Species of coccidia (Apicomplexa: Eimeriidae) infecting pikas from Alaska, U.S.A. and northeastern Siberia, Russia.

Eighty-eight fecal samples from 2 species of pika, Ochotona collaris and Ochotona hyperborea, collected in Alaska (N = 53) and Russia (N = 35), respectively, were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Five oocyst morphotypes were observed. In O. collaris, we found Eitmeria calentinei, Eimeria cryptobarretti, and Eimeria klondikensis, whereas in O. hyperborea, we found Eimeria banffensis, E. calentinei, E. cryptobarretti, E. klondikensis, and Isospora marquardti. This study represents new geographic records for all 5 coccidia and new host records for E. cryptobarretti and I. marquardti. Only minor quantitative differences were seen between the sporulated oocysts we studied and those reported in their original descriptions.