Screening for coinfection with Cryptosporidium and Giardia in Oregon public health clinic patients.

During 1984, we screened 1,710 local public health clinic patients for Giardia and Cryptosporidium. Six patients (0.35 per cent) were positive for Cryptosporidium, and 214 (12.5 per cent) were positive for Giardia. One patient was positive for both parasites. In contrast to other reported studies, no evidence was found for an association between the two parasites (odds ratio = 1.39, 95 per cent CI 0.16, 11.8). The apparent prevalence of Cryptosporidium in our study population was lower than has been reported previously. More laboratory screening could contribute to a better understanding of the distribution of Cryptosporidium and its role in human diarrheal disease, especially in immunocompetent patients.