A novel bat-like human G3P[10] rotavirus strain from Thailand shares its VP7 lineage with equine Erv105 and human DS-1-like G3P[8] strains: a possible origin in bats

An unusual rotavirus strain with the G3P[10] genotype, designated RVA/Human-wt/THA/PK2016-1-0120/2016/G3P[10] (short name “PK2016-1-0120”), was detected in a stool specimen from a hospitalized 10-year-old boy with acute gastroenteritis in Thailand. In this study, we sequenced and characterized its whole genome. The strain possesses the genotype constellation G3-P[10]-I8-R3-C3-M3-A9-N3-T3-E3-H6, similar to several previously reported bat and bat-like rotavirus strains (MYAS33-like). In line with this, phylogenetic analyses and sequence comparisons indicate that 10 of the 11 genomic segments (VP4, VP6, VP1-VP3, and NSP1-NSP5) are most similar to those found in MYAS33-like strains. In contrast, the VP7 genomic segment of PK2016-1-0120—which defines the G genotype—is most closely related to those of the Indian equine rotavirus strain Erv105 and DS-1-like G3P[8] human strains. These findings imply a history of segment reassortment involving independent acquisition of the VP7 segment. Given that bats are likely donors in interspecies RVA transmission chains, we speculate that this VP7 lineage originated in bats. In summary, our characterization of the novel bat-like human strain PK2016-1-0120 suggests that the VP7 lineage as found in human DS-1-like G3P[8] strains may have originated from a bat-associated rotavirus, offering an alternative model to the previously proposed equine origin.