Hematologic effects of cytauxzoonosis in Florida panthers and Texas cougars in Florida

Cytauxzoon felis is a long-recognized hemoparasite of free-ranging Florida panthers (Puma concolor coryi), but its prevalence and effect on the popula tion has not been assessed. Red blood cell indices and white blood cell cou nts were compared between infected and noninfected Florida panthers and Tex as cougars (Puma concolor stanleyana) from 1983-1997 in Florida (USA). The prevalence of cytauxzoonosis for both populations was 39% (11/28) for Texas cougars, 35% for Florida panthers (22/63) and 36% overall. Thirteen hemato logic parameters were compared between C. felis positive and negative panth ers and cougars. Florida panthers had significantly lower mean cell hemoglo bin count (MCHC) and higher white blood cell (WBC), neutrophil, monocyte an d eosinophil counts (P less than or equal to 0.05) than Texas cougars. Infe cted Florida panthers had significantly lower mean cell hemoglobin (MCH) an d monocyte counts and higher neutrophil and eosinophil counts than infected Texas cougars. Although statistically significant differences were measure d for hematologic parameters in C. felis positive panthers and cougars, bio logically significant differences were not likely because values were gener ally within expected reference ranges for healthy animals. Cytauxzoonosis d oes not appear to have a negative effect on the hematologic parameters of c hronically infected panthers and cougars. Potential transient changes durin g initial infection were not evaluated.