一起诺如病毒GⅠ、GⅡ组混合感染聚集性疫情分析

An epidemic of mixed infection of norovirus GⅠand GⅡ

目的调查2018年11月浙江省台州市一起诺如病毒聚集性疫情,查找病原和传播因素,为类似疫情调查处置提供依据。方法搜索病例,开展个案调查、现场卫生学调查,通过病例对照研究分析危险因素;采集病例粪便标本,利用实时荧光定量反转录-聚合酶链式反应方法进行诺如病毒核酸检测。结果共搜索到确认病例16例,罹患率为5.82%(16/275),病例均为学生,无教职工患病,无重症和死亡病例;病例起病急,临床表现为呕吐(100.0%)、恶心(100.0%)、腹痛(62.5%)、发热(25.0%);16份粪便样本检出诺如病毒阳性标本13份,其中GⅠ、GⅡ组诺如病毒混合阳性2份,GⅠ组诺如病毒阳性2份、GⅡ组诺如病毒阳性9份;在校外寄宿(OR=154,95%CI:19.82~1196.45)和在呕吐现场围观是发病的危险因素(OR=143,95%CI:18.31~1116.71)。结论该疫情为诺如病毒聚集性疫情,可能原因为通过吸入首例病例呕吐物气溶胶传播。

Objective To investigate an epidemic of norovirus infection,identify the pathogen and transmission factors,and provide evidence for the response of similar epidemic.Methods The cases were searched,and case survey and field hygiene survey conducted.The risk factors were analyzed through case-control study.The stool samples were collected from the cases for norovirus nucleic acid detection with real time fluorescence reverse transcriptase polymerase chain reaction.Results A total of 16 confirmed cases were found,the attack rate was 5.82%(16/275).The cases were all students,no teacher and school staff were affected.No severe case and death occurred.Acute illness was observed in the cases,the clinical manifestations included vomiting(100.0%),nausea(100.0%),abdominal pain(62.5%)and fever(25.0%);Thirteen norovirus positive samples were detected in 16 stool samples,i.e.2 norovirus GⅠand GⅡmixed positive samples,2 norovirus GⅠpositive samples,9 norovirus GⅡpositive samples.Off-campus boarding(OR=154,95%CI:19.82-1196.45)and onlooking at vomiting sites were risk factors for the infection(OR=143,95%CI:18.31-1116.71).Conclusion The epidemic was a norovirus caused infection cluster,which might be caused by aerosol transmission through the inhalation of vomit of the index case.