西尼罗热的流行及其应对措施

西尼罗热是由西尼罗病毒感染引起的一种急性传染病.该病以野生鸟类为储存宿主,通过蚊虫叮咬而传播.此病主要发生在中东、热带非洲、亚热带非洲及西南亚,近年来传入北美洲,在美国和加拿大爆发流行.由于目前尚无疫苗广泛用于西尼罗热的预防,西尼罗病毒对我国又是一种新的病原,人群缺乏免疫力.为预防西尼罗热在我国的爆发流行,对西尼罗热的流行概况、流行病学特征、对我国的威胁和预防与控制措施作一综述.     

卫生部办公厅关于印发埃博拉出血热等6种传染病预防控制指南和临床诊疗方案的通知（三）卫办应急发[2008]140号

西尼罗热预防控制技术指南 西尼罗热是由西尼罗病毒（West Nile Virus,WNV）感染引起的人畜共患病,主要感染鸟类、人类和马、牛等哺乳动物。鸟类是该病毒的储存宿主,人主要通过带毒蚊虫叮咬而感染。人感染西尼罗病毒后多数没有症状,约20％可主要表现为西尼罗热、西尼罗病毒性脑炎。近年来,本病的流行区域逐渐扩大,在北美、欧洲和非洲等地引起流行。我国尚未发现西尼罗病毒感染引起的疾病,也未分离到西尼罗病毒,但随着国际交流的日益频繁,同样面临着该病输入的威胁。     

西尼罗病预防控制现状与进展

西尼罗病是由西尼罗病毒感染引起的人兽共患、虫媒、自然疫源性、急性传染病。该病以野生鸟类为储存宿主,通过蚊虫叮咬而传播。临床表现以发热为主的叫西尼罗热,并伴关节痛;以中枢神经系统损害为主,引发脑炎的叫西尼罗病毒性脑炎;引发脑膜炎的叫西尼罗病毒性脑膜炎;引发脑膜脑炎的叫西尼罗病毒性脑膜脑炎;表现有脑膜刺激症状,严重者可导致死亡。西尼罗病于2002年在美国爆发造成大流行,严重危害人类健康,引起全球公共卫生界的关注。为预防西尼罗病在我国的爆发流行,我们需高度警惕,未雨绸缪,开展西尼罗病毒监测,防止西尼罗病传入。为此,对西尼罗病的病原学、流行病学、临床表现、实验室检查、预防控制措施等方面作一综述。     

西尼罗热传入风险因子监测及口岸预防控制措施

[目的]分析西尼罗热传人我国的各种风险因子,并对其进行监测;提出在国境口岸预防控制西尼罗热的措施。[方法）了解国内外对西尼罗热的研究进展,分析和监测影响西尼罗热传人我国的各种风险因子。其包括候鸟迁徙,可传播西尼罗热的蚊类的分布,疫区入境人群等。[结果]鸦科的鸟类对西尼罗热特别易感,我国共有鸦科鸟类11属27种,并且是常见鸟类。我国有3条候鸟迁徙路线,传播西尼罗热的风险较高。致倦库蚊、淡色库蚊、三带喙库蚊、凶小库蚊等我国常见蚊种可以传播西尼罗热。西尼罗病毒与在我国流行较为广泛的乙型脑炎病毒存在交叉免疫反应。[结论]目前尚未发现我国存在西尼罗病毒的证据,但存在传入风险,国境口岸可以采取分级应对的措施。     

气候变化对蚊媒病毒性疾病流行病学影响研究现状

蚊虫传播的登革热、圣路易斯脑炎、流行性乙型脑炎等病毒性疾病严重威胁着人类健康。气候变化诸如气温和降雨量的变化，可改变蚊虫地理分布、影响蚊虫生长发育和病毒在蚊虫体内的繁殖速度，也改变着疾病流行和传播的特征。现就气候变化对蚊媒病毒性疾病影响的研究进展进行介绍，并综述蚊媒病毒性疾病的流行趋势，试图全面了解气候变化之下蚊虫传播的病毒性疾病流行病学现状。     

近年来西尼罗热的流行现状及其流行毒株的表型和基因型特性

西尼罗热(West Nile Fever，WNF)是由西尼罗病毒(West Nile Virus，WNV)通过蚊虫传播感染引起的一种急性传染病。WNV于1937年在乌干达西尼罗地区的一位发热妇女的血液首次分离到，为黄病毒属日本脑炎(乙脑)病毒抗原复合组内成员。该组成员包括在亚洲广泛流行的日本脑炎病毒，在美国流行的圣路易脑炎病毒，在澳洲流行的Kunjin和墨立谷脑炎病毒，成员间抗原性关系密切，基因同源性高达70％以上，相互间有较高的交互中和保护作用。     

近年来西尼罗热的流行现状及其流行毒株的表型和基因型特性

西尼罗热(WestNileFever,WNF)是由西尼罗病毒(WestNileVirus,WNV)通过蚊虫传播感染引起的一种急性传染病。WNV于1937年在乌干达西尼罗地区的一位发热妇女的血液首次分离到,为黄病毒属日本脑炎(乙脑)病毒抗原复合组内成员。该组成员包括在亚洲广泛流行的日本脑炎病毒,在美国流行的圣路易脑炎病毒,在澳洲流行的Kunjin和墨立谷脑炎病毒,成员间抗原性关系密切,基因同源性高达70%以上,相互间有较高的交互中和保护作用。以后于20世纪50年代在埃及和其他地区,从患者、鸟和蚊子也分离到该病毒。由WNV引起的WNF是黄病毒中流行最广的一种疾病…     

卫生部办公厅关于印发埃博拉出血热等6种传染病预防控制指南和临床诊疗方案的通知(三)

西尼罗热预防控制技术指南西尼罗热是由西尼罗病毒(West Nile virub,WNV)感染引起的人畜共患病,主要感染鸟类、人类和马、牛等哺乳动物.     

西尼罗病毒E蛋白的结构和应用进展

西尼罗病毒是一种单股正链RNA病毒,属于黄病毒属黄病毒科,主要通过库蚊传播,能引起西尼罗热及神经侵袭性疾病如脑炎、脑膜炎等。近年来,该病毒在多个国家和地区间广泛流行,给发病国家带来了极大的危害。目前对于西尼罗病毒尚未有可用于人类的疫苗上市,也没有特定的抗病毒药物可用,因此加强病毒监测、研发新的疫苗及掌握实验室诊断方法变得尤为重要。本文主要通过对西尼罗病毒E蛋白的结构、疫苗及检测方法的最新进展加以探讨,为研发西尼罗病毒疫苗及诊断试剂盒提供理论依据。     

埃及伊蚊传播西尼罗病毒的媒介效能研究

目的研究我国埃及伊蚊传播西尼罗病毒的潜在能力。方法人工配制病毒血餐感染埃及伊蚊并进行传播实验,应用反转录聚合酶链反应（RT？PCR）、病毒分离和间接免疫荧光法（IFA）检测蚊虫和来亨鸡体内病毒。结果动物实验结果表明敏感动物来亨鸡感染西尼罗病毒后,第2天其体内病毒量达到最高,说明进行传播实验后的第2天是检测传播是否成功的最佳时间。感染与传播实验结果表明埃及伊蚊对西尼罗病毒的感染率达到了63.3%,而且通过刺叮敏感动物（来亨鸡）能够传播该病毒,其传播率为30.0%。结论在未来我国可能的西尼罗热暴发中,埃及伊蚊可能成为其在海南等地的潜在传播媒介。     

Import of West Nile Virus Infection in the Czech Republic

We report West Nile virus infection of the central nervous system in a 69-year-old man, residing in North Moravia (Czech Republic), who visited the USA from 6 July to 31 August 2002. He developed fever with fatigue at the end of his US stay, and was hospitalized in Ostrava after his return on 3 September with fever (up to 39.5 °C), fatigue, anorexia, moderate laryngotracheitis, dizziness, insomnia, blurred speech, and a marked bradypsychism. EEG demonstrated a slow bifrontal theta–delta activity, and CT of the brain a slight hydrocephalus. A significant increase of antibodies neutralizing West Nile virus was detected between the first (1:16) and second (1:256) blood serum sample. The patient recovered gradually and was released from hospital on 16 September. This is the first recorded human case of West Nile fever (WNF) imported to the Czech Republic. Nine similar cases of WNF import from the USA have already been reported in other European countries – France, Denmark, the Netherlands, and Germany.     

Alligators as West Nile virus amplifiers

Recent evidence suggests that American alligators (Alligator mississippiensis) may be capable of transmitting West Nile virus (WNV) to other alligators. We experimentally exposed 24 juvenile alligators to WNV parenterally or orally. All became infected, and all but three sustained viremia titers >5.0 log10 PFU/mL (a threshold considered infectious for Culex quinquefasciatus mosquitoes) for 1 to 8 days. Noninoculated tankmates also became infected. The viremia profiles and multiple routes of infection suggest alligators may play an important role in WNV transmission in areas with high population densities of juvenile alligators.     

Construction and characterization of a second-generation pseudoinfectious West Nile virus vaccine propagated using a new cultivation system

Safer vaccines are needed to prevent flavivirus diseases. To help develop these products we have produced a pseudoinfectious West Nile virus (WNV) lacking a functional C gene which we have named RepliVAX WN. Here we demonstrate that RepliVAX WN can be safely propagated at high titer in BHK cells and vaccine-certified Vero cells engineered to stably express the C protein needed to trans-complement RepliVAX WN growth. Using these BHK cells we selected a better growing mutant RepliVAX WN population and used this to generate a second-generation RepliVAX WN (RepliVAX WN.2). RepliVAX WN.2 grown in these C-expressing cell lines safely elicit strong protective immunity against WNV disease in mice and hamsters. Taken together, these results indicate the clinical utility of RepliVAX WN.2 as a vaccine candidate against West Nile encephalitis.     

新疆伊犁地区动物脑组织西尼罗病毒E基因片段的检测

目的了解新疆伊犁地区动物中西尼罗病毒（West Nile virus,WNV）感染现状,为我国WNV的防治提供资料。方法采用一步法实时荧光定量反转录-聚合酶链反应（RT-PCR）,对采自新疆伊犁地区的70头驴和100只牧羊犬的脑组织进行WNV包膜蛋白（E）基因片段检测。结果 70头驴和100只牧羊犬脑组织标本的西尼罗病毒包膜蛋白基因片段检测有2例可疑阳性,但经3%凝胶电泳法再次验证后排除。故所有待检样本WNV包膜蛋白基因检测均为阴性。结论我国新疆伊犁地区的驴和牧羊犬脑组织中未检测到WNV的感染。     

Epidemiological history and phylogeography of West Nile virus lineage 2

West Nile virus (WNV) was first isolated in Uganda. In Europe WNV was sporadically detected until 1996, since then the virus has been regularly isolated from birds and mosquitoes and caused several outbreaks in horses and humans. Phylogenetic analysis showed two main different WNV lineages. The lineage 1 is widespread and segregates into different subclades (1a–c). WNV-1a includes numerous strains from Africa, America, and Eurasia. The spatio-temporal history of WNV-1a in Europe was recently described, identifying two main routes of dispersion, one in Eastern and the second in Western Europe. The West Nile lineage 2 (WNV-2) is mainly present in sub-Saharan Africa but has been recently emerged in Eastern and Western European countries. In this study we reconstruct the phylogeny of WNV-2 on a spatio-temporal scale in order to estimate the time of origin and patterns of geographical dispersal of the different isolates, particularly in Europe. Phylogeography findings obtained from E and NS5 gene analyses suggest that there were at least two separate introductions of WNV-2 from the African continent dated back approximately to the year 1999 (Central Europe) and 2000 (Russia), respectively. The epidemiological implications and clinical consequences of lineage 1 and 2 cocirculation deserve further investigations.     

West Nile Virus infection in humans and horses, Cuba

A surveillance system to detect West Nile virus (WNV) was established in Cuba in 2002. WNV infection was confirmed by serologic assays in 4 asymptomatic horses and 3 humans with encephalitis in 2003 and 2004. These results are the first reported evidence of WNV activity in Cuba.     

West Nile virus in Mexico: evidence of widespread circulation since July 2002

West Nile virus (WNV) antibodies were detected in horses from five Mexican states, and WNV was isolated from a Common Raven in the state of Tabasco. Phylogenetic studies indicate that this isolate, the first from Mexico, is related to strains from the central United States but has a relatively high degree of sequence divergence.     

Preclinical and clinical development of YFV 17D-based chimeric vaccines against dengue,West Nile and Japanese encephalitis viruses

Dengue viruses (DENV), West Nile virus (WNV) and Japanese encephalitis virus (JEV) are major global health and growing medical problems. While a live-attenuated vaccine exists since decades against the prototype flavivirus, yellow fever virus (YFV), there is an urgent need for vaccines against dengue or West Nile diseases, and for improved vaccines against Japanese encephalitis. Live-attenuated chimeric viruses were constructed by replacing the genes coding for Premembrane (prM) and Envelope (E) proteins from YFV 17D vaccine strain with those of heterologous flaviviruses (ChimeriVax™ technology). This technology has been used to produce vaccine candidates for humans, for construction of a horse vaccine for West Nile fever, and as diagnostic reagents for dengue, Japanese encephalitis, West Nile and St. Louis encephalitis infections. This review focuses on human vaccines and their characterization from the early stages of research through to clinical development. Phenotypic and genetic properties and stability were examined, preclinical evaluation through in vitro or animal models, and clinical testing were carried out. Theoretical environmental concerns linked to the live and genetically modified nature of these vaccines have been carefully addressed. Results of the extensive characterizations are in accordance with the immunogenicity and excellent safety profile of the ChimeriVax™-based vaccine candidates, and support their development towards large-scale efficacy trials and registration.