浅谈禽流感的预防与控制

通过对近年来禽流感防控现状的分析,阐述了禽流感防控的不利因素、存在的误区和问题、防控的综合措施,以及从疫苗、管理角度对禽流感防控的思考,以期对禽流感防控工作具有一定的参考价值。1概述     

目前禽流感的流行特点及防控对策

近年来,随着国家对家禽禽流感强制免疫和业内对禽流感防控的高度重视,我国禽流感疫情总体呈逐年下降趋势。但目前,无论是高致病性禽流感,还是低致病性禽流感,仍是严重威胁养禽业的大敌。秋冬初春季节是禽流感的高发期,在气候突变、寒冷应激,机体抵抗力下降的情况下最易发生禽流感。希望养禽生产者尽早做好防护工作,防患于未然。     

浅谈高致病性禽流感防疫技术

禽流感是禽流行性感冒的简称，具有传染性强、死亡率高的特点。禽流感不仅会影响禽养殖业的发展，也威胁着人类的身体健康。因此，重视禽流感防疫工作，增强禽流感防疫技术十分必要。本文首先对禽流感进行了概述，接着提出了禽流感防疫措施，旨在为禽流感防疫工作提供参考。     

禽流感临床、病理诊断与防治实践

由于韩国、日本、越南和泰国相继发生禽流感，对我国家禽饲养行业产生了不小的影响。不少饲养业主由于对禽流感不了解，无法正确认识高致病性禽流感与现实中常常出现的低致病性，甚至温和型禽流感的区别，因而思想压力很大。笔者多年从事禽病门诊业务，现将自己对禽流感的认识、门诊诊     

H9N2亚型禽流感的流行动态及防制策略

禽流感根据致病性的不同,可以分为高致病性禽流感(HPAI)和低致病性禽流感(LPAI)。高致病性禽流感一旦发生会造成家禽的大批死亡,所以各国政府对高致病性禽流感病毒高度重视,采取了各种措施来严密监控其的发生和流行。高致病禽流感所造成的危害往往是迅即的、猝不及防的。与之相比,低致病禽流感的发生是潜在性的,但也可以给养禽业带来灭顶之灾,对人类的威胁同样严重。低致病性禽流感病毒的流行特点是     

禽流感灭活疫苗的标准化研究

本文对我国禽流感灭活疫苗研制的现状、国际上标准化禽流感灭活疫苗的研究、禽流感疫苗标准化的必要性、研究和生产标准化禽流感疫苗硬件设施的需求、标准化禽流感疫苗用种毒和免疫佐剂的选择、标准化流感灭活疫苗中血凝素含量的测定、以及标准化禽流感疫苗生产中的关键技术问题等分别进行了论述,同时阐明了作者观点。     

禽流感及其防制建议

禽流感是一种呈世界性分布、严重危害养禽业的重要传染病，对人类健康的威胁已逐渐显现。本文对禽流感的病原、流行病学、症状和病变、诊断及防制等方面进行了全面介绍，以期提高人们对禽流感的认识，为正确科学地防控禽流感提供参考。     

基于社会网络对国内近十年禽流感领域研究热点分析

近年来禽流感影响范围越来越大,不仅对养殖业造成严重的经济损失,更是危害到人类健康,因此禽流感引起了世界各国人民的关注。笔者通过收集CNKI数据库中收录的有关禽流感的文献,运用共词分析方法,梳理禽流感的研究脉络,绘制网络知识图谱,对该领域的热点进行剖析。结果表明:近十年来禽流感研究的三个热点领域为Ⅰ禽流感基础科学研究、Ⅱ禽流感病原学研究、Ⅲ禽流感防治研究。     

禽流感的流行和防控

一．禽流感流行 1．世界情况。禽流感在世界上依然存在,在一些地方还呈现地方性流行,尤其是埃及、印尼等地,我国周边国家的禽流感也时有发生,对我国造成威胁。今年我国的禽流感也比去年发生的多,辽宁幼儿园里养的几只鸡发生了禽流感,宁夏扑杀了600万只鸡,台湾也发生了禽流感,广东、贵州主要是人感染禽流感。     

浅析与禽流感类似的禽病鉴别与排除

根据禽流感致病性的不同,可以将禽流感分为高致病性禽流感、低致病性禽流感和无致病性禽流感。高致病性禽流感的潜伏期短,其临床特征是发病急、传播快、死亡率高,目前我国政府对高致病性禽流感,采取一系列严厉的控制和扑灭措施,如疫点周围约30km^2划为疫区,疫边周围200km^2划为受威胁区;疫区的所有禽类实行强制免疫注射。     

再谈特禽鸟禽流感的发展现状与我国的防控思路

介绍了近年来禽流感(AI)与禽流感病毒(AIV)的变化以及对其的重新认识,特别是对哺乳动物的易感性与在人群中的流行。同时对特种禽鸟禽流感作了新的概述,至今已证实约有50种以上特种禽鸟感染AIV,并出现大批驯养的、观赏的、野生的禽鸟发病死亡。同时,对我国大陆地区动物禽流感的综合防控提出了一些新的思路。     

鸭与禽流感防控

禽流感（Avian Ifluenza,AO是由禽流感病毒（Avian Influenza Virus,AIV）引起的一种传染病,也是当今全球范围内严重危害养禽业的禽病之一。早期研究认为水禽不容易感染禽流感,所以对水禽的禽流感防治没有给予足够的重视。随着禽流感病毒的不断变异和研究的不断深入,人们发现鸭不仅已成为禽流感的易发种群,而且成为散播禽流感病毒的重要传染源。本文综述了禽流感病毒对鸭的致病性变化、致病性特征以及鸭在禽流感传播中作用,并针对我国养鸭中存在的问题提出了对策建议。     

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。     

特禽禽流感概况及防制思路

对近几十年来AI与AIV发生的变化 ,例如AIV变异多样、易感动物谱扩大、致病力增强、显性感染病例增多、感染哺乳动物 (禽—猪—人、禽—人—人 )和AI疫源地等作了归纳阐述。介绍了特禽 (火鸡、鸵鸟、野鸭与鸭、鹌鹑、孔雀和八哥等 )禽流感概况 ,论述了我国防制禽流感的思路。     

禽流感疫苗研究进展

近几年禽流感的大范围流行,不仅给养禽业造成了巨大的经济损失,而且由于禽流感可直接感染人并导致死亡,故对人类健康也带来严重的威胁。疫苗免疫仍然是防止禽流感暴发的主要措施,但禽流感病毒变异性强,血清型众多,给疫苗的研究带来极大困难。就目前而言,能在实践上应用的禽流感疫苗主要还是灭活疫苗,这种疫苗具有亚型特异性,但也正是这种特性限制了这种疫苗的发展。随着生物技术的快速发展,其他新型疫苗尤其是基因工程疫苗的研究也取得了一定的进展。使我国应用禽流感疫苗,预防高致病力禽流感的防制策略成为可能。文章就目前禽流感疫苗的研究方面介绍了国内外的一些研究进展。     

中国禽流感诊断技术和疫苗的研究进展

介绍了我国在禽流感诊断技术和疫苗研制方面的一些新技术、新成果，新特点和新思路，分析比较了目前建立的诊断方法和各类疫苗，从整体上展示了我国禽流感诊断技术和疫苗研究状况，对了解和掌握禽流感研究动态，优化禽流感监测手段，调整禽流感防疫策略等有一定的参考价值。     

Development of enzyme-linked immunosorbent assay with nucleoprotein as antigen for detection of antibodies to avian influenza virus

During the avian influenza outbreak of 2003-04 in Southeast Asia, two avian influenza viruses (AIV), one of H5N1 subtype and the other H9N2 subtype, were isolated and identified from local farms. The nudeoprotein (NP) gene of the H5N1 AI isolate was cloned, and the segment encoding amino acid 47-384, which covers its major antigenic domains, was subcloned and expressed in E. coli. Subsequently, the NP (47-384) expression product was purified and used as the diagnostic antigen to develop a NP-based type-specific indirect enzyme-linked immunosorbent assay (ELISA) for detecting antibodies to AI from chicken sera. The ELISA is shown to be specific for AIV and does not cross-react with chicken sera that has antibodies to other avian viruses. The NP(47-384)-ELISA was compared with a hemagglutination inhibition test and a commercial AIV ELISA kit in evaluating 150 sera samples from experimentally AIV-infected or vaccinated specific-pathogen-free (SPF) chickens. Our NP(47-384)-ELISA was more sensitive than the two tests and showed an 82% agreement ratio with the HI test and an 80.67% agreement ratio with the commercial kit. The NP(47-384)-ELISA and the commercial AIV ELISA were used to evaluate 448 field sera samples from diseased chickens or vaccinated chickens during the 2003-04 AI outbreak in China. The two ELISA tests had a 95% agreement ratio. We conclude that the NP(47-384)-ELISA developed in our laboratory was specific and sensitive and it has great application potential in China's long-term prevention and control of AI.     

Effect of Newcastle disease and infectious bronchitis live vaccines on the immune system and production parameters of experimentally infected broiler chickens with H9N2 avian influenza

H9N2 Avian influenza (AI) is an infectious disease which considered to have low pathogenic virulence, but in the case of coinfection with other pathogens it has the potential to become a major threat to the poultry industry. Infectious bronchitis (IB) and Newcastle diseases (ND) are other common problems to the poultry industry, which there are an extensive vaccination program against these viral pathogens. To investigate the effects of administration of infectious bronchitis and Newcastle disease live vaccines (IBLVs and NDLVs) in the presence of H9N2 AI infection on the immune system and some production parameters, 180 one-day-old broiler chicks were randomly allocated into six groups with different vaccination programs including H120 IBLV, 4/91 IBLV, B1 NDLV and LaSota NDLV. At the age of 20 days, all birds of the experimental groups except the negative control group, were inoculated intra-nasally (at dose of 10⁶ EID₅₀) with H9N2 AIV. After the inoculation, gross and microscopic lesions of the immune organs, serological changes and some production parameters were examined. The findings of this study showed that coinfection of H9N2 AI with NDLVs exacerbated the gross and microscopic injuries in the immune organs; especially the bursa of Fabricius. LaSota + AIV group had the most severe lesion in the bursa of Fabricius, spleen and thymus. Furthermore, the birds of LaSota + AIV group consumed the least amount of feed and water and their final body weight were significantly (P ≤ 0.05) lower in comparison with the other groups. Interestingly, in the context of this experiment both 4/91 and H120 IB live vaccines enhanced the HI antibody titers against H9N2 AIV, but the 4/91 showed the most significant (P ≤ 0.05) increase compared to the other experimental groups.     

Development of Indirect Enzyme-linked Immunosorbent Assay with Nucleoprotein as Antigen for Detection and Quantification of Antibodies against Avian Influenza Virus

Avian influenza (AI) is a serious infectious disease caused by avian influenza virus (AIV) belonging to type A Orthomyxovirus. In the present study, we developed an indirect enzyme-linked immunosorbent assay (ELISA) employing E. coli-expressed full-length nucleoprotein (NP) of H9N2 avian influenza virus for the detection and quantification of antibodies against AIV nucleoprotein. The NP-ELISA was compared with the AI agar gel propagation (AGP) test, haemagglutination inhibition (HI) test, and IDEXX-FlockChek ELISA using 263 sera. The NP-ELISA was significantly more sensitive than the AGP and HI tests, and showed 96.2% agreement ratio with IDEXX-FlockChek ELISA. With results obtained using the NP-ELISA, an ELISA titre (ET) prediction equation, with which the ELISA titres of a flock or individual chickens can be determined, was derived from a positive/negative (P/N) ratio standard curve. The NP-ELISA enables an alternative rapid serological diagnosis and is suitable for influenza A antibody screening, especially in species that harbour several influenza subtypes.     

Failure of a recombinant fowl poxvirus vaccine containing an avian influenza hemagglutinin gene to provide consistent protection against influenza in chickens preimmunized with a fowl pox vaccine

Vaccines against mildly pathogenic avian influenza (AI) have been used in turkeys within the United States as part of a comprehensive control strategy. Recently, AI vaccines have been used in control programs against highly pathogenic (HP) AI of chickens in Pakistan and Mexico. A recombinant fowl pox-AI hemagglutinin subtype (H) 5 gene insert vaccine has been shown to protect specific-pathogen-free chickens from HP H5 AI virus (AIV) challenge and has been licensed by the USDA for emergency use. The ability of the recombinant fowl pox vaccine to protect chickens preimmunized against fowl pox is unknown. In the current study, broiler breeders (BB) and white leghorn (WL) pullets vaccinated with a control fowl poxvirus vaccine (FP-C) and/or a recombinant fowl poxvirus vaccine containing an H5 hemagglutinin gene insert (FP-HA) were challenged with a HP H5N2 AIV isolated from chickens in Mexico. When used alone, the FP-HA vaccine protected BB and WL chickens from lethal challenge, but when given as a secondary vaccine after a primary FP-C immunization, protection against a HP AIV challenge was inconsistent. Both vaccines protected against virulent fowl pox challenge. This lack of consistent protection against HPAI may limit use to chickens without previous fowl pox vaccinations. In addition, prior exposure to field fowl poxvirus could be expected to limit protection induced by this vaccine.