Diarrhea due to Cryptosporidium infection in artificially reared lambs

Abstract

Severe diarrhea which lasted 7-12 days occurred in 40 of 48 artifically reared lambs within 5-12 days of birth; 16 died. Of 16 diarrheic fecal samples examined, 10 contained Cryptosporidium oocysts and 1 contained rotavirus but no other known enteropathogen was detected. Upon histological examination, cryptosporidia were found in the ilea of 3 affected lambs, and in 1, villous atrophy and fusion with epithelial cross-bridging between villi, were present in the distal small intestine. Diarrhea was induced in 2 specific pathogen-free lambs by oral inoculation with fecal homogenate containing Cryptosporidium oocysts. The small and the large intestines became infected with the organism and associated lesions included stunting, fusion and deformities of villi in the distal small intestine, with replacement of columnar erythrocytes by immature cuboidal cells. Subclinical infections were induced in newborn specific pathogen-free mice and rats. Judged by these data, the lamb-derived Cryptosporidium sp. is similar to those recovered from calves, deer and humans.