Outbreak of acute gastroenteritis caused by human group C rotavirus in a primary school.

In most cases, gastroenteritis caused by human group C rotaviruS (CHRV) is sporadic. However, beginning with an outbreak in Fukuil Prefecture in 1988 ( I ), several mass outbreaks of CHRV gastroenteritis have been reported in Japan (2-6). Asshown in Table I, outbreak at schools has been frequent in April and May. This report briefly summarizes a similar outbreak in a primary school in Okayama Prefecture (7). On May 21 1999, a prefecturalpublic healthcenter received a report on an outbreak of gastroenteritis with diarrhea and vomltlng in the first and second year classes of a pnmary schu)I inthe northwest part of Okayama Prefecture. The outbreak was investigated immediately. The patients were all children. Teachers or other employees of the school were not affected. The first patient appeared on May 15. The outbreakpeaked on May 21, though new patients continued to appear until June 3 (Fig. 1). Among 210 children in the school, 76 showed symptoms of gastroenteritis・ The lower age group was the more affected: 55% (36/66) in 1-2 year classes (6-8 years of age), 27% (17/ 64) in 3-4 year classes (8-10 years of age) and 29% (23/80) in 5-6 year classes (10-12 years of age). Clinical symptoms exhibited by each group are summarized in Table 2. The lower