北京地区诺如病毒感染的流行病学调查

Study on the epidemiologic characteristics of norovirus infection in Beijing

目的调查北京地区诺如病毒感染的流行情况。方法对暴发疫情的急性胃肠炎患者和散发诺如病毒阳性患者全部进行现场问卷式调查,并采集患者粪便标本,应用ELISA和RT-PCR方法检测诺如病毒,选择阳性PCR产物进行克隆测序。结果2006年11月至2007年3月,北京市共计报告急性诺如病毒胃肠炎暴发疫情8起,经现场流行病学调查全部确认为院内感染暴发。在报告的409例急性散发病毒性胃肠炎病例中,共检出诺如病毒阳性患者158例,检出率38.63%。其中40～44岁年龄组检出率最高,为55.00%,55～59岁年龄组检出率最低,为21.74%。阳性患者中年龄最大者91岁,最小者仅6个月,平均年龄为40岁。男性患者84例,女性74例。序列分析结果显示,北京地区诺如病毒流行株与2006年荷兰和日本的诺如病毒流行株最为接近,为GⅡ/4型变异株。结论诺如病毒是2006—2007年北京地区冬季病毒性腹泻的一个重要病原体,北京地区诺如病毒流行株与2006年荷兰和日本的诺如病毒流行株属同一类GⅡ/4型变异株。

Objective To investigate the epidemiological characteristics of norovirus infection in Beijing. Methods Both outbreaks and sporadic cases of acute gastroenteritis were studied through questionnaires while the stools of patients were collected. Noroviruses were detected by ELISA or RT-PCR, and PCR products were cloned and sequenced. Results Eight outbreaks were reported between November 2006 and March 2007, which were confirmed as nosocomial infections. A total of 158 positive cases were detected among 409 sporadic cases of acute virus gastroenteritis with a positive rate of 38.63%. The highest positive rate （55.00 % ） was found in group aged from 40 to 44, while the lowest positive rate （21.74 % ） fell into groups aged from 55 to 59. The positive cases aged from 6 months to 91 years with the mean age of 40 years old including 84 males and 74 females. Data from sequence analysis showed that norovirus epidemic strains belonged to the G Ⅱ/4 variants in Beijing, which were almost identical to the variants causing epidemics both in the Netherlands and in Japan. Conclusion Norovirus was important, causing virus-borne diarrhea between 2006 and 2007 in Beijing, and the epidemic strains were consistent with those isolated from both the Netherlands and Japan in 2006.