Enteric cryptosporidial infection in pigs: 184 cases (1981-1985).

Cryptosporidia organisms were detected histologically in the microvillus brush border of 5.3% (184/3,491) of consecutive live pigs submitted for routine diagnostic evaluation between 1981 and 1985. Infected pigs came from 133 farms and usually were 6 to 12 weeks old, but ranged from 1 to 30 weeks old. Organisms were found in the jejunum, ileum, cecum, and colon, but primarily in microvilli of dome epithelium in the ileum. A seasonal incidence was not observed. Only 26% of the cryptosporidia-infected pigs had diarrhea, and most of those had other primary diarrheagenic agents or lesions capable of causing their diarrhea.