Cytauxzoon felis infection in cats in the mid-Atlantic states: 34 cases (1998-2004)

Objective - To describe the demographic and clinical characteristics of feline cytauxzoonosis in the mid-Atlantic states and compare the Cytauxzoon felis 18S rRNA gene sequences from affected cats with sequences reported from affected cats in other regions. Design - Retrospective case series. Animals - 34 cats with C felis infection. Procedure - Medical records of cats in which C felis infection was diagnosed from May 1998 through June 2004 were reviewed; data collected included signalment, month of diagnosis, geographic location, clinicopathologic abnormalities, medical treatments, outcome, and necropsy findings when applicable. Cytauxzoon felis DNA was amplified, cloned, and sequenced from 4 of these cats and compared with previously reported C felis DNA sequences. Results - Of 34 C felis-infected cats, 28 resided in North Carolina, 3 resided in South Carolina, and 3 resided in Virginia; in 32 cats, a diagnosis of C felis infection was made in April through September. Pancytopenia and icterus were the most common clinicopathologic abnormalities. Thirty-two cats either died or were euthanatized, and 2 cats survived. At 5 veterinary hospitals, multiple cases were identified, and 4 multicat households had > 1 cat infected with C felis. The 18S rRNA gene sequences characterized in organisms obtained from 4 cats were nearly identical to C felis DNA sequences reported from other US regions. Conclusions and Clinical Relevance - Data indicate that veterinarians in the mid-Atlantic region of the United States should consider C felis infection in cats that become ill with fever, icterus, and pancytopenia or bicytopenia, especially in the spring and summer months.