Culture isolation and partial characterization of a Babesia sp. from a North American elk (Cervus elaphus).

Three North American yearling elk (Cervus elaphus) died with clinical symptoms suggestive of babesiosis. Babesia sp. organisms similar in morphology to B. odocoilei of white-tailed deer (Odocoileus virginianus) were observed in Giemsa-stained blood films from one of the elk. Continuous cultures of the parasite were established. Antiserum raised against the elk Babesia sp. isolate was compared to B. odocoilei specific antiserum in an immunofluorescent antibody assay; we found evidence of differences in reactivity to several Babesia spp. isolated from wildlife and domestic ruminants. Cultured parasites from the elk were not infective to either intact or splenectomized Bos taurus steers.