FATAL CYTAUXZOONOSIS IN A CAPTIVE-REARED WHITE TIGER (PANTHERA-TIGRIS)

Fatal (Panthera tigris) cytauxzoonosis was diagnosed in a 7-year-old f emale white tiger. The tiger presented with a 2-day history of anorexi a and lethargy. She was mildly dehydrated, with a temperature of 105.2 F and a hematocrit of 26%. Over the next day, icterus developed, and her physical condition progressed to recumbency, coma, and death. Hema tologic findings obtained shortly before death included icteric plasma , severe thrombocytopenia, mild anemia, hematuria, and parasites consi stent with Cytauxzoon felis in circulating erythrocytes. Gross necrops y findings included generalized icterus, generalized petechiae and ecc hymoses, splenomegaly, and peribronchial edema. Histologic changes inc luded large numbers of intravascular macrophages containing developmen tal stages of Cytauxzoon felis that partially or completely occluded b lood vessels in the lung, spleen, liver, and bone marrow. Except for a n experimental infection of a bobcat, fatal cytauxzoonosis has not pre viously been diagnosed in felids other than domestic cats. These findi ngs raise questions regarding the pathogenicity of this organism in fe lids and may impact husbandry and interstate transfer of captive large cats.