Characterization of human rotavirus strains with G12 and P[9] detected in Japan.

Two G12 human rotavirus strains, CP727 and CP1030, were isolated from the respective diarrheic stools of an infant and an adult in Japan. VP7 gene sequences of strains CP727 and CP1030 showed high identity with that of the G12 prototype strain L26, and with those of G12 strains reported recently from Thailand, the United States, and India. VP4 gene sequences of strains CP727 and CP1030 showed the highest identity with those of P[9] rotaviruses. In Northern blot hybridization, strains CP727 and CP1030 were found to be closely related to strain AU-1 (G3P[9]); nine RNA segments hybridized to each other. Moreover, all segments each of the two Japanese G12 strains hybridized to those of the Thai G12 strain T152. These results suggest that Japanese G12 strains detected in this study are reassortants between a L26-like strain and a strain in the AU-1 genogroup. A similar reassortant was found in the Thai G12 strain T152.