禽业信息

我国禽流感防控科研又有新成果农业部新闻办近日发布消息,国家禽流感参考实验室疫苗研制和诊断技术研究又取得新突破,三种新型禽流感疫苗和一项禽流感诊断技术近日研制成功。这是我国重大动物疫病疫苗研制和诊断技术研究在不断取得新成果、为我国乃至世界禽流感防控发挥重大作用后,又一次取得的科研新进展。据农业部有关负责人介绍,新研制成功的三种疫苗分别是新型禽流感(H5N1)标记灭活疫苗、密码子优化H5亚型HA基因禽流感DNA疫苗和禽流感重组亚单位疫苗,其中新型禽流感(H5N1)标记灭活疫苗为国际首创,该疫苗可经血清学方法区分自然感染…     

我国研制成功三种新型禽流感疫苗

农业部6月14日宣布，国家禽流感参考实验室疫苗研制和诊断技术研究又取得新突破，三种新型禽流感疫苗和一项禽流感诊断技术近日研制成功。     

3种新型禽流感疫苗合用可优势互补

2006年6月14日，我国农业部有关负责人在北京宣布，国家禽流感参考实验室叉成功研制出3种新型禽流感疫苗，同时成功获得1项禽流感诊断技术。3种新疫苗联合使用，可优势互补：     

资讯

农业部核发147家企业兽药生产许可证;禽流感新药试验在青海湖鸟岛进行;农业部最新GMP公告和公示;中兽药新制剂产业化项目开建;哈兽研新型禽流感疫苗步入产业化阶段;兽药评审机构进行调整；我国重大动物疫病疫苗研制和诊断技术研究取得新突破。     

我国多种新型重大动物疫病疫苗及诊断试剂相继研制成功

日前，农业部有关负责人在京对外宣布。国家禽流感参考实验室又研制成功3种新型禽流感疫苗和一项禽流感诊断技术。这3种新疫苗联合使用，可优势互补。     

禽流感诊断和预防研究进展

综述了近年来禽流感流行的特征、对养禽业的危害、对人类健康的影响，总结了禽流感诊断技术如单克隆抗体诊断技术、竞争性ELISA法、rNP-ELISA法、RT－PCR法、RFLP亚型分型法等的最新研究进展，分析了全病毒灭活禽流感佐剂疫苗预防禽流感的效果和缺点，概述了在禽流感基因工程亚单位疫苗、核酸疫苗等的实验研究突破和临床使用效果。     

禽流感的研究与体会

作为技术贮备，１９９５年，华南农业大学动物医学系禽病研究室获批准，开展对禽流感的研究。几年来，已获得资助的省部级研究项目包括：禽流感基因诊断的研究，禽流感防治技术的研究，禽流感疫苗的研究，禽流感、新城疫、传染性喉气管炎快速鉴别诊断的研究，禽流感分子流行病学的研究，禽流感病毒遗传衍化关系的研究，禽流感疫苗产业化生产的研究等。其中，“禽流感预防与控制的研究”已获２０００年广东省科技进步二等奖。上述研究，不仅丰富了动物流感的研究资料，及时为生产上提供一些行之有效的防制技术，同时也得到一些体会和启发。１…     

科技

我国重大动物疫病疫苗研制和诊断技术研究取得新突破；唐山利用秸秆资源开发奶牛专用饲料；新疆畜科院马胚胎移植技术全国领先；重视科技创新科虎再次承担攻关项目；西藏牦牛胚胎移植研究获得成功；河南奶牛饲喂自动化设备开发项目获成功；喷雾型禽流感疫苗在荷兰问世。     

我国动物疫苗技术进步加快

为做好重大动物疫病防控工作，农业部高度重视防控科技工作，积极组织国家参考实验室等单位开展重大动物疫病新型疫苗和诊断技术研究开发工作。经过广大科研人员艰苦努力．多种新型重大动物疫病疫苗及诊断试剂相继研制成功．并已大面积推广使用．对我国乃至世界禽流感等重大动物疫病防控起到了积极推动作用。有关国际组织对我国禽流感防控工作在全球和区域发挥的作用及我国疫苗科研水平给予了高度评价。     

我国禽流感的研究进展及成就

本文从禽流感类型、致病性、发病特点、病原学、诊断技术以及疫苗研制等方面着手,阐述了我国在禽流感研究方面取得的进展以及相应成就。     

禽流感新型疫苗研究进展

禽流感是由A型流感病毒引起的一种急性呼吸道传染病,家禽、野鸟和部分哺乳动物均可感染.禽流感给中国养殖业造成了巨大的损失,同时,随着病毒的种间传播,人类的生命安全也受到了严重威胁.目前,疫苗免疫仍是防控禽流感最主要的手段,传统的疫苗主要有鸡胚灭活苗和禽流感弱毒疫苗.虽然在过往几次禽流感暴发过程中,传统疫苗发挥了重要作用,但其自身却存在诸多弊端,因此研制新型疫苗来弥补传统疫苗的不足是很有必要的.文章主要对禽流感重组活载体疫苗、基因工程亚单位疫苗、DNA疫苗和病毒样颗粒疫苗等新型疫苗的研究进展进行综述,旨在为禽流感的防控提供参考.     

Research Progress on Novel Vaccine of Avian Influenza

Avian influenza (AI) is an acute respiratory disease caused by influenza A virus.Avian influenza virus (AIV) can infect poultry,wild birds and some mammals including human.AI is a big threat to both poultry and human health because the virus can cross the species barrier to get the capacity of transmitting from poultry to human.Vaccination is the most efficient measure against AI outbreaking.Traditional vaccines include inactivated vaccine based on chick embryo and attenuated vaccine.Although the traditional vaccines play important roles in the past AI epidemics,many disadvantages have been proved to exist in traditional vaccines.Forced by major drawbacks of traditional vaccines,several studies focused on the development of novel vaccines.In this review,we reviewed recombinant live vector vaccine,subunit vaccine,DNA vaccine and virus-like particle vaccine of AI in order to provide some references for prevention and control of AI.     

Use of vaccination in avian influenza control and eradication

Vaccination against avian influenza (AI) infections caused by viruses of the H5 and H7 subtypes has been used in several occasions in recent years with the general objective of controlling and in some cases eradicating the disease. To contain AI infections effectively, vaccination should only be used as part of a comprehensive control strategy that also includes biosecurity, quarantine, surveillance, education, and elimination of infected and at-risk poultry. Although properly used, potent AI vaccines can prevent disease and death, increase resistance to infection, reduce virus replication and shedding, and reduce viral transmission, they cannot completely prevent AI virus replication. A wide variety of vaccines against AI has been developed and tested in experimental conditions, but only inactivated whole AI virus vaccines and recombinant H5-AI vaccines have been licensed and widely used in various countries. AI vaccination programmes should be adapted to local conditions to guarantee efficacy and sustainability. In particular, vaccination programmes should be modulated in diverse situations according to the virus strain involved, the characteristics of the poultry producing sector, the capacity of the veterinary infrastructure, and the availability of adequate resources. Based on the eco-epidemiological situation in the affected region/area/compartment and the assessment of the risk of AI introduction, different vaccination strategies could be implemented to control AI: (i) routine vaccination performed in endemic areas; (ii) emergency vaccination in the face of an epidemic; and (iii) preventative vaccination carried out whenever a high risk of virus incursion is identified.     

Avian influenza vaccines and therapies for poultry

Vaccines have been used in avian influenza (AI) control programs to prevent, manage or eradicate AI from poultry and other birds. The best protection is produced from the humoral response against the hemagglutinin (HA) protein. A variety of vaccines have been developed and tested under experimental conditions with a few receiving licensure and field use following demonstration of purity, safety, efficacy and potency. Current licensed vaccines are predominately inactivated whole AI vaccines, typically produced from low pathogenicity (LP) AI virus strains, or occasionally from high pathogenicity AI virus strains. Recently, reverse genetic procedures have been developed that allow construction of vaccine strains using a genetically altered HA gene (changing HP HA proteolytic cleavage site to LP) and a backbone of internal gene segments for safe, high growth production. Other licensed AI vaccines include recombinant fowl poxvirus vector with an AI H5 insert and a recombinant Newcastle disease virus vector with an AI H5 gene insert. The latter vaccine can be mass administered via aerosol application.     

Vaccines protect chickens against H5 highly pathogenic avian influenza in the face of genetic changes in field viruses over multiple years

Inactivated whole avian influenza (AI) virus vaccines, baculovirus-derived AI haemagglutinin vaccine and recombinant fowlpoxvirus-AI haemagglutinin vaccine were tested for the ability to protect chickens against multiple highly pathogenic (HP) H5 AI viruses. The vaccine and challenge viruses, or their haemagglutinin protein components, were obtained from field AI viruses of diverse backgrounds and included strains obtained from four continents, six host species, and isolated over a 38-year-period. The vaccines protected against clinical signs and death, and reduced the number of chickens shedding virus and the titre of the virus shed following a HP H5 AI virus challenge. Immunization with these vaccines should decrease AI virus shedding from the respiratory and digestive tracts of AI virus exposed chickens and reduce bird-to-bird transmission. Although most consistent reduction in respiratory shedding was afforded when vaccine was more similar to the challenge virus, the genetic drift of avian influenza virus did not interfere with general protection as has been reported for human influenza viruses.     

Optimization of hydrophile-lipophile balance for improved efficacy of Newcastle disease and avian influenza oil-emulsion vaccines

Preparations of inactivated Newcastle disease (ND) and avian influenza (AI) oil-emulsion vaccines with surfactant hydrophile-lipophile-balance (HLB) values between 4.3 and 9.5 were evaluated for their efficacy in broiler-type white rock chickens. Chickens were vaccinated at 3-4 weeks of age and bled at 2-week intervals over 8 weeks. Post-vaccinal hemagglutination-inhibition (HI) geometric mean titers (reciprocals) ranged from 197 to 485 for ND vaccines and from 184 to 1040 for AI vaccines. Based on the HI response, an HLB value of 7.0 induced the greatest stimulation of antibody titers. Ten percent surfactant in the oil phase of the vaccines induced maximum titers at this HLB. The oil:aqueous ratios of the vaccines did not greatly influence the overall serologic response when the vaccines had an HLB of 7.0. These results indicate that manipulating surfactant HLB values of OE vaccine may maximize the HI response in broilers.     

Efficacy of avian influenza vaccine in poultry: a meta-analysis

Vaccination is an effective method for controlling avian influenza (AI), especially in countries with endemic infection. This study conducted a Bayesian meta-analysis to evaluate the efficacy of AI vaccines in chickens. We included both inactivated and recombinant fowlpox virus expressing H5 (rFPV-H5) vaccine studies that used specific-pathogen-free chickens where outcomes against the H5N1 or H5N2 AI viruses were measured. Vaccine efficacy was evaluated by protection from mortality, protection from morbidity, reductions in virus isolation from the respiratory tract, and reductions in virus isolation from the cloaca. The efficacies for homologous inactivated vaccines by those four outcomes were 92% (95% confidence interval 90%-95%), 94% (91%-96%), 54% (50%-58%), and 88% (84%-91%), respectively. Corresponding figures for heterologous inactivated vaccines were 68% (63%-73%), 78% (74%-81%), 24% (16%-31%), and 71% (64%-77%); and efficacies for rFPV-H5 vaccine were 97% (94%-99%), 93% (90%-94%), 21% (14%-27%), and 78% (72%-84%), respectively. Although those vaccines protect chickens from morbidity and mortality, virus shedding would be an important biosecurity issue for further AI endemic control.     

Immunogenicity and efficacy of fowlpox-vectored and inactivated avian influenza vaccines alone or in a prime-boost schedule in chickens with maternal antibodies

Inactivated and fowlpox virus (FP)-vectored vaccines have been used to control H5 avian influenza (AI) in poultry. In H5 AI endemic countries, breeder flocks are vaccinated and therefore, maternally-derived antibodies (MDA) are transferred to their progeny. Results of three immunogenicity and one efficacy studies performed in birds with or without MDA indicated that the immunogenicity of an inactivated vaccine based on a H5N9 AI isolate (inH5N9) was severely impaired in chicks hatched from inH5N9-vaccinated breeders. This MDA interference was lower when breeders received only one administration of the same vaccine and could be overcome by priming the chicks at day-of-age with a live recombinant FP-vectored vaccine with H5 avian influenza gene insert (FP-AI). The interference of anti-FP MDA was of lower intensity than the interference of anti-AI MDA. The highest interference observed on the prime-boost immunogenicity was in chicks hatched from breeders vaccinated with the same prime-boost scheme. The level of protection against an antigenic variant H5N1 highly pathogenic AI isolate from Indonesia against which the FP-AI or inH5N9 alone was poorly protective could be circumvented by the prime-boost regimen in birds with either FP or AI MDA. Thus, the immunogenicity of vaccines in young chicks with MDA depends on the vaccination scheme and the type of vaccine used in their parent flocks. The heterologous prime-boost in birds with MDA may at least partially overcome MDA interference on inactivated vaccine.     

鸡传染性法氏囊病中等毒力活疫苗对H9亚型禽流感灭活疫苗体液免疫应答影响的研究

将150只维扬麻鸡商品雏鸡随机分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ 5组,Ⅰ、Ⅱ、Ⅲ组对应免疫A、B、C 3种IBD活疫苗和同一种H9亚型AI灭活疫苗,Ⅳ组为免疫对照组,只免疫H9亚型AI灭活疫苗,Ⅴ组为空白对照组。IBD中等毒力活疫苗二免后,定期监测鸡群H9亚型AI灭活疫苗免疫后的HI抗体消长情况,以评价这3种IBD活疫苗对H9亚型AI灭活疫苗体液免疫应答的影响。结果发现,45日龄前（即IBD疫苗二免后23 d前、H9亚型AI灭活疫苗二免后20 d前）,Ⅰ组与Ⅳ组、Ⅱ组与Ⅳ组H9亚型AIV抗体水平均差异显著（P<0.05）,Ⅲ组与Ⅳ组间差异不显著（P>0.05）。在45日龄后（即H9亚型AI灭活疫苗二免20 d后）,试验鸡的H9亚型AIV HI抗体水平均无显著差异。     

Influenza vaccines and vaccination strategies in birds

Although it is well accepted that the present Asian H5N1 panzootic is predominantly an animal health problem, the human health implications and the risk of human pandemic have highlighted the need for more information and collaboration in the field of veterinary and human health. H5 and H7 avian influenza (AI) viruses have the unique property of becoming highly pathogenic (HPAI) during circulation in poultry. Therefore, the final objective of poultry vaccination against AI must be eradication of the virus and the disease. Actually, important differences exist in the control of avian and human influenza viruses. Firstly, unlike human vaccines that must be adapted to the circulating strain to provide adequate protection, avian influenza vaccination provides broader protection against HPAI viruses. Secondly, although clinical protection is the primary goal of human vaccines, poultry vaccination must also stop transmission to achieve efficient control of the disease. This paper addresses these differences by reviewing the current and future influenza vaccines and vaccination strategies in birds.