The Endogenous Phase of the Life Cycle of Eimeria bovis

Abstract

During the past several years an intensive study of bovine coccidia has been under way at this laboratory. Since Eimeria bovis is so widespread and causes such serious losses, it has received more attention than the other species. Christensen (1941) pointed out that E. smithi is a synonym of E. bovis, redescribed the unsporulated o6cyst, and determined the time required for sporulation under optimum conditions. Boughton (1942) reported that the cyst-like structures in the mucosa of the small intestines of cattle described under the names of Globidium and Gastrocystis are the schizonts of E. bovis. He (1943) found also that sulfaguanidine can be used as a preventive in experimentally inoculated calves. Hammond, Davis, and Bowman (1944) described the symptoms and pathology observed in calves inoculated with this species, and recorded a definite relation between the size of the inoculum and the symptoms produced. This paper reports the results of further studies of this parasite with emphasis on the endogenous phase of its life cycle.