The emergence and rapid spread of unusual DS-1-like G1P rotaviruses in Japan have been recently reported. During rotavirus surveillance in Thailand, three DS-1-like G1P strains (RVA/Human-wt/THA/PCB-180/2013/G1P, RVA/Human-wt/THA/SKT-109/2013/G1P, and RVA/Human-wt/THA/SSKT-41/2013/G1P) were identified in stool specimens from hospitalized children with severe diarrhea. In this study, we sequenced and characterized the complete genomes of strains PCB-180, SKT-109, and SSKT-41. On whole genomic analysis, all three strains exhibited a unique genotype constellation including both genogroup 1 and 2 genes: G1-P-I2-R2-C2-M2-A2-N2-T2-E2-H2. This novel genotype constellation is shared with Japanese DS-1-like G1P strains. Phylogenetic analysis revealed that the G/P genes of strains PCB-180, SKT-109, and SSKT-41 appeared to have originated from human Wa-like G1P strains. On the other hand, the non-G/P genes of the three strains were assumed to have originated from human DS-1-like strains. Thus, strains PCB-180, SKT-109, and SSKT-41 appeared to be derived through reassortment event(s) between Wa-like G1P and DS-1-like human rotaviruses. Furthermore, strains PCB-180, SKT-109, and SSKT-41 were found to have the 11-segment genome almost indistinguishable from one another in their nucleotide sequences and phylogenetic lineages, indicating the derivation of the three strains from a common origin. Moreover, all the 11 genes of the three strains were closely related to those of Japanese DS-1-like G1P strains. Therefore, DS-1-like G1P strains that have emerged in Thailand and Japan were assumed to have originated from a recent common ancestor. To our knowledge, this is the first report on whole genome-based characterization of DS-1-like G1P strains that have emerged in an area other than Japan. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G1P rotaviruses.
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