A novel human G11P[25] rotavirus strain in Japan with a mosaic genome representing porcine, human, and feline rotavirus lineages

Human G11P[25] rotaviruses reported to date have been porcine-like strains with relatively conserved Wa-like genomic backbones. A novel human G11P[25] strain, RVA/Human-wt/JPN/S22-592/2023/G11P[25] (short name, S22-592), was detected in stool from a 17-year-old boy hospitalized with severe gastroenteritis in Japan. In this study, we sequenced and characterized the whole genome of strain S22-592. Whole-genome analysis revealed a unique genotype constellation, G11-P[25]-I12-R2-C3-M3-A3-N2-T3-E1-H1. Phylogenetic analysis and sequence comparisons indicated that five of the 11 genomic segments (VP7, VP4, VP6, NSP4, and NSP5) are most similar to those of Korean porcine-like human G11P[25] CAU12-2-like strains, which possess the genotype constellation G11-P[25]-I12-R1-C1-M1-A1-N1-T1-E1-H1, representing an I12-containing Wa-like backbone. Of the remaining segments, VP1 and NSP1-NSP3 are most closely related to Chinese feline-like human G3P[9] 2020999/23582009-like strains, which have the genotype constellation G3-P[9]-I2-R2-C2-M2-A3-N2-T3-E3-H3, whereas VP2 and VP3 are most closely related to Thai/Japanese human G3P[9] B2682/To16-11-like strains, which have the genotype constellation G3-P[9]-I3-R3-C3-M3-A3-N3-T3-E3-H6. Together, these findings expand the known range of human G11P[25] rotaviruses beyond the relatively conserved porcine-like/Wa-like lineages described previously, and suggest that S22-592 represents a genomic mosaic assembled from segment groups with distinct porcine-, human-, and feline-associated evolutionary histories.