兰州市某养老院一起由诺如病毒引起的聚集性疫情流行病学及病原学分析  

Epidemiological and etiological analysis of a case cluster caused by norovirus in a nursing home in Lanzhou

作　　者：王雪莹 连雪屏 康倩[1] 陈建华[1] 张慧[1] 汪鹏[1] 张慧敏[1] 于德山[1] WANG Xue-ying;LIAN Xue-ping;KANG Qian;CHEN Jian-hua;ZHANG Hui;WANG Peng;ZHANG Hui-min;YU De-shan(Gansu Provincial Center for Disease Control and Prevention,Lanzhou,Gansu 730000,China;不详)

机构地区：[1]甘肃省疾病预防控制中心,甘肃兰州730070 [2]甘肃省兰州市安宁区疾病预防控制中心,甘肃兰州730070

出　　处：《中国病毒病杂志》2022年第5期353-357,共5页Chinese Journal of Viral Diseases

基　　金：国家“艾滋病和病毒性肝炎等重大传染病防治”科技重大专项(2017ZX10103006);甘肃省科技计划项目青年科技基金计划(20JR5RA140)。

摘　　要：目的 对甘肃省兰州市安宁区某养老院肠胃炎腹泻暴发疫情进行流行病学和病原学分析,为社区养老机构诺如病毒腹泻疫情防控提供科学依据。方法 2021年1月28日—2月4日对兰州市安宁区某养老院所有腹泻暴发病例、护理人员、厨师等进行流行病学调查,采集调查对象肛拭子、粪便、呕吐物等用实时荧光聚合酶链反应(real time fluorescence quantitative PCR)进行诺如病毒检测,选取不同人员阳性标本(Ct值≤25)进行诺如病毒的ORF1/ORF2核苷酸序列测定,使用MEGA-X软件的邻接法构建系统进化树并进行遗传进化分析。结果 本起疫情首发病例发病时间为2021年1月20日,1月25—29日为发病高峰,累计报告有临床诊断病例58例,其中老年人57人,住院老年人罹患率为15.83%(57/360),症状以腹泻(50/58,86.21%)、呕吐(35/58,60.34%)、恶心(13/58,22.41%)和腹痛(6/58,10.34%)为主,均为轻症病人;从厨师、保洁、护理等人员中检出无症状感染者53人。共检测163份标本,诺如病毒GⅡ型阳性率49.08%(80/163),护理人员、厨师、保洁人员等粪便阳性率48.62%(53/109),物表拭子阳性率11.11%(2/18),患者标本检测相继排除了SARS-CoV-2等其他病原感染。选取13份阳性样本进行测序,结果9份(4份老年人肛拭子、4份护理人员粪便样本、1份厨师粪便样本)测序成功,均为重组GⅡ.4 Sydney_2012[P16],处于独立的一簇,与兰州市2020年GⅡ.10[P16]、2019年GⅡ.2[P16]病毒株处于一个大进化分支,亲缘关系较近。结论 GⅡ.4 Sydney_2012[P16]基因型毒株是本起暴发疫情的致病病原体。饮食、卫生、护理活动等是引起暴发和感染持续存在的主要因素,应关注诺如病毒无症状感染者在诺如病毒传播中的作用,强化养老院等集中护理疗养场所的公共卫生管理,尤其要预防通过养老院工作人员等携带病毒造成疾病的传播。Objective To understand the epidemiology and etiology of a cluster of cases with gastroenteritis in a nursing home in Anning district of Lanzhou, and to provide a scientific evidence for the prevention and control of norovirus diarrhea in community nursing centers. Methods From January 28 to February 4 2021, an epidemiological investigation was conducted on all diarrhea cases, nursing staff and chefs in a nursing home in Anning district, Lanzhou city.Samples of patients′ anal swabs, feces, vomitus were collected for norovirus detection by real-time fluorescent PCR.ORF1/ORF2 junction region of norovirus in some selected positive samples(Ct value ≤ 25) was sequenced.MEGA-X software was used to construct a phylogenetic tree for genetic evolution analysis using the neighboring method. Results The first case was confirmed on January20,2021,and the number of cases peaked during January 25and 29.A total of 58clinically diagnosed cases were reported,57were older people,with an incidence of(57/360,15.83%).Diarrhea(50/58,86.21%),vomiting(35/58,60.34%),nausea(13/58,22.41%)and abdominal pain(6/58,10.34%)were common symptoms,all cases were mild.Fifty-three asymptomatic cases were detected among chefs,housekeepers and nurses.A total of 163specimens were tested,the positive rate of norovirus GⅡwas 49.08%(80/163).The positive rate of fecal samples collected from nurses,chefs and housekeepers was 48.62%(53/109),and was11.11%(2/18)in environmental surface swabs.The possibility of other pathogenic infections such as SARS-CoV-2was ruled out by further tests.Thirteen positive samples were selected for sequencing,and 9were successfully sequenced,they were all recombinant GⅡ.4Sydney_2012 [P16]genotypes,forming an independent cluster,while in a large evolutionary branch with the 2020GⅡ.10 [P16]and 2019GⅡ.2 [P16]virus strains in Lanzhou city,showing a relative close genetic connection. Conclusions GⅡ.4Sydney_2012[P16]genotype of norovirus is found to be causative pathogen of this outbreak,and close contact is the main reaso

关 键 词：肠胃炎 腹泻 诺如病毒 疫情 病原学 基因分析 

分 类 号：R183.4[医药卫生—流行病学]