The Seville Lab

During the summers of 1997 and 1998, 95 southern red-backed voles from northwestern Wyoming were examined for coccidia by necropsy or collection of feces from live-caught individuals. Because vole specimens caught in 1997 were frozen, eimerian oocysts did not sporulate, but morphology of unsporulated oocysts suggests that 3 species, Eimeria clethrionomyis, Eimeria marconii and Eimeria pileata might be present. In 1998 sporulated oocysts of E. clethrionomyis (prevalence = 11%) were observed. Oocysts of E. clethrionomyis were similar to the original description of this species from southern red-backed voles in Pennsylvania, U.S.A. This report is only the second identifying eimerians from this host species in North America, and the first from the western U.S.A.