Molecular etiological characteristics of the gastroenteritis outbreak associated to norovirus infection in Anhui province

Abstract

Objective To study the genotype and phylogenetic characterization of the pathogens associated to the epidemic outbreak of acute gastroenteritis. Methods A total of 19 anal swab and feces samples from acute gastroenteritis outbreak in a junior middle school were collected in November 2014, Anhui province. Norovirus (NoV) nucleic acid was detected by Real-time PCR method, and the partial capsid gene of the all positive specimens were amplified by conventional RT-PCR and sequenced. Phylogenetic tree was constructed by the Neighbor-Joining method based on partial capsid gene sequences of norovirus to perform phylogenetic analysis. Results Of the 19 specimens, 12(12/19) were positive for NoV, and the positive samples of those were sequenced. Phylogenetic analysis showed that 11 strains were belong to genotype GII.2, and one strain was belong to genotype GII.6 norovirus. The nucleotide identity of the partial capsid gene sequences were 95.60% between 11 genotype GII.2 strains identified and Melksham strain of norovirus. Conclusion The epidemic outbreak of acute gastroenteritis from Anhui province was caused by genotype GII.2 and GII.6 norovirus co-infection, and genotype GII.2 norovirus was predominant strains in this outbreak. Key words: Norovirus; Gastroenteritis; Disease outbreaks; Genotype; Phylogeny