2019—2021年深圳地区诺如病毒暴发分子流行特征

Molecular epidemiological characteristics of norovirus outbreaks in Shenzhen from 2019 to 2021

目的了解深圳地区2019—2021年诺如病毒暴发分子流行特征。方法收集2019年1月至2021年12月诺如病毒暴发信息及标本,应用实时荧光反转录聚合酶链式反应样本进行诺如病毒检测,阳性样本通过RT-PCR扩增、测序和序列分析;对其中3株GII.2[P16]进行基因组扩增和序列分析。结果2019年1月至2021年12月,共报告诺如病毒暴发246起,主要发生在幼儿园(132,53.66%)和小学(52,21.14%)。每起暴发发病数范围为3~130,中位数为8。每年11月至次年3月为诺如病毒暴发的流行高峰。211起暴发分型成功,GI和GII分别检出7种和11种基因型,78起(36.97%)诺如病毒暴发由GII.2[P16]引起。对GII.2[P16]基因组分析表明,深圳2020年暴发株仍属于GII.2[P16](2016-2017)亚群,在非结构蛋白P22(L777S)和3C蛋白酶(A1047V和P1074T)上出现氨基酸变异。结论GII.2[P16]是2019年1月至2021年12月引起深圳市诺如病毒暴发的流行株,主要发生在学校和幼儿园,持续监测和基因组分析有助于发现流行株的变异和新毒株的出现。

Objective To understand the molecular epidemiological features of norovirus outbreaks in Shenzhen of China from January 2019 to December 2021.Methods The norovirus outbreaks information and specimen from January 2019 to December 2021 were collected.Norovirus was detected by real-time reverse transcriptase polymerase chain reaction(RT-PCR).Positive samples were amplified by RT-PCR and sequenced.The sequences were then analyzed.Genome amplification and sequence analysis were performed on three strains of GII.2[P16].Results From January 2019 to December 2021,a total of 246 outbreaks caused by norovirus were reported,mainly in kindergartens(132,53.66%)and primary schools(52,21.14%).The number of cases in an outbreak ranged from 3 to 130,with a median value of 8.The epidemic peak of norovirus outbreak was from November to the next March.The viruses in 211 outbreaks were successfully genotyped.Seven genotypes of GI group and eleven genotypes of GII group were detected.Norovirus GII.2[P16]was responsible for 78(36.97%)outbreaks.According to the genome analysis of GII.2[P16],the strains from the outbreaks in 2020 still belonged to GII.2[2016](2016-2017)subcluster.Amino acid mutations were observed in the non-structural protein P22(L777S)and 3C protease(A1047V and P1074T).Conclusions GII.2[P16]was the predominant genotype that caused the outbreak of norovirus in Shenzhen from January 2019 to December 2021,mainly in kindergartens and schools.Continuous surveillance and genome analysis can help to find the mutations of epidemic strains and the emergence of novel variants.