2013年无锡地区诺如病毒腹泻病的监测研究

Surveillance of norovirus-associated diarrhea in Wuxi in 2013

目的监测2013年无锡地区诺如病毒腹泻的流行情况及流行株的基因型特征。方法 2013年1—12月连续采集409份哨点医院急性腹泻病人的粪便标本,采用实时荧光定量RT-PCR检测诺如病毒GⅠ和GⅡ基因组,对部分GⅡ基因组阳性标本经RT-PCR扩增诺如病毒部分衣壳蛋白（VP1）和多聚酶蛋白（RdRp）序列,对核苷酸序列进行基因分型。结果 2013年采集的急性腹泻病人粪便标本诺如病毒阳性率为9.78%（40/409）,其中1月,4-5月份及10-11月份的病人粪便标本诺如病毒阳性率分别为13%、10.26%、17.65%、31.43%和15.15%,均高于月平均阳性率10%。诺如病毒腹泻在5岁以下儿童中发病率最高,达到13.40%;其次是19-35岁组,发病率为12.50%。所测35株诺如病毒分为5种基因型,分别为：GⅡ.Pe/GⅡ.4型28株（80.00%）、GⅡ.P12/GⅡ.3型4株（11.43%）,GⅡ.P16/GⅡ.13型2株（5.71%）,GⅡ.P7/GⅡ.6和GⅡ.16各1株（2.86%）。结论诺如病毒是无锡地区非细菌性腹泻常见病原体,诺如病毒腹泻全年流行。无锡地区诺如病毒流行株具有多种基因型,并存在不同基因型间重组株,以GⅡ.Pe/GⅡ.4型（Sydney_2012）为绝对优势流行株。

Objective To monitor the epidemiology of norovirus infection in patients with diarrhea in Wuxi in 2013 and to characterize the genotypes of norovirus strains. Methods Stool samples were collected from patients visiting sentinel hospitals for acute gastroenteritis in 2013.One-step real-time RT-PCR was used to screen for norovirus genogroups G I and GⅡ.The genotypes of norovirus genogroup GⅡ were classified based on the nucleotide sequences of both a capsid protein and a polymerase. Results Subjects were 409 patients with acute diarrhea.Of these,40（9.78%）had fecal specimens that tested positive for norovirus according to real-time RT-PCR.Increased norovirus infection was observed in January（incidence rate：13%）,April（incidence rate：10.26%）,May（incidence rate：17.56%）,October（incidence rate：31.43%）,and November（incidence rate：15.15%）.These incidence rates were higher than the average monthly incidence rate（10%）.The highest rate of norovirus infection was observed in children under 5years of age（13.4%）,followed by that in younger people ages 19-35years（12.5%）.Five distinct genotypes were identified in 35 norovirus GⅡ strains,including GⅡ.Pe/GⅡ.4Sydney 2012recombinant（28strains,accounting for 80%）,GⅡ.P12/GⅡ.34recombinant（4strains,accounting for 11.43%）,GⅡ.P16/GⅡ.13recombinant（2strains,accounting for 5.71%）,GⅡ.P7/GⅡ.6（1strain,accounting for 2.86%）and GⅡ.16（1strain,accounting for 2.86%）. Conclusion Norovirus is a common causative agent responsible for diarrhea in Wuxi.Norovirus-associated diarrhea was prevalent year-round,with higher activity in late spring and late autumn in Wuxi.Children younger than 5years of age are more susceptible to norovirus infection than other age group.The norovirus that is prevalent displayed genetic diversity.The GII.Pe/GII.4（Sydney_2012）variant was predominant in Wuxi in 2013.