Klossiella equi infection in a Hartmann's Mountain zebra (Equus zebra hartmannae)

An 18-mo-old female Hartmann's Mountain zebra (Equus zebra hartmannae) died secondary to a traumatically induced cervical fracture. Microscopic examination of renal tissues revealed occasional coccidian sporocysts and budding sporonts containing sporoblasts encased within a bilaminated cell membrane within the renal tubules, compatible with a morphologic diagnosis of Klossiella equi, a coccidian parasite of renal parenchyma in equids. Repeated urinalyses of several Hartmann's Mountain zebra failed to reveal sporocysts, which are believed to be the infective stage of the parasite. The definitive life cycle of K. equi is unknown, although transmission is presumed to be via oral ingestion of sporocysts that are passed in the urine. Although generally considered an incidental finding, K. equi has been associated with nephrosis and nephritis in immune-compromised equids and should be considered when evaluating renal disease in equids, including zebras.