A long-term survey of rotavirus infection in Japanese children with acute gastroenteritis.

Human rotavirus was detected by electron microscopic examination of the stools of 320 (63%) of 506 infants and young children hospitalized with acute gastroenteritis between December 1974 and March 1977. Serologic responses to infection with the rotavirus were revealed by the complement-fixation test in 130 (70%) of 185 patients examined. During the study period three epidemics of human rotavirus infection occurred during the winter months. The peak incidences occurred in January 1975 (88% of patients positive by serologic analysis or electron microscopy of stools), January 1976 (92%), and February 1977 (96%). Rotavirus was detected in the stools of 288 (79%) of 365 patients tested during the cooler months (December to March) and 35 (25%) of 141 during the rest of the year. In the summer (June to August), rotavirus infection occurred rarely. The frequency of human rotavirus infection was highest among patients aged six to 11 months. These results indicate that human rotavirus can be regarded as a major etiologic agent of acute gastroenteritis in infants and young children, of which wintertime epidemics are common in Japan.