Low Pathogenic Avian Influenza (H7N1) Transmission Between Wild Ducks and Domestic Ducks

This article describes a virological investigation in a mixed flock of ducks and geese following detection of avian influenza virus antibodies in domestic geese. Low pathogenic H7N1 was found in both domestic and wild birds, indicating that transmission of virus was likely to have taken place between these. The importance of implementing and maintaining appropriate biosecurity measures is re‐emphasized.     

三种禽流感灭活疫苗对农村散养鸭的免疫效果比较

采用重组禽流感灭活疫苗(H5N1亚型,Re-1株)、禽流感灭活疫苗(H5亚型,N28株)、禽流感H5-H9二价灭活疫苗三种疫苗免疫农村散养鸭,结果表明,在一次免疫和加强免疫中,重组禽流感灭活疫苗、禽流感灭活疫苗的抗体效价都分别明显高于H5-H9二价灭活疫苗同期的H5抗体效价,因此对水禽免疫宜使用重组禽流感灭活疫苗或禽流感灭活疫苗;加强免疫明显比一次免疫效果好,应用禽流感灭活苗对散养鸭免疫,必须加强方可达到理想的免疫效果。     

禽流感抗体斑点—ELISA诊断技术的研究

以混合纤维素酯微孔滤膜为固相载体,用自制的禽流感全病毒抗原和酶标抗体,建立了禽流感抗体斑点 Ｅ Ｌ Ｉ Ｓ Ａ 检测法,其抗原最适包被量为 ０．０６μｇ／点;血清抗体最佳稀释度为 １１００;酶标抗体作 １２００ 稀释;出现明显清晰的斑点者判为禽流感抗体阳性。该方法对 Ｓ Ｐ Ｆ鸡血清及新城疫、传染性法氏囊病等其它 １１ 种鸡疫病阳性血清均为阴性,对不同亚型特异性的禽流感病毒（ Ａ Ｉ Ｖ）分型血清、琼扩（ Ａ Ｇ Ｐ）阳性血清及血凝抑制（ Ｈ Ｉ）阳性而 Ａ Ｇ Ｐ疑似的血清样品均呈阳性;对人工接种 Ａ Ｉ Ｖ 的 Ｓ Ｐ Ｆ鸡第 ３ 天即能检出抗体阳性,第 ５～１１７ 天可全部检出。与间接 Ｅ Ｌ Ｉ Ｓ Ａ 法比较,不仅其特异性、敏感性、重复性相一致,而且结果可用肉眼判定,更适合现地禽流感抗体监测及流行病学调查。     

2株H5N1亚型禽流感病毒人工感染鸭的组织病理学观察

鸭经肌肉接种禽流感病毒A/duck/Guangdong/185/2004（H5N1）和A/duck/Guangdong/221/2004（H5N1）后,2周内未见死亡,但具有一些显微和超微病理学变化,主要表现为呼吸道、消化道黏膜受损,心脏、肝脏、肺脏、肾脏、脑等器官一定程度的充血、淤血、出血、水肿及实质细胞变性、坏死和炎症等。     

H9N2亚型禽流感病毒中和单克隆抗体的制备与应用

为建立H9N2亚型禽流感病毒（Avian influenza virus,AIV）免疫层析快速检测技术,本研究以差速离心法纯化H9N2亚型AIV免疫BALB/c小鼠,将免疫小鼠脾细胞与骨髓瘤细胞SP2/0进行细胞融合和HAT选择性培养;以H9N2亚型AIV感染MDCK细胞建立异源免疫过氧化物酶单层细胞试验（IPMA）的单克隆抗体检测方法,通过对杂交瘤细胞的IPMA筛选和连续克隆化筛选鉴定抗H9N2亚型AIV中和性单克隆抗体;以胶体金标记HA单克隆抗体,配对HA单克隆抗体和羊抗小鼠IgG为检测线和质控线,制备H9N2亚型AIV快速检测试纸条,测定其特异性和敏感性。结果显示,获得了11株稳定分泌抗H9N2亚型AIV单克隆抗体的杂交瘤细胞,其单克隆抗体腹水IPMA效价在1.28×10^-4至2.56×10^-5之间。单克隆抗体3A2、5H6、6B8、7E10和9G12血凝抑制试验（HI）显示血凝抑制活性,其（HI）效价在6log2~9log2之间。单克隆抗体3A2、6B8和9G12在病毒中和试验中对H9N2亚型AIV有显著病毒中和活性,中和效价分别1∶6 400、1∶25 600和1∶25 600。Western blotting结果提示,该中和单克隆抗体识别HA蛋白线性抗原表位。利用配对单克隆抗体3A2和9G12研制的H9N2亚型AIV检测试纸条检测H9N2亚型AIV尿囊液的效价为9log2,灵敏度与经典血凝试验（HA）相当,与其他亚型AIV （H1、H3、H5、H7）,以及新城疫病毒和鸡传染性法氏囊病病毒等相关病毒均无交叉反应。本研究制备了具有病毒中和活性的抗H9N2亚型AIV单克隆抗体,并初步研制了H9N2亚型AIV检测试纸条,为H9N2亚型AIV新型疫苗研制和快速检测奠定良好的研究基础。     

2株H5N1亚型禽流感病毒人工感染鸭的11项血液生化指标测定

鸭肌肉接种禽流感病毒A/duck/Guangdong/185/2004（H5N1）和A/duck/Guangdong/221/2004（H5N1）后,血清中的丙氨酸氨基转移酶、天门冬氨酸氨基转移酶、碱性磷酸酶、总蛋白、肌酐、总胆固醇、钙和磷明显升高;葡萄糖和甘油三酯明显降低;白蛋白表现为先下降后升高的变化趋势。作者认为,检测这些血液生化指标对于诊断禽流感具有一定的参考价值。     

禽流感病毒跨种传播机制的研究进展

禽流感病毒(AIV)是一种重要的人畜共患病病原,严重威胁着畜禽养殖业及人类的公共卫生安全.通常情况下,AIV由于对人唾液酸受体的亲和性较低而不能直接感染人.但自1997年香港报道了首例人感染高致病性H5N1 AIV的事件后,AIV感染人的事件便时有发生.本文从禽流感的危害、AIV的基因组结构及功能、AIV跨种传播的影响...     

鸡源H9N2亚型禽流感病毒感染鸡鸭和小鼠后对血液指标的影响

流感可以跨种属传播,通过了解地方性低致病禽流感H9N2亚型病毒感染不同种属动物后的血液变化情况,可为研究禽流感病毒的致病机制提供参考依据。选用52d黑羽乌骨鸡24只,52d樱桃谷鸭24只,6周龄～8周龄昆明系小鼠24只分成3组,攻毒前作为0d空白对照,鸡、鸭和小鼠采用静脉注射感染H9N2亚型流感病毒,分别在感染前(0d)、感染后3d、6d、9d采样,用PE-6800VET三分类动物血细胞分析仪测定血液常规指标。通过对不同种类白细胞和血小板数量变化的分析,结果表明,低致病性禽流感病毒H9N2可以跨种属感染,鸭炎性反应最小,小鼠炎性反应最严重。     

禽流感血清学监测影响因素研究

对禽流感血清学监测过程的各个环节进行分析、研究和总结,找出影响监测结果的因素,并提出应对措施,提高了禽流感血清学监测的准确性,为禽流感的诊断和防制工作提供科学依据。     

禽流感病毒核蛋白基因在重组杆状病毒中的表达

利用ＲＴ－ＰＣＲ方法成功地扩增了我国禽流感病毒分离株Ａ／Ｘｉｎｇｊｉａｎｇ／１／９６（Ｈ１４Ｎ５）的核蛋白（ＮＰ）基因,其限制性内切酶图谱和核苷酸序列与鸭源的标准Ｈ１４Ｎ５毒株几乎完全一致,与其它毒株则有较大差异,说明该鸡源分离株与鸭源毒株有非常近的亲缘关系。将ＮＰ基因定向克隆到杆状病毒转移载体ｐＶＬ１３９３中,再与杆状病毒线性ＤＮＡ（ＢＡＣ－Ｎ－ＢｌｕｅＤＮＡ）共转染于Ｓｆ９昆虫细胞中,经过三次蚀斑筛选,获得重组病毒ｒＢ２。用其细胞表达产物裂解后作ＳＤＳ－ＰＡＧＥ蛋白电泳、Ｗｅｓｔｅｒｎ－ｂｌｏｔ和ｄｏｔ－ＥＬＩＳＡ,结果表明ＮＰ基因在杆状病毒系统中获得了表达。同时用表达产物作琼脂扩散试验,结果表明表达产物与现行标准禽流感琼扩抗原具有相同的生物学活性。     

陕北地区鸡禽流感免疫监测及免疫方案研究

H5及H9型禽流感是目前养禽业主要防疫的两种流感病毒亚型,为调查陕西省神木县两种亚型流感病毒的防疫情况,本研究在2011年∽2012年间从神木多家种鸡场、商品鸡场及散养户采集血样,测HI效价,评价禽流感的免疫效果.结果表明：2011年在普遍采用单价疫苗免疫的情况下,H5抗体合格率较低,最好免疫效果合格率为82.40％,最差免疫效果合格率只有67.7％,而H9抗体合格率100％;2012年推广H5和H9二联疫苗免疫,H5抗体合格率达100％,而H9抗体合格率有所下降,为H5和H9禽流感免疫提供了临床参考依据,同时也为二联疫苗的使用提供参考.     

Design and Results of an Intensive Monitoring Programme for Avian Influenza in Meat‐Type Turkey Flocks During Four Epidemics in Northern Italy

Surveillance programmes for low pathogenicity (LPAI) and high pathogenicity avian influenza (HPAI) infections in poultry are compulsory for EU Member States; yet, these programmes have rarely been evaluated. In Italy, following a 1999 HPAI epidemic, control measures, including vaccination and monitoring, were implemented in the densely populated poultry area (DPPA) where all epidemics in Italy have been concentrated. We evaluated the monitoring system for its capacity to detect outbreaks rapidly in meat‐type turkey flocks. The evaluation was performed in vaccination areas and high‐risk areas in the DPPA, in 2000–2005, during which four epidemics occurred. Serum samples and cloacal swabs were taken from vaccinated birds and unvaccinated (sentinel) birds. We compared the detection rate of active, passive and targeted surveillance, by vaccination status, using multinomial logistic regression. A total of 13 275 samplings for serological testing and 4889 samplings for virological testing were performed; 6315 production cycles of different bird species were tested. The outbreaks detection rate in meat‐type turkeys was 61% for active surveillance (n = 222/363 outbreaks), 32% for passive surveillance and 7% for targeted surveillance. The maximum likelihood predicted values for the detection rates differed by vaccination status: in unvaccinated flocks, it was 50% for active surveillance, 40% for passive surveillance and 10% for targeted surveillance, compared to respectively 79%, 17% and 4% for vaccinated flocks. Active surveillance seems to be most effective in detecting infection, especially when a vaccination programme is in place. This is the first evaluation of the effectiveness of different types of surveillance in monitoring LPAI infections in vaccinated poultry using field data.     

2009—201O年新疆地区家禽禽流感免疫抗体监测与分析

2009--2010年,对新疆部分地区蛋鸡、肉鸡、家养水禽的养殖场随机采集血清样品10193份,活禽市场采集血清样品1620份。用HI方法对禽流感免疫抗体进行检测,结果表明：蛋鸡的H5免疫抗体合格率为33．33％～100％,其中0效价率为33．33%-80．00％;H9免疫抗体合格率为62．4%-100％,20%-33％蛋鸡场存在100％的0效价现象。肉鸡H5免疫抗体合格率为0％-100％,其中7．69%-69．6％肉鸡群中H5抗体0效价率为100％。水禽的H5免疫抗体合格率为0%-100％,有25％33．33％鸭群全部是0效价。活禽市场H5抗体效价≥410g2的比例为10．59％-83．57％,H9抗体效价至410醇的比例21．70％-67．14％。     

禽流感感染人的分子机制研究进展

禽流感病毒可以感染多种动物,包括人、猪、鸟、马、海豹、鲸和雪貂等。流感病毒在不同的宿主存在一定的屏障,但禽流感毒株能突破宿主屏障直接感染人,造成死亡。因此流感病毒的变异和病毒如何选择物种跨越物种流行的机制,对预防和控制流感的爆发是非常重要的。本文综述病毒毒力的分子生物学基础、禽流感染人的分子机制研究进展及在控制禽流感方面的研究。     

生物安全隔离区划在禽流感防控中的应用

简要回顾了生物安全隔离区划的应用进展,重点介绍了生物安全隔离区划在禽流感防控中常用的技术手段,以期对我国禽流感防控工作和无禽流感生物安全隔离区建设提供参考。     

2009—201O年新疆地区家禽禽流感免疫抗体监测与分析

2009—2010年,对新疆部分地区蛋鸡、肉鸡、家养水禽的养殖场随机采集血清样品10193份,活禽市场采集血清样品1620份。用HI方法对禽流感免疫抗体进行检测,结果表明:蛋鸡的H5免疫抗体合格率为33.33%～100%,其中0效价率为33.33%～80.00%;H9免疫抗体合格率为62.4%～100%,20%～33%蛋鸡场存在100%的0效价现象。肉鸡H5免疫抗体合格率为0%～100%,其中7.69%～69.6%肉鸡群中H5抗体0效价率为100%。水禽的H5免疫抗体合格率为0%～100%,有25%～33.33%鸭群全部是0效价。活禽市场H5抗体效价≧4log2的比例为10.59%～83.57%,H9抗体效价≧4log2的比例21.70%～67.14%。     

青海湖地区野禽禽流感监测与分析

采用反转录-聚合酶链反应(RT-PCR)、血凝试验(HA)和血凝抑制试验(HI)及流行病学调查方法,对青海湖地区野禽禽流感进行了监测。共计检测斑头雁等野禽样品486份,血清样品112份,检测结果均为阴性。     

一株H5N1亚型高致病力禽流感病毒人工感染鸭的18项血液生化指标测定

鸭接种高致病力禽流感病毒A/duck/Guangdong/220/2004（H5N1）后,血清中的丙氨酸氨基转移酶（谷丙转氨酶）、天门冬氨酸氨基转移酶（谷草转氨酶）、γ-谷氨酰基转移酶、肌酸激酶和乳酸脱氢酶明显升高;碱性磷酸酶明显下降;α-淀粉酶先升高后下降;总蛋白、球蛋白、尿素氮、胆固醇、钙和磷轻微升高;白蛋白、肌酐、葡萄糖、甘油三酯和尿酸轻微下降。作者认为,检查这些血液生化指标的变化,对于诊断禽流感具有一定意义。     

青海野生鸟类禽流感监测防控亟待关注解决的问题

近年来,青藏高原迁徙的野生鸟类不断发生高致病禽流感疫病,给生态安全和人们的健康带来了极大的威胁。如何面对和做好野生鸟类的疫源疫病监测与防控,本文通过青海省发生和开展的防控工作情况,就面临和亟待解决的问题,提出对策建议。     

Development of Disease‐specific,Context‐specific Surveillance Models: Avian Influenza (H5N1)‐Related Risks and Behaviours in African Countries

Avian influenza virus (H5N1) is a rapidly disseminating infection that affects poultry and, potentially, humans. Because the avian virus has already adapted to several mammalian species, decreasing the rate of avian–mammalian contacts is critical to diminish the chances of a total adaptation of H5N1 to humans. To prevent the pandemic such adaptation could facilitate, a biology‐specific disease surveillance model is needed, which should also consider geographical and socio‐cultural factors. Here, we conceptualized a surveillance model meant to capture H5N1‐related biological and cultural aspects, which included food processing, trade and cooking‐related practices, as well as incentives (or disincentives) for desirable behaviours. This proof of concept was tested with data collected from 378 Egyptian and Nigerian sites (local [backyard] producers/live bird markets/village abattoirs/commercial abattoirs and veterinary agencies). Findings revealed numerous opportunities for pathogens to disseminate, as well as lack of incentives to adopt preventive measures, and factors that promoted epidemic dissemination. Supporting such observations, the estimated risk for H5N1‐related human mortality was higher than previously reported. The need for multidimensional disease surveillance models, which may detect risks at higher levels than models that only measure one factor or outcome, was supported. To develop efficient surveillance systems, interactions should be captured, which include but exceed biological factors. This low‐cost and easily implementable model, if conducted over time, may identify focal instances where tailored policies may diminish both endemicity and the total adaptation of H5N1 to the human species.