A large outbreak of acute gastroenteritis associated with astrovirus among students and teachers in Osaka, Japan.

In June 1991, a large outbreak of acute nonbacterial gastroenteritis occurred among students and teachers at 10 primary and 4 junior high schools in Katano City, Osaka, Japan. The outbreak affected > 4700 persons, lasted 5 days, and was believed to have been linked to contaminated food from a common supplier. Astrovirus, identified as the etiologic agent, was detected by direct electron microscopy in 10 of 38 fecal samples obtained from patients with diarrhea. Detection was confirmed by solid-phase immune electron microscopy (IEM), EIA, reverse transcription-polymerase chain reaction, and virus isolation in CaCo-2 cells. Several patients who had astrovirus in their stool also demonstrated a significant antibody response to a reference strain of astrovirus by IEM and EIA and to their own isolate by IEM. Astrovirus can be an important agent of epidemic acute nonbacterial gastroenteritis in school-aged children and adults in Japan.