怀宁县某幼儿园一起诺如病毒感染暴发疫情调查

Investigation on an outbreak of norovirus infection in a kindergarten in Huaining County

目的通过对怀宁县某幼儿园诺如病毒感染暴发疫情的现场调查和处置,探讨幼儿园诺如病毒感染暴发疫情发生的原因及防控策略。方法采用现场流行病学调查方法对怀宁县某幼儿园诺如病毒感染暴发疫情中病例进行调查,采集病例标本、食品标本采用荧光定量-聚合酶链式反应方法进行诺如病毒核酸检测。结果怀宁县某幼儿园共报告诺如病毒感染病例32例,罹患率为26.67%(32/120),病例主要分布在首发病例所在的班级,疫情历时3 d,男女发病差异无统计学意义(χ~2=0.13,P=0.719)。11份患者肛拭子标本中7份肛拭子样本诺如病毒核酸阳性,且均为G-Ⅱ型,阳性率为63.64%;4份密切接触者肛拭子样本和6份食品样品诺如病毒核酸阴性。结论此次疫情由G-Ⅱ型诺如病毒感染引起;患病儿童没有采取有效隔离、未能及时规范处理病例在教室内的呕吐物,通过密切接触和呕吐物的气溶胶而造成人与人传播可能是导致该起暴发疫情的主要原因。

Objective To investigate the causes and control strategies of norovirus infection outbreak in a kindergarten in Huaining County through field investigation and disposal.Methods Field epidemiological investigation was used to investigate the cases of norovirus infection outbreak in a kindergarten in Huaining County.The samples of cases and food samples were collected and the nucleic acid of norovirus was detected by fluorescence quantitative-polymerase chain reaction.Results A total of 32 cases of norovirus infection were reported in a kindergarten in Huaining County.The incidence rate was 26.67%(32/120).The cases were mainly distributed in the class where the first case occurred.The epidemic lasted for three days.There was no significant difference between male and female(χ~2=0.13,P= 0.719).Among 11 anal swabs, 7 were positive for norovirus nucleic acid, and all of them were G-II, with a positive rate of 63.64%.4 anal swabs from close contacters and 6 food samples were negative for norovirus nucleic acid.Conclusion The outbreak was caused by Norovirus type G-II infection, and the main cause of the outbreak was that the children did not take effective isolation and failed to deal with the vomit in the classroom in time.Close contact with the vomit aerosol and human-to-human transmission may be the main cause of the outbreak.