石家庄市2015年Echo18脑炎脑膜炎疫情的流行病学调查

An epidemiological survey of acute encephalitis and meningitis epidemic caused by Echo18 in Shijiazhuang in 2015

目的分析石家庄市2015年Echo18脑炎脑膜炎暴发流行的流行特征与危险因素。方法采用国家急性脑炎脑膜炎监测项目个案调查表对病例进行调查,对病例脑脊液、血、粪便、咽拭子标本进行肠道病毒RT-PCR检测与基因测序分型,采用1∶1病例对照研究分析疫情危险因素。结果全市2015年5~7月共报告1607例急性病毒性脑炎脑膜炎病例,月均发病率为9.74/10万。疫情于6月上旬达到高峰,主要聚集在平山县与灵寿县。78.69%的病例为1~9岁儿童。平均潜伏期8.63天,均为轻型病例。实验室检测Echo18阳性病例71例。系统进化树分析Echo18发生基因重组。发病前10天接触类似病例(OR=3.35,P=0.008)、发病前10天去过医院(OR=2.38,P=0.012)、常用厕所卫生较差(OR=2.11,P=0.017)为发病危险因素,便后洗手(OR=0.69,P=0.040)是发病保护因素。结论石家庄市2015年5~7月发生急性脑炎脑膜炎流行为Echo18病毒基因重组变异所致,与病例密切接触、个人卫生习惯不良、环境卫生较差、医源性感染是本次疫情的危险因素。

Objective To analyze the epidemic characteristics and risk factors of actue encephalitis and meningitis outbreak caused by Echo18 in Shijiazhuang in 2015.Methods Cases were investigated using the National Actue Encephalitis and Meningitis Surveillance Project Case Questionnaire.Samples of cerebrospinal fluid,blood,feces and throat swab were tested by RT-PCR and gene sequencing for the enterovirus.A 1∶1 case-control study was conducted to analyze the risk factors of epidemic situation.Results From May to July 2015,a total of 1607 cases of acute viral encephalitis and meningitis were reported in the city,with an average monthly incidence of 9.74/100000.The outbreak peaked in early June,mainly in Pingshan County and Lingshou County.78.69%of the cases were children aged 1 to 9 years.The mean incubation period was 8.63 days,all of which were mild cases.The laboratory detected 71 cases with Echo18 positive.The phylogenetic tree analysis suggested that Echo18 resulted in genetic recombination.Exposure to similar cases 10 days before onset(OR=3.35,P=0.008),visits to the hospital 10 days before onset(OR=2.38,P=0.012),and poor sanitation in common toilets(OR=2.11,P=0.017)were risk factors for this epidemic,while hand washing after going to the toilet(OR=0.69,P=0.040)was a disease prevention factor.Conclusion The epidemic of acute encephalitis and meningitis in Shijiazhuang from May to July in 2015 was caused by the genetic recombination mutation of Echo18 virus.Close contact with cases,poor personal hygiene habits,poor environmental hygiene and iatrogenic infections could be the risk factors of this epidemic.