FATAL BABESIOSIS IN AN AMERICAN WOODLAND CARIBOU (RANGIFER TARANDUS CARIBOU)

An American woodland caribou (Rangifer tarandus caribou) housed at the Minnesota Zoological Garden developed signs consistent with acute bab esiosis, including hemoglobinuria, anemia, and fever. Stained blood sm ears revealed numerous Babesia parasites infecting the erythrocytes. I mmunofluorescent antibody tests showed cross-reactivity between the ca ribou Babesia isolate and specific antisera to B. bovis and B. diverge ns. Weaker cross-reactions were observed with B. bigemina, B. odocoile i, and a Babesia species from bighorn sheep (Ovis canadensis nelsoni). Gross and microscopic lesions, including hemoglobinuric nephropathy, hepatic centrilobular degeneration, and cardiac and adrenocortical hem orrhage, were consistent with a diagnosis of babesiosis. This diagnosi s was further supported by electron microscopic demonstration of intra erythrocytic Babesia organisms in tissues from the animal.