一起水源性诺如病毒感染性腹泻爆发的调查

目的了解一起社区感染性腹泻爆发的特点和流行原因,探讨爆发疫情调查处理的经验并为制定防治对策提供科学依据。方法采用现场流行病学调查分析和实验室检测方法。结果2月11日至18日,该社区发生感染性腹泻病例173例,罹患率为2.40%,病例最小1岁,最大89岁,男女性别比为1.25∶1,发病最多的为40～49岁组,所有病例均为居住或工作在该社区的人员,工厂、居家均有病例出现,居家病例呈一定的家庭聚集性,病例的临床表现基本相同,以腹泻、腹痛、恶心、呕吐和发热等症状为主,大部分症状较轻,病程1～3 d。从病人粪便标本中检测到诺如病毒抗原,采取改善饮用水、隔离治疗病人和健康教育等综合措施后,疫情迅速得到控制。结论本次疫情为一起诺如病毒感染性腹泻爆发,爆发原因可能是该社区水厂供水系统被污染。社区小水厂卫生安全存在诸多薄弱环节,建议完善水厂卫生管理制度,落实水质消毒措施,尽快改用市政自来水供水。     

河北省保定市一起水源性诺如病毒暴发疫情的流行特征及病原学研究

目的:对河北省保定市一起水源性诺如病毒感染性腹泻暴发疫情进行调查分析,了解其流行特征,确定致病原。方法:开展现场流行病学调查,采集患者呕吐物、肛拭子或粪便标本,居民末梢水以及污水井井水标本,采用荧光定量PCR（real-time PCR）检测诺如病毒核酸,对阳性标本进行扩增并测序分析。结果:该小区发现病例70例,罹患率...     

实验感染蚊虫及来亨鸡体内西尼罗病毒的RT-PCR检测

根据已发表的西尼罗病毒Chin-01株基因序列,参照文献资料选择合成一对引物,建立西尼罗病毒的RT-PCR检测方法,对反应条件进行了系列优化后,应用于感染蚊虫样本及来亨鸡血液样本中的病毒核酸检测。该方法的检测敏感性达到1·0PFU,感染蚊虫样本和来亨鸡血液样本均能够扩增出与预期值大小一致的特异性区带,经序列测定证明,与实验感染所用病毒株序列完全相同。可见RT-PCR是检测实验感染蚊虫和来亨鸡体内西尼罗病毒行之有效的方法。     

北京市市售结球生菜诺如病毒和轮状病毒污染状况调查

目的 调查北京市市售结球生菜诺如病毒(norovirus,NoV)和轮状病毒(rotavirus,RV)污染情况。方法 2015年11月至2016年10月,在北京市某菜市场摊位采集结球生菜54件。用离心法和直接法,分别对应3种洗脱液洗脱菜叶中病毒并浓缩,用荧光PCR法检测NoV和RV核酸。用半巢式RT-PCR方法扩增NoV阳性样本的衣壳蛋白区基因,PCR产物直接测序,用BioEdit7.0. 9.0软件进行序列比对,用MEGA6.06软件构建进化树。结果 54件结球生菜,未检出RV。NoV总检出率为11.1%(6/54),其中GI组1件、GⅡ组3件、GI/GⅡ组混合2件。春夏秋冬季检出率依次为8.3%(1/12)、0.0%(0/8)、28.6%(4/14)和5.0%(1/20)。1件GⅡ阳性样本测序成功,为GⅡ.3基因型,该毒株与2014年广东省人源毒株KY348698相似性最高100.0%。结论 北京市市售部分结球生菜存在人源NoV污染,生食未洗净结球生菜有引起病毒性急性胃肠炎的风险。     

水中诺如病毒富集及定量检测研究

目的评估MCE—PEG富集法（混合硝酸纤维素膜第一次富集和PEG沉淀第二次富集）对水中诺如病毒的富集效果及检测灵敏度。为水源性诺如病毒胃肠炎疫情暴发的确定提供有效的实验室检测方法。方法把含有诺如病毒的粪便加入纯净水中,用MCE．PEG方法富集后,荧光PCR绝对定量检测富集前后水的病毒浓度．评估该方法的病毒回收率。同时梯度稀释粪便悬液,分别加入纯净水中,评估该方法的灵敏度。结果经过混合硝酸纤维素膜第一次富集后待滤水被浓缩100倍,病毒平均回收率为56．12％,灵敏度是待滤水中病毒浓度为10拷贝μl。PEG沉淀第二次富集后,浓缩倍数为1000倍,病毒平均回收率为42．47％,灵敏度是待滤水中病毒浓度为1拷贝／μl。结论MCE—PEG富集法操作简单、材料价格实惠、易于购买、病毒回收率及灵敏度较高。可望进一步优化后广泛应用于不同水中病毒富集浓缩检测,为水源性诺如病毒胃肠炎疫情暴发的确定提供了有效的实验室检测方法。     

多重PCR检测婴幼儿腹泻样本中常见病毒

目的初步了解深圳地区引起临床婴幼儿急性腹泻中常见病毒的病原分布情况,为临床防治提供依据。方法采用多重RT-PCR方法检测婴幼儿急性腹泻常见病毒：轮状病毒（RV）、星状病毒（AstV）、诺如病毒（NV）,采用单重PCR法筛查临床腹泻标本肠道腺病毒（EAdV）。结果在440份标本中,共检出197例至少感染一种腹泻病毒,总阳性率为44.77%（197/440）,其中183例为一种病毒感染,14例（3.18%）为混合感染。4种腹泻病毒以RV感染为主,阳性率为28.64%（126/440）;其次是EAdV,阳性率为8.86%（39/440）;NV阳性率为5.45%（24/440）;AstV阳性率为1.82%（8/440）。混合感染以RV合并其他病毒感染为主,占92.86%。结论 RV、EAdV和NV是引起深圳地区婴幼儿急性腹泻的主要病毒致病原,混合感染以RV联合其他病毒感染为主,临床上应根据所感染病原体制定有针对性的诊治措施。     

GⅡ.17型诺如病毒人源中和性单链抗体制备及生物特性鉴定

目的:基于一起暴发疫情,构建人源噬菌体单链抗体库,筛选特异性GⅡ.17型诺如病毒(NoV)单链抗体(scFv),并进行表达纯化及鉴定.方法:采集患者粪便或肛拭子样本,RT-PCR检测肠道病毒核酸,PCR扩增NoV衣壳蛋白N/S区和P区序列,Mega 4.0构建系统进化树.采集并分离患者恢复期外周血PBMC,Trizol...     

实验感染来亨鸡及蚊虫体内西方马脑炎病毒RT-PCR检测

本研究建立了西方马脑炎病毒的RT-PCR检测方法,应用于实验感染西方马脑炎病毒的来亨鸡血液及蚊虫样本中的病毒核酸检测。结果从感染病毒的来亨鸡血液及蚊虫样本中均能扩增出与预期分子量一致的特异性条带,经序列测定证明,与西方马脑炎71V-1658(NC-003908)病毒株核酸序列有较高的同源性。表明所建立的RT-PCR检测方法能够快速敏感地检测出实验感染来亨鸡血液样本及蚊虫体内西方马脑炎病毒。     

Molecular detection and characterization of noroviruses from children in Botswana

Stool specimens were collected from 100 children in Botswana. RT‐PCR analysis detected noroviruses (NoVs) in 24% of samples tested. Genogroup I and genogroup II strains were identified. There was no association between NoV detection and age or gender. This study is the first indication that NoVs circulate widely in Botswana. J. Med. Virol. 82:321–324, 2010. © 2009 Wiley‐Liss, Inc.     

Detection and molecular characterization of noroviruses and sapoviruses in children admitted to hospital with acute gastroenteritis in Vietnam

Noroviruses (NoV) and sapoviruses (SaV) are recognized as important causes of acute gastroenteritis in children worldwide. In this study, the prevalence and genetic variability of NoV and SaV were determined in hospitalized children <5 years of age with acute gastroenteritis in Hanoi, Vietnam. A total of 501 fecal specimens collected between November-2007 and October-2008, that previously had been tested for rotavirus (RV), were tested for NoV and SaV by realtime RT-PCR. Positive samples were genotyped by conventional RT-PCR followed by sequencing. GII NoV was detected in 180 (36%) and SaV in 7 (1.4%) of the samples. NoV was detected year-round ranging from 9.5% in April to 81.5% in September among RV negative samples. NoV GII.4 Minerva (2006b) was the dominant genotype (93%) with a few other genotypes detected including GII.3 (4.4%), GII.13 (1.7%), and GII.2 (0.6%) but no GI strains. Only GI and GII SaV strains were detected in this study. No difference in NoV prevalence between age groups was noted. Frequency of vomiting or fever was similar between children with NoV and RV infection, yet, NoV caused diarrhea with longer duration. In conclusion, NoV is the second most frequent cause of diarrhea in hospitalized children in North Vietnam.     

Detection of GII‐4/2006b variant and recombinant noroviruses in children with acute gastroenteritis,South Korea

Norovirus (NoV), a single‐stranded, positive RNA virus, is an important etiologic agent of acute gastroenteritis in children worldwide. In this study, a total of 434 fecal samples collected from 434 children with acute gastroenteritis in Seoul, between September 2007 and July 2008 were tested to determine the molecular epidemiology of NoVs and characterize recombinant strains by using RT‐PCR followed by sequencing. Of the 434 specimens, NoV, rotavirus, and adenovirus were detected in 155 (35.8%), 72 (16.6%), and 19 specimens (4.3%), respectively. NoV GI was detected in 7 specimens (1.6%) and GII in 148 (34.1%) specimens. Phylogenetic analysis of capsid sequences in the GII‐positive specimens revealed the presence of the following strains: GII‐4, 111 (75.0%); GII‐3, 35 cases (23.6%); GII‐6b, 1 case; and GII‐16, 1 case. Most of the GII‐4 strains were grouped with the GII‐4/2006b variant with 98–100% nucleotide identity. Eleven strains were identified as recombinant (GII‐4/GII‐3 in 10 cases and GII‐b polymerase/GII‐16 capsid in 1 case) by sequencing based on the RdRP and capsid genes. The putative recombination point in the recombinant strains was the ORF‐1/ORF2 overlap, located at nucleotide 5,046 with reference to Lordsdale. In conclusion, GII‐4/2006b variants were detected predominantly and a new recombinant strain (GII‐4/GII‐3) was found in the Korean children with gastroenteritis. Continuous monitoring of the genetic diversity of NoVs is important to determine the trend of the predominant genotype and new recombinant strain. J. Med. Virol. 82:146–152, 2010. © 2009 Wiley‐Liss, Inc.     

Analysis of genomic homology of murine gammaherpesvirus (MHV)-72 to MHV-68 and impact of MHV-72 on the survival and tumorigenesis in the MHV-72-infected CB17 scid/scid and CB17+/+ mice

Murine gammaherpesvirus (MHV)-68-infected mice are well-known as models for Epstein-Barr virus (EBV)-related lymphoproliferative diseases. MHV-72 may be a relative of MHV-68, but any genetic comparison between the two (except for the M7 gene) has never been reported. The genetic compositions of MHV-72 and MHV-68 were compared and the pathology of MHV-72 infection studied in CB-17 severe combined immunodeficiency (scid/scid; SCID) and CB17 wild-type (CB17+/+) mice. The MHV-72 DNA sequence was almost identical to MHV-68 except for approximately 7000 bp corresponding to the MHV-68 M1-M3 genes. Twenty-seven of 30 MHV-72-infected SCID mice (90%) died from generalized infection with intranuclear viral inclusions for approximately 1 month, while MHV-72-infected CB17+/+ mice recovered from acute infection. Long observation and pathological study of 68 MHV-72-infected mice for up to 24 months revealed that the survival rate (29.4%) and survival time (21.3 months) of MHV-72-infected CB17+/+ mice were significantly lower (P = 0.0127) and shorter (P = 0.0065) than those of the controls (61.1% and 22.9 months), respectively. The malignancy development rate (60.3%) of the infected CB17+/+ mice was also significantly higher (P = 0.004) than those of the controls (22.2%). However, no MHV-72 DNA was detected in the tumors of infected mice. MHV-72 may have some tumor-promoting effects but the tumorigenesis in infected CB17+/+ mice is different from EBV-associated tumors.