2013-2016年北京市西城区诺如病毒感染聚集性疫情流行特征分析

目的 对2013-2016年北京市西城区诺如病毒感染聚集性疫情的流行病学特征进行分析。方法 采用现场流行病学方法,对2013年1月至2016年12月北京市西城区报告的诺如病毒感染聚集性疫情开展流行病学调查,采集病例及相关人员标本进行腹泻相关病毒检测。结果 2013-2016年西城区共报告15起聚集性疫情,每起疫情发病人数在8~37例之间,罹患率在13.7%-53.3%之间。疫情流行期中位数为3d。四年报告疫情起数呈逐年递增趋势,冬春季为高发季节,其中12月至次年4月共报告10起(66.7%)。疫情主要发生在小学 10起(66.67%)。采集患者、密接及食品从业者便标本共188件,检出诺如病毒核酸103件,阳性率为54.8%,其中患者便标本阳性率最高80.8%。除1起聚集性疫情由GⅠ组诺如病毒引起外,其余14起均由GⅡ组诺如病毒引起。结论 2013-2016年北京市西城区诺如病毒聚集性疫情冬春季高发,小学为重点场所,应加强疫情的监测、报告工作,加强食堂员工及隐性感染者的监测与管理。

Epidemiological features of norovirus outbreak in Xicheng District of Beijing,2013-2016

Objective To understand the epidemiological characteristics of norovirus outbreaks in Xicheng District of Beijing from 2013 to 2016. Methods The field epidemiological survey method was used to investigate the epidemic situation of norovirus infection and the samples were collected from cases and close contacts to detect the virus. Results A total of 15 norovirus outbreaks in Xicheng District of Beijing occurred between 2013 and 2016 involving 8-37 cases every time and attack rates ranging from 13.7% to 53.3%.The median duration of aggregation epidemic was 3 days.The norovirus outbreaks increased every year from 2013 to 2016,and the peak seasons appeared in winter and spring.10 events occurred during December to April,accounting for 66.7%,and 10 events occurred in primary schools (66.7%).A total of 188 specimens were collected and tested with the total positive rate of 50.8% and the positive rate of cases of 80.8%.All the events investigated were caused by norovirus Ⅱ except one which was caused by norovirus Ⅰ. Conclusion Outbreak of norovirus usually occurs during winter and spring in Xicheng District,2013-2016.It is the primary school that should be the focus of surveillance.Monitoring efforts and report work for norovirus infection should be strengthened,and the health monitoring of the canteen staff or stealth infection should also be enhanced.