Table 1.

Concurrent findings and diagnostic plan suggestions for feline tick- or sandfly-borne pathogens associated with fever

		Diagnosis *
	Concurrent findings	Direct identification techniques	Serology	Comments
Tick-associated pathogens
Anaplasma phagocytophilum	• Anorexia • Lethargy • Lameness • Thrombocytopenia	• Blood smear or joint fluid cytology • PCR assay on blood	• Several techniques • Available in some laboratories • Canine SNAP 4DXPlus used in two experimental studies2,4	• Morulae in neutrophils
Anaplasma platys	• Lethargy • Thrombocytopenia	• Blood smear cytology • PCR assay on blood	• Not commercially available	• Whether canine serologic assays cross react with infected cats is unknown
Babesia species	• Hemolytic anemia	• Blood smear cytology • PCR assay on blood	• Not commercially available	• Cytology is likely falsely negative frequently
Borrelia burgdorferi	• Lethargy • Lameness	• PCR assay on skin affected by tick bites • PCR assay on synovial fluid	• Several techniques • Available in some laboratories • Canine SNAP 4DXPlus used in two experimental studies2,4	• PCR assay on blood of affected dogs is generally negative; unknown in cats
Borrelia persica	• Anemia • Thrombocytopenia	• Blood smear cytology • PCR assay on blood	• Not commercially available
Cytauxzoon species	• Anemia • Dyspnea • Findings consistent with shock	• Blood smear cytology • PCR assay on blood	• Not commercially available
Ehrlichia species	• Anemia • Thrombocytopenia • Pancytopenia • Hyperglobulinemia • Uveitis • Other	• Blood smear cytology • PCR assay on blood	• Available in some US laboratories	• Cytology commonly falsely negative • Morulae in mononuclear cells • Serum antibodies have been falsely negative in some cats • Most clinical findings in dogs have been described in cats
Francisella tularensis	• Lymphadenopathy	• Cytology • Fluorescent antibody staining • Culture • PCR assay	• Available in some laboratories	• Lymph nodes, abscesses, airway wash samples used for direct identification techniques • Rising titers can be used to confirm recent infection if direct techniques are negative
Hepatozoon species	• Currently unknown	• Blood smear cytology • PCR assay on blood	• Not commercially available
Rickettsia rickettsii Rickettsia conorii Rickettsia massiliae	• Currently unknown	• PCR assay on blood	• Not commercially available	• Rickettsia rickettsii is the predominant species in the USA and others exist in Europe
Sandfly-associated pathogens
Leishmania species (mainly Leishmania infantum)	• Skin lesions • Hyperglobulinemia • Lymphadenopathy • Uveitis • Other	• PCR assay on aspirates or imprints • Cytology • Histopathology	• Available in some laboratories	• In contrast to dogs, even a low antibody titer likely proves infection

^*Results of direct tests (cytology ± staining techniques, culture, PCR assays) confirm infection when they are positive. However, for some agents, such as Ehrlichia species and Hepatozoon species, there can be a carrier phase in healthy cats and so positive test results do not confirm disease induced by the agent. Similarly, most positive antibody test results merely indicate past or current infection but do not confirm current infection or disease