北京市东城区2013-2015年诺如病毒感染聚集性疫情流行病学特征分析

目的 对2013-2015年北京市东城区诺如病毒感染聚集性疫情的流行病学特征和病原学特征进行分析.方法 采取面对面问卷调查的方式,对2013年1月至2015年12月北京市东城区报告的诺如病毒感染聚集性疫情开展流行病学调查,描述性分析疫情流行病学特征;采集病例及环境标本进行诺如病毒实时荧光PCR检测和基因序列分析,掌握疫情病原学特征.结果 2013-2015年共报告20起聚集性疫情,每起疫情发病人数在8-78例之间,罹患率在6.3-61.5％之间.三年报告起数呈逐年递增趋势,34月和10-12月报告17起,占总起数的85.0％.疫情主要发生在小学、幼儿园、集体单位和医院病房.采集患者便标本、密接便标本和环境涂抹标本260份,检出诺如病毒GⅡ型核酸阳性122份,阳性率为46.9％.对14起疫情的阳性标本基因序列分析结果:GⅡ.17型6起,GⅡ.6型3起,GⅡ.4Sydney-2012型2起,GⅡ.2、GⅡ.3、GⅡ.7型各1起.结论 2013-2015年北京市东城区诺如病毒聚集性疫情春季和秋冬季高发,应加强学校和托幼机构疫情的监测,加强集体单位食堂员工以及医院护理人员的监测与管理.     

一起由札如病毒引起的急性胃肠炎暴发疫情的分子流行病学研究

目的 调查深圳市某幼儿园发生的一起急性胃肠炎暴发疫情的病原体,并分析病原体的分子流行病学特征.方法 收集患病幼儿及相关人员的粪便标本16份,剩余食物6份,采用国家卫生行业标准规定方法检测肠道致病菌、实时荧光RT-PCR法检测诺如病毒、札如病毒、轮状病毒核酸,逆转录RT-PCR法对病毒衣壳区和聚合酶区序列进行扩增,对PCR产物进行序列测定.序列用Clustalx软件进行多重比对、Mega 5.0软件绘制系统进化树.结果 16份样本中检出11例札如病毒核酸阳性,对其中3例阳性标本进行札如病毒衣壳区和聚合酶区序列测定,3株札如病毒与GII.3型参考株AY603425衣壳区核苷酸同源性为86.3％,聚合酶区核苷酸同源性为90.2％,3株札如病毒与GII.3型参考株AY603425、AB455793同属于GII.3型遗传分支.结论 此起急性胃肠炎爆发是由GII.3型札如病毒导致,GII.3型引起的急性胃肠炎暴发属广东省首次报道.     

3起老人院诺如病毒胃肠炎暴发疫情分析

目的分析3起发生在老人院内的诺如病毒胃肠炎局部暴发疫情的流行特征,为今后预防类似事件的发生提供参考依据。方法收集2007年佛山市老人院诺如病毒胃肠炎暴发疫情现场流行病学调查报告．采用描述性流行病学方法对疫情调查处理情况进行分析。结果2007年佛山市共报告3起老人院诺如病毒胃肠炎暴发疫情,共发病56例,无死亡病例;疫情集中发生在2～3月份;每起疫情均从部分患者粪便标本中检测诺如病毒Ⅱ型核酸;3起疫情主要以人-人密切接触的途径传播。结论早发现、早报告、早处理疫情．以及日常加强院内卫生,强化护工的规范操作,是预防和控制诺如病毒胃肠炎在老人院发生的关键。     

南京地区婴幼儿杯状病毒感染的分子流行病学研究

目的 了解南京地区婴幼儿杯状病毒腹泻的感染状况、临床表现以及分子流行病学特征.方法 采集2010年7月至2011年6月南京医科大学附属南京儿童医院5岁以下腹泻患儿粪便标本及儿童保健中心健康婴幼儿粪便标本各428份.采用反转录-聚合酶链反应( RT-PCR)检测杯状病毒,测序确定其基因型别.结果 428份腹泻样本中有63份为杯状病毒阳性,检出率为14.72％.其中诺如病毒GⅡ型58例,未检出诺如病毒GⅠ型,札如病毒5例,以诺如病毒GⅡ-4 2006b型为主要流行株.428份健康对照组标本杯状病毒检出19例,诺如病毒6例,札如病毒11例,2例为诺如病毒GⅡ型和札如病毒混合感染.结论 南京地区婴幼儿中存在不同基因型杯状病毒感染,流行毒株以GⅡ.2006b为主.     

一起旅行团诺如病毒感染性腹泻暴发疫情调查

目的 对一起感染性腹泻暴发疫情的病原和危险因素进行调查分析.方法 根据病例定义进行主动搜索,利用回顾性队列研究寻找可疑餐次和可疑食物.采集病例和密切接触者粪便、肛拭子等标本进行诺如病毒核酸检测和肠道致病菌分离培养.结果 该旅行团共发现病例28例,流行曲线提示为点源暴露.共采集患者和密切接触者标本分别为12件和7件,经RT-PCR检测11名患者和2名密切接触者GⅡ组诺如病毒核酸检测阳性.对其中1份阳性标本进行测序,该病毒与2014年8月日本提交的GⅡ.17型AB983218和2014年12月中国台湾提交GⅡ.17型KJ156329毒株相似度达到98％.根据诺如病毒的潜伏期和病例的发病时间推测暴露时点为2月6日中餐和晚餐可能性大.应用回顾性队列研究结果显示2月6日晚餐中的深海鱼是危险食物(RR=6.25,95％CI:1.05～37.32).结论 该起疫情是旅行团外出引起的诺如病毒感染性腹泻的暴发,感染来源可能是在旅行期间食用了诺如病毒污染的深海鱼.     

分型引物RT-PCR法在杯状病毒分子流行病学研究中的应用

目的:应用分型引物RT-PCR法确定五个地区病毒性腹泻粪便标本中杯状病毒流行型别及感染情况。方法:对五个地区收集的<5岁病毒性腹泻粪便标本应用针对病毒壳体区域设计的四对引物(GI-SKF/GI-SKR、COG2F/G2-SKR、SLV5317/SLV5749、PreCAP1/82b)进行反转录-聚合酶链反应(RT-PCR)扩增诺如病毒GI和GII组、扎如、星状病毒(Astrovirus),扩增产物通过1·5%琼脂糖凝胶电泳鉴定。选取部分阳性标本测序研究型别流行特点。结果:本实验从663例标本中共检出单独感染诺如病毒、扎如病毒和星状病毒阳性标本数分别为84、4、11株,同时还发现3株混合感染标本。选取24株诺如病毒阳性标本测序分析发现19株为GII/4型,2株为GII/3型,1株为GII/1型,1株为GII/13型,1株为GII/15型,4株扎如病毒中2株为SGI/1型,1株为SGII/3型,1株为SGII/1型。结论:研究表明杯状病毒是我国婴幼儿腹泻重要病原体,诺如病毒流行株为GII/4型毒株,同时存在其它型别的散在流行;福建、兰州检测到不同型别扎如病毒证明我国存在多种型别的扎如病毒感染。     

北京市东城区5岁以下婴幼儿病毒性腹泻病原学研究

目的 了解北京市东城区5岁以下婴幼儿病毒性腹泻的主要病原体.方法 2011年10月-2015年9月在东城区第二妇幼保健院收集1 754例5岁以下腹泻患儿便标本,用RT-PCR和PCR法检测轮状病毒、诺如病毒、札如病毒、星状病毒和肠道腺病毒.结果 标本腹泻病毒总检出率为36.0％(632/1 754);轮状病毒检出率12.4％;诺如病毒检出率10.1％;札如病毒检出率5.4％;肠道腺病毒检出率9.4％;星状病毒检出率3.5％.腹泻病毒检出高峰为每年10月-次年2月.诺如病毒和肠道腺病毒以24～60月龄患儿检出率较高,其余几种病毒以6～24月龄检出率较高;男女性别检出率没有统计学差异(x2=0.276,P＞0.05).结论 婴幼儿腹泻病人中5种病毒均有检出,其中轮状病毒和诺如病毒是主要的病原体,肠道腺病毒检出率明显高于国内其他地区.     

新型联检GI和GII型诺如病毒荧光微球检测条的研制和应用

制备并评估联检GI和GII型诺如病毒荧光微球检测条的检测效率。以层析材料和特异性双抗体,按常规双抗体夹心法制备联检GI和GII型诺如病毒荧光微球检测条。以轮状病毒细胞培养物和343例临床表现为胃肠道感染症状病人的粪便标本作为检测对象,用联检GI和GII型诺如病毒荧光微球检测条检测并与CerTest Norovirus GI-GII one step combo card test检测结果比较。成功制备了联检GI和GII型诺如病毒荧光微球检测条。检测性能:1联检GI和GII型诺如病毒荧光微球检测条的敏感性较CerTest Norovirus GI-GII one step combo card test方法高(4~8)倍;2与轮状病毒(Wa株)等一些肠道病毒无交叉反应。结果表明成功制备联检GI和GII型诺如病毒荧光微球检测条,其检测性能良好。     

诺如病毒与轮状病毒所致的110例婴幼儿急性腹泻病例临床特征分析

目的 对诺如病毒与轮状病毒所致婴幼儿急性腹泻的临床特点进行分析探讨.方法 收集2010年1月-2015年3月间病毒性婴幼儿急性腹泻患者110例临床资料进行回顾性分析,按照病原学检测情况分为诺如病毒组51例及轮状病毒组59例.另取45例细菌感染所致急性腹泻患儿作为对照组.对诺如病毒与轮状病毒所致婴幼儿急性腹泻的实验室检查、临床症状以及流行病学特征进行分析比较.结果 诺如病毒组患者与轮状病毒组患者在各项实验室检查及临床症状方面均无统计学差异(P＞0.05),但与对照组相比均有统计学差异(P＜0.05).两组病毒均易感小于2岁的患儿,其中诺如病毒组患儿年龄在13-24个月中所占全部患儿比例为17.65％、轮状病毒组为35.59％,两者比较差异有统计学意义(P＜0.05).诺如病毒及轮状病毒组患儿集中检出月份均为11月、12月及1月.结论 诺如病毒与轮状病毒感染所致的婴幼儿急性腹泻在实验室检查、临床特点以及流行情况差异均不显著,为明确诊断,需进行病原学实验室检查.     

2013年11月北京丰台区轮状病毒腹泻流行的实验室分析

目的 了解2013年11月北京市丰台区腹泻中轮状病毒和诺如病毒发病率升高的流行情况及其基因特征 方法 2013年11月在哨点医院门诊随机采集47份腹泻患者便标本、30份环境标本,使用real-time RT-PCR进行轮状病毒（rotavirus）和诺如病毒（norovirus）的筛查;并对轮状病毒阳性标本使用RT-PCR方法扩增VP4和VP7基因,扩增产物进行序列测定.使用Blast、BioEdit及Mega4.0等软件进行序列比对及基因进化分析.结果 47份粪便标本中,37份为轮状病毒检出率为78.7％（37/470,诺如病毒阳性率为14.9％（7/47）,轮状病毒和诺如病毒混合感染率为10.6％ （5/47）;30份环境标本中,轮状病毒检出率为23.3％ （7/30）,未检出诺如病毒.核酸序列比对及进化分析表明此次流行的轮状病毒为G9P[8]a型,与2010-2012年北京地区感染儿童的G9株高度同源.结论 2013年11月北京市丰台区其他感染性腹泻标本中以轮状病毒检出为主,其基因型别为G9P[8]a型,检出率远高于北京市往年水平,提示应加强对轮状病毒进行监测.     

Molecular epidemiology of norovirus gastroenteritis outbreaks in New Zealand from 2002-2009

Noroviruses are the most common cause of acute non-bacterial gastroenteritis outbreaks worldwide, including New Zealand. New Zealand has a population of 4.4 million, which allows for centralized outbreak surveillance and a Norovirus Reference Laboratory, which facilitates efficient diagnosis, surveillance, and tracking of norovirus outbreaks. Norovirus outbreak strains are identified, sequenced, and compared with international reference strains. Between January 2002 and December 2009, 1,206 laboratory-confirmed norovirus outbreaks were recorded. The predominant outbreak settings were healthcare institutions for the elderly and acute care patients. Other outbreak settings included catering establishments, cruise ships, homes, community events, school camps, child-related settings, and consumption of contaminated shellfish. Of the 1,206 outbreaks, 105 (8.7%) were caused by norovirus genogroup I (GI) strains, 1,085 (89.9%) were caused by genogroup II (GII) strains, and both GI and GII strains were detected in 9 (0.8%) outbreaks. The genogroup was not identified in 7 (0.6%) outbreaks. A range of norovirus genotypes, including GI genotypes 1-6, GII genotypes 2-8, and GII.12, were associated with these outbreaks. The predominant genotype was GII.4, which was identified in 825 (68.4%) outbreaks. Norovirus GII.4 variant strains, including 2002 (Farmington Hills), 2004 (Hunter), 2006a (Laurens, Yerseke), 2006b (Minerva), and 2010 (New Orleans) implicated in overseas outbreaks also occurred in New Zealand, providing evidence of global spread.     

Molecular and epidemiological features of gastroenteritis outbreaks involving genogroup I norovirus in Victoria, Australia, 2002-2010

GI noroviruses are relatively rare and systematic studies of the molecular epidemiology of GI norovirus outbreaks are lacking. The current study examined the molecular virology of GI norovirus outbreaks in Victoria, Australia (2002–2010). Of 1,617 norovirus outbreaks identified, 69 (4.3%) were associated with GI norovirus alone, 1,540 (95.2%) with GII norovirus alone and 8 (0.5%) with GI + GII. Some differences between GI and GII outbreak epidemiology were found. GI outbreaks peaked in the 2‐month period November/December whereas GII outbreaks peaked in the 2‐month period September/October and GI norovirus outbreaks were significantly more common in non‐healthcare settings (37.7%) than GII outbreaks (9.5%). ORF 1/ORF 2 genotypes found in the 69 outbreaks involving GI norovirus alone were: GI.2/GI.2, 7 outbreaks; GI.2/GI.6, 18 outbreaks; GI.3b/GI.3, 14 outbreaks; GI.4/GI.4, 21 outbreaks; GI.8/GI.8, one outbreak; GI.d/GI.3, four outbreaks; and GI.e/GI.13, one outbreak. The current study appears to be the first to have identified the recombinant form, GI.2/GI.6. Whereas GI.2/GI.6 and GI.3b/GI.3 outbreaks occurred with equal frequency in both healthcare and non‐healthcare settings, GI.4/GI.4 occurred predominantly in healthcare settings. GI ORF 1/ORF 2 genotypes found in the eight outbreaks involving GI + GII norovirus were GI.2/GI.6, GI.3b/GI.3, and GI.4/GI.4, indicating GI genotypes in GI + GII outbreaks were similar to those found in outbreaks involving GI alone. Apparent differences in the evolution of different GI genotypes were noted. GI.2/GI.2, GI.2/GI.6, and GI.4/GI.4 strains tended to undergo periodic shifts in nucleotide sequence whereas various GI.3b/GI.3 strains tended to circulate simultaneously. J. Med. Virol. 84:1437–1448, 2012. © 2012 Wiley Periodicals, Inc.     

Molecular and epidemiological features of GIIb norovirus outbreaks in Victoria,Australia, 2002–2005

The epidemiology of GIIb norovirus outbreaks and the characteristics of GIIb open reading frame (ORF) 2 recombinant forms are poorly understood and this study examined these questions using norovirus‐associated gastroenteritis outbreaks in Victoria, Australia, during 2002–2005. Twenty‐one GIIb outbreaks were detected and were the second most common ORF 1 norovirus outbreak genotype (5%) after GII.4 (90%). Both GIIb and GII.4 outbreaks peaked in warmer months of the year but their periodicity was different. ORF 2 sequencing analysis was carried out in the two regions previously designated C and D. RT‐PCR region D primers were less sensitive than region C primers. No evidence of recombination between regions C and D was found. ORF 2 genotypes for the 21 GIIb outbreaks were: GII.1 (10 outbreaks), GII.3 (10 outbreaks) and, apparently for the first time, GII.13 (1 outbreak). GIIb outbreaks could occur in a broad range of settings and there was no correlation between ORF 2 genotype and setting except that all 5 outbreaks involving mainly young children were associated with GIIb/GII.3. J. Med. Virol. 81:1652–1660, 2009. © 2009 Wiley‐Liss, Inc.     

Differences in clinical presentation between norovirus genotypes in nursing homes

BackgroundIn healthcare settings, norovirus (NoV) outbreaks are predominated by genotype II.4 (GII.4) strains. Periodically, new variants of GII.4 emerge, causing a temporary increase of outbreaks.ObjectivesTo study the relationship between symptoms and NoV genotype.Study designData of 49 nursing homes which were monitored for NoV outbreaks in the winter seasons of 2005/2006 and/or 2006/2007 were used.ResultsData on symptoms and duration of illness were available for 465 residents and 174 staff members from 28 NoV outbreaks. Genotype GII.4 was responsible for 21 outbreaks. Attack rates for residents seemed to be higher in GII.4 outbreaks compared to other genotypes. In outbreaks caused by GII.4, residents vomited more often than in outbreaks with other genotypes. They also had more often complaints of nausea, abdominal cramps, fever, and mucus in stool. The GII.4 2004 variant outbreaks showed higher percentages of nausea, stomach ache, and fever than outbreaks with the GII.4 2006a variant. Differences in duration of illness were not found. In nursing home staff, no clear differences were found between outbreaks caused by GII.4 and non-GII.4 NoVs.ConclusionsGenotype GII.4 was found to be related to more symptomatic disease, including more residents vomiting, and to a lesser extent, higher attack rates among residents.     

Molecular epidemiology of norovirus outbreaks in Argentina, 2013-2018

Noroviruses are a leading cause of endemic and epidemic acute gastroenteritis in all age groups. However, in Latin America, there are limited and updated data regarding circulating genotypes. The aim of this study was to assess the prevalence and genetic diversity of norovirus outbreaks in Argentina from 2013 to 2018. Stool samples from 29 acute gastroenteritis (AGE) outbreaks were available for viral testing. Norovirus was detected in samples from 18 (62.1%) outbreaks (2 GI and 16 GII). Both GI outbreaks were typed as GI.6[P11] whereas 10 different GII genotypes were detected, in which GII.4 viruses were the most frequently detected (29.4%, associated with GII.P31 and GII.P16) followed by GII.1[P33] and GII.6[P7] (17.6% each). Like GII.4 viruses, GII.2 viruses were also detected in association with different polymerases (GII.P2 and GII.P16). Our findings underscore the importance of dual RNA-dependent RNA polymerase-VP1 typing since recombinant strains with new polymerase sequences emerge frequently suggesting a possible role in improved fitness of these viruses. This study represents the most recent multi-year assessment of the molecular epidemiology of norovirus strains associated with AGE outbreaks in Argentina. Molecular surveillance of norovirus has to be considered to monitor possible changes in dominant genotypes which may assist to inform the formulation of future vaccines.     

Genetic diversity of noroviruses in Taiwan between November 2004 and March 2005

Summary. Noroviruses are a major health burden and are responsible for the majority of outbreaks of gastroenteritis in the world. Human noroviruses can be genetically divided into two main genogroups (GI and GII) and subdivided into many genotypes. In this study, stool specimens collected from 12 outbreaks of gastroenteritis in Taiwan were screened for viral agents between the 23rd of November 2004 and 9th of March 2005. Noroviruses were detected in all outbreaks. We detected six different norovirus genotypes: GI/11, GI/14, GII/3, GII/4, GII/6, and GII/18. Noroviruses belonging to GII/4 were dominant, 50 of 60 (83%) sequences, and were detected in 10 of 12 outbreaks. Furthermore, the norovirus GII/4 strains were detected throughout Taiwan, demonstrating their widespread distribution. We also found that three outbreaks had noroviruses from multiple genotypes. Our results have shown for the first time that noroviruses are an important cause of gastroenteritis in Taiwan.     

Genetic relatedness of noroviruses identified in sporadic gastroenteritis in children and gastroenteritis outbreaks in northern Alberta

We compared the proportion and genotype distribution of norovirus (NoV) identified in sporadic acute gastroenteritis in children younger than 7 years old with the NoV strains found in outbreaks from January 2003 through April 2004 in northern Alberta, Canada. Eight genogroup I (GI) and 133 GII NoV cases were detected in 1,166 cases of acute sporadic childhood gastroenteritis with a monthly detection rates varying from 6.0% to 20.4% and no sporadic gastroenteritis case in October 2003. Seventy-eight outbreaks (65%) tested positive for NoV during the study period with an obvious winter predominance and no NoV outbreaks in August, September, and October 2003. Three GI and 51 GII strains from the sporadic childhood gastroenteritis cases and seven GI and 37 GII strains from gastroenteritis outbreaks were sequenced and analyzed. Strains belonging to the GII.4 cluster predominated in outbreaks (68%) while the strains in sporadic childhood gastroenteritis demonstrated significant heterogeneity with the majority belonging to the GII.3 cluster (36%). Further analysis of NoV strains from 34 sporadic childhood gastroenteritis cases and 38 gastroenteritis outbreaks in chronologically and geographically related groups failed to demonstrate clear link between strains circulating in the setting of sporadic childhood gastroenteritis and those found in outbreaks.