Sequence homology analysis
We found that the nucleotide sequences of S genes of 91 samples had a homology of 94.2%–100%. Four strains in GII-a subgroup shared a homology of 97.3%–99.7%, while eight strains in GII-b subgroup shared a homology of 96.8%–100%. The newly detected seven S-INDEL like strains shared 95.1%–95.6% and 94.2%–96.8% homology with non-S-INDEL like strians in subgroups GII-a and GII-b, respectivly. The strains in GII group shared 93.2%–93.8% and 96.7%–99.1% homologies with Chinese vaccine strain CV777 (GI-b) and AJ1102 (GII-b), respectively. In addition, the S-INDEL like strains had a homology of 94.8%–95.2% s with Chinese vaccine strains (Table 1).