深圳地区2006年诺如病毒分子流行病学研究

诺如病毒是世界范围内引起急性胃肠炎的主要病原体,1990年首次证实我国也存在该病毒引起的感染[1],此后北京、长春、河北、兰州、广州、福州等地均发现存在诺如病毒感染,表明我国急性胃肠炎病例诺如病毒感染亦相当普遍.本研究对2006年深圳地区急性胃肠炎中诺如病毒进行分子生物学研究.     

一起诺如病毒胃肠炎聚集性疫情的调查

目的:调查某学校发生的一起胃肠炎暴发疫情,分析传播途径和传染来源。方法:于2010年3月7日至25日,在该学校查看缺课登记表、医务室门诊日志,设立临时报告系统等方法收集胃肠炎病例,病例定义采用症状指数方法,症状指数大于3者为病例。开展病例对照研究,分析发病危险因素。并采集病例标本,食品留样,水样等标本进行诺如病毒和致病菌检测。结果:共收集到20个病例,其中5例病例2型诺如病毒检测阳性。食物和饮水中未发现致病菌和诺如病毒。病例对照研究发现,洗手次数大于5次为发病的保护因素。结论:在校外感染的首例病例为本次疫情传染源,首例病例未及时隔离为疫情蔓延的主要原因。     

Combination of three virus-derived nanoparticles as a vaccine against enteric pathogens; enterovirus,norovirus and rotavirus

Enteric viruses cause diverse infections with substantial morbidity and mortality in children, rotavirus (RV) and norovirus (NoV) being the leading agents of severe pediatric gastroenteritis. Coxsackie B viruses (CVB) are common enteroviruses (EV), associated with increased incidence of severe neonatal CVB disease with potentially fatal consequences. To prevent majority of childhood gastroenteritis, we have developed a non-live NoV–RV combination vaccine consisting of NoV virus-like particles (VLPs) and RV oligomeric rVP6 protein that induced protective immune responses to NoV and RV in mice. Moreover, rVP6 acted as an adjuvant for NoV VLPs. Here, we investigated a possibility to include a third enteric virus-derived antigen in the candidate NoV–RV vaccine, by adding recombinant nanoparticles derived from EV CVB1. To examine immunogenicity of EV-NoV-RV vaccine, BALB/c mice were immunized intramuscularly twice with 10 µg CVB1 VLPs, GII.4 VLPs and rVP6 nanotubes, either separately or combined. To evaluate the adjuvant effect of rVP6 on EV responses, mice received 0.3 µg CVB1 VLPs with or without 10 µg rVP6. Comparable serum IgG antibodies were detected whether the antigens were administered separately or in combination. Each formulation generated IgG1 and IgG2a antibodies, indicating a mixed Th2/Th1-type response. CVB1 VLPs skewed the isotype distribution slightly towards IgG1 subtype, while EV-NoV-RV combination vaccine induced unbiased Th1/Th2 responses to CVB1. Each antigen also induced T cell mediated immunity measured by IFN-γ secretion to specific stimulants ex vivo. Antisera raised by single antigens and combined formulation also exhibited strong neutralizing ability against CVB1 and NoV GII.4. Further, rVP6 showed an adjuvant effect on CVB1 responses, sparing the VLP dose and homogenizing the responses. Finally, the results support inclusion of additional antigens in the candidate NoV-RV combination vaccine to combat severe childhood infections and confirm adjuvant effect of rVP6 nanostructures.     

A bivalent virus-like particle based vaccine induces a balanced antibody response against both enterovirus 71 and norovirus in mice

Noroviruses are the main cause of severe viral gastroenteritis, which results in estimated 200,000 deaths each year, primarily in children in the developing world. Genogroup II.4 (GII.4) strains are responsible for the majority of norovirus outbreaks. Enterovirus 71 (EV71), the leading causative agent of hand, foot and mouth disease, has recently been prevalent in Asia-Pacific regions, resulting in significant morbidity and mortality in young children. However, no vaccine is commercially available for either norovirus GII.4 or EV71. Recombinant virus-like particles (VLPs) derived from either GII.4 or EV71 have been shown to be promising monovalent vaccine candidates. In this study, we investigate the possibility to formulate a VLP-based bivalent vaccine for both norovirus GII.4 and EV71. The GII.4- and EV71-VLPs were produced in a baculovirus-insect cell expression system. A bivalent combination vaccine comprised of GII.4 and EV71 VLPs was formulated and compared with monovalent GII.4- and EV71-VLPs for their immunogenicity in mice. We found that the bivalent vaccine elicited durable antibody responses toward both GII.4 and EV71, and the antibody titers were comparable to that induced by the monovalent vaccines, indicating there is no immunological interference between the two antigens in the combination vaccine. More significantly, the bivalent vaccine-immunized mouse sera could efficiently neutralize EV71 infection and block GII.4-VLP binding to mucin. Together, our results demonstrate that the experimental combination vaccine comprised of GII.4 and EV71-VLPs is able to induce a balanced protective antibody response, and therefore strongly support further preclinical and clinical development of such a bivalent VLP vaccine targeting both norovirus GII.4 and EV71.     

2011年苏州地区诺如病毒GⅡ组变异株的分子特征研究

目的 了解苏州地区诺如病毒的感染状况及其变异株的分子特征.方法 收集苏州市儿童医院疑似病毒性腹泻粪便标本419例,采用荧光定量PCR方法检测粪便中诺如病毒RNA及其基因组别,并对部分阳性标本测序分析.结果 419份粪便标本中,GⅡ组诺如病毒为122例,阳性率为29％,未检测出GⅠ组诺如病毒,对本地区部分诺如病毒阳性标本进行测序,A区(RdRp区)测序的25份GⅡ标本中25株均为GⅡ.4型;C区(N-S区)测序的26份GⅡ标本中17株为GⅡ.4型,8株为GⅡ.3型,1株为GⅡ.2型;D区(P区)测序的25份GⅡ标本中16株为GⅡ.4型,9株为GⅡ.3型.结论 诺如病毒是本地区婴幼儿病毒性腹泻的重要病原体,以诺如病毒GⅡ.4-2006b亚型为主,此外发现有GⅡ.4-2010亚型(GⅡ.4 New Orleans株)的流行,这是国内首次对该亚型毒株进行报道,同时还检测到部分重组毒株,提示诺如病毒在本地区的遗传变异日趋复杂.     

Brote de gastroenteritis causado por norovirus en un hotel de Menorca,España

ObjectivesTo establish the agent responsible for a gastroenteritis outbreak in a hotel in Menorca (Spain) in September 2016.MethodsThe study included epidemiological and laboratory analysis. Environmental and stool samples were examined for bacterial and viral pathogens.ResultsOne hundred and fifty-one cases were detected, 123 among the tourists staying in the hotel and 28 affecting the staff. The presence of genotype II norovirus was discovered in the microbiological studies of patient's faeces, as well as in the surface samples of rooms and common areas. The control plan implemented allowed for control of the outbreak.ConclusionsThis study on a genotype II norovirus outbreak reveals the importance of a rapid response for controlling these types of outbreaks.     

2011-2015年北京市肠道门诊老年腹泻患者诺如病毒感染的流行特征分析

目的 分析北京市肠道门诊60岁及以上老年腹泻患者中诺如病毒感染的流行特征.方法 收集2011年3月-2015年12月北京市肠道门诊监测点上报的老年腹泻患者监测数据,并采集患者粪便样本,采用RT-PCR和荧光定量RT-PCR检测方法对粪便样本进行诺如病毒核酸检测.应用卡方检验进行组间率的比较,采用系统聚类分析的方法分析不同地区检出率的差异.结果 2011年3月-2015年12月期间,共l 450例老年腹泻患者,其中诺如病毒检出率为15.45％(224/1 450).诺如病毒检出率高峰为秋冬季.地区分布显示,昌平区、怀柔区、东城区、西城区、顺义区、房山区、海淀区聚为一类,诺如病毒检出率较高.不同性别(x2=0.02,P=0.90)及年龄组间(x2=3.58,P=0.17)诺如病毒检出率差异均无统计学意义.结论 诺如病毒为我市肠道门诊老年人散发腹泻的重要病原,秋冬季节为高发季节.     

Norovirus in feces and nasopharyngeal swab of children with and without acute gastroenteritis symptoms: First report of GI.5 in Brazil and GI.3 in nasopharyngeal swab

BackgroundNoroviruses (NoVs) are an important cause of acute gastroenteritis (AGE), worldwide.ObjectivesTo evaluate the frequency, viral load and molecular profile of NoV in fecal and nasopharyngeal swab samples from hospitalized children, and to determine children’s secretor status.Study designFrom May 2014 to May 2015, 219 children were included in the study, 96 with gastroenteric symptoms and 123 without gastroenteric symptoms. All fecal and nasopharyngeal swab samples were screened by TaqMan RT-qPCR duplex (GI/GII NoV) and quality samples were characterized by genomic sequencing.ResultsNorovirus positivity rate in feces was 15.4% in asymptomatic and 18.8% in the symptomatic group. The median viral loads in feces were 2.69 × 10⁸ GC/g and 4.32 × 10⁷ GC/g from children with or without AGE symptoms, respectively. In nasopharyngeal swab samples, the NoV positivity was 11.4% in symptomatic children, with a median viral load of 2.20 × 10⁷ GC/mL and 6.5% in asymptomatic children, with an average viral load of 1.73 × 10⁶ GC/mL. In only two cases NoV was detected in both samples. A considerable genomic variability was observed in feces, with six genotypes being detected, as follows: GII.4, GII.6, GI.3 and GII.3, GI.2 and GI.5. Two GI.3 was detected in nasopharyngeal swab.ConclusionsOur data reveal considerable NoV frequencies in both nasopharyngeal and fecal samples from symptomatic and asymptomatic children. Higher viral loads were detected in samples from AGE symptomatic children, when compared to asymptomatic children. High genomic variability was observed, with this being the first report of GI.5 NoV in Brazil and of GI.3 in nasopharyngeal swab samples.