Detection and molecular characterization of two rare G8P[14] and G3P[3] rotavirus strains collected from children with acute gastroenteritis in Japan

This study describes the detection and molecular characterization of two rare G8P[14] and G3P[3] rotavirus strains, which were collected from children with acute gastroenteritis in 2014 in Japan. Among 247 rotaviruses, one G8P[14] (strain 12,597) and one G3P[3] (strain 12,638) rotaviruses were detected. The genotypes of 11 gene segments of these two rotavirus strains (RVA/Human-wt/JPN/12597/2014/G8P [14] and RVA/Human-wt/JPN/12638/2014/G3P [3]) were characterized. The genotype constellation of strain 12,597 was assigned to G8P[14]-I2-R2-C2-M2-A3-N2-T9-E2-H3, and this strain possessed a rare T9 genotype of NSP3 gene which has never been reported previously in combination with G8 genotype of VP7 gene. Molecular characterization and phylogenetic analysis suggested that the strain 12,597 had the consensus G8P[14] backbone that originated from the rotaviruses of animal origins such as cows, deer, dogs, and cats. The genotype constellation of strain 12,638 was identified as G3-P[3]-13-R3-C3-M3-A9-N2-T3-E3-H6. The VP7 and VP4 genotypes of strain 12,638 was similar to those of the Cat97-like strains, but the VP1, VP2, and VP3 were closely related to those of the AU-1-like strain. Interestingly, the NSP1 to NSP3 genes shared highest identities with those of a bat rotavirus (RVA/Bat-wt/ZMB/LUS12-14/2012/G3P[3] strain). These findings indicated that the strain 12,638 was an intra-genotype reassortant strain among the AU-1-like strains, the Cat97-like strains and the bat strain. Interestingly, the strains 12,597 and 12,638 possessed the same N2 genotype of NSP2 gene. The results of this study support the possible roles of interspecies transmission and multiple reassortment events for generating the genetic diversity of rotavirus in human.