禽流感病毒感染哺乳动物模型研究进展

禽流感(avian influenza, AI)是由禽流感病毒(avian influenza virus,AIV)引起的以人类和禽类的呼吸道与消化道为主要病变部位的人兽共患病。良好动物模型的建立可以更好地了解AI的流行病学特点、致病性和病理症状以及AIV的跨种传播机制,为人类预防和治疗AI提供可靠的依据。本综述主要概括了常见AIV感染哺乳动物模型的方式,接种AIV后的临床特征、病理变化、病毒复制情况及免疫后的抗体水平等,为AIV的试验研究提供必要的参考。     

H9N2亚型禽流感病毒研究进展

禽流感(AI)是由禽流感病毒(AIV)引起的一种高度接触性传染病,主要感染家禽和野禽,1966年首次分离得到H9N2。H9N2是AIV的一个亚型,经过长达数十年的遗传变异,已成为当前流行的禽流感病毒主要亚型之一。除了感染鸡、鸭等禽类,H9N2亚型AIV还可感染猪、水貂等哺乳类动物,甚至还可以感染人。虽然H9N2亚型AIV是低致病性的,但它能与其他病毒或细菌引起共感染,还能与其他亚型流感病毒进行重排,形成新型重组病毒,对公共卫生安全造成了不容忽视的潜在危害。文章就H9N2亚型AIV的遗传变异、重组、致病力和跨种传播等方面进行了简要论述。     

H6亚型禽流感病毒研究进展

禽流感病毒(Avian influenza virus,AIV)是一种单股负链RNA病毒,可对禽类和哺乳动物造成严重的呼吸系统疾病。H6 AIV属于低致病性禽流感病毒(LPAIV),在野鸟和家禽中广泛存在。研究表明,H6 AIV的基因片段中出现氨基酸残基突变时,使其具有跨越种属障碍而感染哺乳动物的潜在风险,对人类的生命安全及家禽产业经济发展造成威胁。因此,加强对H6 AIV的监控对畜牧业生产和公共卫生安全至关重要。论文从H6 AIV遗传进化特征、H6 AIV在家禽和野鸟中感染情况、受体结合特征对H6 AIV跨物种传播的影响、H6 AIV对哺乳动物的致病力及对公共卫生安全造成的威胁等方面进行了论述。     

H9N2亚型禽流感病毒流行病学研究进展

H9N2亚型禽流感病毒(Avian influenza virus,AIV)在我国已有二十多年的流行历史,且在我国鸡群中广泛传播,给家禽养殖业造成了巨额损失;H9N2亚型AIV感染人事件的报道也屡见不鲜,给公共卫生带来了巨大的压力和挑战。为了有效控制H9N2亚型AIV的流行和传播,降低其感染风险,文章从流行特点、分子适应机制、感染宿主范围以及防控措施等方面对H9N2亚型AIV的流行病学进行了系统阐述,在阐明H9N2亚型AIV的流行规律及趋势的同时,概述了其分子致病机制,并初步评估了其进化方向和风险性,为AIV的综合防控提供参考依据和理论支持。     

禽流感病毒感染哺乳动物神经系统分子机制研究

正禽流感病毒(AIV)不仅对家禽养殖业可造成严重的经济损失,而且病毒跨宿主感染人类事件不断出现,对公共卫生构成了严重威胁。AIV感染人主要引起呼吸系统疾病,但临床调查表明相当部分病例表现神经系统症状。统计显示,31.36%(74/236)的H5N1 AIV感染患者表现烦躁、易怒等症状,25%(59/236)的患者出现意识障碍等症状,且出现神经症状的患者往往预后不良。多项研究报道了在H5N1、 H7N9 AIV感染患者神经系统中能够检测到流感病毒抗原。这表明与季节性流感相比,AIV感染人更易引起神经症状和严重的后果。目前对于AIV感染人与哺乳动物神经系统的分子机制尚不清楚。     

中草药防治禽流感研究进展

禽流感（avian influenza,AI）是由A型流感病毒引起的家禽或野禽的疾病综合征。根据禽流感病毒（AIV）的致病力通常分为高致病性禽流感（HPAI）和低致病性禽流感（MPAI）,HPAI传播快,具有高度致死性;MPAI多呈隐性感染或症状较轻,不导致严重病变或死亡。AI历来被认为是人类流感的最大基因库,是人流感病毒发生变异的新基因来源。1997年,中国香港H5N1 AIV及1999年中国大陆和香港H9N2AIV首次突破种间障碍直接感染人甚至致死。不但打破了自然条件下仅有H1、H2和H3亚型流感病毒可以感染人和其他哺乳动物的常规,而且为人流感增添了新的毒株亚型（H5和H9）。由此赋予了AIV（禽流感病毒）全新的公共卫生意义。     

H9N2亚型禽流感病毒流行病学及其疫苗的研究进展

禽流感(avian influenza AI)是由A型流感病毒引起的一种高度接触性传染病。H9N2是A型流感病毒的1个亚型,其谱系复杂,流行范围广,已经成为我国AI的主要亚型。尽管我国自1998年就开始进行H9N2亚型禽流感病毒(AIV)的防疫,但目前其疫苗株与流行株的抗原性已经出现了较大的差异。带毒野禽的迁徙不仅使H9N2AIV防控难度加大,而且使AI的流行不断复杂化;活禽交易市场为AIV重排以及跨种传播提供了有利的条件。此外,H9N2AIV感染谱在不断扩大,不仅感染哺乳动物,甚至已经感染了人群;因此,有必要重新认识H9N2AIV的兽医学和公共卫生学意义。现就H9N2AIV近年在我国的流行情况及其疫苗的研究进展作一综述。     

三黄鸡免疫重组禽流感病毒(H5+H7)二价灭活疫苗血清抗体检测试验报告

正禽流感(avian influenza,AI)是禽流感病毒(AIV)感染家禽后引起的各种综合征,从无临床症状感染到呼吸道疾病和产蛋下降,到死亡率接近100%的严重全身性疾病不等。根据禽流感病毒的致病性和毒力的不同,可将其分为高致病性禽流感(HPAI),低致病性禽流感(LMPAI)。高致病性禽流感可导致严重的家禽群体发病和死亡,不仅给家禽养殖业带来毁灭型的打击,还可以不断地跨种间传播感染人类,人感染后死亡率高达60%。     

鸡与鸭重要免疫相关基因结构与功能差异及其禽流感抗性关联分析

禽流感(AI)是禽流感病毒(AIV)引起的一种急性传染病。天然免疫是宿主抵抗病毒感染的第一道防线,在机体抗病毒感染过程中发挥重要作用。鸭和鸡是H5N1AIV感染和传播的主要宿主,但鸭对AI禽流感的抗性远大于鸡,目前公认与其机体天然免疫相关基因有关。比较这两种亲缘关系相近模式生物的遗传结构,可以揭示AI抗性差异的分子基础。本文比较分析鸭和鸡主要免疫相关基因的结构与功能及其在AIV抗性差异方面的潜在作用,为AI防控新技术研究提供理论基础。     

PB2-340K和PB2-588V突变导致H9N2禽流感病毒在哺乳动物间传播

H9N2亚型禽流感病毒(Avian influenza virus,AIV)于1966年首次在美国火鸡中发现,它在禽类之间的有效传播使其在全世界家禽中流行。H9N2亚型AIV也能够感染人和多种哺乳动物(如猪、狗、水貂、蝙蝠),中国于1998年报导了第一例人感染H9N2 AIV的病例。血清学研究发现具有家禽接触史的人(特别是从事家禽职业的工人),H9N2 AIV抗体的阳性率比普通人要高,说明H9N2 AIV可以从家禽传播感染人。     

Antiviral efficacy of oseltamivir against avian influenza virus in avian species

Avian influenza is one of the most contagious viral diseases in bird species and, increasingly, interspecies transmission to mammalian species has been reported. Prevention and eradication of avian influenza virus (AIV) infection in birds may require vaccines as part of a comprehensive program including biosecurity, culling, diagnostics, and surveillance. However, for valuable bird species in zoos, novel eradication strategies are needed, including antiviral treatments. The present study evaluated the anti-influenza efficacy of the potent neuraminidase inhibitor oseltamivir in avian species using the orders Galliformes (chickens) and Anseriformes (ducks). Viral replication of low pathogenic AIV was significantly reduced in the chicken model and completely reduced in the duck model. Anti-influenza drug administration to valuable bird species with an appropriate extrapolation approach could be useful for control of AIV in combination with active surveillance and vaccination strategies. Further, evaluation of oseltamivir against highly pathogenic avian influenza (HPAI) using avian models would be needed to optimize the oseltamivir application guideline for HPAI control.     

禽流感病毒分子生物学的研究进展

禽流行性感冒(av ian in fluenza,A I,简称禽流感)是由A型禽流感病毒(av ian in fluenza v irus,A IV)引起的禽类烈性传染病。作为被世界动物卫生组织(O IE)定为A类的传染病,A I不仅给世界养禽业造成了巨大的经济损失,而且对人类健康和生命安全构成了严重威胁。因此,A I已经成为人们关注的焦点,国内外学者也对其进行了大量研究。作者从病原基因组及其编码的蛋白质、致病力、变异性以及对人类感染A IV的分子机制等角度就A IV的分子生物学研究作一综述,为防制A I提供理论基础,并在此基础上探讨了人类禽流感的防治措施,加深人们对A I的认识。     

H10N8亚型禽流感病毒的研究进展

中国于2013年底首次发现H10N8亚型禽流感病毒（AIV）能感染人并致死的病例,而在此之前从未有过关于H10N8亚型病毒能感染人的报道,目前也未在其他国家监测到H10N8亚型AIV感染人的病例。与H7N9亚型AIV相似,H10N8亚型AIV在家禽中致病性很弱,可一旦感染人能表现出很强的致病性。感染了H10N8亚型AIV的患者病情恶化快、死亡率高、对人的健康危害很大,但至今尚无有效的防制手段。目前还不太清楚H10N8亚型AIV是通过何种途径传播给人的,今后H10N8亚型AIV是否会在人群中引发新的疫情暴发是人们普遍关心的问题。文章简要介绍了H10N8亚型AIV的特点及研究现状。     

Development and evaluation of a DAS-ELISA for rapid detection of avian influenza viruses

Rapid detection of avian influenza virus (AIV) infection is critical for control of avian influenza (AI) and for reducing the risk of pandemic human influenza. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was developed for this purpose. The method employed a monoclonal antibody (MAb) as the capture antibody and rabbit polyclonal IgG labeled with horseradish peroxidase as the detector antibody, and both antibodies were against type-specific influenza A nucleoprotein (NP). The DAS-ELISA could detect minimally 2.5 ng of influenza viral protein in virus preparations treated with Triton X-100, which is equvilent to 2.5 x 10(2) EID50 virus particles. This DAS-ELISA could detect all 15n AIV subtypes (H1-H15) and did not cross react with other avian pathogens tested. The DAS-ELISA were directly compared with virus isolation (VI) in embryonated chicken eggs, the current standard of influenza virus detection, for 805 chicken samples. The DAS-ELISA results correlated with VI results for 98.6% of these samples, indicating a sensitivity of 97.4% and specificity of 100%. The method was further tested with H5N1 and H9N2 AIV experimentally infected chickens, ducks, and pigeons, as well as field samples obtained from central China in 2005. The DAS-ELISA method has demonstrated application potential as an AIV screening tool and as a supplement for virus isolation in Asia.     

H5亚型鸭源流感病毒HA基因序列生物信息学分析

A型流感病毒（AIV）引起的禽类禽流行性感冒（avian influenza,AI）或相关疾病,被国际兽疫局定为甲类传染病。AIV中最容易突变的基因是血凝素（HA）基因,具有亚型和株的特异性,是区分病毒亚型的依据之一。本研究从GenBank中下载了所有209条鸭源H5禽流感病毒HA基因的全序列,利用生物信息学软件构建进化树研究序列的聚类特点;比较不同年份毒株的HA基因的受体结合位点氨基酸,找出受体结合位点氨基酸的变异规律;比较不同年份分离的鸭源H5N1序列的HA1和HA2蛋白的剪切位点,找出各年份毒株的剪切位点的特点;比较不同年份分离序列的潜在糖基化位点,统计各年份潜在糖基化位点的数量以及序列变化。期望找到H5亚型鸭源流感病毒的变异规律和变异方向,为鸭源流感的防控起到积极的作用。     

Host range of avian influenza virus in free-living birds

Isolation of avian influenza virus (AIV) has been reported from 12 orders and 88 species of free-living birds. Most isolations are reported from species in the orders Anseriformes and Charadriiformes and it is recognized that species in Anseriformes represent important reservoirs of AIV. Morbidity and mortality among free-living birds attributable to AIV infection are rare, but differences in prevalence of AIV occur within and between avian species. Seasonal variation has been reported from free-living and sentinel ducks with peak AIV infection occurring in late summer and early fall. Prevalence of AIV is age-related, with highest isolation rates reported from juvenile birds. Differences in susceptibility to AIV infection among species have been demonstrated under experimental conditions. The dynamics and epidemiology of species-related variation in populations of free-living birds require further study.     

The role of rodents in avian influenza outbreaks in poultry farms: a review

Wild migratory birds are associated with global avian influenza virus (AIV) spread. Although direct contact with wild birds and contaminated fomites is unlikely in modern non-free range poultry farms applying biosecurity measures, AIV outbreaks still occur. This suggests involvement of other intermediate factors for virus transmission between wild birds and poultry. This review describes current evidence of the potential role of rodents in AIV transmission from wild birds to poultry and between poultry houses. Rodents can be abundant around poultry houses, share their habitat with waterfowl and can readily enter poultry houses. Survival of AIV from waterfowl in poultry house surroundings and on the coat of rodents suggests that rodents are likely to act as mechanical vector. AIVs can replicate in rodents without adaptation, resulting in high viral titres in lungs and nasal turbinates, virus presence in nasal washes and saliva, and transmission to naïve contact animals. Therefore, active AIV shedding by infected rodents may play a role in transmission to poultry. Further field and experimental studies are needed to provide evidence for a role of rodents in AIV epidemiology. Making poultry houses rodent-proof and the immediate surroundings unattractive for rodents are recommended as preventive measures against possible AIV introduction.