Molecular identification of Eimeria species in liver and feces of naturally infected rabbits in Japan.

Abstract

Among the 11 species of Eimeria in rabbits, some of which are known to be pathogenic and cause enteritis, E. stiedae induces severe liver lesions resulting in elevated mortality. Unlike in other countries, the incidence and prevalence of the parasites in rabbits have not been reported in Japan. In the present study, we histopathologically analyzed hepatic coccidiosis in a rabbit and attempted several primers to genetically identify the parasites and investigated the prevalence of Eimeria species at the same farm. In the liver of the affected rabbit, we observed fibrosis and edema around multiple bile ducts and epithelial cell hyperplasia of the bile ducts. Large numbers of developing parasites of Eimeria spp., mainly oocysts, were present in the bile ducts. PCR and sequencing analyses with the published primers for Cyclospora and Eimeria spp. were used to successfully identify the parasites in the liver as E. stiedae. The oocysts of Eimeria spp. were detected in 13 out of 20 fecal samples collected from other rabbits at the farm, and five Eimeria spp. (E. perforans, E. flavescens, E. exigua, E. magna, and E. vejdovskyi) were genetically confirmed. Our results provide the first indication that Eimeria spp., including highly pathogenic species, are present in Japan and the primer set used herein can be a useful tool for the identification of rabbit Eimeria spp.