Human calicivirus-associated diarrhea in children attending day care centers.

We investigated human calicivirus (HCV)-associated diarrhea in children attending day care centers by using stool specimens collected in 1981-1983. We used a screening enzyme-linked immunosorbent assay (ELISA) derived from reagents prepared against the Sapporo strain of HCV and confirmed positive results with a blocking ELISA and immunosorbent electron microscopy. HCV was detected in 11 (2.9%) of 375 diarrheal stools and in none of 86 stools from asymptomatic contacts. This incidence rate was half that noted for rotaviruses and higher than that noted for Campylobacter, Salmonella, and Shigella in the original study. HCV was found in stool specimens from children in nine day care centers; HCV-associated diarrhea was sporadic, occurred with greater frequency in young children, and had a summer-fall predominance. Our results indicate that HCV is an important cause of diarrhea in day care centers and that frozen stool samples can yield epidemiological data on HCV infection.