2020年北京市门头沟区急性胃肠炎病例诺如病毒分子流行病学特征分析

Molecular epidemiology characterization of norovirus in acute gastrointestinal cases in Mentougou distract of Beijing,2020

目的分析2020年北京市门头沟区急性胃肠炎病例诺如病毒分子流行病学特征。方法对2020年门头沟区急性胃肠炎散发监测病例、聚集性疫情样本及流行病学资料进行系统收集和回顾性分析。采用实时荧光定量聚合酶链式反应对样本进行检测,GⅡ组阳性样本使用一步法逆转录聚合酶链式反应(RT-PCR)方法扩增,阳性扩增产物进行聚合酶区和衣壳区片段测序,并构建系统进化树。结果共收集126件样本,诺如病毒检出率为34.13%(43/126),其中GⅠ组检出率为1.59%(2/126),GⅡ组检出率为32.54%(41/126)。聚合酶区和衣壳区测得基因型包括:GⅡ.2[P16]、GⅡ.6[P7]、GⅡ.4[P16]和GⅡ.3[P12]。引起急性胃肠炎聚集性疫情的诺如病毒基因型为GⅡ.2[P16]、GⅡ.6[P7]和GⅡ.3[P12]。2015-2020年散发监测病例中诺如病毒的检出率呈每2~3年出现一个高峰的现象,不同年份间诺如病毒的检出率比较,差异有统计学意义(χ^(2)=11.765,P=0.038),且每年检出的诺如病毒均以GⅡ型为主。结论2015-2020年门头沟区散发监测病例诺如病毒的检出率呈每2~3年出现一个高峰的现象,且每年检出的诺如病毒均以GⅡ型为主。2020年诺如病毒GⅡ型流行基因型呈多样性。

Objective To analyze the molecular epidemiology characteristics of norovirus in acute gastrointestinal cases in Mentougou distract,Beijing in 2020.Methods The samples and epidemiological data from acute gastroenteritis patients in daily surveillance and clusters of the disease in Mentougou district in 2020 were collected and retrospectively analyzed.Fluorescence quantitative Polymerase Chain Reaction(PCR)was used to detect the samples.The GⅡpositive samples were amplified by one-step Reverse Transcription Polymerase Chain Reaction(RT-PCR),and the positive PCR products were sequenced for fragments of the polymerase and capsid regions,and a phylogenetic tree was constructed.Results A total of 126 samples were collected,and the detection rate of norovirus was 34.13%(43/126),among which the detection rate of GⅠgroup was 1.59%(2/126)and GⅡgroup was 32.54%(41/126).The norovirus genotypes measured in the polymerase and capsid regions included GⅡ.2[P16],GⅡ.6[P7],GⅡ.4[P16]and GⅡ.3[P12].The norovirus genotypes causing the acute gastroenteritis outbreaks were GⅡ.2[P16],GⅡ.6[P7]and GⅡ.3[P12].From 2015 to 2020,the detection rate of norovirus in sporadic surveillance cases showed a peak every 2-3 years,with statistically significant difference in the detection rate of norovirus between years(χ^(2)=11.765,P=0.038),and the predominant type of norovirus detected in each year was GⅡ.Conclusions From 2015 to 2020,the detection rate of norovirus in sporadic surveillance cases showed a peak every 2-3 years,and GⅡwas the predominant type of norovirus detected every year.The genotypes of norovirus GⅡtype in Mentougou distract in 2020 were diverse.