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The huge potential economic impact of highly pathogenic avian influenza (HPAI) substantiates specific and rigorous legal regulations worldwide. According to the O.I.E. Terrestrial Animal Health Code fowl plague is a notifiable disease. International trading activities concerning poultry and poultry products originating from countries with active HPAI are rigorously restricted. In EU member states directive 92/40/EEC subsumes measures against fowl plague and has been transferred into German legislation by the "Geflügelpest-Verordnung". These acts specify that vaccination against HPAI is principally prohibited. The aim of all sanctions is the extinction of disease and the eradication of the causative agent. However, HPAI viruses, exclusively belonging to subtypes H5 and H7, can re-emerge de novo from progenitor viruses of low pathogenicity which are perpetuated in the wild bird population. An outbreak of HPAI requires prompt action by a stamping out strategy. Fast and accurate diagnosis, a strict stand-still and the culling of affected flocks are at the basis of success. In areas with a high density of poultry holdings preemptive culling and creation of buffer zones, devoid of susceptible poultry, may be neccessary. In these cases emergency vaccinations can be considered as a supportive measure in order to limit mass culling. Vaccinations on merely prophylactic grounds, not being connected to acute outbreaks, should be avoided beware of selective pressures on the virus leading to antigenic drift and escape of vaccine-induced immunity. Instead, high standard biosecurity measures, particularly limiting direct and indirect contacts with wild birds, should be maintained. 相似文献
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禽流感检测方法研究进展 总被引：6，自引：0，他引：6
禽流感不仅对世界养禽业带来巨大的经济损失，而且可以感染人，公共卫生意义重大。由于其病毒亚型众多，抗原性变异极快，毒株的致病性也相差很大，早期快速诊断和血清学检测就成为预防和控制禽流感的前提条件。禽流感病毒的传统诊断方法是分离病毒和检测抗体。近年来，又相继建立了血凝抑制试验、神经氨酸酶抑制试验、酶联免疫吸附试验等血清学诊断技术及分子诊断技术。文章对禽流感检测方法快速诊断进行了概述。 相似文献
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Fuchs W Veits J Mettenleiter TC 《Berliner und Münchener tier?rztliche Wochenschrift》2006,119(3-4):160-166
To help in the control of fowl plague caused by highly pathogenic avian influenza A viruses of hemagglutinin (HA) subtypes H5 and H7 several vaccines have been developed. A prophylactic immunization of poultry with inactivated influenza viruses in non-endemic situations is questionable, however, due to the impairment of serological identification of field virus-infected animals which hinders elimination of the infectious agent from the population. This problem might be overcome by the use of genetically engineered marker vaccines which contain only the protective influenza virus hemagglutinin. Infected animals could then be unambiguously identified by their serum antibodies against other influenza virus proteins, e.g. neuraminidase or nucleoprotein. For such a use, purified HA or HA-expressing DNA vaccines are conceivable. Economically advantageous and easier to apply are modified live virus vaccines in use against other poultry diseases, which have been modified to express influenza virus HA. So far, recombinant HA-expressing fowlpox virus (FPV) as well as infectious laryngotracheitis and Newcastle disease viruses have been asssessed in animal experiments. An H5-expressing FPV recombinant is already in use in Central America and Southeast Asia but without accompanying marker diagnostics. Advantages and disadvantages of the different viral vectors are discussed. 相似文献
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An avian influenza virus with surface antigens similar to those of fowl plague virus (Hav 1 Nav 2) was isolated in 1979 from 2 commercial turkey flocks in Central Texas. Two flocks in contact with these infected flocks developed clinical signs, gross lesions, and seroconversion but yielded no virus. This was the first recorded incidence of clinical avian influenza in Texas turkeys and only the second time that an agent with these surface antigens was isolated from turkeys in U.S. 相似文献
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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。 相似文献
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禽流感（Avian influenza,AI）是由A型流感病毒所引起的禽类的一种传染病。能引起禽类呼吸系统到严重全身败血症等多种症状的烈性传染病。禽类感染后病死率很高,但对野生禽类多为不显性感染。自从1997年香港发生禽流感病毒H5N1亚型首次突破种属屏障感染人类并引起死亡以来,世界各国纷纷报道各种人禽流感病例的发生,人禽流感的关注程度也达到了前所未有的高度。近几年全球共有三大洲的19个国家和地区发生禽流感疫情。一些地区的疫情呈现蔓延的趋势,并且出现了人感染禽流感病毒的病例。禽流感不仅对养殖业造成重大损失,更对人类健康造成严重威胁。本文全面地介绍了禽流感的病原、流行病学、临床症状、病理变化、诊断和防制。 相似文献
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Avian influenza viruses are highly infectious micro-organisms that primarily affect birds. Nevertheless, they have also been isolated from a number of mammals, including humans. Avian influenza virus can cause large economic losses to the poultry industry because of its high mortality. Although there are pathogenic variants with a low virulence and which generally cause only mild, if any, clinical symptoms, the subtypes H5 and H7 can mutate from a low to a highly virulent (pathogenic) virus and should be taken into consideration in eradication strategies. The primary source of infection for commercial poultry is direct and indirect contact with wild birds, with waterfowl forming a natural reservoir of the virus. Live-poultry markets, exotic birds, and ostriches also play a significant role in the epidemiology of avian influenza. The secondary transmission (i.e., between poultry farms) of avian influenza virus is attributed primarily to fomites and people. Airborne transmission is also important, and the virus can be spread by aerosol in humans. Diagnostic tests detect viral proteins and genes. Virus-specific antibodies can be traced by serological tests, with virus isolation and identification being complementary procedures. The number of outbreaks of avian influenza seems to be increasing - over the last 5 years outbreaks have been reported in Italy, Hong Kong, Chile, the Netherlands, South Korea, Vietnam, Japan, Thailand, Cambodia, Indonesia, Laos, China, Pakistan, United States of America, Canada, South Africa, and Malaysia. Moreover, a growing number of human cases of avian influenza, in some cases fatal, have paralleled the outbreaks in commercial poultry. There is great concern about the possibility that a new virus subtype with pandemic potential could emerge from these outbreaks. From the perspective of human health, it is essential to eradicate the virus from poultry; however, the large number of small-holdings with poultry, the lack of control experience and resources, and the international scale of transmission and infection make rapid control and long-term prevention of recurrence extremely difficult. In the Western world, the renewed interest in free-range housing carries a threat for future outbreaks. The growing ethical objections to the largescale culling of birds require a different approach to the eradication of avian influenza. 相似文献
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In early 2007, H2N3 influenza virus was isolated from a duck and a chicken in two separate poultry flocks in Ohio. Since the same subtype influenza virus with hemagglutinin (H) and neuraminidase (N) genes of avian lineage was also identified in a swine herd in Missouri in 2006, the objective of this study was to characterize and compare the genetic, antigenic, and biologic properties of the avian and swine isolates. Avian isolates were low pathogenic by in vivo chicken pathogenicity testing. Sequencing and phylogenetic analyses revealed that all genes of the avian isolates were comprised of avian lineages, whereas the swine isolates contained contemporary swine internal gene segments, demonstrating that the avian H2N3 viruses were not directly derived from the swine virus. Sequence comparisons for the H and N genes demonstrated that the avian isolates were similar but not identical to the swine isolates. Accordingly, the avian and swine isolates were also antigenically related as determined by hemagglutination-inhibition (HI) and virus neutralization assays, suggesting that both avian and swine isolates originated from the same group of H2N3 avian influenza viruses. Although serological surveys using the HI assay on poultry flocks and swine herds in Ohio did not reveal further spread of H2 virus from the index flocks, surveillance is important to ensure the virus is not reintroduced to domestic swine or poultry. Contemporary H2N3 avian influenza viruses appear to be easily adaptable to unnatural hosts such as poultry and swine, raising concern regarding the potential for interspecies transmission of avian viruses to humans. 相似文献
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The knowledge of the genome constellation in pandemic influenza A virus H1N1 2009 from different countries and different hosts is valuable for monitoring and understanding of the evolution and migration of these strains. The complete genome sequences of selected worldwide distributed influenza A viruses are publicly available and there have been few longitudinal genome studies of human, avian and swine influenza A viruses. All possible to download SIV sequences of influenza A viruses available at GISAID Platform (Global Initiative on Sharing Avian Influenza Data) were analyzed firstly through the web servers of the Influenza Virus Resource in NCBI. Phylogenetic study of circulating human pandemic H1N1 virus indicated that the new variant possesses a distinctive evolutionary trait. There is no one way the pandemic H1N1 have acquired new genes from other distinguishable viruses circulating recently in local human, pig or domestic poultry populations from various geographic regions. The extensive genetic diversity among whole segments present in pandemic H1N1 genome suggests that multiple introduction of virus have taken place during the period 1999-2009. The initial interspecies transmission could have occurred in the long-range past and after it the reassortants steps lead to three lineages: classical SIV prevalent in the North America, avian-like SIV in Europe and avian-like related SIV in Asia. This analysis contributes to the evidence that pigs are not the only hosts playing the role of "mixing vessel", as it was suggested for many years. 相似文献
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The pathogenicity for chickens of 91 strains of avian influenza A virus isolated from such free-living waterfowl as whistling swan, pintail, tufted duck, mallard and black-tailed gull in Japan was tested. The majority of the virus strains infected and were pathogenic for the chickens. The virulence of these viruses seemed not to be as high as that of fowl plague virus. There were no significant differences in the intracerebral index score among the viruses belonging to the same subtype, irrespective of year of isolation or host. 相似文献
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To get an impression of the presence of pathogens in multi-aged flocks of old fancy chicken breeds in the Netherlands, plasma samples originating from 24 flocks were examined for antibodies against 17 chicken pathogens. These flocks were housed mainly in the centre and east of the Netherlands, regions with a high poultry density. The owners of the tested flocks showed their chicken at national and international poultry exhibitions. Antibodies against Avian Influenza, Egg Drop Syndrome '76 virus, Pox virus, Salmonella pullorum/gallinarum, Salmonella Enteritidis or Salmonella Typhimurium were not detected. However, antibodies against other Salmonella species, Mycoplasma gallisepticum, infectious bursal disease virus, infectious bronchitis virus, avian encephalomyelitis virus, chicken anaemia virus, infectious laryngotracheitis virus, and avian leukosis virus, subgroups A and B, and subgroup J were detected in a varying proportion of the flocks. This study shows that antibodies against many chicken pathogens are present among the flocks of old fancy chicken breeds that are exhibited at international poultry exhibitions. 相似文献
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流感病毒是一类危害人和动物健康的RNA病毒,其在宿主细胞内的有效复制离不开宿主蛋白酸性核磷蛋白32家族成员A （ANP32A）和病毒RNA聚合酶的协助和支持。病毒RNA聚合酶由3种蛋白PB1、PB2和PA组成,且ANP32A与病毒RNA聚合酶的最强相互作用需要这3种蛋白的共同参与。ANP32A是酸性富含亮氨酸的核磷蛋白32（ANP32）家族成员,其被确认为支持细胞核中病毒RNA聚合酶活性的关键宿主因子,对流感病毒的复制具有重要的作用。ANP32A的物种特异性差异决定了病毒RNA聚合酶的宿主范围：独特的33个氨基酸序列存在于禽类ANP32A （avANP32A）,而在哺乳动物ANP32A中缺乏此氨基酸序列。avANP32A中特有的33个氨基酸序列能增强ANP32A的功能,从而增加禽源特征流感病毒聚合酶活性。禽流感病毒（Avian influenza virus,AIV）不能有效利用较短的ANP32A （即缺乏独特33个氨基酸序列的ANP32A）,因而哺乳动物ANP32A无法支持禽源特征聚合酶活性,然而在人ANP32A （huANP32A）中插入这33个氨基酸能促进其对AIV聚合酶的支持作用。此外,流感病毒的适应性突变也能增强AIV在哺乳动物中的传播力和致病性。AIV适应哺乳动物时往往会发生E627K突变,以增强其在哺乳动物中的复制能力。作者主要介绍了宿主蛋白ANP32A对流感病毒复制、转录的影响和流感病毒发生适应性突变的作用机制,简要论述了ANP32A与聚合酶的相互作用对流感病毒跨物种感染的分子机制。 相似文献
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禽流感病毒分子生物学的研究进展 总被引：5，自引：0，他引：5
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。 相似文献
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Avian influenza A H5N6 virus is a highly contagious infectious agent that affects domestic poultry and humans in South Asian countries. Vietnam may be an evolutionary hotspot for influenza viruses and therefore could serve as a source of pandemic strains. In 2015, two novel reassortant H5N6 influenza viruses designated as A/quail/Vietnam/CVVI01/2015 and A/quail/Vietnam/CVVI03/2015 were isolated from dead quails during avian influenza outbreaks in central Vietnam, and the whole genome sequences were analyzed. The genetic analysis indicated that hemagglutinin, neuraminidase, and polymerase basic protein 2 genes of the two H5N6 viruses are most closely related to an H5N2 virus (A/chicken/Zhejiang/727079/2014) and H10N6 virus (A/chicken/Jiangxi/12782/2014) from China and an H6N6 virus (A/duck/Yamagata/061004/2014) from Japan. The HA gene of the isolates belongs to clade 2.3.4.4, which caused human fatalities in China during 2014–2016. The five other internal genes showed high identity to an H5N2 virus (A/chicken/Heilongjiang/S7/2014) from China. A whole-genome phylogenetic analysis revealed that these two outbreak strains are novel H6N6-like PB2 gene reassortants that are most closely related to influenza virus strain A/environment/Guangdong/ZS558/2015, which was detected in a live poultry market in China. This report describes the first detection of novel H5N6 reassortants in poultry during an outbreak as well as genetic characterization of these strains to better understand the antigenic evolution of influenza viruses. 相似文献