1Section of Wildlife Health, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA; 2Section of Clinical Pathology, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA; 3College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
Two captive reindeer (Rangifer tarandus tarandus) in New York were diagnosed with Babesia odocoilei. Both animals developed acute clinical signs consistent with babesiosis including fever, hemoglobinuria, and hemolytic anemia. Diagnosis was confirmed by visualization of intraerythrocytic parasites on blood smears, polymerase chain reaction (PCR), and speciation of the Babesia by sequencing a hypervariable region of the 18S rRNA gene. One animal died with gross and histopathologic lesions including pigmentary nephrosis with severe acute tubular degeneration and necrosis secondary to intravascular hemolysis. The other was successfully treated with supportive care and a babesiacide, imidocarb dipropionate (Imizol®, 12%, Schering-Plough Animal Health, Union, New Jersey 07083, USA) at 3 mg/kg s.c or i.m. s.i.d. on days 1, 2, 6, 9, and 21. Two other reindeer in the exhibit tested negative for Babesia by PCR and were treated prophylactically with imidocarb. Additionally, B. odocoilei was identified in three previously unknown asymptomatic host species within the collection: yak (Bos grunniens), muntjac (Muntiacus reevesi), and markhor goat (Capra falconeri).
Babesia are protozoan parasites in the phylum Apicomplexa, order Piroplasmida, and are transmitted by Ixodid ticks. The course of infection is more severe in naïve, stressed, or otherwise immune-compromised animals.1 Acute babesiosis demands immediate treatment since 75% of RBCs can by lysed within a few days.2 Prognosis is guarded after the onset of hemoglobinuria. After treatment, the animal’s hemogram must be closely monitored as infected cells will continue to be removed from circulation, which may necessitate blood transfusions.
1. Gallatin, L. L., A. R. Irizarry-Rovira, M. L. Renninger, P. J. Holman, G. G. Wagner, J. E. Sojka, and J. A. Christian. 2003. Babesia odocoilei infection in elk. J. Am. Vet. Med. Assoc. 223: 1027–1032.
2. Vial, H. J., and A. Gorenflot. 2006. Chemotherapy against babesiosis. Vet. Parasitol. 138: 147–160.