Seroepidemiology of human group C rotavirus in Japan based on a blocking enzyme-linked immunosorbent assay

A novel blocking enzyme-linked immunosorbent assay (BL-ELISA) was developed for detection of antibodies to human group C rotavirus (CHRV), The specifi city of the BL-ELISA was confirmed by using animal sera hyperimmunized to g roup A and group C rotaviruses and paired sera from five patients with acut e CHRV gastroenteritis. Furthermore, there was concordance between the BL-E LISA and a neutralization assay for CHRV in 226 (95%) of 238 samples. By us ing the BL-ELISA, we determined the seroprevalence of CHRV in 704 serum sam ples obtained from nine different age groups of inhabitants of Okayama Pref ecture, Japan, in 1992, 1994, and 1996, As a result, 211 sera (30%) were fo und to be positive for CHRV antibodies. The seroprevalence gradually increa sed with age and reached 52.7% in the oldest individuals. A further analysi s of the youngest age group suggested that CHRVs predominantly prevail in p ersons older than 3 years of age in Japan. When comparing the three samplin g years, a larger percentage of antibody-positive sera was detected in 1994 than in either 1992 or 1996 in individuals between 6 and 15 years of age, reflecting the occurrence of a CHRV outbreak among children during the wint er of 1992 to 1993 that was previously documented, These results indicate t hat CHRV infections may occur more frequently in spite of the relatively lo w detection rate of the virus.