Prevalence and genetic diversity of noroviruses in adults with acute gastroenteritis in Huzhou, China, 2013–2014

Xiaofang Wu,Xiaojuan Zhu,Liping Chen,Jiankang Han,Deshun Xu,Lei Ji,Yunfeng Zha,Yuehua Shen

doi:10.1007/s00705-015-2440-0

Abstract

Norovirus (NoV) infection is the most common cause of nonbacterial acute gastroenteritis, which affects both adults and children. However, the molecular epidemiology of NoV in adults with acute gastroenteritis in China has not been investigated extensively. In this study, we investigated the occurrence of NoV infections and analyzed the genetic diversity of NoV in adults with acute gastroenteritis in Huzhou, China. A total of 796 fecal samples were collected from outpatients (≥16 years of age) between March 2013 and February 2014. Real-time RT-PCR was performed to detect NoV genogroups I (GI) and II (GII). For genotyping, the capsid and RNA-dependent RNA polymerase (RdRp) genes were partially amplified and sequenced for phylogenetic analysis. NoVs were detected in 26.51 % (211/796) of the specimens, with GII being predominant, representing 96.20 % of the NoV infections. At least nine genotypes were identified among GI and GII specimens, including GI.P2/GI.2, GI.P3/GI.3, GI.P4/GI.4, GII.Pe/GII.4 Sydney_2012, GII.P12/GII.3, GII.P7/GII.6, GII.P16/GII.13, GII.Pe, and GII.Pg (RdRp only). This is the first report of a GII.P16/GII.13 recombinant virus in adults in China. GII.Pe/GII.4 Sydney_2012 was the most prevalent genotype and the only GII.4 variant identified during the study period. Our findings suggested that NoV was a common causative agent of acute gastroenteritis in adults in Huzhou, China. During the study period, the NoVs circulating in adults in Huzhou were predominantly GII.4 Sydney_2012 variants and GII NoV recombinants.

Highlights

Acute gastroenteritis is one of the most common illnesses and a major public health problem worldwide
We investigated the occurrence of NoV infections and analyzed the genetic diversity of NoV in adults with acute gastroenteritis in Huzhou, China
Our findings suggested that NoV was a common causative agent of acute gastroenteritis in adults in Huzhou, China

Summary

Introduction

Acute gastroenteritis is one of the most common illnesses and a major public health problem worldwide. More than 30 genotypes within GI, GII, and GIV can infect humans, the majority of NoVrelated outbreaks and sporadic cases of acute gastroenteritis. RNA recombination is one of the major driving forces of virus evolution, and recombination of NoV genomes increases their genetic divergence. Analysis of these recombinants has suggested that the majority of recombination points are located near or within the ORF1/ORF2 overlap [2, 3]. During the past several years, most studies of NoV infection in China focused on the role of human NoV in acute gastroenteritis in children [9, 11, 42]. The present study was carried out to investigate the prevalence and genetic diversity of NoVs in adults with acute gastroenteritis in Huzhou, a medium-sized city located in eastern China. The extracted RNA was dissolved in 60 lL of RNase-free water and stored at -70 °C until used

Materials and methods

Results

Discussion