[Molecular characteristics of noroviruses causing outbreaks of acute gastroenteritis in Huzhou].

Abstract

To study the molecular characteristics of Noroviruses causing outbreaks of acute gastroenteritis in Huzhou. During April 2008 and February 2009, fecal specimens of patients collected from 2 outbreaks of acute gastroenteritis were tested for Norovirus by real-time RT-PCR. Partial sequence of RNA dependent RNA polymerase(RdRp) of the positive samples were amplified by RT-PCR, the PCR products were then purified, sequenced and phylogenetic analysis was conducted. Both genogroup II (GII) and genogroup I (GI) noroviruses were detected in 2 outbreaks. Phylogenetic analysis revealed that two of the GI norovirus strains isolated from 2008 belonged to genotype GI/2 and one of the GI Norovirus strain isolated from 2009 belonged to genotype GI/3. The other GIIú norovirus strains isolated from 2009 had high nucleotide identity with GIIb genotype that had been reported frequently in European countries during 2000 and 2001 and in Asian countries recently. These results suggested that the epidemic strains of norovirus isolated in Huzhou had a high degree of genetic diversity and prevalent genotypes at different times were also different. To our knowledge this is the first report of detecting GIIb variant in outbreaks of acute gastroenteritis in China.