Abstract

Cytauxzoon felis is a protozoal organism found in domestic cats and wild felids that is transmitted by tick bites. During a study to evaluate hematology and biochemistry parameters in captive lions, piroplasms were observed in stained blood films of 26 adult lions (one fourth of the total lion population) housed in a rescue center and lion safari of Bannerghatta Biological Park. Intra-erythrocytic, signet ringed shaped piroplasms measuring 1 to 1.5 µm, were identified in wet blood smears using Hayem’s fluid and Giemsa-stained blood films. Eight out of 26 animals subsequently became ill, but the remaining 18 animals did not exhibit any clinical signs of disease. Anorexia, lethargy, weakness, pale mucous membranes, hematuria, icterus, pancytopenia and thrombocytopenia were the most common clinicopathologic abnormalities noticed. The hematocrit value in all affected lions decreased below 8 g/dL. A regenerative response to anemia was recognized in six lions that were subjected to treatment with azithromycin (10 mg/kg) and supportive therapy for three days. Thrombocytopenia and probable leukopenia occurred in two animals out of eight infected lions which died subsequently without responding to treatment. The most consistent clinical chemistry findings were increased serum bilirubin concentrations, increased alanine aminotransferase and aspartate aminotransferase activities at the time of initial recognition of parasitemia. Serum protein findings were not consistent in those eight infected lions. In this report, we demonstrate the mild hemolytic anemia, and probably liver dysfunction, concomitant with infection of Cytauxzoon felis piroplasms in lions.

Acknowledgments

The authors would like to acknowledge Executive Director, Bannerghatta Biological Park and Assistant Director (Veterinary Services), and Bannerghatta Biological Park for their continuing support.