基于血凝素裂解位点的DNA条形码在A型流感病毒分型中的应用

为了建立一种快速鉴别AIV的HA亚型的RT-PCR方法,本研究探讨了流感病毒血凝素裂解位点基因作为DNA条形码对A型流感病毒进行亚型鉴定的可行性。通过生物信息学方法对16种A型流感病毒的血凝素基因全长进行比对,在HA裂解位点的两端高度保守区设计一对DNA条形码引物,RT-PCR扩增获得约170bp的核苷酸片段。利用MEGA5.0软件构建N-J系统树并计算亚型间及亚型内平均遗传距离。结果显示,不同A型流感病毒裂解位点氨基酸具有单系性,每一亚型可分别形成各自独立的分支。不同亚型间平均遗传距离为0.277,相同亚型内平均遗传距离0.032。研究表明,利用DNA条形码技术可在A型流感病毒分型方面进行有效的分子分类鉴定。     

应用电化学基因芯片鉴别A型流感病毒亚型

为了验证电化学基因芯片技术检测A型流感亚型的可行性,应用建立的电化基因芯片方法分别检测了9株不同亚型的A型流感病毒抗原、1株新城疫病毒抗原和10份临床样品。结果为电化学基因芯片均能特异检出相应的A型流感病毒亚型,与新城疫病毒抗原无交叉反应;临床样品中,检出5份为H6N6亚型流感病毒核酸阳性、2份为H6H2亚型禽流感病毒核酸阳性、3份为H9H2亚型禽流感病毒核酸阳性。结果表明,电化学基因芯片方法适合A型流感病毒各亚型的鉴别,具有快速、特异的特点。     

A型流感病毒在野禽中的全球分布

亚洲爆发的H5N1亚型高致病性禽流感随后传播至俄罗斯、中东、欧洲和非洲,现已将人们的注意力逐渐吸引到野禽在流感病毒持续存在所起的作用上。如果不考虑病毒宿主的生态学,就不能全面了解病毒的生态学、流行病学、遗传学及其进化。本文作者回顾了目前所掌握的流感病毒感染在野鸟中的全球分布模式,并根据宿主生态学、特别是鸟类行为学讨论这些模式,确定所掌握知识中的一些重大差距。     

整合H1亚型流感病毒血凝素蛋白伪型病毒的构建

为构建包装含有H1亚型流感病毒HA蛋白的伪型病毒,本研究将人工合成的H1N1流感病毒(A/Califorma/04/2009株)血凝素(Hemagglutinin,HA)基因连接至真核表达载体pcDNA3.1,该重组质粒与表达逆转录病毒相关元件的骨架质粒pHIT111及pHIT60共转染人胚胎肾细胞293T,构建了以鼠白血病病毒为核心、包装含有HA蛋白的伪型病毒.通过对伪病毒感染细胞中LacZ报告基因表达产物的检测,证明伪病毒可以感染MDCK细胞;同时其感染过程可被流感病毒免疫后的小鼠阳性血清所阻断,表明该伪型病毒可模拟野生型病毒完成对宿主细胞的感染过程.本研究所构建的伪病毒系统为研究H1亚型流感病毒HA蛋白抗原特性及新型中和抗体检测方法的建立提供了理想的工具.     

区分禽流感病毒亚型诊断基因芯片的构建

制备了可同时区分AIVH5、H7、H9血凝素亚型及N1、N2神经氨酸酶亚型的基因诊断芯片。试验以重组质粒为模板,进行PCR扩增,然后用异丙醇沉淀法进行纯化,制备探针及内参基因。将探针及内参基因用点样缓冲液稀释到0.3μg/μL后用芯片点样仪将其点制到醛基化基片上,样点中心间距450μm,样点直径220μm。将点好的基片在室温干燥24h以上,后经65℃再水合10s、80℃干燥、65mj紫外线交联照射25min后,再用封闭液封闭,95℃变性处理,成功构建了能区分禽流感血凝素H5,H7,H9亚型及神经氨酸酶N1,N2亚型的检测基因芯片。在PCR扩增中标记待检样品,对制备的检测芯片进行质量检验,结果表明,制备的区分禽流感病毒亚型基因芯片可区分AIV部分亚型。     

鸡A型流感病毒的分离及初步鉴定

从发病率56％而死亡率15％的罗曼父母代蛋种鸡群中,分离到4株A型流感病毒。这些分离毒株可在鸡胚中传代,经尿囊腔途径接种10日龄鸡胚,可80～100％致死鸡胚,能凝集鸡的红细胞,且不被新城疫阳性血清所抑制。用这些分离毒株制备成的琼脂扩散抗原与禽流感阳性血清在琼脂扩散试验中出现明显的白色沉淀线。发病鸡康复后采血制备的血清能与禽流感琼扩抗原在琼脂扩散试验中出现明显的白色沉淀线。分离毒SX_(9401)株具有良好的免疫原性。根据以上实验,所分离到的病毒为鸡A型流感病毒,其血清亚型有待于进一步鉴定。本研究从病原学角度证实禽流感在四川省的存在。     

A型流感病毒在野禽中的全球分布(续完)

3海鸥和燕鸥中的流感病毒1961年,首次报道从燕鸥(sterna hirundo)中分离到流感病毒。该高致病性禽流感H5N3亚型病毒引起了南部非洲禽流感的爆发,并至少造成1300只     

野鸡长期排毒导致A型流感病毒出现变异

近日，美国田纳西州孟菲斯市的圣裘德儿童研究医院由世界最著名的流感研究专家Robert Webster带领的团队证实野鸡对15个HA亚型的A型流感病毒敏感，其中13／23的病毒能从感染超过14天的野鸡体内分离出来，虽然所有试验鸡只体内都存在血清中和抗体，在感染H10亚型流感病毒45天后仍然排毒。     

H9N2亚型A型流感

A型流感病毒能引起各种鸟类、低等哺乳动物和人类的疾病。禽流感(AI)自1878年在意大利首次发现至今，由于候鸟的迁徙和国际间贸易的日益频繁，使得该病呈全球性分布，给养禽业造成巨大的经济损失。1997年“香港禽流感”表明，AI已对人类的健康造成了潜在的威胁。流感病毒(IV)血清亚型繁多，自从1966年Homme等人首次报道从火鸡中分离出H9N2亚型A型IV以来、陆续从鸡、野鸡、鸭、鸽子和鹌鹑中分离到该亚型AIV。除禽和人以外，还从其它动物中分离到。     

Review of Influenza A Virus in Swine Worldwide: A Call for Increased Surveillance and Research

Pigs and humans have shared influenza A viruses (IAV) since at least 1918, and many interspecies transmission events have been documented since that time. However, despite this interplay, relatively little is known regarding IAV circulating in swine around the world compared with the avian and human knowledge base. This gap in knowledge impedes our understanding of how viruses adapted to swine or man impacts the ecology and evolution of IAV as a whole and the true impact of swine IAV on human health. The pandemic H1N1 that emerged in 2009 underscored the need for greater surveillance and sharing of data on IAV in swine. In this paper, we review the current state of IAV in swine around the world, highlight the collaboration between international organizations and a network of laboratories engaged in human and animal IAV surveillance and research, and emphasize the need to increase information in high‐priority regions. The need for global integration and rapid sharing of data and resources to fight IAV in swine and other animal species is apparent, but this effort requires grassroots support from governments, practicing veterinarians and the swine industry and, ultimately, requires significant increases in funding and infrastructure.     

广东省H1和H3亚型猪流感病毒抗体血清学调查

为了解广东省规模化猪场H1和H3亚型猪流感病毒的流行情况,采用ELISA检测方法对采集于广东省14个市的28个规模化猪场的1 015份猪血清进行H1亚型和H3亚型猪流感病毒的抗体检测。结果表明,H1亚型抗体总阳性率为40.9%,猪场阳性率高达92.9%(26/28);H3亚型抗体总阳性率为16.8%,猪场阳性率为78.6%(22/28)。其中粤西和珠三角地区H1亚型抗体阳性率分别为49.6%和45.4%,H3亚型抗体阳性率分别为14%和20.8%;而粤东和粤北地区H1亚型抗体阳性率分别为2.7%和12%,H3亚型抗体阳性率分别为6.3%和0。说明在广东省被调查的猪场中,H1和H3猪流感病毒的感染较为普遍,其中H1型感染率高于H3型。广东省SIV流行情况存在明显的地域性差异。     

蜜蜂囊状幼虫病病毒的基因型分析

为了解蜜蜂囊状幼虫病病毒的遗传进化规律,依据SB14f/SB15r引物所扩增的RNA依赖的RNA聚合酶基因片段序列对该病毒进行基因型分析。结果表明,该病毒主要分为欧洲型、远东型和南非型3个基因型。欧洲基因型分为中欧和英国亚型,远东基因型分为东方蜜蜂和西蜂亚型。提示蜜蜂囊状幼虫病病毒总体上按地域分型。     

A型流感病毒蛋白研究进展

流感是由A型流感病毒引起的一种感染和／或疾病综合征。A型流感病毒已成为鸟类、人类和低等哺乳动物疾病的主要病原之一，其病毒基因组由8个节段组成，共编码10种以上的多肽，每种多肽都有着重要的生物学功能。     

我国H5和H7N9亚型高致病性禽流感的监测及疫情暴发分析

禽流感病毒（avian influenza virus,AIV）是一种重要的人兽共患病病原,严重制约养禽业的健康发展,并对公共卫生安全构成极大威胁。其中,H5（H5N1、H5N2、H5N6、H5N8等）和H7N9亚型高致病性禽流感病毒（highly pathogenic avian influenza virus,HPAIV）引起的高致病性禽流感（highly pathogenic avian influenza,HPAI）对我国养禽业危害巨大。通过实施强制免疫,疫情得到了控制,但在禽群中仍散状暴发,并出现多种新型病毒,防控形势依然严峻。本文总结了截至2021年9月我国禽类暴发H5和H7N9亚型HPAI的所有官方公布的疫情暴发事件以及监测数据,分析了其流行特点,以期为禽流感的预警和防控提供参考。     

Voluntary Surveillance Program for Equine Influenza Virus in the United States from 2010 to 2013

Background

Recent surveillance studies for equine respiratory viruses have shown that equine influenza virus (EIV) continues to be a prevalent respiratory virus of equids throughout the United States and Europe.

Objectives

To gain a better understanding of the prevalence and epidemiology of EIV shed by horses, mules and donkeys in the United States from March 2010 to November 2013.

Animals

2,605 equids.

Methods

Nasal secretions from index cases with acute onset of respiratory disease were tested by qPCR for EIV. Multilevel logistic regression was used to model the association between EIV status and prevalence factors. Furthermore, observations from EIV‐positive study horses were compared to previous data from March 2008 to February 2010.

Results

A total of 230 (9.7%) index cases tested qPCR positive for EIV. A higher‐than‐expected proportion of EIV qPCR‐positive horses occurred in the 1–5, 6–10, and 11–15 age groups when compared to the <1 year of age group. Fever, nasal discharge and coughing were positively associated with EIV‐positive horses. EIV qPCR‐positive study cases were significantly older and more often vaccinated against EIV compared to EIV qPCR‐positive animals from the 2008‐2010 study period.

Conclusions and Clinical Importance

This study provides valuable and contemporary information on the frequency of EIV detected by qPCR in the United States. The results also underscore that older and previously vaccinated horses were susceptible to EIV.     

自噬与A型流感病毒感染

自噬是广泛存在于真核细胞内的新陈代谢过程,对于维持细胞自稳具有关键作用。在病毒感染过程中,自噬表现出两面性,既可被利用来促进病毒复制,又在宿主抗感染免疫应答中发挥重要作用。论文以严重危害畜禽生产和人类健康的A型流感病毒为例,论述了细胞自噬与病毒感染及在宿主免疫应答过程中的相互关系,旨在进一步深入理解A型流感病毒的致病分子机制,为抗流感病毒感染的相关研究提供参考。     

Influenza A Virus Surveillance in the Invasive American Mink (Neovison vison) from Freshwater Ecosystems,Northern Spain

Influenza A viruses (IAVs) are negative‐sense, single‐stranded and segmented RNA viruses of the Orthomyxoviridae family that may cause acute respiratory disease in a wide range of birds and mammals. Susceptibility of several species within the family Mustelidae to IAVs has been reported as a result of natural or experimental infections. The objectives of this study were to assess whether free‐ranging American mink populations from Northern Spain were infected with IAV and try to define the role of this species in the epidemiology of IAV. Sera from 689 American mink from Northern Spain captured between 2011 and 2014 were tested for the presence of antibodies against IAVs using a commercial competition cELISA. Positive sera were further analysed with haemagglutination inhibition (HI) assay. Fifteen of the 689 (2.2%, 1.3–3.6 CI_95%) of the American minks analysed were ELISA positive. No significant differences were observed between years of capture, provinces, river basins, sexes or ages of the animals. All seropositive sera resulted negative to the panel strains used in the HI assay, showing that the most relevant strains circulating in swine, the most relevant avian subtypes (H5 and H7) and the H10N4 subtype isolated in minks have not been circulating in this free‐ranging exotic carnivore from Spain. In the light of these results, the free‐range American mink from Northern Spain do not seem to have an important role in the epidemiology of IAVs.     

禽流感病毒 H3N2亚型三重 RT-PCR 检测方法的建立

为建立检测禽流感病毒（AIV ）且同时区分 H3N2亚型AIV 的方法,本研究根据 H3、N2亚型AIV HA、NA基因及AIV最保守M 基因的保守区域,设计并筛选出3对特异性引物,通过优化反应条件,建立了AIV H3N2亚型和M 基因三重RT‐PCR的检测方法。对该法进行特异性及敏感性检测,并通过该三重RT‐PCR方法对96份临床样品进行检测。结果显示,H3N2亚型AIV可扩增出3条特异性条带,其中518 bp为AIV M 基因、418 bp为N2亚型AIV NA基因、271 bp为H3亚型AIV HA基因;H3亚型和N2亚型AIV均可扩增出2条特异性条带,大小分别为518 bp、271 bp和518 bp、418 bp;其他亚型AIV可扩增出一条特异性条带,大小为518 bp;常见禽病病原体均未扩增出任何条带。敏感性试验表明该法对 H3N2亚型AIV的检测下限为100 pg ;96份临床样品检测结果与病毒分离鉴定结果一致。本研究所建立的AIV H3N2亚型和M 基因三重RT‐PCR为一种简便、快速、有效的检测方法。