NATURAL CRYPTOSPORIDIUM-MURIS INFECTION OF THE STOMACH IN LABORATORY MICE

Histopathological findings were described in naturally infected labora tory mice in conjunction with the presence of oocysts in the feces rel ated to cryptosporidiosis of the stomach. Diagnosis of infection was m ade by the observation of oocysts which were indistinguishable from th ose of Tyzzer's original description of Cryptosporidium muris seen in feces. In addition to this, endogenous developmental stages of the par asite in histologic preparations of tissues obtained at the time of po stmortem examination were observed only in the gastric glands of the s tomach. In light microscopy, numerous small, spherical to ovoid, basop hilic developmental stages of the parasite, embedded in the epithelial microvilli of the stomach, were observed. Most gastric glands were di lated and filled with numerous free or embedded parasites. The gastric glands contained degenerated and atrophied epithelia cells. However, no signs suggested acute inflammation. No lesions or parasites were fo und in other portions of the gastrointestinal tract or other epithelia l tissues of the body.