Genetic analysis of norovirus strains detected from sporadic cases in Anhui province, 2016-2017 / 中华实验和临床病毒学杂志

ABSTRACT

Objective@#To analyze the genotype diversity and phylogenetic characterization of norovirus(NoV) in patients with diarrhea from Anhui province.@*Methods@#NoV positive fecal specimens from sentinel hospitals were collected from January, 2016 to December, 2017. The samples were detected by Real-time fluorescent quantitative PCR. Positive samples were of randomly selected and amplified by RT-PCR and the products were sequenced. Phylogenetic tree was constructed by the Neighbor-Joining method based on partial VP1 gene regions of NoV to perform phylogenetic analysis.@*Results@#A total of 263 NoV positive samples were genotyped, of which 239 belonged to genogroup II, 24 belonged to genogroup I. Fifty-five positive samples were successfully sequenced. There were 6 NoV GII genotypes, which included GII.2, 3, 4/Sydney_2012, 13, 17 and 21, while NV GII.17 and GII.4 were the dominant genotypes from 2016 to 2017. The predominant genotype was GII.4/Sydney 2012 (47.27%, 26/55), followed by GII.17 (23.64%, 13/55) and GII.2 (14.55%, 8/55). Phylogenetic tree showed that 26 strains belonged to genotype GII.4/Sydney 2012, NoV. The nucleotide homology among the 26 VP1 genes was 97.8% to 100%. Analysis of the partial VP1 genes of 26 strains showed that it shared the highest homology of 98.9% with the strain of GII.4Sydney2012 (GenBank ID KU720515). However, the prevailing genotype in the Anhui province has shifted on two separate occasions, the GII.17 strain was dominant in 2016, and the GII.4/Sydney 2012 strain was dominant in 2017.@*Conclusions@#NoV GII was the major pathogen causing sporadic diarrhea in Anhui province during from 2016 to 2017, the genotypes are widely distributed, and shifted into the two predominant strains.