2001至2005年上海部分地区腹泻住院患儿诺若病毒分子临床流行病学研究

目的通过对上海地区腹泻住院患儿进行诺若病毒检测,对其流行株进行基因序列的测定,以了解诺若病毒在上海地区的流行特征,为该病原体所致腹泻的防治提供基础数据和理论依据。方法收集2001至2005年复旦大学附属儿科医院5岁以下腹泻住院患儿的粪便标本。首先进行轮状病毒的检测,在轮状病毒抗原阴性标本中,每隔8个标本按编号顺序行机械随机抽样,建立RT-PCR方法进行诺若病毒的检测。对PCR产物进行双向测序,测序结果通过Clustal W和Mega 4.1软件进行分析。结果研究期间共收集腹泻患儿粪便标本5534份,轮状病毒抗原阴性4084份,机械随机抽得484份用于诺若病毒检测,45/484份(9.3%)检测到诺若病毒。对诺若病毒感染季节分布和患儿年龄特点的分析表明,除4月和7月份未检测到诺若病毒外,其余各月份均检测到诺若病毒,其高发的月份是8至11月。5~6月也呈一个小高峰。77.8%(35/45)的患儿<2岁,其中6~11个月的患儿所占比例最高,达35.6%(16/45),<6个月的婴儿占20%(9/45)。GⅡ-4型是这5年间尤其是2003年之后的主要流行型别,2001至2002年尚存在其他的流行型别GⅡ-3和GⅡ-7...     

E. coli-expressed recombinant norovirus capsid proteins maintain authentic antigenicity and receptor binding capability

The baculovirus expression system has been widely used to produce the capsid proteins of Norovirus (NV) and the proteins form virus-like particles (VLPs) that are useful in many studies, such as immunology, diagnosis, and host-receptor interaction. We report here the application of the E. coli expression system in the production of recombinant NV capsid proteins. In a direct comparison of a previous well-characterized NV strain (VA387), we have demonstrated that the E. coli-expressed capsid proteins maintain the same antigenicity and receptor binding specificity as that of the baculovirus-expressed capsid, although the E. coli-expressed VA387 proteins did not form VLPs. Using the E. coli-expression system, we characterized the receptor-binding patterns of three additional NV strains (OIF1998, Parris Island and VA115), in which OIF1998 binds to HBGA of nonsecretors but did not bind or binds weakly to the HBGA of secretors, as seen in strain VA207. Parris Island binds to HBGA of types A and B but not type O secretors and nonsecretors. VA115 did not show specific binding to any A, B, O secretor nor nonsecretor, which is also observed when the capsid protein of this strain was expressed in baculovirus. Our data indicate that VLP formation is not required for receptor binding, and that the bacteria expression system offers a simple alternative for large production of NV capsid protein for various research purposes, particularly for strains generating low yields in the insect cells.     

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.     

2014年北京市某校连续三起诺如病毒疫情调查分析

目的 调查北京市某校连续三起诺如病毒疫情,为减少同类事件提供经验.方法 应用描述性分析方法,对三起疫情的调查结果进行分析.结果 2014年,北京市某小学2013级新生中连续发生三起诺如病毒疫情,罹患率分别为13.5％、10.56％及9.0％.随疫情起数增加,患儿就诊率下降(趋势x2=34.112,P＜0.001),且就诊患儿均未被诊断为法定报告传染病.造成三起疫情的诺如病毒基因型分别为GII.7型、GII.6型和GII.17型.结论 诺如病毒极易在集体单位内传播,扎实做好日常消毒和疫情报送工作,是预防及处置诺如疫情的关键措施.     

2007-2021年我国诺如病毒急性胃肠炎暴发疫情流行特征及影响因素分析

目的 分析我国诺如病毒急性胃肠炎暴发疫情流行病学特征,探讨暴发疫情规模的影响因素,为及早控制暴发疫情提供科学依据。方法 对突发公共卫生事件管理信息系统2007年1月1日至2021年12月31日全国诺如病毒急性胃肠炎暴发疫情进行描述性流行病学分析,应用非条件logistic回归模型分析暴发疫情规模的影响因素。结果 2007-2021年共报告暴发诺如病毒急性胃肠炎疫情1 725起,报告疫情起数呈上升趋势。南方省份每年10月至次年3月为疫情高峰,北方省份疫情高峰为每年10-12月和次年3-6月。疫情报告地区从东南沿海省份逐步向中部、东北和西部省份扩散。疫情主要发生在学校和托幼机构（1 539起,89.22%）,其次为企事业单位（67起,3.88%）和社区家庭（55起,3.19%）。人与人接触为主要传播途径1 262起（73.16%）,GⅡ基因型为引起暴发疫情的主要病原型别（899起,81.58%）。首例病例发病至疫情报告时间间隔M（Q₁,Q₃）为3（2,6）d,疫情规模M（Q₁,Q₃）为38（28,62）例。近年来,疫情报告及时性提升,疫情规模随年份呈下降趋势,二者在不同发生场所之间差异均有统计学意义（P<0.001）。发生场所、传播途径、报告及时性和居住地类型是暴发疫情规模的影响因素（P<0.05）。结论 2007-2021年我国诺如病毒急性胃肠炎暴发疫情整体呈上升趋势,疫情波及地区范围不断扩大,但疫情发生规模整体呈下降趋势,疫情报告及时性提升,提高监测灵敏度和及早报告可有效控制疫情发生规模。     

济南市多起诺如病毒感染暴发疫情的流行特征

目的总结济南市近1年内发生的多起诺如病毒感染暴发疫情流行特征。方法收集济南市2015年6月1日至2016年5月31日期间发生的诺如病毒感染暴发疫情的时间分布特征、地区分布特征、实验室RT-PCR检测和基因测序结果、疫情报告和处置信息。结果 1年间,济南市共发生6起诺如病毒感染暴发疫情,疫情罹患率从0.41%到15.56%不等,3起发生于冬春季,4起发生于济南市历城区高校片区。3起疫情病例数超过250人,1起还超过了1 000人。GII感染疫情3起,GI和GII混合感染疫情3起,首次监测到诺如病毒感染新型别GI.1和GII.17。从疫情开始到报告、从介入调查到结束、疫情持续时间平均分别为2d、4d及6d。结论济南市诺如病毒感染暴发疫情在发生时间、发生场所、疫情规模以及诺如病毒感染型别已呈现出新的流行特征与趋势,尤其是应进一步加强学校重点场所的传染病监测和疫情报告能力,争取疫情早控制。     

Is closure of entire wards necessary to control norovirus outbreaks in hospital? Comparing the effectiveness of two infection control strategies

The standard approach for norovirus control in hospitals in the UK, as outlined by the Health Protection Agency guidance and implemented previously by Lancashire Teaching Hospitals, involves the early closure of affected wards. However, this has a major impact on bed-days lost and cancelled admissions. In 2008, a new strategy was introduced in the study hospital, key elements of which included closure of affected ward bays (rather than wards), installation of bay doors, enhanced cleaning, a rapid in-house molecular test and an enlarged infection control team. The impact of these changes was assessed by comparing two norovirus seasons (2007-08 and 2009-10) before and after implementation of the new strategy, expressing the contrast between seasons as a ratio (r) of expected counts in the two seasons. There was a significant decrease in the ratio of confirmed hospital outbreaks to community outbreaks (r = 0.317, P = 0.025), the number of days of restricted admissions on hospital wards per outbreak (r = 0.742, P = 0.041), and the number of hospital bed-days lost per outbreak (r = 0.344, P <0.001). However, there was no significant change in the number of patients affected per hospital outbreak (r = 1.080, P = 0.517), or the number of hospital staff affected per outbreak (r = 0.651, P = 0.105). Closure of entire wards during norovirus outbreaks is not always necessary. The changes implemented at the study hospital resulted in a significant reduction in the number of bed-days lost per outbreak, and this, together with a reduction in outbreak frequency, resulted in considerable cost savings.     

Gastroenteritis caused by norovirus GGII.4, The Netherlands, 1994-2005

From 1994 through 2005, gastroenteritis outbreaks caused by norovirus generally increased in the Netherlands, with 3 epidemic seasons associated with new GGII.4 strains. Increased percentages of GGII.4 strains during these epidemics, followed by a sharp decrease in their absolute and relative numbers, suggest development of immunity.     

一起农村中学发生的诺如病毒感染性腹泻暴发的调查

目的通过对一起诺如病毒引起的腹泻暴发疫情的调查和处理分析,进一步了解诺如病毒引起的急性胃肠道疾病暴发疫情的流行病学、病原学特点,为学校等集体单位制定相应的预防控制对策提供依据。方法对腹泻学生开展现场流行病学调查,采集食堂可疑食物留样,腹泻学生的呕吐物、排泄物、学校自挖井水水样进行有关检测。结果该起疫情首例病例发病时间为2009年9月5日,疫情历时7天,全校在校学生罹患率为1．28％（76／5965）,以高三学生为主,占43．42％。通过对呕吐物、排泄物进行病原学检测发现诺如病毒核酸阳性。结论此起群体性腹泻暴发疫情是由诺如病毒感染引起,主要为水源污染和生活接触传播所致。