SURVEY OF HUMAN GROUP-C ROTAVIRUSES IN JAPAN DURING THE WINTER OF 1992 TO 1993

Fecal specimens from patients with acute diarrhea were collected from 10 prefectures in Japan over a 6-month period (November 1992 to April 1993), and the specimens that were negative for human group A rotaviru ses were screened for the presence of human group C rotaviruses (CHRVs ) by the reverse passive hemagglutination test, Of 784 specimens exami ned, 53 samples (6.8%) that were collected in 7 of 10 prefectures were positive for CHRV, indicating that CHRVs are widely distributed acros s Japan. Most of the CHRV isolates were detected in March and April, a nd CHRVs mainly prevailed in children ages 3 to 8 years. The genome el ectropherotypes of eight strains isolated in five individual prefectur es were surprisingly similar to each other and were different from tho se of CHRV strains isolated to date. The outer capsid glycoprotein (VP 7) gene homologies of the isolates retrieved in 1993 were subsequently analyzed by the dot blot hybridization method. As a result, the VP7 g enes of the isolates revealed very high levels of homology not only wi th each other but also with the VP7 gene of the OK118 strain isolated in 1988. These results suggest that a large-scale outbreak of CHRV occ urred during the winter of 1992 and 1993 in Japan.