Molecular epidemiologic study on norovirus gastroenteritis outbreaks in Zhuhai from 2011 to 2016 / 中华实验和临床病毒学杂志

ABSTRACT

Objective@#To describe the molecular epidemiological characteristics of norovirus gastroenteritis outbreaks in Zhuhai from 2011 to 2016.@*Methods@#Anal swab specimens were collected from 576 cases with 56 outbreaks of acute norovirus gastroenteritis from 2011 to 2016. Specimens were tested by real-time RT-PCR. Three to four of norovirus positive specimens were selected from every outbreak to amplify the VP1 gene by RT-PCR and one strain was chosen randomly from every outbreaks to determine the genotype by phylogenetic tree analysis.@*Results@#Eight genotypes were identified from 56 outbreaks and all of them belonged to GⅡ genogroup. The genotype of norovirus strain changed with prevalence time. The GⅡ.4/2006b was dominant from 2011 to 2012, and replaced by GⅡ.4/Sydney _2012 during the 2012—2013 norovirus season, and both of them never appeared after Feb. 2013. GⅡ.17 was the only genotype during the 2014—2015 norovirus season. All the 7 outbreaks occurred from 2015 to 2016 were caused by GⅡ.3 norovirus. The GⅡ.17and GⅡ.3 were identified from Apr. to Sep. 2016; GⅡ.p16-GⅡ.2 were the only genotype in 12 outbreaks from Nov. to Dec. 2016. The GⅠ genogrope was never identified from 2011 to 2016 in Zhuhai.@*Conclusions@#The Norovirus GⅡ was the only pathogeny which caused the outbreaks of norovirus gastroenteritis. The recombinant norovirus strain GⅡ.p16-GⅡ.2 emerged and caused large outbreaks in the last two months of 2016 in Zhuhai; several recombinant strains of the GⅡ.p16 RdRp gene were found now, which suggests that attention should be focused on the prevalence and evolution of the recombinant norovirus.