Norovirus prevalence and estimated viral load in symptomatic and asymptomatic children from rural communities of Vhembe district,South Africa

BackgroundHuman Norovirus (NoV) is recognized as a major etiological agent of sporadic acute gastroenteritis worldwide.ObjectivesThis study describes the clinical features associated with Human NoV occurrence in children and determines the prevalence and estimated viral burden of NoV in symptomatic and asymptomatic children in rural South Africa.Study designBetween July 2014 and April 2015, outpatient children under 5 years of age from rural communities of Vhembe district, South Africa, were enrolled for the study. A total of 303 stool specimens were collected from those with diarrhea (n = 253) and without (n = 50) diarrhea. NoVs were identified using real-time one-step RT-PCR.ResultsOne hundred and four (41.1%) NoVs were detected (62[59.6%] GII, 16[15.4%] GI, and 26[25%] mixed GI/GII) in cases and 18 (36%) including 9(50%) GII, 2(11.1%) GI and 7(38.9%) mixed GI/GII in controls. NoV detection rates in symptomatic and asymptomatic children (OR = 1.24; 95% CI 0.66⿿2.33) were not significantly different. Comparison of the median C_T values for NoV in symptomatic and asymptomatic children revealed significant statistical difference of estimated GII viral load from both groups, with a much higher viral burden in symptomatic children.ConclusionsThough not proven predictive of diarrhea disease in this study, the high detection rate of NoV reflects the substantial exposure of children from rural communities to enteric pathogens possibly due to poor sanitation and hygiene practices. The results suggest that the difference between asymptomatic and symptomatic children with NoV may be at the level of the viral load of NoV genogroups involved.     

一起诺如病毒感染性腹泻暴发的调查

2007年7月初,江西省某高校出现多例感染性腹泻患者,后被证实由诺如病毒(NV)感染引起,是江西省首起经实验室确认的NV感染性腹泻暴发疫情,现将调查结果报道如下.     

贝类中诺如病毒ELISA与荧光定量PCR检测技术的研究

目的:贝类中诺如病毒是世界范围内急性非细菌性流行性胃肠炎的重要病原。目前我国沿海地区也暴发了诺如病毒,为了更准确的检测,本文寻找和建立了贝类产品中诺如病毒的快速检测方法。方法:用荧光定量PCR和ELISA法对大连地区的贝类样品进行检测。结果:大连地区的贝类样品未检测出诺如病毒。结论:通过实验证明荧光定量PCR法和ELISA法都可用于快速检测诺如病毒,但ELISA法更适于检测诺如病毒含量低的样品。     

国境口岸快速处置一起邮轮诺如病毒性急性胃肠炎爆发疫情

〔目的〕通过对某大型豪华邮轮一起诺如病毒性肠胃炎疫情处置,关注国际间疫情变化,为国境口岸突发公共卫生事件快速反应提供对策依据。〔方法〕对来沪某大型豪华邮轮发生旅客不明原因腹泻的情况开展临床诊断、流行病学调查、实验室检测和实施卫生检疫措施。探讨口岸突发疫情的快速反应对策。〔结果〕经过对邮轮患者标本和食品样品的细菌学和病毒学检验,结合流行病学调查和临床表现确定为诺如病毒引起的群发性腹泻,采取了以传染源控制和管理为重点,切断传播途径和保护易感人群等卫生检疫措施后控制了疫情的蔓延。〔结论〕国境卫生检疫应在排除检疫传染病的情况下,扩大疾病的监测范围,以控制常见的、多发的、易引起突发公共卫生事件的传染病作为重点。根据新的《国际卫生条例》,调整国境口岸卫生检疫策略,加强口岸卫生检疫核心能力建设,为防止疾病的国际传播提供技术保障,建立应对突发疫情快速反应体系。     

Gastroenteritis outbreak in British troops, Iraq

Gastroenteritis affected many British military personnel during the war in Iraq. In the first month, 1,340 cases were seen; 73% of patients required hospital admission and 36% were hospital staff. In a survey of 500 hospital staff, 76% reported gastroenteritis, which was more likely in clinical workers. Investigations showed only caliciviruses.     

Genetic diversity of noroviruses and sapoviruses in children with acute sporadic gastroenteritis in New Delhi, India

BACKGROUND: Human caliciviruses (HuCVs) cause gastroenteritis throughout the world. Limited information is available on molecular epidemiology of caliciviruses from developing countries including India. OBJECTIVES: Standardization and evaluation of a two-step multiplex RT-PCR assay for HuCVs and characterization of strains. STUDY DESIGN: Two hundred and twenty-six stool samples were collected from children with acute gastroenteritis (AGE) over a one and half year to study the prevalence and diversity of HuCVs in children with AGE in New Delhi, India. A multiplex two-step RT-PCR using 3 sets of external and 4 sets of internal primers from the RdRp gene was standardized for detection of NoVs and SaVs. Molecular characterization of some HuCV strains was done by sequencing followed by phylogenetic analysis. RESULTS: Fifty-nine HuCVs strains were detected in 54 (24%) of the samples; 5 samples had mixed infections. Of these 59 HuCVs, 36 (61%) were norovirus (34 were GGII; 2 were GGI) and 23 (39%) were sapovirus (22 were GGI; 1 was GGII). Phylogenetic analysis of partial RdRp gene of 12 HuCV strains identified three genotypes (GGI/4, GGII/3 and a newly identified GIIb/Hilversum cluster) in NoVs and one genotype (GGI/1) in SaVs. CONCLUSION: This is one of the few reports from India on detection and characterization of HuCVs by multiplex RT-PCR assay. This assay can be a useful tool for epidemiological studies of HuCV infections.     

牡蛎和粪便中GⅠ、GⅡ型诺如病毒实时聚合酶链反应检测方法的建

目的 建立适用于牡蛎和粪便中快速、特异、灵敏的GⅠ、GⅡ型诺如病毒(NV)定量分型诊断方法．方法 通过对GⅠ、GⅡ型NV基因组保守序列的比对分析，设计高度特异的引物和探针，建立以TaMan探针为基础的实时聚合酶链反应方法(TaMan Real-time RT-PCR)．结果 该方法对NV核酸检测高度特异，且GⅠ和GⅡ型之间无交叉反应，最低检出限达102 copies/μl．对90份新鲜牡蛎样品和37份腹泻粪便标本分别用常规RT-PCR和笔者建立的TaMan Real-time RT-PCR进行NV检测，发现牡蛎样品中后者的检出率明显高于前者，而粪便标本中两者无明显差别．同时对阳性标本的测序分析证实结果准确可靠．结论 研究中建立的TaMan Real-time RT-PCR方法可用于海产品标本及粪便中NV定量及分型检测，可作为应对NV胃肠炎暴发的有效诊断方法．     

2000-2013年我国诺如病毒感染性胃肠炎暴发流行病学特征分析

目的 了解我国诺如病毒的流行病学特征及变化趋势,为制定有效的防控措施提供依据。方法 以诺如病毒、诺瓦克样病毒以及暴发、调查为关键词检索,收集整理2000-2013年在CNKI、万方和维普等中文数据库中的文献并进行分析。结果 共收集符合要求的文献52篇,涉及诺如病毒暴发疫情72起,累计报道病例11 778例,平均164例/起,疫情持续时间平均8.57 d。报道疫情数居前3位的省份依次是广东省28起（占38.89%）,浙江省18起（占25.00%）,广西壮族自治区6起（占8.33%）。暴发场所以学校及托幼机构为主,有53起,占73.61%,其中中学25起、小学及幼儿园17起,大学11起;其次是养老/医疗机构10起,占13.89%。传播途径以经水传播为主,有27起,占37.50%,人-人接触传播24起,占33.33%,食源性传播17起,占23.61%。不同场所疫情传播途径差异有统计学意义（2=48.899,P=0.000）。在经水传播的疫情中,由桶装水污染引起的暴发最多,占48.15%。基因组别分布GⅡ24起,占72.73%,GⅠ6起,占18.18%。结论 需加强关注我国诺如病毒感染性胃肠炎暴发,特别是学校和幼托机构等人群聚集的场所。建议加强高危场所管理和水质监测,提高菌株检测鉴定水平。     

2013-2015年吉林省病毒性腹泻监测资料分析

目的 分析2013-2015年吉林省诺如病毒胃肠炎的流行病学特征和规律,并针对疫情防控提出措施和建议。方法 对2013-2015年吉林省监测的疑似病毒性腹泻病例进行描述性分析和统计学检验。结果 2013-2015年吉林省共报告疑似病毒性腹泻病例2489例,389例检出诺如病毒核酸阳性,阳性率为15.63%。其中16例检出诺如病毒GⅠ组,371例检出GⅡ组,2例同时检出GⅠ组和GⅡ组,GⅠ组检出率为0.72%（18/2489）,GⅡ组检出率为14.99%（373/2489）。2015年诺如病毒检出率（17.26%）高于2013年（P=0.030）,第一、二季度的检出率（31.00%、18.66%）高于第三、四季度（P=0.000）,12月至次年5月诺如病毒的检出率依次为27.59%、30.22%、36.36%、27.39%、25.33%和19.70%,高于其他月份。不同性别（P=0.374）、城市和农村（P=0.122）的诺如病毒检出率差异无统计学意义。不同年龄组诺如病毒检出率差异有统计学意义（P=0.001）,85岁以上和5岁以下年龄组检出率较高,分别为22.73%和18.90%。商业服务（44.44%）和儿童（18.11%）检出率较高。结论 2013年以来吉林省诺如病毒检出率呈逐年升高趋势,第一、二季度检出率高于第三、四季度,以诺如病毒GⅡ组占优势,85岁以上和5岁以下年龄组,商业服务人员和儿童易受诺如病毒感染。     

广州市腹泻监测病例诺如病毒分子流行病学特征

目的 了解广州市腹泻监测病例中诺如病毒分子流行病学特征。方法 2014-2015年选取广州市两家医院的门诊科室作为监测哨点,每间哨点医院每周采集5岁以下和5岁及以上腹泻病例粪便样本各3份,将采集的标本送至广州市疾病预防控制中心检测诺如病毒。阳性标本进行基因序列测定并进行同源性分析。通过中国传染病疫情和突发公共卫生事件网络直报系统收集2014-2015年广州市报告的诺如病毒感染引起的暴发疫情数据,开展流行病学分析。结果 共收集腹泻标本732份,诺如病毒阳性136份,阳性率为18.58%。各年龄组诺如病毒阳性率不同（2=20.39,P=0.001）,其中5岁以下年龄组最高（24.21%）。基因分型结果显示GⅡ组133份（97.80%）,GⅠ组3份（2.20%）。分别对2014年（4份）及2015年（5份）阳性标本进行测序,结果提示,2014年诺如病毒流行株以GⅡ.4 Sydney_2012变异株（75.00%）为主,2015年以GⅡ.17变异株（55.60%）为主。2014-2015年共报告诺如病毒感染性腹泻暴发疫情23起,其中14（60.80%）起由GⅡ组引起。结论 广州市诺如病毒感染性腹泻流行毒株仍以GⅡ组为主,其中2014年优势毒株为GⅡ.4 Sydney_2012变异株,2015优势毒株为GⅡ.17变异株。