Hosts: Domestic rabbit, California jack rabbit (Lepus californicus), whitetailed jack rabbit (L. townsendii).
Location: Thruout small intestine.
Geographic Distribution: Worldwide.
Prevalence: Quite common. Kessel and Jankiewicz (1931) found this species in 10% of over 2000 rabbits in California.
Morphology: The oocysts are ovoid, smooth, and 38 by 26 u. The micropyle is prominent. An oocyst polar granule and oocyst residuum are absent. The sporocysts are elongate ovoid, with a Stieda body. A sporocyst residuum is present. The sporulation time is 2 to 2.5 days.
Life Cycle: Rutherford (1943) described the life cycle of this species. The endogenous stages are found above or below the epithelial cell nuclei of the intestinal villi and also occur in the submucosa. There are 2 asexual generations of merozoites followed by microgamete and macrogamete production. Completion of the endogenous cycle takes 9 to 10 days, and the prepatent period is 9 to 10 days.
Pathogenesis: This is one of the more pathogenic of the intestinal coccidia of rabbits. It causes the usual signs of intestinal coccidiosis. The affected areas are hyperemic, there may be extravasation of blood, and the epithelium may slough and become denuded.