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Dutta P, Islam A, Sayeed MA, Rahman MA, Abdullah MS, Saha O, Rahman MZ, Klaassen M, Hoque MA, Hassan MM. Epidemiology and molecular characterization of avian influenza virus in backyard poultry of Chattogram, Bangladesh. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 105:105377. [PMID: 36220485 DOI: 10.1016/j.meegid.2022.105377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 10/01/2022] [Accepted: 10/08/2022] [Indexed: 06/16/2023]
Abstract
Ducks, the natural reservoir of avian influenza virus (AIV), act as reassortment vessels for HPAI and low pathogenic avian influenza (LPAI) virus for domestic and wild bird species. In Bangladesh, earlier research was mainly focused on AIV in commercial poultry and live bird markets, where there is scanty literature reported on AIV in apparently healthy backyard poultry at the household level. The present cross-sectional study was carried out to reveal the genomic epidemiology of AIV of backyard poultry in coastal (Anowara) and plain land (Rangunia) areas of Bangladesh. We randomly selected a total of 292 households' poultry (having both chicken and duck) for sampling. We administered structured pre-tested questionnaires to farmers through direct interviews. We tested cloacal samples from birds for the matrix gene (M gene) followed by H5 and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). All AIV-positive samples were subjected to four-gene segment sequencing (M, PB1, HA, and NA gene). We found that the prevalence of AIV RNA at the household level was 6.2% (n = 18; N = 292), whereas duck and chicken prevalence was 3.6% and 3.2%, respectively. Prevalence varied with season, ranging from 3.1% in the summer to 8.2% in the winter. The prevalence of subtypes H5 and H9 in backyard poultry was 2.7% and 3.3%, respectively. The phylogenetic analysis of M, HA, NA, and PB1 genes revealed intra-genomic similarity, and they are closely related to previously reported AIV strains in Bangladesh and Southeast Asia. The findings indicate that H5 and H9 subtypes of AIV are circulating in the backyard poultry with or without clinical symptoms. Moreover, we revealed the circulation of 2.3.2.1a (new) clade among the chicken and duck population without occurring outbreak which might be due to vaccination. In addition to routine surveillance, molecular epidemiology of AIV will assist to gain a clear understanding of the genomic evolution of the AIV virus in the backyard poultry rearing system, thereby facilitating the implementation of effective preventive measures to control infection and prevent the potential spillover to humans.
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Affiliation(s)
- Pronesh Dutta
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram 4225, Bangladesh
| | - Ariful Islam
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram 4225, Bangladesh; Centre for Integrative Ecology, School of Life and Environmental Science, Deakin University, Victoria 3216, Australia; EcoHealth Alliance, New York, NY 10001-2320, USA.
| | - Md Abu Sayeed
- EcoHealth Alliance, New York, NY 10001-2320, USA; Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka 1212, Bangladesh
| | - Md Ashiqur Rahman
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram 4225, Bangladesh
| | - Md Sadeque Abdullah
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram 4225, Bangladesh
| | - Otun Saha
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka 1212, Bangladesh; Department of Microbiology, Noakhali Science and Technology University, Noakhali 3814, Bangladesh
| | | | - Marcel Klaassen
- Centre for Integrative Ecology, School of Life and Environmental Science, Deakin University, Victoria 3216, Australia
| | - Md Ahasanul Hoque
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram 4225, Bangladesh
| | - Mohammad Mahmudul Hassan
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram 4225, Bangladesh; Queensland Alliance for One Health Sciences, School of Veterinary Science, The University of Queensland, Gatton 4343, Queensland, Australia.
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Rahman MA, Belgrad JP, Sayeed MA, Abdullah MS, Barua S, Chisty NN, Mohsin MAS, Foysal M, Hossain ME, Islam A, Akwar H, Hoque MA. Prevalence and risk factors of Avian Influenza Viruses among household ducks in Chattogram, Bangladesh. Vet Res Commun 2022; 46:471-480. [PMID: 35022959 DOI: 10.1007/s11259-021-09874-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 12/04/2021] [Indexed: 11/25/2022]
Abstract
Avian influenza viruses (AIV) increase commercial and backyard poultry mortality and morbidity, reduces egg production, and elevates public health risk. Household ducks propagate and transmit HPAI and LPAI viruses between domesticated and wild birds in Southeast Asian countries, including Bangladesh. This study was conducted to identify epidemiological factors associated with AIV infection among household ducks at Chattogram, Bangladesh. We randomly selected and collected blood and oropharyngeal swab samples from 281 households ducks. We evaluated the serum for AIV antibody using cELISA and tested for H5 and H9 subtypes using the HI test. We tested the swabs with real-time reverse transcriptase PCR (rRT-PCR) for M gene, and H5, H9 subtypes. In the duck populations, the household level AIV sero-prevalence was 57.7% (95% CI: 51.6-63.3) and RNA prevalence was 2.4% (95% CI: 1.0-5.0). H5 and H9 subtype sero-prevalence was 31.5% (95% CI: 22.2-42.0) and 23.9% (95% CI: 15.6-33.9). H5 and H9 subtype RNA prevalence were 0% (95% CI: 0.0-1.3) and 2.4% (95% CI: 1.0-5.0). We determined household-level OR (Odds Ratios) for the "combined (mixed materials-mud and concrete or metallic)" category was 2.2 (95% CI: 1.1-4.2) compared with "wooden/bamboo" category (p = 0.02); 2.8 (95% CI: 1.2-6.6) in households with duck plague vaccine coverage compared with no coverage (p = 0.01); and 2.4 (95% CI: 0.6-9.7) in households that threw dead birds in bushes and the roadside compared with households that buried or threw dead birds in garbage pits (p = 0.21). M gene phylogenetic analysis compared M gene sequences to previously reported Bangladeshi H9N2 isolates. The evidence presented here shows AIV circulation in the Chattogram, Bangladesh study areas. AIV reduction can be achieved through farmer education of proper farm management practices.
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Affiliation(s)
- Md Ashiqur Rahman
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh
| | - Joseph P Belgrad
- Tufts Cummings School of Veterinary Medicine, 200 Westboro Rd., North Grafton, MA, 01536, USA
| | - Md Abu Sayeed
- Institute of Epidemiology Disease Control and Research, Dhaka, 1212, Bangladesh
- EcoHealth Alliance, New York, NY, USA
| | - Md Sadeque Abdullah
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh
| | - Shanta Barua
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh
| | - Nurun Nahar Chisty
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh
| | - Md Abu Shoieb Mohsin
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh
| | - Mohammad Foysal
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh
| | - Mohammad Enayet Hossain
- International Centre for Diarrheal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Ariful Islam
- EcoHealth Alliance, New York, NY, USA
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia
| | - Holy Akwar
- Food and Agriculture Organization, Rome, Italy
| | - Md Ahasanul Hoque
- Department of Medicine and Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Zakir Hossain Road, Khulshi, Chattogram, 4225, Bangladesh.
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Aston EJ, Wang Y, Tracy KE, Gallardo RA, Lamont SJ, Zhou H. Comparison of cellular immune responses to avian influenza virus in two genetically distinct, highly inbred chicken lines. Vet Immunol Immunopathol 2021; 235:110233. [PMID: 33823380 DOI: 10.1016/j.vetimm.2021.110233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 12/24/2022]
Abstract
Low pathogenicity avian influenza causes mild disease involving the respiratory, gastrointestinal, and reproductive systems of wild and domestic birds. Avian influenza research often emphasizes the effect of the virus genetics on disease, but the influence of host genetics on resistance to infection is not well understood. The genetic determinants of enhanced resistance to influenza can be explored by using genetically distinct, highly inbred chicken lines that differ in susceptibility to influenza. In this study, we compared the mucosal cellular immune responses between the relatively resistant Fayoumi M43 chicken line and the relatively susceptible Leghorn GB2 chicken line after challenging with low pathogenicity avian influenza virus (LPAIV) H6N2. The birds were inoculated at 21 days of age with 107 50 % egg infective dose (EID50) LPAIV H6N2 via nasal and tracheal routes in two separate experiments. Clinical signs were recorded, tracheal swabs were collected to measure viral titer, and tracheas and lungs were harvested for flow cytometric analysis of macrophage, B cell, and T cell populations at 4 days post-infection (dpi) (Experiments 1 and 2) and 6 dpi (Experiment 2). Blood and tears were also collected at 7 and 14 dpi (Experiment 1) to measure antibody levels. Compared to both the non-challenged Fayoumis and the relatively susceptible Leghorn chickens, relatively resistant Fayoumi chickens challenged with LPAIV demonstrated enhanced MHC class I expression on antigen-presenting cells and increased macrophage, B cell, and T cell frequencies in the trachea, which were associated with reduced tracheal viral titers at 4 dpi. In contrast, MHC class I expression and immune cell frequencies in the trachea were not different between challenged Leghorns and non-challenged Leghorns. Furthermore, Leghorns shed higher virus titers in their trachea compared to Fayoumis. Challenged Fayoumis and Leghorns both produced AIV-specific IgY detected in the serum and tears, but AIV-specific IgA was not detected in the tears. In this study, we provide new insight into immune mechanisms of enhanced resistance to avian influenza in chickens, which may lead to improved vaccination strategies and breeding programs.
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Affiliation(s)
- Emily J Aston
- Department of Animal Science, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA, United States
| | - Ying Wang
- Department of Animal Science, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA, United States
| | - Karen E Tracy
- Department of Animal Science, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA, United States
| | - Rodrigo A Gallardo
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA, United States
| | - Susan J Lamont
- Department of Animal Science, Iowa State University, Ames, IA, USA
| | - Huaijun Zhou
- Department of Animal Science, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA, United States.
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Ramamurthy M, Sankar S, Abraham AM, Nandagopal B, Sridharan G. B cell epitopes in the intrinsically disordered regions of neuraminidase and hemagglutinin proteins of H5N1 and H9N2 avian influenza viruses for peptide-based vaccine development. J Cell Biochem 2019; 120:17534-17544. [PMID: 31111560 DOI: 10.1002/jcb.29017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/15/2019] [Accepted: 04/18/2019] [Indexed: 12/12/2022]
Abstract
Avian influenza viruses (AIV) are very active in several parts of the globe and are the cause of huge economic loss for the poultry industry and also human fatalities. Three dimensional modeling was carried out for neuraminidase (NA) and hemagglutinin (HA) proteins of AIV. The C-score, estimated TM-Score, and estimated root-mean-square deviation (RMSD) score for NA of H5N1 were -1.18, 0.57 ± 0.15, and 9.8 ± 7.6, respectively. The C-score, estimated TM-Score, and estimated RMSD score for NA of H9N2 were -1.43, 0.54 ± 0.15, and 10.5 ± 4.6, respectively. The C-score, estimated TM-Score, and estimated RMSD score for HA of H5N1 were -0.03, 0.71 ± 0.12, and 7.7 ± 4.3, respectively. The C-score, estimated TM-Score, and estimated RMSD score for HA of H9N2 were -0.57, 0.64 ± 0.13, and 8.9 ± 4.6, respectively. Intrinsically disordered regions were identified for the NA and HA proteins of H5N1 and H9N2 with the use of PONDR program. Linear B cell epitope was predicted using BepiPred 2 program for NA and HA of H5N1 and H9N2 avian influenza strains. Discontinuous epitopes were predicted by Discotope 2 program. The linear epitopes that were considered likely to be immunogenic and within the intrinsically disordered region for the NA of H5N1 was TKSTNSRSGFEMIWDPNGWTGTDSSFSVK, and for H9N2 it was VGDTPRNDDSSSSSNCRDPNNERGAP. In the case of HA of H5N1, it was QRLVPKIATRSKVNGQSG and ATGLRNSPQRERRRKK; for H9N2 it was INRTFKPLIGPRPLVNGLQG and SLKLAVGLRNVPARSSR. The discontinuous epitopes of NA of H5N1 and H9N2 were identified at various regions of the protein structure spanning from amino acid residue positions 90 to 449 and 107 to 469, respectively. Similarly, the discontinuous epitopes of HA of H5N1 and H9N2 were identified in the amino acid residue positions 27 to 517 and 136 to 521, respectively. This study has identified potential and highly immunogenic linear and conformational B-cell epitopes towards developing a vaccine against AIV both for human and poultry use.
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Affiliation(s)
- Mageshbabu Ramamurthy
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Vellore, Tamil Nadu, India
| | - Sathish Sankar
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Vellore, Tamil Nadu, India
| | - Asha Mary Abraham
- Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Balaji Nandagopal
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Vellore, Tamil Nadu, India
| | - Gopalan Sridharan
- Sri Sakthi Amma Institute of Biomedical Research, Sri Narayani Hospital and Research Centre, Vellore, Tamil Nadu, India
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Generation of a reassortant avian influenza virus H5N2 vaccine strain capable of protecting chickens against infection with Egyptian H5N1 and H9N2 viruses. Vaccine 2015; 34:218-224. [PMID: 26620838 DOI: 10.1016/j.vaccine.2015.11.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/09/2015] [Accepted: 11/15/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND Avian influenza H5N1 viruses have been enzootic in Egyptian poultry since 2006. Avian influenza H9N2 viruses which have been circulating in Egyptian poultry since 2011 showed high replication rates in embryonated chicken eggs and mammalian cells. METHODS To investigate which gene segment was responsible for increasing replication, we constructed reassortant influenza viruses using the low pathogenic H1N1 PR8 virus as backbone and included individual genes from A/chicken/Egypt/S4456B/2011(H9N2) virus. Then, we invested this finding to improve a PR8-derived H5N1 influenza vaccine strain by incorporation of the NA segment of H9N2 virus instead of the NA of H5N1. The growth properties of this virus and several other forms of reassortant H5 viruses were compared. Finally, we tested the efficacy of this reassortant vaccine strain in chickens. RESULTS We observed an increase in replication for a reassortant virus expressing the neuraminidase gene (N2) of H9N2 virus relative to that of either parental viruses or reassortant PR8 viruses expressing other genes. Then, we generated an H5N2 vaccine strain based on the H5 from an Egyptian H5N1 virus and the N2 from an Egyptian H9N2 virus on a PR8 backbone. This strain had better replication rates than an H5N2 reassortant strain on an H9N2 backbone and an H5N1 reassortant on a PR8 backbone. This virus was then used to develop a killed, oil-emulsion vaccine and tested for efficacy against H5N1 and H9N2 viruses in chickens. Results showed that this vaccine was immunogenic and reduced mortality and shedding. DISCUSSION Our findings suggest that an inactivated PR8-derived H5N2 influenza vaccine is efficacious in poultry against H5N1 and H9N2 viruses and the vaccine seed replicates at a high rate thus improving vaccine production.
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Kim IH, Kwon HJ, Park JK, Song CS, Kim JH. Optimal attenuation of a PR8-derived mouse pathogenic H5N1 recombinant virus for testing antigenicity and protective efficacy in mice. Vaccine 2015; 33:6314-9. [PMID: 26428455 DOI: 10.1016/j.vaccine.2015.09.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 09/04/2015] [Accepted: 09/16/2015] [Indexed: 10/23/2022]
Abstract
The PR8-based reverse genetics vector system is widely used to generate commercial vaccine strains, but the pathogenicity of PR8-derived recombinant viruses in mice hinders further immunological studies. In the present study, we generated PR8-derived H5N1 recombinant viruses, in which haemagglutinin (HA) and neuraminidase (NA) originated from a mouse-pathogenic H5N1 low pathogenic avian influenza virus (LPAIV), and the non-structural proteins (NS) and polymerase basic protein 2 (PB2) originated from different H9N2 LPAIVs. In contrast to the control H5N1 recombinant virus, harboring six internal genes from PR8, the NS and PB2 recombinant viruses did not cause body weight loss in mice. However, the NS recombinant virus replicated in the lungs of mice. It was more immunogenic than the PB2 recombinant virus to protect efficiently against a lethal challenge of a H5N1 highly pathogenic AIV with 89 and 88% amino acid identity in HA and NA, respectively. Therefore, the NS gene may be useful for generating nonpathogenic and immunogenic PR8-derived recombinant viruses for studies of antigenicity and protective efficacy in mice.
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Affiliation(s)
- Il-Hwan Kim
- Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Hyuk-Joon Kwon
- Laboratory of Poultry Clinical Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Farm Animal Clinical Training and Research Center, Institutes of Green Bio Science and Technology, Seoul National University, Seoul, Republic of Korea; Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea.
| | - Jae-Keun Park
- Laboratory of Avian Diseases, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea
| | - Chang-Seon Song
- Laboratory of Avian Diseases, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea
| | - Jae-Hong Kim
- Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea; Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
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Park EH, Song BM, Yum J, Kim JA, Oh SK, Kim HS, Cho GJ, Seo SH. Protective efficacy of a single dose of baculovirus hemagglutinin-based vaccine in chickens and ducks against homologous and heterologous H5N1 virus infections. Viral Immunol 2014; 27:449-62. [PMID: 25211640 DOI: 10.1089/vim.2014.0029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Outbreaks of the highly pathogenic H5N1 virus in poultry and humans are ongoing. Vaccination is an efficient method for prevention of H5N1 infection. Using chickens and ducks, we assessed the efficacy of a vaccine comprising H5N1 hemagglutinin (HA) protein produced in a baculovirus expression system. The immunized chickens and ducks were protected against lethal infection by H5N1 in an antigen dose-dependent manner. Complete protection against homologous challenge and partial protection against heterologous challenge were achieved in chickens immunized with 5 μg HA protein and in ducks immunized with 10 μg HA protein. The IgG antibody subtype was mainly detected in the sera and tissues, including the lungs. The neuraminidase (NA) inhibition assay was negative in immunized chickens and ducks. Our results indicated that the expressed HA protein by baculovirus was immunogenic to both chickens and ducks, and the immunized chickens and ducks were protected from the lethal infections of highly pathogenic H5N1 influenza virus, though ducks required more HA protein than chickens to be protected. Also, baculovirus HA-vaccinated poultry can be differentiated from infected poultry by NA inhibition assay.
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Affiliation(s)
- Eun Hye Park
- 1 Laboratory of Influenza Research, Chungnam National University , Daejeon, Republic of Korea
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Spackman E, Swayne DE. Vaccination of gallinaceous poultry for H5N1 highly pathogenic avian influenza: current questions and new technology. Virus Res 2013; 178:121-32. [PMID: 23524326 DOI: 10.1016/j.virusres.2013.03.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 03/05/2013] [Accepted: 03/05/2013] [Indexed: 11/18/2022]
Abstract
Vaccination of poultry for avian influenza virus (AIV) is a complex topic as there are numerous technical, logistic and regulatory aspects which must be considered. Historically, control of high pathogenicity (HP) AIV infection in poultry has been accomplished by eradication and stamping out when outbreaks occur locally. Since the H5N1 HPAIV from Asia has spread and become enzootic, vaccination has been used on a long-term basis by some countries to control the virus, other countries have used it temporarily to aid eradication efforts, while others have not used it at all. Currently, H5N1 HPAIV is considered enzootic in China, Egypt, Viet Nam, India, Bangladesh and Indonesia. All but Bangladesh and India have instituted vaccination programs for poultry. Importantly, the specifics of these programs differ to accommodate different situations, resources, and industry structure in each country. The current vaccines most commonly used are inactivated whole virus vaccines, but vectored vaccine use is increasing. Numerous technical improvements to these platforms and novel vaccine platforms for H5N1 vaccines have been reported, but most are not ready to be implemented in the field.
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Affiliation(s)
- Erica Spackman
- Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Rd., Athens, GA 30605, United States.
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