| recurrent outbreaks of cryptosporidiosis associated with calves among students at an educational farm programme, minnesota, 2003. | enteric illness outbreaks among middle-/high-school students in consecutive semesters of an educational farm programme were investigated with retrospective cohort studies. during the first outbreak, 31/92 (34%) interviewed students were ill. risk factors included participating in animal science class (rr 8.1, 95% ci 1.2-55.2) and contact with calves (rr 4.2, 95% ci 1.1-16.2). stool samples from seven students and two calves yielded cryptosporidium parvum. students cared for animals in street clo ... | 2006 | 16672084 |