广州市腹泻监测病例诺如病毒分子流行病学特征

Molecular epidemiological characteristics of norovirus in diarrhea cases in Guangzhou

目的了解广州市腹泻监测病例中诺如病毒分子流行病学特征。方法 2014-2015年选取广州市两家医院的门诊科室作为监测哨点,每间哨点医院每周采集5岁以下和5岁及以上腹泻病例粪便样本各3份,将采集的标本送至广州市疾病预防控制中心检测诺如病毒。阳性标本进行基因序列测定并进行同源性分析。通过中国传染病疫情和突发公共卫生事件网络直报系统收集2014-2015年广州市报告的诺如病毒感染引起的暴发疫情数据,开展流行病学分析。结果共收集腹泻标本732份,诺如病毒阳性136份,阳性率为18.58%。各年龄组诺如病毒阳性率不同(χ2=20.39,P=0.001),其中5岁以下年龄组最高(24.21%)。基因分型结果显示GⅡ组133份(97.80%),GⅠ组3份(2.20%)。分别对2014年(4份)及2015年(5份)阳性标本进行测序,结果提示,2014年诺如病毒流行株以GⅡ.4 Sydney_2012变异株(75.00%)为主,2015年以GⅡ.17变异株(55.60%)为主。2014-2015年共报告诺如病毒感染性腹泻暴发疫情23起,其中14(60.80%)起由GⅡ组引起。结论广州市诺如病毒感染性腹泻流行毒株仍以GⅡ组为主,其中2014年优势毒株为GⅡ.4 Sydney_2012变异株,2015优势毒株为GⅡ.17变异株。

Objective To analyze the molecular epidemiological characteristics of norovirus isolated from diarrhea cases in Guangzhou. Methods Two hospitals in Guangzhou were selected as sentinels during 2014 - 2015. Each hospital was required to collect 3 stools samples per week from children aged 〈 5 years and ≥ 5 years respectively. The samples were sent to Guangzhou Center for Disease Control and Prevention for the detection of norovirus nucleic acid. Then, all the positive samples were sequenced for homology analysis. Epidemiological data of the outbreaks caused by norovirus between 2014 and 2015 were collected from the Information System of Communicable Disease and Public Health Emergency of China, and the epidemiological characteristics were analyzed. Results Among the 732 samples collected, 136 were norovirus positive （ 18.58% ）. The positive rate varied with age （X2 = 20. 39, P = 0. 001 ）, and the positive rate in age group 〈 5 years was highest （24. 21% ）. 136 norovirus positive samples were genotyped, in which 133 （97.80%） belonged to genogroupⅡ , 3 （2. 20% ） belonged to genogroup I . Four positive samples in 2014 and 5 positive samples in 2015 were further sequenced. The main variant strains were GⅡ. 4 Sydney_2012（75.00% ） in 2014 and G Ⅱ.17（55.60% ） in 2015. G Ⅱ genotype was the main pathogen causing 60. 80% of 23 outbreaks. Conclusion Norovirus G Ⅱ was the major pathogen causing infection in Guangzhou, and the predominant strains were G Ⅱ. 4 Sydney_2012 variant in 2014 and G Ⅱ. 17 variant in 2015.