北京市门头沟区诺如病毒急性胃肠炎疫情分子流行特征分析

Molecular epidemiology of norovirus acute gastrointestinal clusters in Mentougou district of Beijing from 2017 to 2020

目的 分析2017-2020年北京市门头沟区诺如病毒急性胃肠炎疫情的分子流行特征。方法 采用现场流行病学方法开展调查,收集2017-2020年北京市门头沟区由诺如病毒引起的急性胃肠炎疫情粪便样本,采用实时荧光定量PCR的方法对粪便样本进行诺如病毒GI/GII组检测,阳性样本使用逆转录聚合酶链式反应(RT-PCR)的方法对聚合酶区和衣壳区进行扩增,阳性扩增产物送测序,根据测得序列利用MegaX软件构建系统进化树。结果 共接报31起诺如病毒急性胃肠炎疫情,收集172件粪便样本,检出阳性139份,阳性率为80.81%(139/172),以检出GII组为主(97.84%,136/139),GI组检出率低(2.16%,3/139)。诺如病毒急性胃肠炎疫情呈现春季和秋末冬初高发的特点,发病高峰为3~6月和10~11月。31起急性胃肠炎疫情主要发生在2017年,占比70.97%(22/31),2018-2020年维持在低水平。幼儿园为诺如病毒疫情的主要发生场所,占比70.97%(22/31),其次是小学(19.35%,6/31)和中学(9.68%,3/31)。测序获得85株基因序列,共5种基因型:GII.2[P16]、GII.3[P12]、GII.4[P31]、GII.6[P7]和GI.6[P11],以GII.2[P16]为主(80%,68/85)。25起测序成功的急性胃肠炎疫情以GII.2[P16]为主(76%,19/25),且2017-2020年每年都有GII.2[P16]引起疫情的报道,其次为GII.3[P12](16%,4/25),其余基因型引起的疫情数较少。结论 GII.2[P16]是2017-2020年门头沟区诺如病毒急性胃肠炎疫情的流行基因型,应加强诺如病毒分子流行病学监测,以减少诺如病毒急性胃肠炎疫情的发生。

Objective To analyze the molecular epidemiology of norovirus acute gastrointeritis epidemic in Mentougou district of Beijing from 2017 to 2020.Methods Field epidemiological method were used to investigate.Fecal samples of acute gastroenteritis clusters caused by norovirus were collected in Mentougou District of Beijing,from 2017 to 2020.Real-time fluorescence polymerase chain reaction(PCR) was used to detect norovirus GI/GII group in fecal samples.The polymerase and capsid region of the positive samples were amplified by reverse transcription polymerase chain reaction(RT-PCR),then the positive amplification products were sequenced.According to the measured gene sequences,phylogenetic trees were constructed by the software MegaX.Results 31 clusters of acute gastroenteritis were reported in mentougou district,2017-2020.A total of 172 samples were collected,139 stool samples of them were positive,and the positive rate was 80.81%(139/172).GII group was the main positive one(97.84%,136/139),and GI group had a low detection rate(2.16%,3/139).The norovirus acute gastroenteritis clusters showed obvious peaks in spring,late autumn as well as early winter,and the month of 3-6、10-11 had the mostly patients.31 clusters of acute gastroenteritis mainly occurred in 2017,accounting for 70.97%(22/31),then remained at a low level from 2018 to 2020.Kindergartens were the main places where norovirus clusters occurred,accounting for 70.97%(22/31),followed by primary schools(19.35%,6/31) and secondary schools(9.68%,3/31).85 strains were sequenced successfully,and 5 genotypes were included:GII.2[P16]、GII.3[P12]、GII.4[P31]、GII.6[P7] and GI.6[P11].Among them GII.2[P16] was the main genotype(80%,68/85),and it was also the main genotype to cause clusters(76%,19/25).Norovirus acute gastrointeritis clusters which caused by GII.2[P16] were reported every year from 2017 to 2020,next was GII.3[P12](16%,4/25),other genotypes were fewer.Conclusion GII.2[P16] was the epidemic genotype of norovirus acute gastroenteritis clusters in Mentougou district,2017-2020.Molecular epidemiological surveillance of norovirus should be strengthened to reduce the incidence of acute gastroenteritis.