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《The Journal of Applied Poultry Research》2015,24(2):215-221
During the past two decades, food safety issues in China not only posed serious threats to Chinese consumers but also damaged the image of Chinese products internationally. In China, food safety is not only about scientific discoveries, advanced laboratories, and sanitation equipment; it is more about the role of different players in the food supply chain. The poultry meat supply chain is instrumental in the spread of the avian influenza A virus (H7N9), raising questions about how policymakers respond to such threats and whether industries need to be restructured to manage and control this epidemic so that it does not recur. As a short-term measure, to prevent the spread of this disease, government authorities enforced the closure of live bird markets (LBM) in disease-affected areas of China. However, in the long term, the poultry meat supply chain needs to be restructured. The aim of the current study was to analyze distribution channels for chicken meat in China and then describe arrangements in poultry meat sectors that incorporate small- and medium-scale producers into the supply chain while responding to shifts in LBMs. We also assessed the role of LBMs in spreading H7N9 and how these interventions affect the poultry meat supply chain in the Chinese market. 相似文献
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Wisedchanwet T Wongpatcharachai M Boonyapisitsopa S Bunpapong N Jairak W Kitikoon P Sasipreeyajun J Amonsin A 《Avian diseases》2011,55(4):593-602
A one-year influenza A survey was conducted in 10 live bird markets (LBMs) in H5N1 high-risk areas in Thailand from January to December 2009. The result from the survey showed that the occurrence of influenza A virus (IAV) in LBMs was 0.36% (19/5304). Three influenza A subtypes recovered from LBMs were H4N6 (n = 2), H4N9 (n = 1), and H10N3 (n = 16) from Muscovy ducks housed in one LBM in Bangkok. These influenza subtypes had never been reported in Thailand, and therefore such genetic diversity raises concern about potential genetic reassortment of the viruses in avian species in a particular setting. Two influenza A subtypes (H4N6 and H4N9) were isolated from oropharyngeal and cloacal swabs of the same duck, suggesting coinfection with two influenza subtypes and possible genetic reassortment in the bird. In addition, H10N3 infection in ducks housed in the same LBM was observed. These findings further support that LBMs are a potential source of IAV transmission and genetic reassortment. 相似文献
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Kosuke SODA Maya YAMANE Chiharu HIDAKA Kozue MIURA Trang T. H. UNG Hang L. K. NGUYEN Hiroshi ITO Mai Q. LE Toshihiro ITO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(12):1899
Low and highly pathogenic avian influenza viruses (LPAIVs and HPAIVs, respectively) have been co-circulating in poultry populations in Asian, Middle Eastern, and African countries. In our avian-flu surveillance in Vietnamese domestic ducks, viral genes of LPAIV and HPAIV have been frequently detected in the same individual. To assess the influence of LPAIV on the pathogenicity of H5 HPAIV in domestic ducks, an experimental co-infection study was performed. One-week-old domestic ducks were inoculated intranasally and orally with phosphate-buffered saline (PBS) (control) or 106 EID50 of LPAIVs (A/duck/Vietnam/LBM678/2014 (H6N6) or A/Muscovy duck/Vietnam/LBM694/2014 (H9N2)). Seven days later, these ducks were inoculated with HPAIV (A/Muscovy duck/Vietnam/LBM808/2015 (H5N6)) in the same manner. The respective survival rates were 100% and 50% in ducks pre-infected with LBM694 or LBM678 strains and both higher than the survival of the control group (25%). The virus titers in oral/cloacal swabs of each LPAIV pre-inoculation group were significantly lower at 3–5 days post-HPAIV inoculation. Notably, almost no virus was detected in swabs from surviving individuals of the LBM678 pre-inoculation group. Antigenic cross-reactivity among the viruses was not observed in the neutralization test. These results suggest that pre-infection with LPAIV attenuates the pathogenicity of HPAIV in domestic ducks, which might be explained by innate and/or cell-mediated immunity induced by the initial infection with LPAIV. 相似文献
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Avian Influenza (AI), caused by Alphainfluenzaviruses (AIVs), is a contagious respiratory disease in birds and mammals. AIVs have been reported in poultry worldwide and the impact of AIVs on human health is immense. In this study, a serological survey of AIV subtype H5 and H9 was conducted in a live bird market (LBM) in Yangon, Myanmar during February 2016 to September 2016. A total of 621 serum samples were collected from chickens (n = 489) and ducks (n = 132) from 48 vendors in the LBM. The samples were examined for antibodies against influenza viruses by using NP-ELISA and specific antibodies against AIV-H5N1 (Clade 2.3.4) and AIV-H9N2 (Clade 9.4.2) by using Hemagglutination Inhibition (HI) assay. The result of NP-ELISA assay showed that 12.88 % (80/621) of poultry in LBM was positive for AIV antibodies. In detail, 38.06 % (51/134) of layers, 7.08 % (8/113) of backyard chicken, 2.07 % (5/242) of broilers and 12.12 % (16/132) of ducks were AIV positive. The HI test for specific antibodies against AIV-H5N1 and AIV-H9N2 were 1.77 % (11/621) and 4.51 % (28/621), respectively. Our findings revealed the evidence of AIV-H5N1 and AIV-H9N2 exposure in both chicken and ducks in the LBM in Yangon, Myanmar. Risks of influenza infections and transmission among poultry and humans in the LBMs could not be ignored. 相似文献
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Between 1993 and 2000, gallinaceous birds, waterfowl, and environmental specimens from the live bird markets (LBMs) of the northeastern United States and non-LBM premises were tested for the presence of avian influenza virus (AIV), pathogenic properties of AIV subtypes, especially of hemagglutinin (H) subtypes H5 and H7, and a possible association between LBM and non-LBM infections. Ten H subtypes of AIV were isolated from the LBM specimens: H1, H2, H3, H4, H5, H6, H7, H9, H10, and H11. During this period, the 10 subtypes also were isolated from birds in non-LBM premises. In the LBMs, subtypes H2, H3, H4, H6, H7, and H11 were present for 5-8 yr despite efforts to clean and disinfect the premises. The H5 or H7 subtypes present during the same year in both LBMs and non-LBMs within a state or in contiguous states were (subtype/year): H5N2/1993, 1999, and H7N2/1994-99. The AIV subtypes including the H5 and H7 that were evaluated for pathogenicity in chickens were low pathogenic. The deduced amino acid sequence at the H cleavage site of H5 and H7 subtypes was consistent with those of low pathogenic AIV. Although the H5N2 and H7N2 subtypes remained low pathogenic, they did undergo mutations and acquired an additional basic amino acid at the H cleavage site; however, the minimum number of basic amino acids in correct sequence (B-X-B-R, where B = basic amino acid, X = need not be basic amino acid, and R = arginine) required for high pathogenicity was lacking. A low pathogenic H5 or H7 subtype may become highly pathogenic by acquiring additional basic amino acids at the H cleavage site. The LBMs have been and will likely continue to be a source of AIV for commercial poultry. 相似文献
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Infectious dose‐dependent accumulation of live highly pathogenic avian influenza H5N1 virus in chicken skeletal muscle—implications for public health 
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下载免费PDF全文 G. Vasudevan P. R. Vanamayya S. Nagarajan K. Rajukumar S. Suba G. Venketash C. Tosh R. Sood R. H. Nissly S. V. Kuchipudi 《Zoonoses and public health》2018,65(1):e243-e247
Highly pathogenic avian influenza viruses (HPAIV) of H5N1 subtype are a major global threat to poultry and public health. Export of poultry products, such as chicken and duck meat, is a known source for the cross‐boundary spread of HPAI H5N1 viruses. Humans get infected with HPAI H5N1 viruses either by close contact with infected poultry or through consumption of fresh/undercooked poultry meat. Skeletal muscle is the largest soft tissue in chicken that has been shown to contain virus during systemic HPAIV infection and supports productive virus infection. However, the time between infection of a chicken with H5N1 virus and presence of virus in muscle tissue is not yet known. Further, it is also not clear whether chicken infected with low doses of H5N1 virus that cause non‐fatal subclinical infections continue to accumulate virus in skeletal muscle. We investigated the amount and duration of virus detection in skeletal muscle of chicken experimentally infected with different doses (102, 103 and 104 EID50) of a HPAI H5N1 virus. Influenza viral antigen could be detected as early as 6 hr after infection and live virus was recovered from 48 hr after infection. Notably, chicken infected with lower levels of HPAI H5N1 virus (i.e., 102 EID50) did not die acutely, but continued to accumulate high levels of H5N1 virus in skeletal muscle until 6 days post‐infection. Our data suggest that there is a potential risk of human exposure to H5N1 virus through meat from clinically healthy chicken infected with a low dose of virus. Our results highlight the need to implement rigorous monitoring systems to screen poultry meat from H5N1 endemic countries to limit the global spread of H5N1 viruses. 相似文献
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中国H5N1亚型高致病性禽流感病毒抗原变异株的鉴定分析 总被引：2，自引：0，他引：2
对引起中国2006年山西、宁夏2省(区)H5N1亚型禽流感疫情的代表毒株——A/chicken/Shanxi/2/2006(H5N1)(CK/SX/06)进行了全面研究。结果表明该病毒具有高致病性禽流感病毒(HPAIV)特征,基因组序列分析发现其8个基因片段与中国传统H5N1亚型禽流感病毒GS/GD/1/96(H5N1)存在较大差异,属于新的基因型——山西鸡型;抗原性分析结果表明其在抗原性方面与GS/GD/1/96同样存在较大变异,将其命名为"山西鸡型"抗原变异株;以106EID50.0.1 mL-1剂量将该病毒经鼻腔接种4周龄SPF鸭以评价其对水禽的感染能力,结果表明其不感染鸭;常规方法接种BALB/c小鼠以评价其对哺乳动物的感染和致病能力,结果表明其能感染小鼠,但不引起死亡,呈低致病力。说明该类型高致病性H5N1 HPAIV目前仅危害鸡,不具备感染水禽的能力,感染哺乳动物但不致死。该类型病毒的出现与流行为中国禽流感的免疫与防制提出新的课题。 相似文献
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In Egypt, continuous circulation of highly pathogenic avian influenza (HPAI) H5N1 viruses of clade 2.2.1 in vaccinated commercial poultry challenges strenuous control efforts. Here, vaccine-derived maternal AIV H5 specific immunity in one-day old chicks was investigated as a factor of vaccine failure in long-term blanket vaccination campaigns in broiler chickens. H5 seropositive one-day old chicks were derived from breeders repeatedly immunized with a commercial inactivated vaccine based on the Potsdam/H5N2 strain. When challenged using the antigenically related HPAIV strain Italy/98 (H5N2) clinical protection was achieved until at least 10 days post-hatch although virus replication was not fully suppressed. No protection at all was observed against the Egyptian HPAIV strain EGYvar/H5N1 representing a vaccine escape lineage. Other groups of chicks with maternal immunity were vaccinated once at 3 or 14 days of age using either the Potsdam/H5N2 vaccine or a vaccine based on EGYvar/H5N1. At day 35 of age these chicks were challenged with the Egyptian HPAIV strain EGYcls/H5N1 which co-circulates with EGYvar/H5N1 but does not represent an antigenic drift variant. The Potsdam/H5N2 vaccinated groups were not protected against EGYcls/H5N1 infection while, in contrast, the EGYvar/H5N1 vaccinated chicks withstand challenge with EGYvar/H5N1 infection. In addition, the results showed that maternal antibodies could interfere with the immune response when a homologous vaccine strain was used. 相似文献
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The last highly pathogenic outbreak of avian influenza in the United States was caused by an H5N2 influenza virus in Pennsylvania and New Jersey in 1983-84. Through a combined federal and state eradication effort, the outbreak was controlled. However, in 1986-89, multiple H5N2 viruses were isolated from poultry farms and the live bird markets (LBMs) in the United States. To determine the epidemiologic relationships of these viruses, the complete coding sequence of the nonstructural gene and the hemagglutinin protein subunit 1 of the hemagglutinin gene was determined for 11 H5N2 viruses and compared with previously available influenza sequences. The H5N2 isolates from 1986-89 were all closely related to the isolates from the 1983-84 Pennsylvania outbreak by nucleotide and amino acid sequence analysis for both genes, providing additional evidence that the Pennsylvania/83 (PA/83) virus lineage was not completely eradicated. The PA/83 lineage also had a large number of unique amino acid changes not found in other avian influenza viruses, which was suggestive that this lineage of virus had been circulating in poultry for an extended period of time before the first isolation of virus in 1983. High substitution and evolutionary rates were measured by examining the number of nucleotide or amino acid substitutions over time as compared with the index case, CK/PA/21525/83. These rates, however, were similar to other outbreaks of avian influenza in poultry. This study provides another example of the long-term maintenance and evolution of influenza viruses in the U.S. LBMs and provides further evidence of the connection of the LBMs and the Pennsylvania 1983 H5N2 outbreak. 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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Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential. 相似文献
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广东省人H7N9亚型禽流感的高危因素(接触活禽与活禽市场暴露)与活禽相关。为评价活禽交易限制、活禽调运限制与活禽H7N9免疫对人H7N9发病的影响,以接触活禽史病例数和活禽市场暴露史病例数的增减为研究视角,基于广东省2013—2018年H7N9亚型禽流感病例,采用Moran指数、K-means算法和Apriori算法等分析病例的空间分布特征、活禽高危因素导致病例的特征以及防控措施与病例数的关系。结果发现:病例的热点区域在珠三角,且向周边扩散,仅2017年的病例具有显著空间相关性。人活禽接触史病例分为3类,以中年、有基础病史、来自珠三角城市以及从事活禽销售为主;而活禽市场暴露史病例可分为4类,主要以男性、中年、无基础病史为主。未启动活禽交易限制和活禽H7N9免疫则分别增加活禽市场暴露史病例的概率是70.90%和71.70%,而启动活禽调运限制减少接触活禽史病例数的概率为70.60%。这表明,三大防控措施对减少因接触活禽与活禽市场暴露的人H7N9病例具有显著相关性。 相似文献
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Although live bird markets (LBMs) have been associated with outbreaks of avian influenza (AI), there are some LBM systems where AI outbreaks are extremely rare events. The California LBMs have not had any detected avian influenza viruses (AIVs) since December 2005. Responses to a detailed questionnaire on the practices and characteristics of the participants in the California low-pathogenic (LP) AI control program have been described to characterize possible reasons for the lack of AI outbreaks in LBMs. Compliance with an LPAI control program that contains active surveillance, prevention, and rapid response measures by those involved in the LBM system, rendering services to dispose of carcasses, no wholesalers, and few third-party bird deliveries was associated with the lack of LPAIV circulating in the Southern California LBM system. 相似文献
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Serological evidence for exposure to avian influenza viruses within poultry workers in southern China 下载免费PDF全文
下载免费PDF全文 The risk of infection with avian influenza viruses for poultry workers is relatively unknown in China, and study results are often biased by the notification of only the severe human cases. Protein microarray was used to detect binding antibodies to 13 different haemagglutinin (HA1‐part) antigens of avian influenza A(H5N1), A(H7N7), A(H7N9) and A(H9N2) viruses, in serum samples from poultry workers and healthy blood donors collected in the course of 3 years in Guangdong Province, China. Significantly higher antibody titre levels were detected in poultry workers when compared to blood donors for the most recent H5 and H9 strains tested. These differences were most pronounced in younger age groups for antigens from older strains, but were observed in all age groups for the recent H5 and H9 antigens. For the H7 strains tested, only poultry workers from two retail live poultry markets had significantly higher antibody titres compared to blood donors. 相似文献
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Sharon E. Roche Naomi Cogger M. Graeme Garner Anak Agung Gde Putra Jenny-Ann L.M.L. Toribio 《Preventive veterinary medicine》2014
Indonesia continues to report the highest number of human and poultry cases of highly pathogenic avian influenza H5N1. The disease is considered to be endemic on the island of Bali. Live bird markets are integral in the poultry supply chain on Bali and are important, nutritionally and culturally, for the rural and urban human populations. Due to the lack of biosecurity practiced along the supply chain from producer to live bird markets, there is a need to understand the risks associated with the spread of H5N1 through live bird movements for effective control. Resources to control H5N1 in Indonesia are very limited and cost effective strategies are needed. We assessed the probability a live bird market is infected through live poultry movements and assessed the effects of implementing two simple and low cost control measures on this risk. Results suggest there is a high risk a live bird market is infected (0.78), and risk mitigation strategies such as detecting and removing infected poultry from markets reduce this risk somewhat (range 0.67–0.76). The study demonstrates the key role live poultry movements play in transmitting H5N1 and the need to implement a variety of control measures to reduce disease spread. 相似文献
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Pfeiffer DU Otte MJ Roland-Holst D Inui K Nguyen T Zilberman D 《Veterinary journal (London, England : 1997)》2011,(3):309-316
This paper analyses the publicly available data on the distribution and evolution of highly pathogenic avian influenza virus (HPAIV) H5N1 clades, whilst acknowledging the biases resulting from the non-random selection of isolates for gene sequencing. The data indicate molecular heterogeneity in the global distribution of HPAIV H5N1, in particular in different parts of East and Southeast Asia. Analysis of the temporal pattern of haemagglutinin clade data shows a progression from clade 0 (the ‘dominant’ clade between 1996 and 2002) to clade 1 (2003–2005) and then to clade 2.3.4 (2005 onwards). This process continuously produces variants, depending on the frequency of virus multiplication in the host population, which is influenced by geographical variation in poultry density, poultry production systems and also HPAI risk management measures such as vaccination. Increased multilateral collaboration needs to focus on developing enhanced disease surveillance and control targeted at evolutionary ‘hotspots’. 相似文献
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Ramp K Veits J Deckers D Rudolf M Grund C Mettenleiter TC Römer-Oberdörfer A 《Avian diseases》2011,55(3):413-421
To analyze the contribution of neuraminidase (NA) toward protection against avian influenza virus (AIV) infection, three different recombinant Newcastle disease viruses (NDVs) expressing hemagglutinin (HA) or NA, or both, of highly pathogenic avian influenza virus (HPAIV) were generated. The lentogenic NDV Clone 30 was used as backbone for the insertion of HA of HPAIV strain A/chicken/Vietnam/P41/05 (H5N1) and NA of HPAIV strain A/duck/Vietnam/TG24-01/05 (H5N1). The HA was inserted between the genes encoding NDV phosphoprotein (P) and matrixprotein (M), and the NA was inserted between the fusion (F) and hemagglutinin-neuraminidase protein (HN) genes, resulting in NDVH5VmPMN1FHN. Two additional recombinants were constructed carrying the HA gene between the NDV P and M genes (NDVH5VmPM) or the NA between F and HN (NDVN1FHN). All recombinants replicated well and stably expressed the HA gene, the NA gene, or both. Chickens immunized with NDVH5VmPMN1FHN or NDVH5VmPM were protected against two different HPAIV H5N1 and also against HPAIV H5N2. In contrast, immunization of chickens with NDVN1FHN induced NDV- and AIV N1-specific antibodies but did not protect the animals against a lethal dose of HPAIV H5N1. Furthermore, expression of AIV N1, in addition to AIV H5 by NDV, did not increase protection against HPAIV H5N1. 相似文献