一起急性胃肠炎暴发疫情中诺如病毒的分子流行病学分析

Molecular epidemiology of norovirus in an outbreak of acute gastroenteritis

目的研究导致本次急性胃肠炎暴发疫情的诺如病毒的分子流行病学特征。方法对2015年2月7日北京市某旅行团急性胃肠炎暴发疫情病例标本进行实时荧光定量PCR(Real-time PCR)检测,并对感染病例的诺如病毒进行RNA依赖性RNA聚合酶基因(RNA-dependent RNA polymerase,RdRp)和VP1区基因序列的检测和分析。结果 18份便标本经Real-time PCR检出12份GⅡ型诺如病毒阳性标本,RdRp区和VP1区序列扩增各得到11条诺如病毒基因序列。根据RdRp区和VP1区系统进化分析证明感染病例的诺如病毒分型为GⅡ.17型。该病毒株与引起暴发疫情的诺如病毒GⅡ.17型新变异株珠海ZHITHC-12株高度同源,RdRp区和VP1区核苷酸差异分别为0%和0.1%,氨基酸差异均为0%。结论引发北京某旅行团旅客急性胃肠炎暴发疫情的病原体是引起中国2015年暴发流行的诺如病毒GⅡ.17型新变异株。

Objective To study the molecular epidemiology of norovirus causing an outbreak of acute gastroenteritis. Methods Specimens were collected from patients with acute gastroenteritis in a tour group in Beijing on February 7, 2015, and were subjected to norovirus detection by real-time polymerase chain reaction （real-time PCR）. Gene detection and analysis of both RNA-dependent RNA polymerase （RdRp） and VP1 region were performed in the noroviruses isolated. Results Twelve out of 18 stool specimens were detected to be G 11 norovirus-positive by real-time PCR. And 11 norovirus sequences were obtained by gene amplification of both RdRp and VP1 region. Phylogenetic analysis of RdRp and VP1 region indicated that norovirus G II. 17 was the pathogen. The virus strain was highly homologous with Zhuhai ZHITHC-12 strain, which had caused outbreaks of infectious diseases before. The nucleotide difference was 0% between the laboratory strain and Zhuhai ZHITHC-12 strain in the RdRp region, and 0.1% in the VP1 region. The amino acid differences were both 0%. Conclusions It is a new norovirus variant of G II.17 causing outbreaks of acute gastroenteritis in China in 2015 that leads to the outbreak of the acute gastroenteritis in a tour group in Beijing.