Table 1.

Diseases caused by helminths

Type of Helminths	Species	Diseases
Cestodes (Tapeworm)	Coenurus cerebralis - In sheep, rabbits, and rodents, - Humans become an intermediate host after ingesting food contaminated.	Coenurosis - Involvement of CNS. -Cysts are developed into ventricles, and sometimes within the parenchyma of the brain, spinal cord.20
	Diphyllobothrium latum - The fish tapeworm, infect humans who ingest raw and pickled freshwater fish. - Compete with hosts for certain vitamins and related substances particularly for vitamin B12 and split vitamin B12 intrinsic factor complex.	Diphyllobothriasis - Low concentration of vitamin B12 - Systemic and neurologic symptoms, including pallor, glossitis, loss of tongue papillae, numbness, paresthesias of feet and hand, depression, loss of vibratory sensation. - Optic neuropathy.21,22
	Spirometra species - Cats and dogs (definitive host). - Humans are accidental hosts, acquire infection by drinking contaminated water. - Penetrate intestinal wall and migrate to brain and other tissues and grow to full size.	Sparganosis - Slow-growing, tender, migratory, subcutaneous nodules develop for several weeks or years. - Symptoms like fever, chill, edema, and peripheral eosinophilia. - In rare case, helminths travel to the eye and brain.2
	Taenia solium - Tapeworms, migrate through the mucosa and enter in the CNS, eyes, and striated muscle.	Cysticercosis - Affects CNS, causes fever, headaches during the larval stage, progressive muscle weakness.26
Nematodes	Angiostrongylus cantonensis - Infect mollusks or fish. - In humans, it affects the upper respiratory tract, CNS	Angiostrongyliasis - Characterized by eosinophilic meningitis - Symptoms are rash, pruritus, abdominal pain, headache, stiff neck, vomiting, etc.28
	Gnathostoma spinigerum - Parasitizes the stomachs of cats and dogs. - Migrate through human tissue by ingestion of cooked animal flesh, drinking contaminated water	Gnathostomiasis - Mainly CNS can be affected, the spinal cord is affected initially. - Patients experience nausea, vomiting, upper abdominal pain, urticaria, pruritus, etc.27
	Loa loa - Group of nematodes, also called filaria. - White, threadlike worms transmitted to humans by biting tabanid flies.	Loiasis - Infections are usually asymptomatic. - To treat loasis, one should consult an expert on tropical infectious diseases.29
	Onchocerca volvulus - Similar to Loa loa. - Transmitted to humans by female black flies.	Onchocerciasis - Granulomatous reaction followed by fibrosis. - Skin lesions, characterized by erythematous, pruritis, rash, etc.29
	Strongyloides stercoralis - Small nematodes, can parasitize the small bowel of humans. - This female worm hatch in the intestinal duodenum and jejunum and pass into feces.	Strongyloidiasis - Infection is caused in humans by skin contact with the contaminated soil. - Intestinal parasitism30
	Toxocara canis and cati - Infects dogs and related mammals. - Eggs hatch into the small intestine of the host and larvae migrate into lungs, and trachea.	Toxocariasis - Human toxocariasis occurs accidentally by ingesting the faeces of infected dogs. - Conditions may develop to the eye, CNS, producing nonspecific systemic manifestations.31
	Trichinella spiralis - Human infection occurs by eating raw and undercooked pork, bear, wild boar. - After eating, the larvae migrate to the stomach, then to the small intestine.	Trichinosis - Characterized by abdominal pain, vomiting, and diarrhea followed by fever, headache, lethargy, and severe muscle pain, weakness and tenderness.32
	Paragonimus spices - Lung flukes, humans and other mammals are the final host, first intermediate host are snails, second intermediate host crustaceans. - Penetrating intestinal wall, entering into peritoneal cavity then migrating through diaphragm go to lungs. Schistosoma spices - Humans and other mammals are the final host, first intermediate host are snails, second intermediate host are crustaceans. - Found in intramedullary granuloma, spinal cord, CNS	Paragonimiasis - Most cases mild and asymptomatic. - Brownish sputum with cough and intermittent hemoptysis. - Chronic bronchitis.27 Schistosomiasis - Involvement of CNS. - Chronic schistosomiasis is more common than acute. - Acute schistosomiasis is caused by an immunological response to helminths. Chronic schistosomiasis is an inflammatory response to eggs.27

Notes: CNS: central nervous system.