophytes. Variation in clinical manifestations between outbreaks is probably due to differences in alkaloid types in the feed. The classical manifestation is gangrene of the extremities, particularly the lower part of the hindlimbs, the tail and the tips of the ears with reddening, swelling, coldness, loss of hair or wool, and lack of sensation initially, followed by necrosis and separation from normal tissues. When large amounts are ingested, there are neurologic signs characterized by initial drowsiness, incoordination, and subsequently convulsions. Abortion occurs in some instances. Hyperthermia is the principal manifestation in some intoxications and occurs in hot weather. Affected animals are hyperthermic, poorly tolerant to exercise, seek water or shade, and have decreased growth rate and milk production. Exposure to high environmental temperatures may result in death. Abnormality in reproduction occurs in mares grazing endophyte infested Festuca arundinacea (see Fescue toxicisi) and in pigs where ergotism is manifested by lack of udder development and agalactia in sows, and the birth of small pigs that suffer a high neonatal mortality. See also fescue toxicosis, summer slump, fescue foot.

• ergotoxin a mixture of alkaloids extracted from Claviceps purpurea. Has vasoconstrictor and ecbolic actions.

• ergovaline ergot alkaloid found in some endophyte-infected fescue and ryegrasses, implicated in the expression of ergotism-like symptoms of grazing livestock, as well as in the protection of the plant against invertebrate predation

• Eriobotrya japonica tree in the family Rosaceae, has edible fruits the seeds of which contain sufficient cyanide to cause poisoning if eaten in quantity. Called also loquat.

• Eriocephalus ericoides, E. glaber African plant in the Asteraceae family; causes pyloric obstruction because of high content of indigestible fiber.

• Eriochloa contracta a grass in the family Poaceae; has caused photosensitization of cattle in Texas. Called also prairie cupgrass.

• Eristalis [er-is′t -lis] a genus of flies in the family Syrphidae whose maggots breed in drains. Called filth flies, rat-tailed maggots.

• ermine 1. (Mustela erminea) a small member of the family Mustelidae; known also as the stoat or weasel, distributed over a large range of North America, Europe and Asia. Introduced to New Zealand in the 19th century where they are a pest species and a major threat to native birds. Highly prized for its fur, which is brown in summer and white in winter. 2. the pelt of Mustela erminea.

  • e. marks in a horse, small brown or black spots on a white section of coat surrounding one or more coronets; resembles ermine.

• Ermine Rex a type of rabbit; see Rex (2).

• Erodium a plant genus in the family Geraniaceae, associated with photosensitization. Includes E. cicutarium (redstem storksbill) and E. moschatum (musky storksbill). Called also storksbill.

• Erophaca baetica Astragaluslusitanicus.

• erosion [-ro′zh n] an eating or gnawing away; a shallow or superficial ulceration; in dentistry, the wasting away or loss of substance of a tooth by a chemical process that does not involve known bacterial action.

• erosive stomatitis [ -ro′siv] a disease of the mouth characterized by the presence of discrete, superficial ulcers or erosions of the mucosal surface, as in bovine mucosal disease, rinderpest, and mucosal disease of cattle. Secondary ulcerative stomatitis is common.

  • endemic e. s. of cattle recorded in Africa. Similar to and may be identical with bovine papular stomatitis.

• ERPF effective renal plasma flow.

• errhine [er′īn] promoting a nasal discharge; an agent that so acts.

• Errington’s disease a disease of snowshoe hare, rabbit, and muskrat characterized by hemorrhagic enteritis and focal hepatic necrosis. The cause is not defined but Clostridium perfringens, Francisella tularensis, and Leptospira spp. have all been implicated.

• error [er′ r] the wrong answer in an experiment or result to a questionnaire.

  • experimental e. of two types, errors of objectivity when the experimenter knows the groups and the expected result, and errors of detection or measurement due to inadequate technique or the uneven application of measuring techniques.
  • random e. error that occurs due to chance.
  • sampling e. one due to the fact that the result obtained from a sample is only an estimate of that obtained from using the entire population.
  • standard e. the standard deviation of an estimate.
  • standard e. of mean the sampling variability of the mean.
  • systematic e. when the error is applied to all results, i.e., those due to bias.
  • e. types I and II in making a statistical test, you can reject the null hypothesis when it is true (type I) or accept the null hypothesis when it is false (type II).

• ertapenem a β-lactam antibiotic of the carbapenem class. It is active against most gram-positive and gram-negative bacteria; it is less active against Pseudomonas aeruginosa than other carbapenems.

• ERU equine recurrent uveitis.

• eructate performance of the act of eructation.

• eructation [-rk-ta′sh n] the oral ejection of gas or air from the stomach; belching. A normal activity for ruminants who void gases, principally methane, produced by fermentation in the rumen. Interference with eructation in those species causes ruminal tympany or bloat.

• eruption [ě-rup′sh n] 1. the act of breaking out, appearing or becoming visible, as eruption of the teeth. 2. visible efflorescent lesions of the skin due to disease, with redness, prominence, or both; a rash.

  • creeping e. see cutaneous larva migrans.
  • drug e. see drug eruption.
  • grouped tooth e. permanent posterior teeth erupting side by side with no replacement horizontally.
  • sequential tooth e. permanent posterior teeth replaced by craniad movement of caudal teeth; seen in macropods and elephants.
  • tooth e. times see Table 18. Used in veterinary medicine as a guide to an animal’s age.

• ERV expiratory reserve volume.

• Ervum see Vicia ervilia.

• Erwinia [r-win′e-] a genus of plant pathogens and saprophytes. See also Enterobacteriaceae.

• Erysimum cheiranthoides toxic plant in the family Brassicaceae; contains mustard oil glucosinolates that cause stomatitis, vomiting, diarrhea. Called also wormseed mustard, treacle mustard.

• erysipelas [er″ -sip′-l s] 1. infection with Erysipelothrix rhusiopathiae; occurs rarely in cattle and sheep, principally as an arthritis and laminitis, occasionally as a systemic infection. It is a common and serious infection in pigs, and turkeys. In pigs it may be a septicemia with characteristic diamond-shaped skin lesions or a chronic disease manifested principally as arthritis, sometimes as endocarditis. Turkeys are the only bird species affected at a significant level. In them, the disease is manifested as a septicemia with no diagnostic signs. 2. an erythematous–edematous lesion, commonly on the hand, resulting from contact with infected meat, hides, or bones; the usual lesion in humans and is called erysipeloid.

• erysipeloid [er″ -sip′ -loid] an acute infection, usually of the skin but rarely systemic, in humans caused by Erysipelothrix rhusiopathiae. It is acquired by direct contact with infected animals or meat; an occupational hazard for farmers and abattoir workers.

• Erysipelothrix [er″ -sip′ -lo-thriks″] a genus of Gram-positive rod shaped bacteria.

  E-63.

  

  Diamond (rhomboid)-shaped lesions on abdomen of a sow with erysipelas.

  • E. rhusiopathiae the causative organism of swine erysipelas. Also infects sheep, turkeys, and rats and causes the zoonotic disease erysipeloid in humans. Formerly called E. insidiosa. Has remarkable longevity in alkaline soils. Once infection appears on a farm it is likely to recur.

• erythema [er″ -the′m] redness of the skin caused by congestion of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection or inflammation.

  • e. ab igne see chronic radiant heat dermatitis.
  • e. chronicum migrans the early skin rash at the site of the tick bite which infects humans with Borrellia burgdorferi (Lyme disease); rarely seen in dogs.
  • e. multiforme (EM) a necrotizing skin disease, most often related to drugs being administered, including penicillins, cephalosporins, sulfona-mides, levamisole, and 5-fluorocytosine, but sometimes associated with systemic disease. It occurs in all species and is characterized by an acute onset of erythematous macules, papules, vesicles, or bullae. There may also be fever, depression, and anorexia. A very painful condition in young pet pot-bellied pigs where it is known as ‘dippity pig’.
  • e. multiforme major a rapidly fulminating, ulcerative form of erythema multiforme with involvement of oral mucosa and systemic signs.
  • necrolytic migratory e. an uncommon skin disease of dogs, rare in cats, associated with glucagon-secreting tumors of the pancreas or chronic liver disease. There are pruritic crusted, ulcerated lesions, mainly on the face, mucocutaneous areas, distal limbs, and feet. Called also hepatocutaneous syndrome, superficial necrolytic dermatitis, metabolic epidermal necrosis, diabetic dermatopathy.

• erythematous [er″ -them′-t s] characterized by erythema.

• erythremia [er″ -thre′me-] polycythemia vera.

• erythremic myelosis [er″ -thre′mik] a myeloproliferative disorder of cats, rarely other species, manifested by marked anemia but with marked anisocytosis without an accompanying polychromasia. Usually associated with feline leukemia virus infection. Large numbers of rubricytes can be found in the bone marrow and sometimes in the circulation. Called erythroleukemia under current classification systems. The condition has been compared to Di Guglielmo syndrome in humans.

• Erythrina [er″ -thri′n] a plant genus in the family Fabaceae; contains isoquinoline alkaloids; suspected of poisoning horses and cattle. Called also coral tree.

• erythritol [ -rith′rľ-tol] the sugar present in high concentration in the genital tract of the male and the pregnant female and enhances the growth of Brucella abortus, which preferentially utilizes erythritol.

• erythr(o)- word element. [Gr.] relationship to red or erythrocyte.

• erythroblast [ -rith′ro-blast] originally, any nucleated erythrocyte, but now more generally used to designate the nucleated precursor from which an erythrocyte develops. Called also normoblast, rubriblast.

  • basophilic e. see prorubricyte.
  • orthochromatic e. metarubricyte, normoblast.
  • polychromatophilic e. see rubricyte; called also polychromatophilic normoblast.

• erythroblastemia [-rith″ro-blas-te′me-] the presence in the peripheral blood of abnormally large numbers of nucleated red cells; erythro-blastosis.

• erythroblastic [ -rith″ro-blas′tik] of, or relating to erythroblasts.

  • e. islets a bone marrow unit consisting of a central macrophage and surrounding erythroblasts and in which differentiation of erythroblasts takes place.

• erythroblastoma [-rith″ro-blas-to′m] a tumor-like mass composed of nucleated red cells.

• erythroblastopenia [-rith″ro-blas″to-pe′ne-] abnormal deficiency of erythroblasts.

• erythroblastosis [ -rith″ro-blas-to′sis] the presence of erythroblasts in the circulating blood.

  • avian e. caused by the viruses of the leukosis/sarcoma group. Manifested by weakness, pallor, comb cyanosis, diarrhea, and spontaneous hemorrhage.
  • e. fetalis, e. neonatorum see neonatal hemorrhagic disease, alloimmune hemolytic anemia of the newborn.

• erythrochromia [-rith″ro-kro′me-] hemorrhagic, red pigmentation of the cerebrospinal fluid.

• erythroclasia [er″ -throk-la′zh] splitting up of erythrocytes.

• erythroclasis [er″ -throk′l -sis] fragmentation of the red blood cells.

• erythrocuprin [ -rith″ro-koo′prin] see ceruloplasmin.

• erythrocytapheresis [-rith″ro-si″t-f -re′sis] the withdrawal of blood, separation and retention of red blood cells, and retransfusion of the remainder into the donor.

• erythrocyte [ -rith′ro-sīt] a red blood cell, or corpuscle; one of the formed elements in the peripheral blood. For immature forms, rubriblast, prorubricyte, rubricyte, metarubricyte, and reticulocyte. In most mammals, mature erythrocytes are biconcave disks that have no nuclei. The degree of concavity varies between species, as does the size. Birds, reptiles, and amphibians have nucleated, oval erythrocytes. The cell consists mainly of hemoglobin and a supporting framework, called the stroma. Erythrocyte formation (erythropoiesis) takes place in the red bone marrow in the adult, and in the liver, spleen, and bone marrow of the fetus. Erythrocyte formation requires an ample supply of certain dietary elements such as iron, cobalt and copper, amino acids, and certain vitamins. See also erythrocytic series.

  • e. antigen see blood group antigen and blood group.
  • e. casts see urinary cast.
  • e. count see blood count.
  • e. ghosts see ghost cell (1).
  • hypochromatic e. see hypochromia (2).
  • e. indices calculated values for the mean corpuscular (cell) volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular (cell) hemoglobin concentration (MCHC), taken from the hematocrit, hemoglobin concentration and red blood cell count. Used in determining the likely etiology of anemias and other abnormalities of the erythron. Called also mean cell constants.
  • matchstick e. describes the appearance of sickled deer erythrocytes containing hemoglobin II.
  • normochromic e. see normochromia.
  • e. refractile bodies (ERF) a term usually used to describe Heinz bodies in the erythrocytes of cats. Sometimes restricted in definition to the smaller (Heinz) bodies that are normally found in up to 10% of feline erythrocytes, as distinct from larger bodies associated with hemolytic anemia.
  • e. sedimentation rate (ESR) an expression of the extent of settling of erythrocytes in a column of fresh citrated or otherwise treated blood, per unit of time. Of greatest diagnostic value in dogs, as horses normally have a greatly accelerated rate, and ruminants show none except in very extreme circumstances. In the dog, ESR is elevated with inflammatory processes. See also sedimentation rate.
  • e. tonicity the degree of distention of the erythrocyte. This is dependent on the osmotic pressure of the cell’s contents compared with that of the plasma. If it is greater, water will pass into the cell and it may rupture. If it is less, water passes out of the cell, which shrinks and becomes crenated.
  • e. volume mean corpuscular volume (MCV); see erythrocyte indices (above).

• erythrocythemia [-rith″ro-si-the′me-] polycythemia.

• erythrocytic [ -rith″ro-sit′ik] 1. pertaining to, characterized by, or of the nature of erythrocytes. 2. pertaining to the erythrocytic series.

• erythrocyto-opsonin [ -rith″ro-si″to-op-so′nin] see hemopsonin.

• erythrocytolysin [-rith″ro-si-tol′ -sin] a substance that produces erythrocytolysis.

• erythrocytolysis [-rith″ro-si-tol′ -sis] dissolution of erythrocytes and escape of hemoglobin; hemolysis.

• erythrocytorrhexis [ -rith″ro-si″to-rek′sis] a morphological change in erythrocytes, consisting in the escape from the cells of round, shiny granules and splitting off of particles.

• erythrocytosis [ -rith″ro-si-to′sis] increase in the concentration of red blood cells in the peripheral blood; characterized by an increased hematocrit (Hct), increased packed cell volume (PCV) and increased hemoglobin (Hgb). See also polycythemia.

  • e. stimulating factor a lipid isolated from the plasma of anemic animals; distinct from erythropoietin, causes production of microcytes without increasing hemoglobin. Its role in disease is unknown.
  • primary e. see polycythemia vera.
  • relative e. see relative polycythemia.
  • stress e. an apparent polycythemia resulting from diminished plasma volume. Called also relative polycythemia.

• erythroderma [-rith″ro-dur′m] abnormal redness of the skin over widespread areas of the body.

  • exfoliative e. reported in a single cow and her calves; believed to be an immune-mediated disorder associated with colostrum.
  • lymphomatous e. widespread redness of the skin associated with lymphoma.

• erythrodermatitis [-rith″ro-dur-m -ti′tis] hemorrhaging and inflammation of the skin of fish; often a characteristic of skin bacterial infections and some viral diseases. Called also carp erythrodermatitis.

• erythrodontia [-rith″ro-don′sh] reddish-brownish discoloration of teeth; can be seen in congenital erythropoietic porphyria.

  E-64.

  

  A macrophage showing erythrophagocytosis.

• erythrodysesthesia [e-rith″ro-dis″es-the′zh ] see palmar-plantar erythrodysesthesia syndrome.

• erythrogenesis [-rith″ro-jen′ -sis] the production of erythrocytes; erythropoiesis.

• erythrogenic [ -rith″ro-jen′ik] 1. producing erythrocytes. 2. producing or causing erythema.

• erythrogenin [ -rith″ro-jen′in] see erythropoietin.

• erythrogonium tissues from which red blood cells are produced.

• erythrogram [ -rith′ro-gram] includes the red blood cell count, mean corpuscular volume, hematocrit, hemoglobin concentration, and erythrocyte indices.

• erythroid [er″ľ-throid] 1. of a red color; reddish. 2. pertaining to the developmental series of cells ending in erythrocytes.

  • e. aplasia see pure red cell aplasia.
  • burst forming unit-e. (BFU-E) produced in in vitro cultures of erythroid stem cells. It has low sensitivity to erythropoietin and gives rise to colony forming unit-erythroid that, with erythropoietin, gives rise to erythroid cells.
  • e. hyperplasia increased numbers of erythrocyte precursors, as seen in a regenerative response to anemia.
  • e. hypoplasia see hypoplastic anemia.
  • e. leukosis see avian erythroblastosis.
  • e. metaplasia see bone marrow.

• erythrokeratodermia [-rith″ro-ker″-to-dur′me-] a reddening and hyperkeratosis of the skin.

  • e. variabilis autosomal dominant inherited epithelization/keratinization defect in humans. Rare reports in lambs and a foal.

• erythrokinetics [ -rith″ro-kľ-net′iks] the quantitative, dynamic study of in vivo production and destruction of erythrocytes.

• erythroleukemia [-rith″ro-loo-ke′me-] a neoplastic blood dyscrasia of dogs and cats; one of the myeloproliferative disorders, with atypical erythroblasts and myeloblasts in the peripheral blood.

• erythroleukosis [ -rith″ro-loo-ko′sis] see avian erythroblastosis.

• erythrolysis [er″ -throl′ -sis] hemolysis.

• erythromycin [ -rith″ro-mi′sin] a broad-spectrum antibiotic produced by a strain of Streptomyces erythreus. It is effective against a wide variety of organisms, including gram-negative and gram-positive bacteria. The stearate can be given orally; the lactobionate is a soluble salt that can be administered intravenously.

  E-65.

  

  Erythropoietin stimulates the bone marrow to produce red blood cells.

• erythron [er′ -thron] the circulating erythrocytes in the blood, their precursors, and all the body elements concerned in their production.

• erythroneocytosis [ -rith″ro-ne″o-si-to′sis] the presence of immature erythrocytes in the blood.

• erythropenia [-rith″ro-pe′ne-] deficiency in the number of erythrocytes.

• erythrophage [ -rith′ro-fāj] a neutrophil or macrophage that has ingested an erythrocyte.

• erythrophagia [-rith″ro-fa′j] erythrophagocytosis.

• erythrophagocytosis [ -rith″ro-fa″go-si-to′sis] engulfment of erythrocytes by other cells, often macrophages.

• erythropheresis [-rith″ro-f -re′sis] see erythrocytapheresis.

• erythrophil [ -rith′ro-fil] 1. a cell or other element that stains easily with red. 2. erythrophilous.

• erythrophilous [er″ľ-throf′ľ-l s] easily staining red.

• erythrophleine alkaloid esters of diterpenoid acids, the toxic agent in the tree Erythrophleum chlorostachys.

• Erythrophleum [-rith″ro-fle′ m] a plant genus of the Caesalpiniaceae family from Africa, Asia and Australia; contain diterpenoid alkaloids, e.g., erythrophleine, cause a clinical syndrome of tremor, ataxia, increased intensity of the heart sounds, dyspnea and sudden death. Includes E. africanum (ordeal tree, samburu), E. chlorostachys (Cooktown ironwood tree, camel poison), E. guineense (E. suaveolens, sassy bark).

• erythrophthisis a condition characterized by severe impairment of the restorative power of the erythrocyte-forming tissues.

• erythroplastid [ -rith″ro-plas′tid] an erythrocyte without a nucleus, as seen in mammals.

• erythropoiesis [ -rith″ro-plas′tid] the formation of erythrocytes. Called also hematopoiesis.

  • balanced e. balanced progressive development of the nucleus and the cytosol of the erythrocytes.
  • ineffective e. hemopoietic production that does not result in the functional release of new erythrocytes.

• erythropoietic [ -rith″ro-poi-et′ik] emanating from or pertaining to erythropoiesis.

• erythropoietin (EPO) [-rith″ro-poi′ -tin] a glycoprotein hormone secreted mainly by the kidney. A profactor, erythropoietinogen, is first produced in the liver, transferred to the kidney, and converted to active erythropoietin in the kidney. The erythropoietin acts on stem cells of the bone marrow to stimulate red blood cell production (erythropoiesis). This effect has given rise to illicit use for performance enhancement in sporting animals. Plasma concentrations increase in anemias, except for those caused by chronic renal disease or inflammation. Measurement may be done to differentiate primary from secondary erythrocytosis. Called also erythropoietin stimulating factor, erythrogenin. See also darbepoetin alfa.

  • recombinant e. produces an initial erythroid response when used to treat dogs and cats with nonregenerative anemia of renal disease, but many animals develop antibodies to the recombinant human product epoetin alfa (reHuEPO), limiting its use. Darbepoetin alfa appears less immunogenic.
  • e. stimulating factor see erythropoietin (above).

• Erythrovirus [-rith′ro-vi″r s] a genus in the family Parvoviridae, subfamily Parvovirinae.

• erythropoietinogen precursor of erythropoietin.

• erythrosine [ -rith′ro-sēn] depresses thyroid function by inhibiting 5′-deiodinase.

  E-66.

  

  Full-thickness burn with eschar in a dog caused by using a heating pad for postoperative warming.

• erythrostasis [ -rith″ro-sta′sis] the stoppage of erythrocytes in the capillaries, as in disseminated intravascular coagulation.

• Erythroxylum a South American genus in the family Erythroxylaceae. E. coca (coca), E. novogranatense and E. bolivianum are sources of cocaine. Fruits of E. argentinum are poisonous to sheep.

• erythruria [er″ľ-thru′re- ] excretion of red urine.

• Es chemical symbol, einsteinium.

• escape [ s-kāp′] the act of becoming free.

  • autoregulatory e. after prolonged tissue hypoxia of shock, sympathetic-mediated vasoconstriction gives way to vasodilation in all organs.
  • vagal e. the exhaustion of or adaptation to neural chemical mediators in the regulation of systemic arterial pressure.
  • ventricular e. extrasystole in which a ventricular pacemaker becomes effective before the sinoatrial pacemaker; it usually occurs with slow sinus rates and often, but not necessarily, with increased vagal tone.

• eschar [es′kahr] a deep cutaneous slough such as that produced by a thermal burn, a corrosive action, a decubitus ulcer, a saddle gall, or setfast.

• escharotic [es″k -rot′ik] 1. capable of producing an eschar; corrosive. 2. a corrosive or caustic agent.

• escharotomy [es″k -rot′ -me] surgical incision of the eschar and superficial fascia of a circumferentially burned limb in order to permit the cut edges to separate and restore blood flow to unburned tissue distal to the eschar. Edema may form beneath the inelastic eschar of a full-thickness burn and compress arteries, thus impairing blood flow and necessitating an escharotomy. The incision is protected from infection with the same antimicrobial agent being used on the burn wound.

• Escherichia [esh″ -rik′e-] a genus of widely distributed gram-negative bacteria in the family Enterobacteriaceae.

• Escherichia coli [esh″ -rik′e-] a species of bacteria in the genus Escherichia constituting a significant proportion of the normal intestinal flora of animals. Pathogenic strains cause urinary tract infections, epidemic diarrheal diseases, especially in newborn animals, pyometra in dogs and late respiratory disease in broiler chickens. Also a common opportunistic pathogen. See also colibacillosis, coliform mastitis, coliform gastroenteritis, avian coliform septicemia, mastitis–metritis–agalactia, enteropathogenic, enterotoxigenic, shiga-like toxins.

  • E. coli 0157:H7 a shiga-like toxin (verotoxin) producing E. coli that has been responsible for outbreaks of hemorrhagic colitis, especially in children, but in all ages. Case fatality rates can be high, especially where there is the complication of the hemolytic uremic syndrome (HUS). The organism is carried by cattle who show no sign of clinical disease and many outbreaks have been epidemiologically linked to food products of bovine origin. The mass handling and marketing of minced beef allow a contaminated batch to affect a large population. The infective dose for man is estimated at a few organisms and infection can also be picked up by children visiting petting zoos or on farm visits. Also linked to hemorrhagic enteritis in dogs. Also called enterohemorrhagic E. coli.
  • E. coli J5 vaccine vaccine prepared from E. coli mutant; provides protection against coliform mastitis in cows.
  • attaching and effacing E. coli (AEEC) cause enteritis, colitis, and diarrhea in a number of different animal species by expressing a virulence factor protein called intimin that allows intimate attachment of the organism to the microvillus brush border of enterocyte forming a characteristic attaching and effacing lesion. Diagnosis is by the detection of the characteristic lesions. Called also enteropathogenic E. coli.
  • diarrheagenic E. coliE. coli that cause diarrhea. Categorized into pathotypes that include enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli (EAEC).

• Eschscholtzia californica [-shōlt′se-] a North American plant in the Papaveraceae family. High content of isoquinoline alkaloids but poisoning not reported. Called also California poppy.

• esculin [es′ku-lin] a hydroxycoumarin glycoside found in the bark of Aesculus spp. Together with ferric citrate, it is used in a broth for the identification of some bacteria that cause hydrolysis and a color change. Also causes animal poisoning; see Aesculus.

• escutcheon [es-kuch′ n] the shield-like pattern of distribution of the haircoat in the area below the vulva, down to the top of the udder, in the cow. The escutcheon itself is composed of hairs that lie vertically downward; its edges consist of a well-demarcated ridge created when this vertically inclined hair meets the horizontally inclined hair of the lateral aspect of the thigh. Wishful-thinking herdsmen used to read predictions of milking capacity into the shape of the escutcheon of a dairy cow.

• eserine [es′ r-in] physostigmine.

• -esis word element. [Gr.] state, condition, process.

• Eskimo dog a term sometimes applied to any of the Arctic breeds of dogs, such as Samoyed, Alaskan malamute, and Siberian Husky, as well as the breeds, American Eskimo dog and Canadian Eskimo dog.

• Esmarch [es′mahrk] having to do with Johann Esmarch, a 19th century German surgeon.

  • E’s bandage an India rubber bandage applied upward around (from the distal part to the proximal) a distal limb in order to expel blood from it; the part is often elevated as the elastic pressure is applied.
  • E. plaster shears, scissors see plaster shears.

• esmolol [es′mo-lol] a class II antiarrhythmic. A cardioselective beta1 receptor blocker with rapid onset, a very short duration of action, and no clinically important intrinsic sympathomimetic or membrane stabilising activity at therapeutic dosages.

• eso- word element. [Gr.] within.

• esoethmoiditis [es″o-eth-moi-di′tis] inflammation of the ethmoid sinuses.

• esogastritis [es″o-gas-tri′tis] inflammation of the gastric mucosa.

• esomeprazole a proton pump inhibitor used in the treatment and prevention of gastrointestinal ulceration. Similar to omeprazole.

• esophageal [-sof″-je′ l] of or pertaining to the esophagus.

  • e. achalasia see megaesophagus.
  • e. anomalies very rare; include atresia, duplication, segmental aplasia, esophagorespiratory fistulae, diverticula, epithelial inclusion cysts.
  • e. atresia congenital lack of continuity of the esophagus, commonly accompanied by tracheoesophageal fistula, and characterized by accumulations of mucus in the nasopharynx, gagging, vomiting when fed, cyanosis, and dyspnea. Treatment is by surgical repair with esophageal anastomosis and division of the fistula.
  • e. distention can result from acute or chronic obstruction of the esophagus, or from defective innervation. See also megaesophagus.
  • e. duplication can be tubular and communicate with the effective esophagus, or cystic appearing as a cystic mass close to the functioning esophagus.
  • e. ectasia see megaesophagus.
  • e. enlargement clinically visible enlargement as seen in esophageal diverticulum, stenosis, paralysis, cardial obstruction.
  • e. fibrosis a cause of acquired megaesophagus; usually caused by trauma or spontaneous ulceration.
  • e. groove see reticular² groove.
  • e. groove lesion includes granuloma, papilloma, foreign body lodgment; cause of obstructive bloat.
  • e. hyperkeratosis hyperkeratotic thickening of the esophageal mucosa due usually to hypovitaminosis A or chlorinated naphthalene poisoning.
  • e. hypomotility see megaesophagus.
  • e. inflammation see esophagitis.
  • e. motility disorders see megaesophagus.
  • e. neoplasm rare, but leiomyoma is most common in dogs and squamous carcinoma in cats; osteosarcoma and fibrosarcomas occur in dogs in association with Spriocerca lupi infection. Causes chronic esophageal obstruction.
  • e. obstruction acute obstruction is manifested by inability to swallow, regurgitation of saliva, food and water through the nose and much discomfort expressed by retching movements and pawing at the throat. Ruminants develop ruminal tympany. Prolonged obstruction leads to dehydration, acid:base abnormalities, disorders of electrolyte metabolism, weight loss and aspiration pneumonia.
  • e. osteosarcoma occurs in dogs following malignant transformation of inflammatory granulomas associated with the parasite Spirocerca lupi; esophageal fibrosarcomas can arise similarly.
  • e. papilloma a cause of obstructive bloat.
  • e. paralysis causes esophageal obstruction.
  • e. patching see patch graft.
  • e. perforation generally caused by penetrating wounds or foreign bodies; causes local cellulitis and compression-obstruction of esophagus.
  • e. pulsion diverticulum a diverticulum that pushes outward causing pressure on surrounding organs and tissues.
  • e. segmental aplasia causes esophageal obstruction in neonates.
  • e. stenosis, e. stricture generally as a result of severe esophagitis or esophageal surgery; causes esophageal obstruction that may be partial, permitting passage of liquids.
  • e. ulcer usually associated with pressure necrosis due to prolonged obstruction and injury by a solid foreign body or, rarely equine dysautonomia or Gasterophilus spp. infestation.
  • e. varices distended veins at the gastric cardia causing dysphagia.

• esophagectasia [-sof--jek-ta′sh] dilatation of the esophagus.

• esophagectomy [-sof″-jek′t -me] excision of a portion of the esophagus.

• esophagism [-sof′-jiz- m] spasm of the esophagus.

• esophagismus [-sof″-jiz′m s] see esophagism.

• esophagitis [-sof″ -ji′tis] inflammation of the esophageal mucosa and sometimes the uderlying muscularis. Primary esophagitis, caused by physical irritants, causes spasm and obstruction, with pain on swallowing or palpation, profuse salivation, regurgitation of slimy, blood-stained saliva and feed, and may lead to stricture formation. Esophagitis also occurs commonly in ruminants as a secondary lesion in diseases characterized by erosive and vesicular lesions of the alimentary tract. Gastric reflux, invasion of the esophageal wall by Hypoderma spp., thallotoxicosis, and paraquat poisoning are other causes.

  • peptic e. inflammation of the esophagus due to a reflux of acid and pepsin from the stomach. Called also reflux esophagitis or peri-operative reflux.
  • reflux e. see peptic esophagitis (above).

• esophagobronchial [-sof″-go-brong′ke- l] pertaining to or communicating with the esophagus and a bronchus, e.g., esophagobronchial fistula.

• esophagocele [-sof′ -go-sēl″] abnormal distention of the esophagus; protrusion of the esophageal mucosa through a rupture in the muscular coat.

• esophagocoloplasty [-sof″ -go-ko′lo-plas″te] excision of a portion of the esophagus and its replacement by a segment of the colon.

• esophagodynia [-sof″-go-din′e-] pain in the esophagus.

• esophagoenterostomy [-sof″-go-en″tr-os′t -me] surgical formation of an anastomosis between the esophagus and the small intestine.

• esophagoesophagostomy [-sof″-go--sof″-gos′t -me] anastomosis between two formerly remote parts of the esophagus.

• esophagogastrectomy [-sof″-go-gas-trek′t -me] excision of the esophagus and stomach.

• esophagogastric [-sof″ -go-gas′trik] pertaining to the esophagus and the stomach.

  • e. ulcer in pigs, manifest with hyperkeratinization and ulceration in the pars esophagea of the stomach. If an ulcer erodes to a blood vessel, the pig can become anemic or bleed to death. In affected herds, a significant proportion of pigs develop hyperkeratosis and ulceration but only a proportion show clinical disease. Risk factors include housing and stocking density, the use of pelleted feeds and low fiber and small particle size of feed.

• esophagogastroanastomosis [-sof--go-gas″tro- -nas″to-mo′sis] esophagogastrostomy.

• esophagogastroduodenoscopy [-sof″-go-gas″tro-doo″od--nos′k -pe] endoscopic examination of the esophagus, stomach, and duodenum using a flexible endoscope. Also known by the acronym EGD.

• esophagogastroplasty [-sof″ -go-gas′tro-plas″te] plastic repair, or reconstruction, of the esophagus and stomach. See also cardioplasty.

• esophagogastroscopy [-sof″-go-gas-tros′k -pe] endoscopic examination of the esophagus and stomach.

• esophagogastrostomy [-sof″-go-gas-tros′t -me] anastomosis of the esophagus to the stomach.

• esophagogram [-sof′ -go-gram] a contrast radiograph of the esophagus.

• esophagography [-sof″-gog′r -fe] radiography of the esophagus.

  E-67.

  

  Lateral radiograph of an esophagogram in dog with a radiolucent foreign body seen as a filling defect within the barium.

• esophagojejunostomy [-sof--go-je″joo-nos′t -me] anastomosis of the esophagus to the jejunum.

• esophagomalacia [-sof″-go-m-la′sh] softening of the walls of the esophagus.

• esophagometer [-sof″-gom′-t r] an instrument for measuring the esophagus.

• esophagomyotomy [-sof″-go-mi-ot′ -me] incision through the muscular coat of the esophagus. See also Heller’s myotomy.

• esophagoplasty [-sof′ -go-plas″te] plastic repair of the esophagus.

• esophagoplication [-sof″-go-plľ-ka′sh n] infolding of the wall of an esophageal pouch.

• esophagoptosis [-sof″-gop-to′sis, -sof″ -go-to′sis] prolapse of the esophagus.

• esophagopulmonary [-sof″ -go-pool′mo-nar″e] pertaining to the esophagus and lungs, e.g. esophagopulmonary fistula.

• esophagorespiratory [-sof″-go-res′-pľ-r -tor″e] pertaining to or communicating with the esophagus and respiratory tract (trachea or a bronchus).

  • e. fistula between the esophagus and trachea.

• esophagorespiratory fistula [-sof″-go-res′-pľ-r -tor″e] congenital or acquired, the latter usually after traumatic injury; characterized by gastric inflation and aspiration pneumonia.

• esophagoscope [-sof′ -go-skōp] a rigid or flexible endoscope for examination of the esophagus.

• esophagoscopy [-sof″ -gos′ko-pe] direct visual examination of the interior (lumen and epithelial surface) of the esophagus with an endoscope. Esophagoscopy is performed as a diagnostic procedure for the purpose of locating and investigating a disorder of the esophagus. After the endoscope has been inserted into the esophagus, it is possible to obtain samples of tissue for microscopic study. In some instances, the endoscope may also be used to treat the disorder, such as removal of a foreign object that has become lodged in the esophagus, and laser ablation of fibrous strictures or luminal masses.

• esophagostenosis [-sof″-go-st -no′sis] stricture of the esophagus.

• esophagostomiasis [-sof″-go-sto-mi′ -sis] infestation with Oesophagostomum spp.

• esophagostomosis [-sof″ -go-sto-mo′sis] infestation with Oesophagostomum spp. worms; causes necrotic nodules in the wall of the intestine. The resulting clinical syndrome includes poor condition and the passage of soft droppings containing more than normal amounts of mucus.

• esophagostomy [-sof″-gos′t -me] the creation of an artificial opening into the esophagus.

  • cervical e. one performed in cervical section of esophagus, often for purposes of placing an indwelling feeding tube when oral alimentation is impossible because of injury or surgery of the oropharynx.

• esophagotomy [-sof″-got′ -me] incision of the esophagus.

• esophagotracheal [-sof″-go-tra′ke- l] pertaining to or communicating with the esophagus and trachea, e.g., esophagotracheal fistula.

• esophagram [-sof′ -gram] see esophagogram.

• esophagus [-sof′-g s] the musculomembranous passage extending from the pharynx to the stomach, consisting of an outer fibrous coat, a muscular layer (all striated in dogs and ruminants, plus some smooth muscle in cats, pigs, and horses), a submucous layer, and an inner mucous membrane. Each end is equipped with a functional sphincter, although these are not distinct anatomically. It is divided into a cervical part that extends from the pharynx to the first rib, a thoracic part that extends from the first rib to the diaphragm, and a final short abdominal part between the diaphragm and stomach.

  • redundant e. a ventral esophageal deviation at the thoracic inlet. Seen on lateral thoracic radiographs as a soft tissue band over the dorsal trachea at the thoracic inlet.
  • rhabditiform e. an anterior esophagus shaped like a club connecting through a narrow neck (isthmus) to a bulbous posterior part (corpus); all free-living nematodes have an esophagus of this type.

• esosphenoiditis [es″o-sfe″noi-di′tis] osteomyelitis of the sphenoid bone.

• esotropia [es″o-tro′pe- ] strabismus in which there is medial deviation of the visual axis of one eye toward that of the other eye, resulting in diplopia. Called also cross-eye and convergent strabismus. Commonly seen in Siamese cats.

• Esox a large predatory freshwater fish in the family Esocidae. The two common species are E. lucius (northern pike) and E. americanus (pikerel), both popular sporting fish. Called also pike.

• espichamento Span.[Span.] see enzootic calcinosis.

• esponja swamp cancer.

• espundia [es-p n′jah] leishmaniasis, particularly L. braziliensis. name used for pythiosis in Columbia.

• ESR erythrocyte sedimentation rate.

• ESRI Environmental Systems Research Institute.

• essence [es′ ns] 1. the distinctive or individual principle of anything. 2. a mixture of alcohol with a volatile oil.

• essential [-sen′sh l] 1. constituting the necessary or inherent part of a thing; giving a substance its peculiar and necessary qualities. 2. indispensable; required in the diet, as essential fatty acids. 3. idiopathic; self-existing; having no obvious external exciting cause.

• Essig wiring technique a method of stabilizing alveolar fractures using wire looped around a group of teeth with secondary wires looped around individual teeth.

• ester [es′t r] chemical combination of an alcohol and an acid. In domestic animals the most common linkage is glycerol with fatty acid to form glycerides.

• esterase [es′t r-ās] any enzyme that catalyzes the hydrolysis of esters into its alcohol and acid.

  • lipid e. an enzyme found in pancreatic secretions that requires bile acids to be active.

• esteratic site that part of a cholinesterase macromolecule that recognizes and binds acetylcholine. This combination results in the hydrolysis of the acetylcholine.

• esterification [es-ter″ľ-fľ-ka′sh n] conversion of an acid into an ester by combination with an alcohol and removal of a molecule of water.

• esterify [es-ter′ľ-fi] to combine with an alcohol with elimination of a molecule of water, forming an ester.

• esterolysis [es″t r-ol′ -sis] the hydrolysis of an ester into its alcohol and acid.

• esterophilic site that part of a cholinergic receptor macromolecule that attracts the ester part of acetylcholine. Hydrolysis of the acetylcholine does not occur at this location.

• esthematology [es″them- -tol′ -je] esthesiology.

• esthesi(o)- word element. [[Gr.] sensation, perception.

• esthesiogenic [es-the″ze-o-jen′ik] producing sensation.

• esthesiology [es-the″ze-ol′ -je] the scientific study or description of the sense organs and sensations.

• esthesiometer [es-the″ze-om′ -t r] an instrument for measuring tactile sensibility; tactometer.

• esthesiometry [es-the″ze-om′ -tre] measurement of sensation; used particularly in relation to the cornea.

• esthesioneurosis [es-the″ze-o-n $\stackrel{⌣}{o}$ $\stackrel{⌣}{o}$ -ro′sis] any disorder of the sensory nerves.

• esthesiophysiology [es-thethe″ze-o-fiz″e-ol′ -je] the physiology of sensation and sense organs.

• esthesodic [es″th -zod′ik] conducting or pertaining to conduction of sensory impulses.

• estimate [es′tľ-m t] a measurement that is believed likely to incorporate a degree of error.

• estimated breeding value see estimated breeding value.

• estimated transmitting ability an estimate of an animal’s ability to transmit its phenotypic value or performance—its breeding value. Called also ETA.

• estival [es′tľ-v l, -sti′v l] pertaining to, or occurring in, summer.

• estivation [es″tľ-va′sh n] prolonged torpor or dormancy of an amphibian, fish or insect during a hot or dry period. The opposite of hibernation.

• estivoautumnal [es″tľ-vo-aw-tum′n l] occurring in summer and autumn.

• estradiol [es″tr -di′ol, es-tra′de-ol] the female steroid hormone produced by the mature ovarian follicle and the adrenal cortex and responsible for sexual receptivity at the time of estrus. Is the dominant estrogenic hormone in the nonpregnant animal. In the pregnant animal, the dominant hormone is estrone; called also estradiol-17β; commercial products include estradiol benzoate, and the cyprionate.

  • e. cyclopentyl propionate a pharmaceutical preparation used in dogs; recorded as a cause of hyperestrogenism.

• estral pertaining to estrus.

  • e. eversion see vaginal prolapse.

• estranes [es′trānz] parent structure of the estrogenic steroids.

• Estrela mountain dog a large, powerful, mastiff type dog with a powerful head, small ears, short, thick neck, and long tail. The coat may be short or long, and fawn, brindle, or wolf gray in color. Named after the Estrela mountain range in Portugal. Called also Portuguese shepherd.

• estrin [es′trin] estrogen.

• estrinization [es″trin-ľ-za′sh n] production of the cellular changes in the vaginal epithelium characteristic of estrus.

• estriol [es′tre-ol] a relatively weak estrogen, a hydroxylated metabolite of estradiol or estrone. A major urinary estrogen of pregnant women and produced by the placenta. Used in treatment of urinary incontinence in spayed female dogs.

• estrogen [es′tr -jen] a generic term for estrus-producing compounds; the naturally occurring female sex hormones include estradiol, estriol, and estrone. In animals, the estrogens are formed in the ovary, adrenal cortex, testis, and fetoplacental unit, are responsible for female secondary sex characteristic development, and act on the female genitalia to produce an environment suitable for fertilization, implantation, and nutrition of the early embryo. A very important function is the creation of a state of sexual receptivity in the female.

  • conjugated e’s a mixture of sulfate esters of estrogenic substances, principally estrone and equilin; the uses are those of estrogens.
  • esterified e’s a mixture of esters of estrogenic substances, principally estrone; the uses are those of estrogens.
  • fungal e. see Fusarium graminearum.
  • placental e. see estrogen (above).
  • plant e. phytoestrogen. Subterranean and red clover may contain significant amounts of an isoflavone, genistein, with estrogenic activity. See also estrogenism.
  • e. poisoning see estrogenism.

• estrogen-induced [es′tr -jen] stimulated by high blood concentrations of estrogen.

  • e.-i. transdifferentation a persistent high estrogen intake causes male behavior in ewes and secondary sex characters, e.g., mammary gland and teat hypertrophy, in wethers, and changes in the promotion of development of endometrial-type glands in the cervix.
  • e.-i. uroliths diets high in estrogens thought to contribute to the development of uroliths by increasing the rate of epithelial desquamation in the urinary tract, thus facilitating the formation of a nidus around which concretion of salts can then develop.

• estrogenic [es-tro-jen′ik] estrus-producing; having the properties of, or properties similar to, an estrogen.

  • e. substances are used in treatment of animals for diseases of the reproductive tract. In some countries, they are still used as growth promotants in food animals. They also occur naturally in cultivated plants, e.g., subterranean clover, in fungi growing on plants, and plant products, e.g., Fusarium graminearum, F. roseum. Poisoning with estrogens can occur in any of these circumstances. The clinical signs are, in general terms, feminization of males, and in females nymphomaniac activity and infertility due to endometrial changes, prolapse of the cervix and uterus, and maternal dystocia due to uterine inertia. See also Trifolium, Fusarium, fusariotoxicosis, growth promotants.

• estrogenism [es-tro-jen′iz- m] the disease state caused by the continued abnormally high serum concentrations of estrogen, which can be due to endocrine disease or more frequently ingestion of low but toxic concentrations of estrogens. This can be iatrogenic in origin in companion animals, but the most important occurrence is in farm animals pastured on plants containing phytoestrogens. The signs are those related to endometrial hyperplasia and vaginal tumefaction, including long-term infertility and rectal prolapse, especially in pigs; uterine prolapse, especially in ewes; and feminization of male castrates. Dogs are particularly susceptible to the myelotoxic effects of estrogens, and high dose or prolonged administration causes severe bone marrow depression with thrombocytopenia, then leukopenia and anemia.

• estrone [es′trōn] an oxidation product of estradiol, and androstenedione in the animal body; less active than estradiol and produced in greater quantities in the pregnant female.

  • e. sulfate test 1. a pregnancy diagnosis carried out in several species; has very high accuracy but impractical because of lateness of applicability, e.g., maximum at day 105 of pregnancy in cows. An important test for the viability of the fetus in equines and camelids. 2. a test using serum that detects the presence of a retained testicle in horses with no testicles in the scrotum but that are demonstrating sexual behavior.

• estrophilin [es″tro-fil′in] a cell protein that acts as a receptor for estrogen, found in estrogenic target tissue and in estrogen-dependent tumors and metastases.

• estropipate [es′tro-pľ-pāt] a preparation of piperazine estrone sulfate used therapeutically for its estrogenic activity.

  E-68.

  

  Diagram of the estrus cycle and anestrus in the dog.

• estrous [es′tr s] pertaining to or emanating from estrus.

• estruation [es″troo-a′sh n] see estrus.

• estrum [es′tr m] see estrus.

• estrus [es′tr s] the time during the reproductive cycle in animals when the female displays interest in mating and in most species will stand to be mated by males. In most cases, the animal is about to or has just ovulated, and is therefore pregnable, but some, including pregnant ones, may not be in true estrus. At the time of estrus, there are behavioral signs and changes in the external genitalia. In cows, these include the passage of very clear mucus, swelling of the lips of the vulva, and hoof brush marks on the side of the rump. Mares show frequent urination with squatting, elevation of the tail, swelling and winking of the vulva, and rhythmic extrusion of the clitoris, usually only in the presence of a stallion. Ewes are not demonstrative other than positioning themselves close to the rams or teasers. Goats do bleat a lot, rub themselves against fixed objects and hold their tail high, urinate frequently, and evert the clitoris. Bitches wander away, stand with their tails held to one side, and are attractive and receptive to males. Queens may be very demonstrative, especially Siamese. They rub against anything, crawl with their belly close to the floor, roll, and vocalize with a deep, throaty growl.

  • e. cycle one of the two types of reproductive cycles, the other is the menstrual cycle of humans and primates. Regularly occurring periods during which the female is sexually active and receptive, estrus, separated by periods in which there is no sexual receptivity. This period is divided, on the basis of ovarian activity into metestrus (early corpus luteum development), diestrus (mature corpus luteum), and pro-estrus (period of follicle development). The details of estral activity are summarized in Table 16.
  • e. detection in natural mating the male is, in most situations, the best possible detector. In artificial breeding or in hand mating, the need to pick cows that are on heat is of paramount importance. Techniques available include the use of infertile teasers combined with heat mount detectors, tail paint, chin ball, or siresine harnesses. In dairy herds, it is usual to dispense with the teasers and depend on other cows to pick out and mount the cows that are in heat. In sheep, crayon or paint marking harnesses are used. In mares, individual teasing with a pony or similar manageable male is used. In the other species, detection is by simple visualization. In horses, estrus detection is done by presenting the mare to a stallion, also referred to as a teaser stallion; also referred to as teasing.
  • e. expectancy chart a wall chart for use at the dairy that points out those cows that are due to come into estrus during the next day or two and need to be observed closely.
  • false e. behavioral and external genital signs of estrus without ovulation occurring.
  • e. induction see estrus synchronization (below).
  • no visible e. abbreviated NVO (to accommodate the British spelling of oestrus) or NVE. Diagnosis indicating reproductive inefficiency; applied to cows that are not observed as being in estrus for a variable period, usually 50 days, after calving. Includes cows with anestrus due to various causes and failure of staff to observe or record estrus. A percentage of more than 10% of cows in a herd that have no visible estrus is an indication of a herd problem.
  • silent e. ovulation occurs, as detected by palpation or estrogen concentrations in the blood in the absence of behavioral signs.
  • split e. occurs in bitches, especially during the first heat. Early signs do not proceed, and the bitch is not mated but comes on heat 1–6 weeks later when she may be fertile. Occurs sporadically also in most other species. In mares, split-heat or split-estrus occurs at the beginning of the breeding season.
  • e. suppression prevention of estral activity in companion animals without spaying them is practiced frequently. A variety of progestins are available and, at times, intravaginal and intrauterine devices have been used for this purpose. See also contraception.
  • e. synchronization aimed at having all of the animals in estrus, and later calving or lambing, at the same time. Prostaglandin injection is a common technique used to induce estrus in cows. Estrus synchronization is based on several combinations of hormones, either interrupting the cycle or “creating” an artificial luteal phase. Ovulation synchronization is used now more commonly in dairy cattle for fixed-time or appointment-time artificial insemination.
  • unexpressed e. see silent estrus (above).

• esu electrostatic unit.

• ETA estimated transmitting ability.

• eta [a′t ] seventh letter of the Greek alphabet, Η or η.

• etching [ech′ing] see acid etch technique.

• ETEC enterotoxigenic Escherichia coli.

• ethacrynic acid [eth″ -krin′ik] a loop diuretic; effective in promoting sodium and chloride excretion.

• ethambutol [ -tham′bu-tol] a tuberculostatic agent.

• ethanol [eth′ -nol] the major ingredient of alcoholic beverages; called also ethyl alcohol and grain alcohol.

  • 20% e. administered intravenously, it can be used in the treatment of ethylene glycol poisoning in dogs. Pets may be poisoned by consumption of ethanol, usually in the form of alcoholic beverages. Signs include an initial period of excitement and incoordination, followed by stupor, coma, respiratory failure, and seizures.
  • e. gel test used to detect the presence of fibrinogen-split products in a blood sample; based on the separation of the split products from fibrinogen by the use of ethanol.

• ethanolamine [eth″ -nol′ -mēn] a colorless, moderately viscous liquid with an ammoniacal odor contained in cephalins and phospholipids, and derived metabolically by decarboxylation of serine.

  • e. phosphotransferase an enzyme of the endoplasmic reticulum, particularly in the liver, that catalyzes the biosynthesis of phosphatidyl-ethanolamine.

• ethaverine an analog of papaverine used as an antispasmodic and smooth muscle relaxant.

• ethene see ethylene.

• ether [e′th r] any organic compound containing an oxygen atom bonded to two carbon atoms.

• ethereal [-the′re- l] 1. pertaining to, prepared with, containing or resembling ether. 2. evanescent; delicate.

  • e. sulfates an important detoxication process in the liver is the formation of these sulfates that are more readily excreted than the parent compounds.

• etherization [e″th r-ľ-za′sh n] induction of anesthesia by means of ether; an antiquated term.

• ethics [eth′iks] rules or principles that govern right conduct. Each practitioner, upon entering a profession, is invested with the responsibility to adhere to the standards of ethical practice and conduct set by the profession.

  • code of e. the written rules of ethics.
  • veterinary e. the values and guidelines governing decisions in veterinary practice.

• ethidium bromide [-thid′e- m] a molecule that intercalates double-stranded nucleic acid and is frequently used as a fluorescent dye for the staining of DNA fragments after electrophoretic separation in agarose gels. See also homidium.

• ethinyl estradiol [eth′ľ-n l] see estradiol.

• ethiofencarb a carbamate pesticide.

• ethmocarditis [eth″mo-kahr-di′tis] inflammation of the connective tissue of the heart.

• ethmoid [eth′moid] 1. sievelike; cribriform. 2. the ethmoid bone.

  • e. bone the sievelike bone that contributes to the roof of the nasal fossae and part of the rostral cranial fossa. See also Table 9.
  • e. sinus see concha.

• ethmoidal [eth-moi′d l] pertaining to the ethmoid bone.

  • enzootic e. tumor see enzootic ethmoidal tumor.
  • e. foramen one or two foramina in the medial wall of the orbit that transmit(s) the ethmoidal nerve as it re-enters the cranial cavity.
  • progressive e. hematoma hematoma in horses that arises from the ethmoid region and grows slowly in paranasal sinuses and the nasal passage. Characterized by epistaxis and nasal obstruction. Most often unilateral. Diagnosis is on clinical signs, upper respiratory endoscopy and radiographic findings. Called also hemorrhagic nasal polyp, progressive nasal hematoma.

• ethmoidectomy [eth″moid-ek′t -me] excision of the ethmoid cells or of a portion of the ethmoid bone.

• ethmoiditis [eth″moi-di′tis] inflammation of the ethmoid bone or ethmoid sinuses.

• ethmoidotomy [eth″moi-dot′ -me] incision into the ethmoid sinus.

• ethmoturbinal [eth″mo-tur′bľ-n l] relating to or consisting of the ethmoturbinates.

• ethmoturbinate [eth″mo-tur′bľ-nāt] the scroll-like, papyraceous parts of the ethmoid bone occupying the caudal part of the nasal fossae.

  • e. tumors see enzootic nasal adenocarcinoma, enzootic ethmoidal tumor.

• ethnoveterinary medicine the folk beliefs, knowledge, skills, methods and practices relating to the health care of animals. Includes medicinal and spiritual aspects, but more commonly taken to mean the use of medicinal plants.

• ethogram a list or catalog of types of defined behaviors or behavior patterns observed in a particular species.

• ethologist [e-thol′ -jist] a person skilled in ethology.

• ethology [e-thol′ -je] the scientific study of animal behavior, particularly in the natural state.

• ethopabate [eth″o-pab′āt] a supplementary drug that improves the coccidiostatic effect of amprolium.

• ethosuximide [eth″o-suk′sľ-mīd] a succinide derivative used as an anticonvulsant. See succinimides.

• ethoxyquin a synthetic antioxidant added to animal feeds to prevent loss of fat, vitamins A and E, and to prevent avian encephalomalacia.

• ethoxzolamide [eth″oks-zol′ -mīd] a carbonic anhydrase inhibitor diuretic, used mainly to reduce intraocular pressure in glaucoma. No longer used.

• ethyl [eth′ l] the monovalent radical, C₂H₅.

  • e. alcohol see ethyl alcohol; called also ethanol and grain alcohol.
  • e. aminobenzoate see benzocaine.
  • e. carbamate see urethane.
  • e. chloride a local anesthetic applied topically to intact skin. It has a very low boiling point, and the skin is temporarily frozen and insensitive to pain.
  • e. lactate an antibacterial agent used in shampoos.

• ethylene [eth′ -lēn] a colorless, highly flammable gas with a slightly sweet taste and odor, once used as an inhalant anesthetic.

  • e. dibromide (EDB) grain fumigant. Treated seed seriously reduces egg production when fed to hens in very small amounts.
  • e. dichloride industrial fumigant; causes respiratory and ophthalmic irritation, narcosis, disturbance of equilibrium.
  • e. glycol antifreeze; palatable enough for animals to drink in quantity. Causes ataxia, depression, coma, polydipsia, vomiting, and convulsions. Death is commonly attributed to severe acidosis and acute renal failure.
  • e. oxide a fumigant used for foodstuffs, surgical equipment, and as an agricultural fungicide. It is a gaseous, flammable alkylating agent with a broad spectrum of activity, being sporicidal and viricidal. It is used (mixed with CO₂ or fluorocarbons because it is explosive above 3%) for disinfecting and sterilizing equipment and instruments that are used in the hospital, surgery, dentistry, and pharmaceutical and other industries, and that are thermolabile or will be adversely affected by immersion in water or other media. Its optimal germicidal effect occurs after a 3-hour exposure at 86°F (30°C). Its vapor is irritating to eyes and respiratory mucosa and can cause serious pulmonary edema. Called also oxirane.

• ethylenediamine [eth″ -lēn-di′ -mēn] an organic compound that is a precursor to other pharmaceuticals and chelating agents. See also aminophylline.

  • e. dihydrochloride a urinary acidifier.
  • e. dihydroiodide used in livestock as an expectorant, anti-inflammatory agent, and iodine supplement. Can cause poisoning if taken in excess. Signs include nasal and ocular discharge, dyspnea, and cough.

• ethylenediaminetetraacetic acid (EDTA) [eth″ -lēn-di′-mēn-tet″r- -se ′tik] see edetate.

• ethylenimine [eth″ l-ēn′ľ-mēn] an industrial chemical known to be a carcinogen.

• ethylmercuri-toluene sulfonanilide a fungicidal agent used in agriculture. Capable of causing organic mercury poisoning.

• ethylmercury [eth″ l-mur′kūr-e] an organic radical once used extensively in agriculture as a basis for fungicides. These uses have been discontinued or banned in many countries

  • e. chloride this antifungal seed dressing is capable of causing organic mercury poisoning.
  • e. iodide used in agriculture as a fungicidal seed dressing. Can cause mercury poisoning.
  • e. phosphate used as a fungistatic seed dressing; seed consumed by animals or humans causes organic mercury poisoning.

• ethylnoradrenaline [eth″ l-nor--dren′ -lin] ethylnorepinephrine.

• ethylnorepinephrine [eth″ l-nor-ep″ľ-nef′rin] a synthetic adrenergic brochodilator. Called also ethylnoradrenaline. See also norepinephrine.

• ethynyl [eth′ -n l] the group −C=CH, when it occurs in organic compounds.

• etidocaine [ -te′do-kān] a local anesthetic of the amide type. Not widely used.

• etidronate [e-tľ-dro′nāt] see bisphosphonates.

• etimizol a xanthine derivative; a stimulant to respiration at the brainstem level and to adrenocorticotropic function of the pituitary gland.

• etiological [e″te-o-loj′ľ-k l] pertaining to etiology.

  • e. diagnosis the name of a disease that includes the identification of the agent, e.g., Streptococcus agalactiae mastitis.
  • e. factors risk factors contributing to the occurrence of a disease.

• etiology [e″te-ol′ -je] literally the science dealing with causes of disease; common usage is the cause of a disease.

• etioporphyrin [e″te-o-por′f -rin] a synthetic porphyrin used as a basis for the classification of porphyrins.

• etodolac [e-to-do′lak] a nonsteroidal anti-inflammatory COX-2 inhibitor used for its analgesic effect in dogs with osteoarthritis.

• etomidate [ -tom′ľ-dāt] an intravenous, nonbarbiturate, fast-inducing anesthetic with no analgesic effect. Also causes suppression of adrenal steroidogenesis and may be used in the treatment of hyperadrenocorticism.

• etoposide [e″to-po′sīd] a semisynthetic derivative of podophyllotoxin with antineoplastic activity; not widely used in veterinary medicine.

• etorphine a very potent, semisynthetic opioid analgesic used as an immobilizer for free-ranging wild animals. Can be antagonized using diprenorphine or naltrexone. Also known as M-99.

• etretinate [e-tret′ľ-nāt] a synthetic retinoid, used orally in the treatment of skin diseases, particularly keratinization disorders. Like other synthetic retinoids, it is teratogenic and has a very long half-life; largely replaced by acitretin.

• ETT endotracheal tube.

• Eu chemical symbol, europium.

• eu- word element. [Gr.] normal, good, well, easy.

• Eubacteria [u″bak-te′re- ] alternative name for the domain of prokaryotes classified as Bacteria. Used as a generic term to describe all the prokaryotic organisms not in the domain Archaea.

• Eubacterium [u″bak-te′re- m] a genus of gram-positive, obligately anaerobic rod-shaped bacteria found in the intestinal tract as parasites, and as saprophytes in soil and water. Belong to the order Clostridiales. Have been found in cerebrospinal fluid of a cat with meningoencephalomyelitis.

  • E. suis see Actinobaculum suis.

• Eubothrium a genus of tapeworms of the family Amphicotylidae. Found in wild and captive salmonids.

• eucalyptol [u″k -lip′tol] a colorless liquid obtained from eucalyptus oil and other plant sources; used as an expectorant, flavoring agent, liniment, vapor for relieving nasal congestion, and local anesthetic. Called also cineole.

• Eucalyptus [u″k -lip′t s] genus of Australian trees in the family Myrtaceae, widely planted throughout the world. Two species E. cladocalyx (sugar gum) and E. viminalis (manna gum) may contain toxic amounts of cyanogenic glycosides. Called also gum trees.

  • E. melanophloia host tree for larvae of Australian sawfly (Lophyrotoma interrupta) that may poison sheep and cattle. Called also silver-leaf ironbark.

• eucalyptus oil [u″k -lip′t s] a volatile oil from fresh leaf of species of Eucalyptus (‘gum tree’), the chief constituent of which is eucalyptol.

• eucaryosis [u-kar″e-o′sis] eukaryosis.

• Eucaryota [u-kar″e-o′te] a kingdom of organisms that includes plants and animals, fungi, protists, protozoa, and algae (not blue-green algae, which are cyanobacteria), characterized by possession of a membrane bound nucleus. Alternative spelling: Eukaryota.

• eucaryotic [u″k r-e-ot′ik] eukaryotic.

• Eucestoda [u-s s-to′d] one of the two classes of cestodes. Includes the true tapeworms identified by having a holdfast organ or scolex, usually a segmented body, and a life cycle that includes an intermediate host.

• euchlorhydria [u″klor-hi′dre- ] the presence of the normal concentration of hydrochloric acid in the gastric juice.

• eucholia [u-ko′le- ] normal condition of the bile.

• Euchoplopsyllus glacialis a flea that parasitizes wild felines.

• euchromatin [u-kro′m -tin] that state of chromatin in which it stains lightly, is genetically active, and is considered to be partially or fully uncoiled.

• Eucoleus aerophilus see Capillaria aerophila.

• Eucotylidae a family of flukes (digenetic trematodes) found in the kidney of birds. Includes the genera Tanaisia and Eucotyle. Neither appears to have significant pathogenicity.

• eucrasia [u-kra′zh ] 1. a state of health; proper balance of different factors constituting a healthy state. 2. a state in which the body reacts normally to ingested or injected drugs, proteins, etc.

• eudiemorrhysis the normal flow of blood through the capillaries.

• eudipsia [u-dip′se- ] ordinary, normal thirst.

• euesthesia a normal state of the senses.

• euflavine acriflavine.

• eugenol [u′j n-ol] the chief constituent of clove oil; also obtained from other plant sources. Used as a topical analgesic for dental pain and as an antiseptic.

• euglobulin [u-glob′u-lin] one of a class of globulins characterized by being insoluble in water but soluble in saline solutions.

  • e. lysis test a test measuring overall fibrinolytic activity of plasma. Used to differentiate between types of pathological fibrinolysis.

• euglycemia [u″gli-se′me- ] a normal concentration of glucose in the blood.

• eugonic [u-gon′ik] growing luxuriantly; said of bacterial cultures.

• Eugonic Fermenter-4 [u-gon′ik] a group of formerly unclassified gram-negative, rod-shaped bacteria isolated from cases of multifocal interstitial pneumonia in miscellaneous Carnivora. Now classified as Neisseria animaloris and N. zoodegmatis.

• eukaryon 1. a highly organized nucleus bounded by a nuclear membrane, a characteristic of cells of higher organisms. 2. eukaryote.

• eukaryosis [u-kar″e-o′sis] the state of having a true nucleus.

• Eukaryota [u-kar″e-o′te] Eucaryota.

• eukaryote [u-kar′e-ōt] an organism that is a member of the kingdom Eucaryota, the cells of which have a nucleus bounded by a membrane containing the chromosomes. Eukaryotic cells also contain membrane-bound organelles, such as mitochondria, chloroplasts, lysosomes, and the Golgi apparatus. Plants, and animals, protozoa, protists, fungi, and algae (except blue-green algae, which are cyanobacteria) are eukaryotes. Other organisms (the bacteria) are prokaryotes.

• eukaryotic [u″k r-e-ot′ik] pertaining to eukaryosis.

  • e. cells see cell.
  • e. transcription see deoxyribonucleic acid.

• eukinesia [u″kľ-ne′zh ] normal or proper motor function or activity.

• Eulaelaps a genus of laelapid mites in the family Laelapidae.

  • E. stabularis a parasite of small mammals found in poultry houses, feed stores and such places where they cause irritation to workers. Avector for Francisella tularensis.

• eulaminate [u-lam′ľ-nāt] having the normal number of laminae, as certain areas of the cerebral cortex.

• eumelanin [u-mel′ -nin] black to brown pigment produced by melanin. See also pheomelanin.

• eumelanosome pigment granules containing eumelanin, produced within cells by melanosomes.

• eumetria [u-me′tre- ] a normal condition of nerve impulse, so that a voluntary movement just reaches the intended goal; the proper range of movement.

• eumycetoma [u″mi-se-to′m ] see mycetoma.

• eunuchoid [u′n -koid] an animal that resembles a human eunuch, typically with reduced or indeterminate sexual characteristics. For example, intact/non-sterilized males with the chromosome trisomy XXY are usually eunuchoid, and scrotal formation may be defective.

  • e. syndrome a state of decreased aggression, disinterest, and loss of stamina in working dogs after ovariectomy.

• eunuchoidism [u′n -koi″diz- m] deficiency of the testes or of their secretion, with impaired sexual power and eunuchoid signs.

• hypergonadotropic e. that associated with secretion of high concentrations of gonadotropins, as in Klinefelter’s syndrome.

• hypogonadotropic e. that due to lack of gonadotropin secretion.

• Euonymus europaeus plant in the family Celastraceae; contains a toxic cardiac glycoside, evonoside, with a digitalis-like action. Called also spindle tree, skewer wood.

• eupancreatism [u-pan′kre- -tiz″ m] normal functioning of the pancreas.

• Euparyphium see Echinostoma.

• Eupatorium [u″p -tor′e- m] see Ageratina.

• eupepsia [u-pep′se- ] good digestion; the presence of a normal amount of pepsin in the gastric juice.

• Euphorbia [u-for′be- ] a genus of the plant family Euphorbiaceae; contains diterpenes that cause enteritis and diarrhea. Some species are suspected of containing cyanogenic glycosides. Toxic species include E. boophthona (Gascoyne spurge), E. characias (Albanian spurge), E. drummondii (mat spurge, caustic creeper), E. helioscopia (sun spurge), E. hydnorae, E. mauritanica, E. melanostica (yellow milk bush), E. phymatoclada, E. ingens (candelabra tree), E. lathyrus (caper spurge), E. marginata (snow-on-the-mountain), E. milii (christplant, crown-of-thorns), E. peplus (petty spurge), E. prostrata, E. pulcherrima (poinsettia), E. tirucalli.

• euplastic [u-plas′tik] readily becoming organized; adapted to tissue formation.

• euploid [u′ploid] 1. having more than one complete set of the haploid number of chromosomes. 2. a euploid individual or cell.

• euploidy [u-ploi′de] the state of being euploid.

• eupnea [ūp-ne′ ] normal, quiet breathing.

• eupraxia [u-prak′se- ] intactness of reproduction of coordinated movements.

• Eurasier a medium-sized spitz-type German dog with prick ears and a thick coat in all colors with a bushy tail that curls over the back. A new breed, developed from crossing Chow Chows and Wolfspitz breeds, and later the Samoyed.

• eurhythmia [u-rith′me- ] regularity of the pulse.

• Eurogroup for animals a coalition of European animal protection organizations.

• European emanating from or pertaining to Europe.

  • E. bat lyssavirus see Lyssavirus.
  • E. blastomycosis see cryptococcosis.
  • E. brown hare syndrome a highly fatal necrotizing hepatitis caused by Lagovirus, occurs naturally and only in Lepus europeus (European hare) and Lepus timidus (Northern hare). Proposed as a possible progenitor virus for rabbit hemorrhagic disease virus.
  • E. Burmese a breed of shorthaired cat separate from the more common ‘American’ Burmese; it has a long, slender body; wedge-shaped head with large ears and long muzzle; and comes in a wider range of coat colors, particularly red. Called also British Burmese and ‘traditional’ Burmese. The breed is affected by a congenital head fault.
  • E. cattle breeds include Belgian blue, Brown Swiss, Central and Upper Belgian, Blonde D’Aquitaine, Charolais, Chiana, Friesian, Holstein-Friesian, Limousin, Maine-Anjou, Marche, Piedmont, Pinzgau, Romagna, Simmental, Steppe.
  • E. feedlot see European feedlot.
  • E. swine fever see classical swine fever.

• European Board of Veterinary Specialisation an umbrella organization for veterinary specialties within Europe. It sets standards, conducts examinations, and awards diplomas of competence in veterinary professional specialties to graduate veterinarians. Similar to the American Board of Veterinary Specialties. Recognized organizations include: European College of Veterinary Anaesthesia and Analgesia (ECVAA), European College of Animal Welfare and Behavioural Medicine (ECAWBM), European College of Aquatic Animal Health (ECAAH), European College of Animal Reproduction (ECAR), European College of Bovine Health Management (ECBHM), European College of Equine Internal Medicine (ECEIM), European College of Laboratory Animal Medicine (ECLAM), European College of Porcine Health Management (ECPHM), European College of Poultry Veterinary Science (ECPVS), European College of Small Ruminant Health Management (EDSRHM), European College of Veterinary and Comparative Nutrition (ECVCN), European College of Veterinary Clinical Pathology (ECVCP), European College of Veterinary Dermatology (ECVD), European College of Veterinary Diagnostic Imaging (ECVDI), European College of Veterinary Emergency and Critical Care (ECVECC), European College of Veterinary Internal Medicine – Companion Animals (ECVIM-CA), European College of Veterinary Microbiology (ECVM), European College of Veterinary Neurology (ECVN), European College of Veterinary Ophthalmologists (ECVO), European College of Veterinary Pathologists (ECVP), European College of Veterinary Pharmacology and Toxicology (ECVPT), European College of Veterinary Public Health (ECVPH), European College of Veterinary Surgeons (ECVS). European College of Zoological Medicine (ECZM), European Veterinary Dental College (EVDC), and European Veterinary Parasitology College (EVPC).

• European Cooperation in Science and Technology (COST) a European framework supporting trans-national cooperation among researchers, engineer and scholars across Europe.

• European Pharmacopoeia (Ph. Eur.) a reference for quality control of medicinal substances in Europe, produced by the European Pharmacopoeia Commission, of the Council of Europe.

• europium (Eu) [u-ro′pe- m] a chemical element, atomic number 63, atomic weight 151.96.

• eury- word element. [Gr.] wide, broad.

• euryblepharon [u″re-blef′ -ron] horizontally elongated palpebrral fissue due to excessive eyelid length (also known as macropalpebral fissure).

  • congenital e. seen in brachycephalic dogs; in association with shallow orbits, the eyes are prominent and subject to exposure keratitis.
  • transient juvenile e. occurs in young German shepherd dogs and usually resolves in several months. It gives the appearance of exophthalmos. No other abnormalities are present.
  • eurycephalic [u″re-s -fal′ik] having a wide head.
  • euryhaline species of fish capable of osmoregulation in waters over a range of salinities; the opposite of stenohaline.
  • Euryhelmis a genus of intestinal flukes (digenetic trematodes) in the family Heterophyidae.
    • E. monorchis found in mink.
    • E. squamula found in wild Carnivora. Causes fatal hemorrhagic enteritis in mink.
  • Eurytrema [u-re-tre′m ] a genus of flukes (digenetic trematodes) in the family Dicrocoeliidae.
    • E. brumpti Concinnumbrumpti.
    • E. coelomaticum, E. pancreaticum found in pancreatic ducts of sheep and cattle.
    • E. fastosum found in the pancreatic and biliary ducts of carnivores.
    • E. ovis found in the perirectal fat of sheep.
    • E. procyonis Concinnumprocyonis.
  • Euschongastia a genus of mites in the family Trombiculidae.
    • E. latchmani causes trombiculidiasis in cats.
  • eustachian tube [u-sta′ke- n] see auditory tube.
  • eustachitis [u″st -ki′tis] inflammation of the pharyngotympanic tube; not likely to be made as a clinical diagnosis in animals but is a common accompaniment of the more severe syndrome of otitis media.
  • Eustachys distichophylla Chlorisdistichophylla.
  • eustress a stress that is beneficial to the animal.
  • Eustrongylides a genus of nematodes in the family Dioctophymatidae. Found in birds and wild and cultured fish.
    • E. papillosus found in the esophagus and proventriculus of ducks and geese. Can cause extensive nodule formation.
    • E. tubifex found in the intestine of anatine birds.
  • euthanasia [u″th -na′zh] 1. an easy or painless death. 2. the deliberate ending of life of an animal suffering from an incurable disease; called also mercy killing, to put down, to put to sleep. In all cases, it must be carried out in a humane manner that is reliable, free of pain or distress for the animal with a minimum period of consciousness, and safe for the operator. For the individual animal, intravenous injection of a massive dose of barbiturate is best. Any narcotizing drug creates difficulties if the carcass is to be disposed of for pet meat. In those cases, shooting with a bullet or captive bolt pistol is recommended because of the speed of the dispatch. For large numbers of animals at a pound or shelter, injection procedures are still superior to the bulk methods that all have the fallibility of poorly managed and supervised machinery. Carbon monoxide is very fast but dangerous to the operators of the cabinet and not sufficiently reliable. Electrocution cannot be performed en masse, and gassing with carbon monoxide or lowering of the atmospheric pressure is not really quick enough. Various methods are approved for small laboratory animals, but they vary for the species and age, as well as the requirements of the experiment. Generally, chemical methods using inhalant or injectable agents are used. Physical methods, including cervical dislocation or decapitation, are sometimes considered appropriate, but only in certain situations. Professional veterinary associations, such as the AVMA, publish guidelines for euthanasia of animals.
    • electrical e. uses mains electrical current passed through the subject’s body via clips applied to the skin of the ear and the tail. Not much employed because of danger to human operators, likelihood of equipment failure, and need for close contact with device.
  • euthanasiate see euthanatize.
  • euthanatize [u′th -n -tiz] to perform euthanasia. Called also euthanize.
  • euthanize [u′th -niz] see euthanatize.
  • euthermic [u-thur′mik] characterized by the proper temperatures; promoting warmth.
  • euthyroid [u-thi′roid] having a normally functioning thyroid gland.
    • e. sick syndrome see nonthyroidal illness syndrome (NTIS).
  • euthyroidism [u-thi′roid-iz- m] state of normal thyroid function.
  • eutocia [u-to′sh ] normal parturition.
  • Eutrombicula [u″trom-bik′u-l ] a genus of mites in the mite family Trombiculidae. See also chigger.
    • E. alfreddugesi the common chigger of the US; called also Trombicula alfreddugesi. Causes dermatitis in most species.
    • E. sarcina causes leg itch and black soil itch of sheep, manifested by dermatitis on the lower limbs, up to about the fetlock.
  • eutrophia [u-tro′fe- ] a state of normal (good) nutrition.
  • eutrophication the accidental or deliberate promotion of excessive growth (multiplication) of one kind of organism to the disadvantage of other organisms in the same ecosystem.
  • eV electron volt.
  • EVA equine viral arteritis.
  • evacuant [e-vak′u- nt] 1. promoting evacuation. 2. an agent that promotes evacuation.
  • evacuation [e-vak″u-a′sh n] 1. an emptying or removal, especially the removal of any material from the body by discharge through a natural or artificial passage. 2. material discharged from the body, especially the discharge from the bowels.
  • evagination [e-vaj″ľ-na′sh n] an outpouching of a layer or part.
  • evaluation [e-val-u-a′sh n] a critical appraisal or assessment; a judgment of the value, worth, character or effectiveness of that which is being assessed.
  • Evans blue [ev′ nz] an odorless green, bluish green, or brown powder dye, used as a diagnostic aid in estimation of blood volume. The dye is injected into the bloodstream and after a sufficient period of time samples of the blood are taken to determine the degree of dilution of the dye. Called also azovan blue.
  • Evans’ syndrome [ev′ nz] immune-mediated hemolytic anemia concurrent with immune-mediated thrombocytopenia.
  • evaporated reduced in volume by evaporation; concentrated to a denser form.
  • evaporative pertaining to evaporation.
    • e. loss loss of body water by evaporation of water from the body to the air; a thermoregulatory mechanism in some mammals.
  • EVDC European Veterinary Dental College. See also European Board of Veterinary Specialisation.
  • Eve tonsil snare a wire loop protruding from a long, hollow tube and a three-finger operated system for closing the snare, the loop. The mechanism may have a ratchet to ensure that the closure of the loop is maintained until the tonsil is removed.
  • evening primrose oil one of the few plant oils containing γ-linolenic acid. Obtained from seeds of Oenothera biennis, it is used for its antiinflammatory effects in the treatment of skin diseases.
  • evening trumpetflower see Gelsemium sempervirens.
  • event 1. an equine contest other than a race, e.g., a 3-day event. 2. in statistics the outcome of a random experiment.
    • e. diary pocket diary designed for farmer use to record all events necessary to complete farm records kept for health and production surveillance purposes.
    • e. horse a horse suitable for use in 3-day events and similar contests.
  • eventration [e″ven-tra′sh n] 1. protrusion of the bowels through the abdominal wall. 2. removal of the abdominal viscera.
  • diaphragmatic e. positioning of the dome of the diaphragm into the thoracic cavity, usually due to phrenic nerve paralysis.
  • evernazione a method of killing an animal for slaughter. A short two-edged knife is plunged into the neck at the atlanto-occipital joint, severing the medulla oblongata. Called also neck stab.
  • eversion [e-vur′zh n] a turning inside out; a turning outward, e.g., of the uterus, the third eyelid. See under each anatomical location.
  • evert [e-v rt′] to turn inside out; to turn outward.
  • evidence-based medicine [ev′ľ-d ns-bāst] clinical decision-making based on critical evaluation of scientific evidence available in medical literature, as opposed to personal opinion or traditional practices not supported by medical research. See also GRADE, evisceration [e-vis″ r-a′sh n] extrusion of the viscera, or internal organs; disembowelment.
    • ocular e. removal of the contents of the globe, leaving the fibrous outer corneoscleral shell. Done prior to placement of a silicone prosthesis.
  • evoked potential see evoked response.
  • evoked response a technique for the detection of low amplitude electrical activity in response to stimuli for the purpose of evaluating sensory mechanisms. Called also evoked potential. In the majority of tests performed that utilize an evoked response, the low amplitude of response to a single stimulus is too small to be measurable, and as a result summation of multiple response is often required.
    • brainstem auditory e. r. (BAER) electrodiagnostic test performed to assess hearing and brain function. Tones or clicks are generated at defined volumes from headphones placed within the ears, and the resultant electrical waveforms produced by the cochlear nerve, cochlear nuclei and other structures within the brain are detected by electrodes placed on or under the skin. Called also auditory evoked potential, brainstem auditory evoked response (BAER).
    • visual e. r. electrical potentials recorded over the occipital lobe region in response to light directed onto the retina. Used to evaluate vision.
  • evolution [ev″ -loo′sh n] the process of development in which an organ or organism becomes more and more complex by the differentiation of its parts; a continuous and progressive change according to certain laws and by means of resident forces.
    • convergent e. the development, in animals that are only distantly related, of similar structures or functions in adaptation to similar environment.
    • divergent e. the development of different characteristics in animals that were closely related in response to being placed in different environments.
  • evonoside a cardiac glycoside found in the plant Euronymus europaeus.
  • EVPC European Veterinary Parasitology College. See also European Board of Veterinary Specialisation.
  • evulsion [e-vul′sh n] extraction by force; see avulsion.
  • ewe a female sheep of breeding age. May be qualified as maiden ewes, not yet bred, or ewe lambs, up to 1 year.
    • dry e. 1. a ewe without milk whatever the reason. 2. female sheep of breeding age without a lamb at foot.
  • ewe-necked a defect in conformation in a horse. The topline of the neck is concave when viewed from the side.
  • ex- word element. [L.] away from, without, outside; sometimes used to denote completely.
  • ex vivo outside the living body; denoting removal of an organ (e.g., the kidney) for reparative surgery, after which it is returned to the original site.
  • exa- (E) [Gr.] six; a prefix used in the metric system of measurement to indicate an amount 10¹⁸ (a million-million-million or quintillion) times the uni, as exametre.
  • exacerbation [eg-zas″ r-ba′sh n] increase in severity of a disease or any of its clinical signs.
  • examination [eg-zam″ľ-na′sh n] inspection or investigation, especially as a means of diagnosing disease, qualified according to the methods used, as physical, cystoscopic, environmental, etc.
    • breeding soundness e. of a male usually, although it could be a practical request in a female, a standardized examination requiring ideally a physical clinical examination, a special physical examination of the reproductive system, a field and a laboratory examination of semen and for evidence of freedom from venereal disease, and a test of serving efficiency.
    • digital e. done with a finger of a gloved hand, usually in rectal or vaginal examinations of dogs.
    • environmental e. examination of factors such as housing, ventilation, pasture, etc. for factors that might predispose the condition under consideration.
    • hands-off e. done without handling the animal and may be from a distance; includes observation of the animal’s behavior, gait, or stance, responses to sound and visual stimuli, and general body condition. May be a preliminary to a hands-on examination or, in the case of wild or intractable animals, all that can be achieved.
    • necropsy e. see necropsy. Called also postmortem, autopsy.
    • physical e. examination of the bodily state of a patient by ordinary physical means, as inspection, palpation, percussion, and auscultation.
    • postnatal e. in cows to ensure that the uterus is clean and the ovaries cycling so that the next pregnancy can commence without delay. Called also ‘fresh cow exam’. In bitches and queens, commonly done to ensure that all puppies or kittens have been delivered.
    • presale e. may be at any level. In horses usually a clinical physical examination, a special examination of the limbs and the gaits of the animal. Companion animals are usually examined for general health and special attention for any defect that could be heritable.
  • exanthem [eg-zan′th m] in humans, a rash; typically, of viral origin in children. A term not used in veterinary medicine. See exanthema.
  • exanthema [eg″zan-the′m ] pl. exanthemata [Gr.]. See vesicular exanthema of swine, coital exanthema.
  • exarticulation [eks″ahr-tik″u-la′sh n] amputation at a joint; partial removal of a joint.
  • excavatio [eks″k -va′she-o] see excavation.
  • excavation [eks″k -va′sh n] 1. the act of hollowing out. 2. a hollowed-out space, or pouch-like cavity.
    • atrophic e. cupping of the optic disk, due to atrophy of the optic nerve fibers.
    • optic disk e. a normally occurring depression in the center of the optic disk.
    • rectovesical e. the space between the rectum and bladder in the peritoneal cavity of the male.
    • vesicouterine e. the space between the bladder and uterus in the peritoneal cavity of the female. Called also pouch of Douglas.
  • excavator [eks′k -va″t r] a scoop or gouge for surgical use.
  • excerebration [eks-ser″ -bra′sh n] removal of the brain.
  • exchange diffusion a carrier transport mechanism across a membrane. The transport is faster than can be explained by simple diffusion but does not result in net transport.
  • excipient [ek-sip′e- nt] any more-or-less inert substance added to a drug to give suitable consistency or form to the drug; a vehicle.
  • excise [ek-sīz′] to remove by cutting.
  • excision [ek-sizh′ n] removal, as of an organ, by cutting, which may be by steel scalpel, cryosurgery or electrosurgery.

    E-69.

    

    Pasture grass fire injury to a horse with burns of limbs and excoriation of burnt skin by tail movements.

  • e. DNA repair comprises four distinct sequential steps—incision, in which the damaged base is recognized, excision in which the damaged base is removed, resynthesis and ligation.
  • e. en bloc see en bloc resection.
  • radical e. extensive removal, usually of a tumor mass, which includes surrounding tissues that might be involved and sometimes regional lymph nodes as well.
  • shave e. biopsy of superficial lesions of the gingival mucosa can be performed with a scalpel blade, slicing off a thin layer from the surface, without the need for sutures to close the defect.

• excitability [ek-sīt″ -bil′ľ-te] readiness to respond to a stimulus; irritability.

• excitant [ek-sīt′ nt] stimulant.

• excitation [ek″si-ta′sh n] an act of irritation or stimulation; a condition of being excited or of responding to a stimulus; the addition of energy, as the excitation of a molecule by absorption of photons.

  • e.–conduction–contraction in the stimulation of muscle contraction this is the coupling that occurs at the sarcolemma–sarcoplasmic reticulum junction.
  • e.–contraction coupling conversion of an excitation stimulus into contraction of the effector muscle fiber.
  • indirect e. electrostimulation of a muscle by placing the electrode on its nerve.
  • e.–secretion in the stimulation of muscular contraction this is the stimulation of secretion of acetylcholine from the vesicles in the cholinergic nerve terminals into the synaptic cleft at the nerve–muscle junction.
  • e. signs see irritation nervous signs.

• excitement [ek-sīt′ment] a mental state of greater excitation than normal, but less than frenzy. To be distinguished from, but similar to, the increased motor activity state of restlessness.

• excitomotor [ek-si″to-mo′t r] tending to produce motion or motor function; an agent that so acts.

• excitosecretory [ek-si″to-se-kre′to-re] producing increased secretion.

• excitotoxicity [ek-si″to-tok-sis′ľte] exaggerated and continuous stimulation by a neurotransmitter resulting in disordered function or disease, especially in those neuronal systems that use glutamate as the transmitter.

• excitovascular [ek-si″to-vas′ku-l r] causing vascular changes.

• exclave [eks′klāv] a detached part of an organ.

• exclusion [eks-kloo′zh n] a shutting out or elimination; surgical isolation of a part, as of a segment of intestine, without removal from the body.

  • competitive e. (CE) a term used to describe the protective effect of the natural or native bacterial flora of the intestine in limiting the colonization of some bacterial pathogens. Competitive exclusion products are also called probiotics, direct-fed microbials or CE cultures.
  • e. principle once held belief that it is possible to prove from a parentage test that a particular animal is not the true parent but it is impossible to prove that a particular animal is a parent. No longer true with DNA genetic matching.

• Excoecaria Asian and Australian trees in the family Euphorbiaceae; their milky sap is very irritating and causes intense pain in the eye or on other tender parts. Cause poisoning of livestock. No specific toxin has been identified. Includes E. agallochia (river poison tree, milky mangrove), E. dallychyana (gutta-percha).

• excoriation [eks-ko″re-a′sh n] superficial traumatic abrasions and scratches that remove some of the skin substance; once the epidermis is breached, erosions and ulcers become secondarily infected. In animals, self-inflicted by rubbing, biting, or scratching pruritic skin. The cause may be suggested by the distribution pattern to areas of the body that can be accessed directly or indirectly by the animal.

• excrement [eks′kr -m nt] fecal matter; matter cast out as waste from the body.

• excrementitious [eks″kr -mn-tish′ s] pertaining to or of the nature of excrement.

• excrescence [eks-kres′ ns] an abnormal outgrowth; a projection of morbid origin.

• excreta [eks-kre′t ] excretion products; waste material excreted or eliminated from the body, including feces, urine, and sweat. Mucus and carbon dioxide also can be considered excreta. The organs of excretion are the intestinal tract, kidneys, lungs, and skin.

• excrete [eks-krēt′] to throw off or eliminate, as waste matter, by a normal discharge.

• excretion [eks-kre′sh n] 1. the act, process, or function of excreting. 2. material that is excreted. Ordinarily, what is meant by excretion is the evacuation of feces. Technically, excretion can refer to the expulsion of any matter, whether from a single cell or from the entire body, or to the matter excreted.

  • virus e. see shedding.

• excretory [eks′kr -tor-e] pertaining to excretion.

  • e. behavior see elimination behavior.

• excursion [eks-kur′zh n] a range of movement regularly repeated in performance of a function, e.g., excursion of the jaws in mastication.

• excystation [ek″sis-ta′sh n] escape from a cyst or envelope, as in that stage in the life cycle of parasites occurring after the cystic form has been swallowed by the host.

• exencephaly [ek″s n-sef′ -le] a congenital defect in which the brain is completely exposed or protrudes through a defect in the cranial vault.

• exenteration [ek-sen″t r-a′sh n] surgical removal of all of the internal organs, for example, of the eye or pelvic cavity.

  • ocular e. surgical removal of the globe, adnexa, and all orbital contents. Done for ocular and periocular neoplasia. Compare with enucleation and evisceration.

• exercise [ek′s r-sīz] performance of physical exertion to obtain food or to achieve normal functions such as reproduction, for pleasure, and for improvement of health or correction of physical deformity.

  • active e. motion imparted to a part by voluntary contraction and relaxation of its controlling muscles.
  • e. conditioning repeated exercise to condition an animal for a better performance at another time depends on a set of integrated responses that act to minimise the physiologic stress of that particular form of exercise. Also call training.

    E-70.

    

    Exmoor Pony.

  • corrective e. therapeutic exercise.
  • e. fatigue poor exercise tolerance.
  • e.-induced pulmonary hemorrhage see exercise-induced pulmonary hemorrhage (Below).
  • e. intolerance inability to perform exercise at a level anticipated for the animal’s breed, age, sex, and degree of exercise conditioning. Sometimes referred to as poor performance or failure to perform to expectation.
  • passive e. motion imparted to a segment of the body by a therapist, machine, or other outside force.
  • e. physiology includes the integrated physiological responses to exercise plus physical conditioning by training.
  • e. testing a technique for evaluating one or more physiologic responses of the animal to exercise. Often used as a diagnostic technique to investigate cases of exercise intolerance or failure to perform to expectation.
  • therapeutic e. the scientific use of bodily movement to restore normal function in diseased or injured tissues or to maintain a state of well-being. Called also corrective exercise.
  • e. tolerance expected responses of an animal, based on its breed, age, sex, and conditioning, to exercise.

• exercise-induced collapse in Labrador retrievers an inherited neurological disorder in which affected dogs are typically normal, but with strenuous exercise, they experience episodes of weakness in the hind legs, ataxia, and inability to stand, which lasts for 10–30 minutes before recovery. An autosomal recessive inheritance of dynamin-1 gene mutation.

• exercise-induced pulmonary hemorrhage (EIPH) hemorrhage occurring in the lungs of horses during intense exercise, such as racing, barrel racing, and polo. In approximately 2% of cases, evident as epistaxis. Diagnosis by tracheobronchoscopic examination within hours of racing or examination of bronchoalveolar lavage fluid or tracheal aspirates. Associated with impaired performance by Thoroughbred race horses.

• exercising [ek′s r-sīz″ing] exercise as part of a training program. See exercise conditioning.

• exeresis [ek-ser′ -sis] surgical removal, or excision.

• exergonic [ek″s r-gon′ik] in chemistry, a reaction in which the free energy change (ΔG) is negative, thus energy is released. Such reactions occur spontaneously.

• exertional emanating from or pertaining to exertion.

• exflagellation [eks-flaj″ -la′sh n] the protrusion or formation of flagel-liform microgametes from a microgametocyte in some apicomplexan protozoa.

• exfoliation [eks-fo″le-a′sh n] a falling off in scales or layers.

• exhalation [eks″h -la′sh n] 1. the giving off of watery or other vapor, or of an effluvium. 2. a vapor or other substance exhaled or given off. 3. the act of breathing out.

• exhaust fumes [eg-zawst′] fumes given off by vehicles; contain some carbon monoxide, the amount varying with the efficiency of combustion in the particular engine. In most engines, the use of exhaust fumes for euthanasia is not recommended because it operates partly on the carbon dioxide content, and if the content is high the animal dies slowly of asphyxia. Car exhaust fumes may contain significant amounts of lead if the petrol/gasoline is still leaded, and foliage receiving a lot of exhaust deposit can cause lead poisoning in animals eating it.

• exhausted horse syndrome see exhaustion syndrome.

• exhaustion [eg-zaws′ch n] deprivation of energy with consequent inability to respond to stimuli; lassitude.

  • physical e. occurs most commonly in horses engaged in endurance or marathon events. Also in males engaged in territorial combats; bulls and boars are the usual combatants. There are some lacerations but exhaustion is the main problem. Manifested by lethargy, dehydration, hyperthermia, hyperpnea, tachycardia, muscle tremor and some muscle spasm, restlessness, anal relaxation, unwillingness to stand, fidgeting while down, pale cyanotic mucosa, and poor capillary refill time.
  • e. syndrome multisystemic syndrome due to combined effects of dehydration, hypovolemia, hyperthermia, energy substrate depletion, and acid-base and electrolyte abnormalities induced by prolonged exercise such as endurance racing, 3-day events, and long distance riding. Called also exhausted horse syndrome.

• Exmoor pony English riding pony. Bay, brown, or mousy dun, with no white markings; 12.2–12.3 hands high.

  E-71.

  

  Breed related exophthalmos in a Pug. There is ‘scleral show’ and pigmentary keratitis.

• exo- word element. [Gr.] outside of, outward, external.

• exocardia [ek″so-kahr′de- ] congenital displacement of the heart; ectocardia.

• exocardial [ek″so-kahr′de- l] situated, occurring, or developed outside the heart.

• exocolitis [ek″so-ko-li′tis] inflammation of the outer coat of the colon.

• exocrine [ek′so-krin] 1. secreting externally via a duct. 2. denoting such a gland or its secretion.

• exocytosis [ek″so-si-to′sis] 1. the discharge from a cell of particles that are too large to diffuse through the plasma membrane; the opposite of endocytosis. 2. the aggregation of migrating leukocytes in the epidermis as part of the inflammatory response.

• exodeviation [ek″so-de″ve-a′sh n] a turning outward; in ophthalmology, a turning outward of the eyes; exotropia.

• exodontia [ek″so-don′sh ] removal of teeth.

• exodontics [ek″so-don′tiks] that branch of dentistry dealing with extraction of teeth.

• exoenzyme [ek″so-en′zīm] an enzyme that acts outside the cell that secretes it.

• exoerythrocytic [ek″so- -rith″ro-sit′ik] occurring or situated outside the red blood cells (erythrocytes); a term applied to a stage in the development of protozoan parasites that takes place in cells other than erythrocytes (e.g., in Plasmodium).

• exogamy [ek-sog′ -me] protozoan fertilization by union of elements that are not derived from the same cell.

• exogen shedding of a club hair.

• exogenous [ek-soj′ -n s] originating outside or caused by factors outside the organism.

  • e. fecal contents e.g., calcium taken in with the diet but not absorbed; is distinct from endogenous calcium that is contributed by the body.

• exome the entire set of exons (protein coding regions) transcribed by an organism; estimated to be encoded by about 1.5% of the genome.

• exomphalos [ek-som′f -los] 1. hernia of the abdominal viscera into the umbilical cord. 2. congenital umbilical hernia.

• exon [ek′son] regions of a primary RNA transcript in eukaryotic cells that are coding and are joined together when introns are spliced-out, to make the functional mRNA.

• exonuclease [ek″so-noo′kle-ās] a nuclease that cleaves single mononucleotides from the end of a polynucleotide chain.

  • e. III one from E. coli that removes nucleotides from the 3′ ends of double-stranded DNA.

• exopeptidase [ek″so-pep′tľ-dās] a proteolytic enzyme whose action is limited to terminal peptide linkages.

• Exophiala [ekof″so-fi′ -l] a genus of dematiaceous fungi that cause mycetomas and pheohyphomycosis including cutaneous and systemic lesions, in mammals, fish, and captive frogs and toads. Can cause disseminated mycosis in fish. Includes E. pisciphilia, E. salmonis.

• exophthalmometry [ek″sof-th l-mom′ -tre] measurement of the extent of protrusion of the eye in exophthalmos.

• exophthalmos [ek″sof-thal′mos] abnormal forward protrusion of the globe from within the orbit. Can be conformational or result from a retrobulbar mass/swelling.

  • conformational e. seen in brachycephalic animals (especially dogs) with shallow orbits.
  • inherited e. see bilateral convergent strabismus with exophthalmus.
  • ophthalmoplegic e. inability to move the eye because of exophth-almos.
  • pulsatile e. one in which the degree of exophthalmos varies with the pulse; due to an arteriovenous fistula/varix within the orbit.

• exophytic [ek″so-fit′ik] growing outward; in oncology, proliferating externally or on the surface epithelium of an organ or other structure in which the growth originated.

• exoplasm [ek′so-plaz″ m] the plasma membrane.

  • e. face the side of a membrane facing away from cytosol.

• exorbitism [eg-sor′bľ-tiz- m] exophthalmos.

• exoserosis [ek″so-se-ro′sis] an oozing of serum or exudate.

• exoskeleton [ek″so-skel′ -ton] an external hard framework, as a crustacean’s shell, that supports and protects the soft tissues of lower animals, derived from the ectoderm. In vertebrates, the term is sometimes applied to structures produced by the epidermis, as hair, claws, hoofs, teeth, etc.

• exosmosis [ek″sos-mo′sis] osmosis or diffusion from within outward.

• exostosis [ek″sos-to′sis] pl. exostoses [Gr.] a benign new growth projecting from a bone surface and characteristically capped by cartilage.

  • e. cartilaginea a variety of osteoma consisting of a layer of cartilage developing beneath the periosteum of a bone.
  • inherited multiple e. a benign hereditary disorder in horses. The lesions are visible externally but appear to cause little inconvenience. Similar to multiple cartilaginous exostoses (see below) in dogs and cats.
  • multiple cartilaginous e’s multiple bony exostoses in bones formed by enchondral ossification; a developmental disease in dogs and hereditary predispostion is suspected. Single or multiple lesions are usually on vertebrae, ribs, and long bones. In cats, lesions occur in adults, mainly on the axial skeleton. There is frequently an association with feline leukemia virus infection. The bony enlargements are painless but may cause musculoskeletal or neurological dysfunction. Neoplastic transformation has been reported. Called also diaphyseal aclasis, metaphyseal aclasis, osteochondromatosis, and in horses, inherited multiple exostosis (see above). See also osteophyte.
  • periarticular e. occurs in any joint injury, commencing as cartilaginous osteophytes within a few days of the injury occurring.

• exothermal, exothermic [ek″so-thur′m l, ek″so-thur′mik] marked or accompanied by the evolution of heat; liberating heat or energy.

• exotic [eg-zot′ik] not native, not indigenous.

• Exotic shorthair a cat breed derived from crossing American shorthair cats with Persians. It closely resembles the Persian ancestors, with a massive head, small ears, large round eyes, and a short nose. It has a medium-length coat in many different colors.

• exotoxigenic [ek″so-tok″sľ-jen′ik] caused by an exotoxin.

  • e. organism those capable of producing exotoxins, e.g., Clostridium spp.

• exotoxin [ek′so-tok″sin] a potent toxin formed and secreted by the bacterial cell, and found free in the surrounding medium. Exotoxins are generally heat labile and are protein in nature. Many can be detoxified with retention of antigenicity by treatment with formaldehyde (toxoid). Many are important virulence factors in pathogenic bacteria.

• exotropia [ek″so-tro′pe- ] strabismus in which there is permanent lateral deviation of the visual axis of one eye away from that of the other, resulting in diplopia. Called also divergent strabismus or walleye.

• expanded see gelatinize.

• expander [ek-span′d r] something that enlarges or prolongs; extender.

• plasma volume e. a substance that can be transfused intravenously to restore blood volume in event of an emergency such as acute, severe blood loss, and other types of hypovolemic shock, supplemental to the use of whole blood and plasma. Called also artificial plasma extender and plasma volume extender, and colloid or colloidal fluid replacement therapy.

• expectation of life an epidemiological expression of the probability of dying between one age and the next. Based on the human cohort life table that describes the actual mortality experience of a group of animals which were all born at the same time.

• expected [ek-spek′ted] in statistics refers to the expectation as predicted by the relevant formula or model.

  • e. frequency see expected frequency.
  • e. value see expected value.

• expectorant [ek-spek′t -r nt] an agent that promotes expectoration (expulsion of tracheobronchial mucus).

  • liquefying e. an expectorant that promotes the ejection of mucus from the lower respiratory tract by decreasing its viscosity.

• expectoration [ek-spek″t -ra′sh n] 1. the coughing up and swallowing of material from the lungs, bronchi and trachea. In humans, the coughed up material is discarded by spitting. 2. sputum.

• expeller process use of a screw press to extract oil from seeds. Alternatives are extraction by hydraulic press and chemical extraction.

• experiment [ek-sper′ľ-m nt] with epidemiology, a study involving a comparison group in which the investigator intentionally alters one or more risk factors in order to discover or demonstrate some fact or general truth.

  • blind e. the identities of the animals that are in the treatment and the control groups are unknown to the experimenter until the end of the trial.
  • control e. one made under standard conditions, to test the correctness of other observations.
  • controlled e. one in which an exact replica of the animals experimented on are kept without any treatment in order to show what changes occurred in normal animals, reinforcing the view that the observed changes in the experimental animals were in fact the result of the treatment administered.
  • double blind e. an experiment in which the identity of the animals in the treatment and control groups is unknown to the experimenter, and in addition, the assessment of the results is done without the animals’ identities being known to the experimenter. Called also blind study.
  • factorial e. one set up in such a way that all levels of each intervention or treatment occur with each level of response.
  • field e. one carried out in normal circumstances and environment, e.g., on the farm or in the cattery rather than in an experimental institution where many of the factors affecting the occurrence or severity of a disease may not operate.
  • laboratory e. carried out in a laboratory where conditions can be almost completely controlled.
  • latin square e. a method of laying out a field experiment in such a way as to avoid bias by physical location.
  • natural e. occurs by chance when all variables for a population are constant except one, which is different for one large part of the population compared with the other, e.g., when half of a flock comes from one climate and the other half is a local resident in another climate.
  • prospective e. those carried out to see what happens if certain influences are applied to an animal or a group of animals. Retrospective experiments are those that set out to explain events that have already been observed.

• experimental emanating from or pertaining to experiment.

  • e. animals animals kept expressly for the purposes of conducting experiments on them. Called also laboratory animals.
  • e. design the method of allocating experimental units to treatment groups in an experiment; many complicated and sophisticated designs are available, e.g., balanced, unbalanced, crossover, factorial, randomized, non-random, split-plot.
  • e. model experiment carried out using a model of a real system that contains some of the risk factors that apply in the real state; the model is a simplification of real life.
  • e. study a study in which all of the risk factors are under the direct control of the investigator.

• expert systems computer programs designed to capture the non-numeric knowledge and reasoning methods through a set of rules or tree type decision networks that are not easily represented in traditional computing approaches. Known also as knowledge-based expert systems.

• expirate exhaled air or gas.

  • single e. the gas exhaled at a single expiration.

• expiration [ek″spľ-ra′sh n] 1. the act of breathing out, or expelling air from the lungs. 2. termination, or death.

  • e. date the calendar date on the packaging of a pharmaceutical or food that indicates the last date the item should be used.

• expiratory [ek-spi′r -tor″e] relating to or employed in the expiration of air from the lungs.

  • e. center the nerve center in the descending reticular formation that terminates inspiration and triggers the commencement of expiratory movements.
  • e. groan a groan with expiration; for animals interpreted by observers as an expression of severe pain or extreme fatigue.
  • e. reserve volume maximum air volume that can be exhaled by forced exhalation from the end expiratory point. Difficult to determine in animals.

    E-72.

    

    Pigs that have died of exsanguinations as a result of hemorrhage from esophogastric ulcer. The loss of blood and resultant death in pig A was relatively rapid but in pig B was over many days and the pig has a characteristic runt conformation.

• expire [ek-spīr′] 1. to breathe out. 2. to die.

• explant [eks′plant] 1. to take from the body and place in an artificial medium for growth. 2. tissue taken from the body and grown in an artificial medium.

• exploration [ek″spl -ra′sh n] investigation or examination for diagnostic purposes.

• explorer [ek-splor′ r] a handheld dental instrument with a slender working end that tapers to a sharp-pointed tip used in sedated or anesthetized patients to explore the structural integrity of the tooth surface, detect subgingival and supragingival dental deposits, and evaluate the margins of restorations and prosthodontic crowns. Commonly two types, shepherd’s hook and pigtail

• explosive [ek-splo′siv] substance used for causing explosions. They may be accessible to animals and cause poisoning.

  • plastic e. poisoning see cyclonite. Called also PE4.

• exponential growth [ek″sp -nen′sh l] strictly speaking that of a population where rate of growth is proportional to its population size, but is often used to mean an ever increasing growth.

• export to transport, secrete, or excrete protein out of the cell.

• exportin a protein that binds to a ‘cargo’ protein in the nucleus of a cell and transports the cargo through the nuclear pore complex to the cytoplasm.

• exposure [ek-spo′zh r] 1. the act of laying open, as surgical exposure. 2. the condition of being subjected to something, as to infectious agents or extremes of weather or radiation, which may have a harmful effect. 3. in radiology, a measure of the amount of ionizing radiation at the surface of the irradiated object, e.g., the body.

  • e. button of an x-ray machine. Either a button or foot switch, usually a two-stage mechanism, the first causing preheating of the cathode filament and/or rotating the anode, the second closing the electrical circuit and the creation of the x-ray beam.
  • e. chart see technique chart.
  • climatic e. exposure to the weather without provision of shelter. See hypothermia, hyperthermia.
  • e. error under- or overexposure in radiography causing inferior contrast and detail or a non-diagnostic image.
  • e. factors the milliampere-seconds (mAs) and kilovoltage (kVp) for radiography of a particular body part. The factors are influenced by the speed of the image receptor, the anode to film distance, the grid, and the size of the subject.
  • e. latitude the range of exposures that will create a diagnostic radiographic image. Digital radiography has a wider exposure latitude than film-screen radiography.
  • provocative e. intentional exposure of an animal to substance (e.g., food, drug) for medical assessment.
  • e. time the length of time that the x-ray tube is emitting an x-ray beam. Time should be kept to a minimum to minimize movement artifact. The amount of radiation produced depends on the milliamperage × time in seconds, thus mAs.

• expression [ek-spresh′ n] 1. the aspect or appearance of the face as determined by the physical or emotional state. 2. the act of squeezing out or evacuating by pressure. 3. the manifestation of a heritable trait in an individual carrying the gene or genes which determine it.

  • e. library a DNA library cloned into an expression vector.
  • e. vector a cloning vector, usually a plasmid or a virus, capable of carrying a gene into the host cell and promoting its expression.

• expressivity [ek″sprě-siv′ľ-te] the extent to which a heritable trait is manifested by an individual carrying the principal gene or genes that determine it; the extent of phenotypic variation within a particular genotype. Called also genetic expressivity.

  E-73.

  

  Extensor postural thrust response.

• expulsive [ek-spul′siv] driving or forcing out; tending to expel.

• exsanguination [ek-sang″wľ-na′sh n] extensive blood loss due to internal or external hemorrhage.

• exsection [ek-sek′sh n] see excision.

• Exserohilum rostratum [ek″s r-o-hi′l m] a dematiaceous fungus that causes phaeohyphomycosis.

• exsheathing fluid [eks-shēth′ing] fluid secreted by strongylid larvae preparatory to shedding the current larval stage sheath.

• exsheathment [eks-shēth′m nt] shedding of the retained sheath of the third larval stage of strongylid nematodes before the parasitic stage of its existence can begin.

• exsiccation [ek″sľ-ka′sh n] the act of drying out; in chemistry, the deprival of a crystalline substance of its water of crystallization.

• exstrophy [ek′stro-fe] the turning inside out of an organ.

  • bladder e. congenital absence of a portion of the abdominal wall and bladder wall, the bladder appearing to be turned inside out, with the internal surface of the posterior wall showing through the opening in the anterior wall.
  • cloaca e. a developmental anomaly in which two segments of bladder (hemibladders) are separated by an area of intestine with a mucosal surface, which appears as a large red tumor in the midline of the lower abdomen.

• ext. external; extract.

• extender [ek-sten′d r] something that enlarges or prolongs; expander.

  • artificial plasma e. see plasma volume expander.
  • Kenny’s e. common skim milk-based extender used for cooling and shipping stallion semen.
  • semen e. a diluent for semen. Two types of diluents exist, those for fresh or cooled semen (egg yolk or skim milk based) and those for freezing semen, which contain a cryoprotectant, generally glycerol. The most common one for bull semen is skim or homogenized milk containing 7% glycerol. New, chemically defined media have been developed to prevent the addition of biological fluids and reduce risks of disease transmission.

• extensibility index a measure of the ability of skin to stretch, calculated by lifting a fold of skin over the lumbar spine to its maximum distance. This distance is divided by the body length, times 100. Used to evaluate cutaneous asthenia in dogs and cats.

• extension [ek-sten′sh n] 1. the movement by which the two ends of any jointed part are drawn away from each other. 2. a movement bringing the members of a limb into or toward a straight condition.

  • nail e. extension exerted on the distal fragment of a fractured bone by means of a nail or pin (Steinmann pin) driven into the fragment.

• extensor [ek-sten′sor] [L.] any muscle that extends a joint. See Table 12 for list of all muscles.

  • crossed e. reflex see crossed extensor reflex.
  • e. postural thrust a postural reflex reaction tested in small animals by lifting the patient off the ground, then lowering it to see whether the hindlegs are extended to make contact and support weight and several short steps are taken to maintain posture. Called also extensor reaction.
  • e. process disease see pyramidal disease.
  • e. reaction see extensor postural thrust (above).
  • e. rigidity see upper motor neuron.

• exteriorize [ek-stēr′e- -rīz″] to transpose an internal organ to the exterior of the body.

• extermination mass killing of animals or other pests. Implies complete destruction of the species or other group.

• extern [ek′st rn] one taking part in an externship.

• external [ek-stur′n l] situated or occurring on the outside, toward or near the outside; lateral.

• external ear [ek-stur′n l] the outer ear; it includes the auricle (1) the external auditory meatus and the tympanic membrane.

  • e. e. canal the external auditory meatus.
  • e. e. canal inflammation see otitis externa.
  • e. e. hematoma see aural hematoma.

• externalize see exteriorize.

• exterofective [ek″st r-o-fek′tiv] responding to external stimuli; a term applied to the cerebrospinal nervous system.

• externship a period of practical work, usually at an external location (work place) intended to provide wider experience during a course of study. Called also practicum, work experience.

• externus [ek-stur′n s] external; denoting a structure farther from the center of an organ or cavity.

• exteroceptor [ek″st r-o-sep′t r] a sensory nerve ending stimulated by the immediate external environment, such as those in the skin and mucous membranes.

• extima [ek′stľ-m ] outermost; the outermost coat of a blood vessel; the adventitia.

• extinction [ek-stink′sh n] the disappearance of a conditioned response as a result of nonreinforcement.

• extirpation [ek″st r-pa′sh n] complete removal or eradication of an organ or tissue.

• extorsion [ek-stor′sh n] rotation of the pupil, observed only in animals with horizontal pupils such as cattle and sheep. Caused by paralysis of the dorsal oblique muscle, as seen in polioencephalomalacia of ruminants.

• extra- word element. [L.] outside, beyond the scope of, in addition.

• extra-articular [eks″tr -ahr-tik′u-l r] situated or occurring outside a joint.

• extra-label use of a drug in a way or for a purpose not specified on the product label, or the documents provided by the manufacturer. In the case of an adverse drug reaction, the responsibility for any loss incurred rests with the veterinarian, not the manufacturer. Extralabel use is common in veterinary practice because of the large number of animal species being treated and because many of the diseases encountered in companion animals require drugs that have been registered for use only in humans.

• extralabel drug use (ELDU) use of any drug in an animal in a manner not in accordance with the approved label use. This includes species, dose, volume, route, interval, duration, and indication. Used by veterinarians for drugs that may be approved for human use but have limited or no approval for animal use. When used in food-producing animals, veterinarians must determine appropriate withdrawal times for milk or meat and be confident that the client will adhere to the withdrawal times. In the US, this use is permitted only under the supervision of a veterinarian where there is a valid Veterinarian-Client-Patient Relationship and is only allowed for FDA-approved animal and human drugs. It can only be used for therapeutic purposes. ELDU in feed is prohibited. Extralabel use of animal and human drugs is permitted in nonfood-producing animal practice except when the public health is threatened. Called also off-label use. See also veterinary feed directive drug.

• extra-ocular muscles [eks″tr -ok′u-l r] the muscles within the orbit but outside the eye that include the four rectus m’s (superior, inferior, medial, and lateral); the two oblique m’s (superior and inferior), the retractor bulbi, and the levator palpebrae superioris. See Table 12.1F.

• extra points most acupuncture points are found along the meridians; extra points are not on meridians but have special effects on nearby organs.

• extracapsular [eks″tr -kap′su-l r] situated or occurring outside a capsule.

  • e. cataract extraction removal of the lens, together with a central window of anterior lens capsule, but sparing the posterior capsule.
  • open sky e. extraction one in which the intact lens is removed through a large anterior capsulotomy and corneal incision.

• extracellular [eks″tr -sel′u-l r] situated or occurring outside a cell or cells.

  • e. constituents all of the constituents of the body outside the cells; include water, electrolytes, protein, glucose, enzymes, hormones.
  • e. fluid all of the body fluid lying outside the cells. Includes intravascular fluid or plasma and the interstitial fluid. That part of the extracellular fluid that is in special cavities that have special characteristics, e.g., synovial fluid, urine, aqueous humor of eye, are called transcellular fluids.
  • e. matrix the network of proteins and carbohydrates that surround a cell or fill the intercellular spaces.
  • e. space see intercellular.

• extracorporeal [eks″tr -kor-por′e- l] situated or occurring outside the body.

  • e. circulation the circulation of blood outside the body, as through a hemodialyzer for removal of substances usually excreted in the urine, or through an extracorporeal circulatory support unit for carbon dioxide–oxygen exchange (see below).
  • e. circulatory support unit a heart–lung machine. In animals, used mainly in the investigation of cardiac prosthetic devices.

• extracorticospinal [eks″tr -kor″tľ-ko-spi′n l] outside the corticospinal tract.

• extracranial [eks″tr -kra′ne- l] external to the cranial vault.

• extract [ek′strakt] a concentrated preparation of a herbal or animal drug; a preparation that extracts or concentrates the active principals, such as an alcohol extract (tincture) of a medicinal herb or a crude hormone extracted from a whole gland.

  • allergen e. an extract usually containing protein of any substance (plant, food, insect, etc.) to which an animal may be allergic. It is used for both the diagnosis and treatment of allergic diseases (e.g., intradermal allergy testing, immunotherapy).
  • cell-free e. the solution obtained by rupturing cells and removing all particulate matter.
  • crude e. preparation made from whole tissue (plant or animal) in which no measures are taken to refine the end product to remove cells or other components.

• extraction [ek-strak′sh n] 1. the process or act of pulling or drawing out. 2. the preparation of an extract.

  • breech e. extraction of a fetus from the uterus in cases of breech presentation.
  • oxygen e. the difference between the arterial and venous concentrations of oxygen (CaO₂-CvO₂). Can be measured across a tissue bed or as the difference between arterial and pulmonary arterial (or central venous) oxygen content.
  • vacuum e. removal of the contents of a body cavity by application of a vacuum.

• extractive [ek-strak′tiv] any substance present in an organized tissue, or in a mixture in a small quantity, and requiring extraction by a special method.

• extractor [ek-strak′t r] an instrument for removing a calculus or foreign body.

• extradural [eks″tr -doo′r l] situated or occurring outside the dura mater. See also epidural.

• extraembryonic [eks″tr -em″bre-on′ik] external to the embryo proper, as the extraembryonic celom or the extraembryonic membranes.

  • e. membranes the fetal membranes, chorion, amnion, allantois, yolk sac; term used mostly in the early embryonic period.

• extrafusal [eks″tr -fu′z l] situated outside a striated muscle spindle.

• extragenic [eks″tr -jen′ik] occurring outside a gene or in a gene other than the one in question.

• extralemniscal system a secondary (besides the lemniscal system) spinothalamic sensory system that conveys information from peripheral sensors to the thalamus, on cruder levels of touch, and pressure, pain and temperature.

• extramastoiditis [eks″tr -mas″toi-di′tis] inflammation of tissues adjoining the mastoid process.

• extramedullary [eks″tr -med′u-lar″e] situated or occurring outside any of the medullas including the medulla oblongata and the medullary cavities of the bones.

  • e. hematopoiesis see extramedullary hematopoiesis.

• extramural [eks″tr -mu′r l] situated or occurring outside the wall of an organ or structure.

• extraocular [eks″tr -ok′u-l r] situated or occurring outside the eye.

• extraosseous [eks″tr -os′e- s] occurring outside a bone or bones.

• extraplacental [eks″tr -pl-sen′t l] outside of or independent of the placenta.

• extrapleural [eks″tr -ploor′ l] situated or occurring outside the pleural cavity.

• extrapolation [ek-strap″o-la′sh n] inference of a value on the basis of that which is known or has been observed; usually applied to estimation beyond the range of observed data as opposed to interpolation between data points.

• extrapulmonary [eks″tr -pool′mo-nar″e] not connected with the lungs.

• extrapyramidal [eks″tr -pľ-ram′ľ-d l] outside the pyramidal tracts.

  • e. disease, e. syndrome any of a group of clinical disorders marked by abnormal involuntary movements, alterations in muscle tone, and postural disturbances.
  • e. motor system see extrapyramidal system (below).
  • e. system a functional, rather than anatomical, unit comprising the nuclei and fibers (excluding those of the pyramidal tract) involved in motor activities; they control and coordinate especially the postural, static, supporting, and locomotor mechanisms. It includes the corpus striatum, subthalamic nucleus, substantia nigra, and red nucleus, along with their interconnections with the reticular formation, cerebellum, and cerebrum; some authorities include the cerebellum and vestibular nuclei. Called also extrapyramidal motor system.

• extrascleral [eks″tr -sklēr′ l] situated or occurring outside the sclera of the globe.

  • e. prosthesis see ocular prosthesis.

• extrasystole [eks″tr -sis′to-le] a premature cardiac contraction that is independent of the normal rhythm and arises in response to an impulse outside the sinoatrial node.

  • atrial e. premature beat arising from stimuli discharged in atrial wall ectopic to atrial pacemaker and may or may not initiate cardiac irregularity.
  • atrioventricular e. one in which the stimulus is thought to arise in the atrioventricular node.
  • interpolated e. a contraction taking place between two normal heartbeats without interrupting the regularity of the underlying rhythm (i.e., lacks a compensatory or noncompensatory pause).
  • nodal e. atrioventricular extrasystole.
  • retrograde e. a premature ventricular contraction followed by a premature atrial contraction, due to transmission of the stimulus backward, usually over the bundle of His.
  • triggered e. cardiac ectopic beats triggered by afterdepolarizations.
  • ventricular e. one in which either an abnormal, early heart beat rises from the ventricles.

• extratubal [eks″tr -too′b l] situated or occurring outside a tube.

• extrauterine [eks″tr -u′t r-in] situated or occurring outside the uterus.

  • e. pregnancy ectopic pregnancy.

• extravasation [ek-strav″ -sa′sh n] 1. a discharge or escape, as of blood, from a vessel into the tissues; blood, or other substance so discharged. 2. the process of being extravasated.

• extravascular [eks″tr -vas′ku-l r] situated or occurring outside a vessel or the vessels.

• extraversion [ek″str -vur′zh n] see extroversion.

• extremitas [ek-strem′ľ-t s] pl. extremitates [L.] extremity.

  E-74.

  

  Pigs with greasy pig disease (exudative epidermitis) showing the grease-like appearance of the seborrheic dermatitis that gives rise to its colloquial name.

  E-75.

  

  Frontal view of the external structures of the canine eye.

• extremity [ek-strem′ľ-te] 1. the distal or terminal portion of elongated or pointed structures such as the limb, tail, or ear. 2. the limb, tail, ear.

• extrinsic [ek-strin′zik] of external origin.

  • e. factor a hematopoietic vitamin that combines with intrinsic factor for absorption from the intestine and is needed for erythrocyte maturation; called also cyanocobalamin and vitamin B12.
  • e. pathway see coagulation pathways.

• extroversion [ek″stro-vur′sh n] a turning inside out; exstrophy.

• urinary bladder e. failure of development of ventral abdominal wall so that the bladder and pelvic urethra are exposed.

• extrusion [ek-stroo′zh n] displacement of a tooth out of its alveolus; during orthodontic treatment (forced extrusion of an incompletely erupted or unerupted tooth) or for unknown reason (abnormal tooth extrusion of canine teeth in cats).

• extubation [eks″too-ba′sh n] removal of a tube used in endotracheal intubation.

• exuberant [eg-zoo′b r- nt] copious or excessive in production; showing excessive proliferation.

• exudate [eks′u-dāt] a fluid with a high protein concentration and cellularity that has escaped from blood vessels and has been deposited in tissues or on tissue surfaces, usually as a result of inflammation. It may be septic or nonseptic. See also exudative.

• exudation [eks″u-da′sh n] 1. the escape of fluid, cells, or cellular debris from blood vessels and deposition in or on the tissue. 2. exudate.

• exudative [ek-soo′d -tiv] of or pertaining to a process of exudation.

  • e. diathesis a disease of young pigs and chickens caused by a nutritional deficiency of vitamin E. Characterized by severe edema of the subcutaneous tissues.
  • e. epidermitis a disease of young pigs caused by Staphylococcus hyicus (S. hyos) and characterized by an acute generalized seborrheic dermatitis. Called also greasy pig disease.
  • e. muscle see porcine stress syndrome.

• exumbilication [ek″s m-bil″ľ-ka′sh n] 1. marked protrusion of the navel. 2. umbilical hernia.

  E-76.

  

  Sunken eye due to dehydration.

• exuviae the shed animal covering, e.g., skin of a snake or other reptile, or the exoskeleton of an arthropod.

• exuviate to cast off or shed skin.

• eyas a nestling raptor bird to be trained as a hawking bird. Also known as eyass.

• eye one of the paired organs of vision; sometimes called the globe. In the embryo the eye develops as a direct extension of the brain. To protect the eye the bones of the skull are shaped so that an orbital cavity protects most aspects of each globe. Anteriorly, the conjunctival sac covers the space between the orbital rim and the eye and lines the upper and lower eyelids. Tears from the lacrimal glands are constantly secreted over the ocular surface to maintain hydration, lubricate and remove foreign objects from the corneal and conjunctival surfaces. The eye is also protected by the eyelids with their sensitive eyelashes. The eye has three coats: the outer fibrous tunic, composed of the cornea (the clear transparent layer on the front of the eye) and the sclera (the white of the eye). Together, this tough outer coat helps protect the delicate mechanisms of the eye. The middle vascular (or uveal) layer is composed of the choroid posteriorly and the iris and ciliary body anteriorly. The innermost neurosensory layer comprises the retina with its specialized light-sensitive rods and cones and present only in the posterior aspect of the globe. Behind the cornea and in front of the lens is the iris, the circular pigmented band around the pupil. The iris works much like the diaphragm in a camera, widening or narrowing the pupil to adjust to different light conditions. Nerve fibers from the retina leave the back of the eye as the optic nerve and transmit nerve impulses to the occipital cortex of the brain where they are interpreted as vision.

  • almond-shaped e. observed with dehydration in birds, where the eye is sunken, particularly in raptors that normally have a prominent, round globe. Also used to describe a feature of some dog or cat breeds such as the British shorthair cat.
  • blue e. a common term for corneal edema. See also blue eye.
  • cancer e. common lay term for ocular squamous cell carcinoma in cattle.
  • cherry e. see cherry eye.
  • china e. one with a blue iris.
  • cross-e. esotropia.
  • diamond-shaped e. seen in various dog breeds, such as St. Bernards, Mastiffs, and Newfoundland with deep orbits, loose eyelid skin, and deformities of the tarsal plate such that their upper and lower eyelids have folds along their length creating a diamond-shaped eyelid aperature. Usually associated with combined entropion and ectropion.
  • e. drop 1. vestibular nerve lesion will cause the eye on the affected side to deviate downward more than the opposite eye when the head is lifted. 2. ophthalmic solution for topical application.
  • dry e. see keratoconjunctivitis sicca.
  • equator of the e. an imaginary line drawn around the eye at its widest point, approximately midway between the poles.
  • fatty e. lipid accumulation in the inferior conjunctiva and causing protrusion or swelling of the lower conjunctival sac in guinea pigs; noted in guinea pigs on a high nutritional plane.
  • meridians of the e. imaginary lines drawn round the eye joining the two poles. The principal meridians are those taking vertical (parasagittal) and horizontal (coronal) paths around the globe.
  • merle e. the iris has brown and blue flecks.
  • mirror e. lay term for congenital cataracts in guinea pigs.
  • oscillation of the e. see nystagmus.
  • pea e. a protrusion from the inferior conjunctival sac in one or both eyes that occurs in adult guinea pigs.
  • pink e. pinkeye; see infectious bovine keratoconjunctivitis of cattle, due to Moraxella bovis; in humans, used as a more generic term for any infectious cause of conjunctivitis.
  • e. preservation response see menace response.
  • protective e. cup a tent-like, miniature aluminum and canvas shield applied to an injured eye in a horse to prevent self-mutilation.
  • rapid e. movement see sleep.
  • red e. an eye showing dilation of conjunctival or episcleral blood vessels.
  • e. size, abnormal see macrophthalmia, microphthalmia.
  • e. specialist see ophthalmologist.
  • sunken e. sinking or depression of globe into the eye socket; a sign of dehydration.
  • e. teeth see canine teeth.
  • wall e. see walleye.
  • e. wash various medicated solutions used to flush the eye; called also collyria.

    E-77.

    

    Anatomy of the normal eyelid.

  • watch e. lay term for walleye.
  • e. white percentage an estimate of the startle response and an indicator of fear in dairy cattle.
  • e. worm see Thelazia, Onchocerca.

• eyeball [i′bawl] eye; called also globe.

• eyeground [i′ground] the fundus of the eye as seen with an ophthalmoscope.

• eyehooks [i′hooks] obstetrical instruments that provide an attachment to the head for purposes of traction. The hook may be a single with a long (3 ft) handle manipulated from outside the cow or mare, for which these instruments are designed. There are also small (2–3 in.) hooks used in pairs hung facing each other on a loop of cord. Each hook is placed in the medial canthus of one of the eyes and traction applied; the traction serves to pull the hooks together and deeper into the eye sockets.

• eyelash [i′lash] cilium; one of the hairs growing on the edge of an eyelid. See also eyelid cilia.

• eyelid [i′lid] a movable cutaneous fold lined by conjunctiva that protects the eye. Typically, upper, lower, and third eyelids are present. However the third eyelid is absent in primates. Some animals such as snakes and ablepharine lizards have no eyelids. Instead, the eye is protected by a spectacle.

  • e. abnormality includes entropion, ectropion, ptosis and others listed below.
  • e. coloboma a congenital, full-thickness defect of varying degrees involving the eyelid margin.
  • e. drooping see ptosis.
  • e. eversion see ectropion.
  • e. inflammation see blepharitis.
  • e. inversion see entropion.
  • premature opening e. opening of eyelids before the usual postnatal period of physiologic ankyloblepharon ends (in puppies and kittens, approximately 7–10 days). May result in exposure keratitis because of inadequate tear production.
  • e. tacking a method of eyelid eversion using sutures or surgical staples to temporarily resolve entropion until definitive surgical correction is performed.
  • third e. see membrana nictitans.

• eyepiece [i′pēs] the lens or system of lenses of a microscope (or telescope) nearest the user’s eye, serving to further magnify the image produced by the objective.