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Pinotti F, Kohnle L, Lourenço J, Gupta S, Hoque MA, Mahmud R, Biswas P, Pfeiffer D, Fournié G. Modelling the transmission dynamics of H9N2 avian influenza viruses in a live bird market. Nat Commun 2024; 15:3494. [PMID: 38693163 PMCID: PMC11063141 DOI: 10.1038/s41467-024-47703-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 04/08/2024] [Indexed: 05/03/2024] Open
Abstract
H9N2 avian influenza viruses (AIVs) are a major concern for the poultry sector and human health in countries where this subtype is endemic. By fitting a model simulating H9N2 AIV transmission to data from a field experiment, we characterise the epidemiology of the virus in a live bird market in Bangladesh. Many supplied birds arrive already exposed to H9N2 AIVs, resulting in many broiler chickens entering the market as infected, and many indigenous backyard chickens entering with pre-existing immunity. Most susceptible chickens become infected within one day spent at the market, owing to high levels of viral transmission within market and short latent periods, as brief as 5.3 hours. Although H9N2 AIV transmission can be substantially reduced under moderate levels of cleaning and disinfection, effective risk mitigation also requires a range of additional interventions targeting markets and other nodes along the poultry production and distribution network.
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Affiliation(s)
| | - Lisa Kohnle
- City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - José Lourenço
- CBR (Biomedical Research Centre), Universidade Católica Portuguesa, Oeiras, Portugal
| | - Sunetra Gupta
- Department of Biology, University of Oxford, Oxford, UK
| | - Md Ahasanul Hoque
- Chattogram Veterinary and Animal Sciences University, Chittagong, Bangladesh
| | - Rashed Mahmud
- Chattogram Veterinary and Animal Sciences University, Chittagong, Bangladesh
| | - Paritosh Biswas
- Chattogram Veterinary and Animal Sciences University, Chittagong, Bangladesh
| | - Dirk Pfeiffer
- City University of Hong Kong, Hong Kong SAR, Hong Kong
- Royal Veterinary College, London, UK
| | - Guillaume Fournié
- Royal Veterinary College, London, UK
- INRAE, VetAgro Sup, UMR EPIA, Université de Lyon, Marcy l'Etoile, 69280, France
- INRAE, VetAgro Sup, UMR EPIA, Université Clermont Auvergne, Saint Genès Champanelle, 63122, France
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2
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Li Z, Peng C, Chen L, Wang P, Wang F. Construction and Immunogenicity Evaluation of Recombinant Bacillus subtilis Expressing HA1 Protein of H9N2 Avian Influenza Virus. Curr Microbiol 2023; 81:25. [PMID: 38040977 DOI: 10.1007/s00284-023-03548-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/31/2023] [Indexed: 12/03/2023]
Abstract
The H9N2 subtype of the avian influenza virus (AIV) is one of the main subtypes of low pathogenic AIV, and it seriously affects the poultry breeding industry. Currently, vaccination is still one of China's main strategies for controlling H9N2 avian influenza. In this study, we selected MW548848.1 on the current popular main branch h9.4.2.5 as the reference strain, and we optimized the amino acid sequence of HA1 to make it suitable for expression in Bacillus subtilis. The B. subtilis expression vector showed good safety and stress resistance; therefore, this study constructed a recombinant B. subtilis expressing H9N2 HA1 protein and evaluated its immunogenicity in mice. The following results were obtained: the sIgA level of HA1 protein in small intestine fluid and the IgG level of PHT43-HA1/B. subtilis in serum were significantly improved (P < 0.01); PHT43-HA1/B. subtilis can cause a special immune response in mice; and cytokine detection interferon-gamma (IFN-γ) (P < 0.05) and Interleukin 2 (IL-2) (P < 0.01) expressions significantly increased. Additionally, the study found that PHT43-HA1/B. subtilis can alleviate the attack of H9N2 AIV in the spleen, lungs, and small intestine of mice. This study was the first to use an oral recombinant B. subtilis-HA1 vaccine candidate, and it provides theoretical data and technical reference for the creation of a new live vector vaccine against H9N2 AIV.
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Affiliation(s)
- Zixuan Li
- Department of Veterinary Public Health, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, Shandong, China
| | - Chong Peng
- Department of Veterinary Public Health, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, Shandong, China
| | - Lijun Chen
- Department of Veterinary Public Health, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, Shandong, China
| | - Peng Wang
- Department of Veterinary Public Health, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China
| | - Fangkun Wang
- Department of Veterinary Public Health, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, China.
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian, Shandong, China.
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Islam A, Amin E, Islam S, Hossain ME, Al Mamun A, Sahabuddin M, Samad MA, Shirin T, Rahman MZ, Hassan MM. Annual trading patterns and risk factors of avian influenza A/H5 and A/H9 virus circulation in turkey birds ( Meleagris gallopavo) at live bird markets in Dhaka city, Bangladesh. Front Vet Sci 2023; 10:1148615. [PMID: 37470075 PMCID: PMC10352991 DOI: 10.3389/fvets.2023.1148615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/12/2023] [Indexed: 07/21/2023] Open
Abstract
The impacts of the avian influenza virus (AIV) on farmed poultry and wild birds affect human health, livelihoods, food security, and international trade. The movement patterns of turkey birds from farms to live bird markets (LBMs) and infection of AIV are poorly understood in Bangladesh. Thus, we conducted weekly longitudinal surveillance in LBMs to understand the trading patterns, temporal trends, and risk factors of AIV circulation in turkey birds. We sampled a total of 423 turkeys from two LBMs in Dhaka between May 2018 and September 2019. We tested the swab samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We used exploratory analysis to investigate trading patterns, annual cyclic trends of AIV and its subtypes, and a generalized estimating equation (GEE) logistic model to determine the factors that influence the infection of H5 and H9 in turkeys. Furthermore, we conducted an observational study and informal interviews with traders and vendors to record turkey trading patterns, demand, and supply and turkey handling practices in LBM. We found that all trade routes of turkey birds to northern Dhaka are unidirectional and originate from the northwestern and southern regions of Bangladesh. The number of trades from the source district to Dhaka depends on the turkey density. The median distance that turkey was traded from its source district to Dhaka was 188 km (Q1 = 165, Q3 = 210, IQR = 45.5). We observed seasonal variation in the median and average distance of turkey. The qualitative findings revealed that turkey farming initially became reasonably profitable in 2018 and at the beginning of 2019. However, the fall in demand and production in the middle of 2019 may be related to unstable market pricing, high feed costs, a shortfall of adequate marketing facilities, poor consumer knowledge, and a lack of advertising. The overall prevalence of AIV, H5, and H9 subtypes in turkeys was 31% (95% CI: 26.6-35.4), 16.3% (95% CI: 12.8-19.8), and 10.2% (95% CI: 7.3-13.1) respectively. None of the samples were positive for H7. The circulation of AIV and H9 across the annual cycle showed no seasonality, whereas the circulation of H5 showed significant seasonality. The GEE revealed that detection of AIV increases in retail vendor business (OR: 1.71; 95% CI: 1.12-2.62) and the bird's health status is sick (OR: 10.77; 95% CI: 4.31-26.94) or dead (OR: 11.33; 95% CI: 4.30-29.89). We also observed that winter season (OR: 5.83; 95% CI: 2.80-12.14) than summer season, dead birds (OR: 61.71; 95% CI: 25.78-147.75) and sick birds (OR 8.33; 95% CI: 3.36-20.64) compared to healthy birds has a higher risk of H5 infection in turkeys. This study revealed that the turkeys movements vary by time and season from the farm to the LBM. This surveillance indicated year-round circulation of AIV with H5 and H9 subtypes in turkey birds in LBMs. The seasonality and health condition of birds influence H5 infection in birds. The trading pattern of turkey may play a role in the transmission of AIV viruses in the birds. The selling of sick turkeys infected with H5 and H9 highlights the possibility of virus transmission to other species of birds sold at LBMs and to people.
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Affiliation(s)
- Ariful Islam
- EcoHealth Alliance, New York, NY, United States
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia
| | - Emama Amin
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Shariful Islam
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Mohammad Enayet Hossain
- One Health Laboratory, International Centre for Diarrheal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Abdullah Al Mamun
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Md. Sahabuddin
- One Health Laboratory, International Centre for Diarrheal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Mohammed Abdus Samad
- National Reference Laboratory for Avian Influenza, Bangladesh Livestock Research Institute (BLRI), Savar, Bangladesh
| | - Tahmina Shirin
- Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh
| | - Mohammed Ziaur Rahman
- One Health Laboratory, International Centre for Diarrheal Diseases Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Mohammad Mahmudul Hassan
- Queensland Alliance for One Health Sciences, School of Veterinary Science, The University of Queensland, Brisbane, QLD, Australia
- Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram, Bangladesh
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Carnegie L, Hasan M, Mahmud R, Hoque MA, Debnath N, Uddin MH, Lewis NS, Brown I, Essen S, Giasuddin M, Pfeiffer DU, Samad MA, Biswas P, Raghwani J, Fournié G, Hill SC. H9N2 avian influenza virus dispersal along Bangladeshi poultry trading networks. Virus Evol 2023; 9:vead014. [PMID: 36968264 PMCID: PMC10032359 DOI: 10.1093/ve/vead014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/30/2023] [Accepted: 02/24/2023] [Indexed: 02/27/2023] Open
Abstract
Avian influenza virus subtype H9N2 is endemic in Bangladesh's poultry population. The subtype affects poultry production and poses a potential zoonotic risk. Insufficient understanding of how the poultry trading network shapes the dissemination of avian influenza viruses has hindered the design of targeted interventions to reduce their spread. Here, we use phylodynamic analyses of haemagglutinin sequences to investigate the spatial spread and dispersal patterns of H9N2 viruses in Bangladesh's poultry population, focusing on its two largest cities (Dhaka and Chattogram) and their poultry production and distribution networks. Our analyses suggest that H9N2 subtype avian influenza virus lineage movement occurs relatively less frequently between Bangladesh's two largest cities than within each city. H9N2 viruses detected in single markets are often more closely related to viruses from other markets in the same city than to each other, consistent with close epidemiological connectivity between markets. Our analyses also suggest that H9N2 viruses may spread more frequently between chickens of the three most commonly sold types (sunali-a cross-bred of Fayoumi hen and Rhode Island Red cock, deshi-local indigenous, and exotic broiler) in Dhaka than in Chattogram. Overall, this study improves our understanding of how Bangladesh's poultry trading system impacts avian influenza virus spread and should contribute to the design of tailored surveillance that accommodates local heterogeneity in virus dispersal patterns.
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Affiliation(s)
- L Carnegie
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire AL9 7TA, UK
| | - M Hasan
- Animal Health Research Division, Bangladesh Livestock Research Institute (BLRI), Dhaka 1341, Bangladesh
| | - R Mahmud
- Department of Medicine & Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University (CVASU), Zakir Hossain Road, Khulshi, Chattogram 4202, Bangladesh
| | - M A Hoque
- Department of Medicine & Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University (CVASU), Zakir Hossain Road, Khulshi, Chattogram 4202, Bangladesh
| | - N Debnath
- Department of Medicine & Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University (CVASU), Zakir Hossain Road, Khulshi, Chattogram 4202, Bangladesh
| | - M H Uddin
- Department of Medicine & Surgery, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University (CVASU), Zakir Hossain Road, Khulshi, Chattogram 4202, Bangladesh
| | - N S Lewis
- Department of Virology, Animal and Plant Health Agency (APHA), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - I Brown
- Department of Virology, Animal and Plant Health Agency (APHA), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - S Essen
- Department of Virology, Animal and Plant Health Agency (APHA), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, UK
| | - Md Giasuddin
- Animal Health Research Division, Bangladesh Livestock Research Institute (BLRI), Dhaka 1341, Bangladesh
| | - D U Pfeiffer
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire AL9 7TA, UK
- Department of Infectious Diseases and Public Health, City University of Hong Kong, 83 Tat Chee Ave, Kowloon Tong, Hong Kong SAR, PR China
| | - M A Samad
- Animal Health Research Division, Bangladesh Livestock Research Institute (BLRI), Dhaka 1341, Bangladesh
| | - P Biswas
- Department of Microbiology and Veterinary Public Health, Chattogram Veterinary and Animal Sciences University (CVASU), Zakir Hossain Road, Khulshi, Chattogram 4202, Bangladesh
| | - J Raghwani
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire AL9 7TA, UK
| | - G Fournié
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire AL9 7TA, UK
- Université de Lyon, INRAE, VetAgro Sup, UMR EPIA, Campus vétérinaire de VetAgro Sup, 1 avenue Bourgelat, Marcy, l’Etoile 69280, France
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR EPIA, Centre INRAE Clermont-Auvergne-Rhône-Alpes, Saint Genes Champanelle 63122, France
| | - S C Hill
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire AL9 7TA, UK
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Badruzzaman ATM, Rahman MM, Hasan M, Hossain MK, Husna A, Hossain FMA, Giasuddin M, Uddin MJ, Islam MR, Alam J, Eo SK, Fasina FO, Ashour HM. Semi-Scavenging Poultry as Carriers of Avian Influenza Genes. Life (Basel) 2022; 12:life12020320. [PMID: 35207607 PMCID: PMC8879534 DOI: 10.3390/life12020320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/29/2022] [Accepted: 02/04/2022] [Indexed: 02/05/2023] Open
Abstract
Ducks are the natural reservoir of influenza A virus and the central host for the avian influenza virus (AIV) subtype H5N1, which is highly pathogenic. Semi-scavenging domestic ducks allow for the reemergence of new influenza subtypes which could be transmitted to humans. We collected 844 cloacal swabs from semi-scavenging ducks inhabiting seven migratory bird sanctuaries of Bangladesh for the molecular detection of avian influenza genes. We detected the matrix gene (M gene) using real-time RT-PCR (RT-qPCR). Subtyping of the AIV-positive samples was performed by RT-qPCR specific for H5, H7, and H9 genes. Out of 844 samples, 21 (2.488%) were positive for AIV. Subtyping of AIV positive samples (n = 21) revealed that nine samples (42.85%) were positive for the H9 subtype, five (23.80%) were positive for H5, and seven (33.33%) were negative for the three genes (H5, H7, and H9). We detected the same genes after propagating the virus in embryonated chicken eggs from positive samples. Semi-scavenging ducks could act as carriers of pathogenic AIV, including the less pathogenic H9 subtype. This can enhance the pathogenicity of the virus in ducks by reassortment. The large dataset presented in our study from seven areas should trigger further studies on AIV prevalence and ecology.
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Affiliation(s)
- A T M Badruzzaman
- Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet 3100, Bangladesh; (A.T.M.B.); (M.M.R.); (M.K.H.); (A.H.); (F.M.A.H.)
| | - Md. Masudur Rahman
- Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet 3100, Bangladesh; (A.T.M.B.); (M.M.R.); (M.K.H.); (A.H.); (F.M.A.H.)
| | - Mahmudul Hasan
- National Reference Laboratory for Avian Influenza, Bangladesh Livestock Research Institute, Savar, Dhaka 1340, Bangladesh; (M.H.); (M.G.)
| | - Mohammed Kawser Hossain
- Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet 3100, Bangladesh; (A.T.M.B.); (M.M.R.); (M.K.H.); (A.H.); (F.M.A.H.)
| | - Asmaul Husna
- Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet 3100, Bangladesh; (A.T.M.B.); (M.M.R.); (M.K.H.); (A.H.); (F.M.A.H.)
| | - Ferdaus Mohd Altaf Hossain
- Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet 3100, Bangladesh; (A.T.M.B.); (M.M.R.); (M.K.H.); (A.H.); (F.M.A.H.)
| | - Mohammed Giasuddin
- National Reference Laboratory for Avian Influenza, Bangladesh Livestock Research Institute, Savar, Dhaka 1340, Bangladesh; (M.H.); (M.G.)
| | - Md Jamal Uddin
- ABEx Bio-Research Center, East Azampur, Dhaka 1230, Bangladesh;
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul 03760, Korea
| | - Mohammad Rafiqul Islam
- Livestock Division, Bangladesh Agricultural Research Council, Farmgate, Dhaka 1215, Bangladesh;
| | - Jahangir Alam
- Animal Biotechnology Division, National Institute of Biotechnology, Savar, Dhaka 1349, Bangladesh;
| | - Seong-Kug Eo
- College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan 54596, Korea;
| | - Folorunso Oludayo Fasina
- Emergency Centre for Transboundary Animal Diseases, Food and Agriculture Organization of the United Nations (ECTAD-FAO), United Nations Office in Nairobi (UNON), UN Avenue, Gigiri, Nairobi 00100, Kenya;
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort 0110, South Africa
| | - Hossam M. Ashour
- Department of Integrative Biology, College of Arts and Sciences, University of South Florida, St. Petersburg, FL 33701, USA
- Correspondence:
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Gupta SD, Fournié G, Hoque MA, Henning J. Farm-Level Risk Factors Associated With Avian Influenza A (H5) and A (H9) Flock-Level Seroprevalence on Commercial Broiler and Layer Chicken Farms in Bangladesh. Front Vet Sci 2022; 9:893721. [PMID: 35799837 PMCID: PMC9255630 DOI: 10.3389/fvets.2022.893721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
A cross-sectional study was conducted to identify farm-level risk factors associated with avian influenza A H5 and H9 virus exposure on commercial chicken farms in Bangladesh. For broiler farms, both H5 and H9 seropositivity were associated with visits by workers from other commercial chicken farms [odds ratio (OR) for H5 = 15.1, 95% confidence interval (CI): 2.8-80.8; OR for H9 = 50.1, 95% CI: 4.5-552.7], H5 seropositivity was associated with access of backyard ducks (OR = 21.5, 95% CI: 2.3-201.1), and H9 seropositivity with a number of farm employees (OR = 9.4, 95% CI: 1.1-80.6). On layer farms, both H5 and H9 seropositivity were associated with presence of stray dogs (OR for H5 = 3.1, 95% CI: 1.1-9.1; OR for H9 = 4.0, 95% CI: 1.1-15.3), H5 seropositivity with hatcheries supplying chicks (OR = 0.0, 95% CI: 0.0-0.3), vehicles entering farms (OR = 5.8, 95% CI: 1.5-22.4), number of farm employees (OR = 5.8, 95% CI: 1.2-28.2), and burying of dead birds near farms (OR = 4.6, 95% CI: 1.2-17.3); H9 seropositivity with traders supplying feed (OR = 5.9, 95% CI: 1.0-33.9), visits conducted of other commercial poultry farms (OR = 4.7, 95% CI: 1.1-20.6), number of spent layers sold (OR = 24.0, 95% CI: 3.7-155.0), and frequency of replacing chicken droppings (OR = 28.3, 95% CI: 2.8-284.2). Policies addressing these risk factors will increase the effectiveness of prevention and control strategies reducing the risk of avian influenza on commercial chicken farms.
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Affiliation(s)
- Suman Das Gupta
- School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia
| | - Guillaume Fournié
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, London, United Kingdom
| | - Md Ahasanul Hoque
- Department of Medicine and Surgery, Chattogram Veterinary and Animal Sciences University, Chattogram, Bangladesh
| | - Joerg Henning
- School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia
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Adlhoch C, Fusaro A, Gonzales JL, Kuiken T, Marangon S, Niqueux É, Staubach C, Terregino C, Aznar I, Muñoz Guajardo I, Baldinelli F. Avian influenza overview September - December 2021. EFSA J 2021; 19:e07108. [PMID: 34987626 PMCID: PMC8698678 DOI: 10.2903/j.efsa.2021.7108] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Between 16 September and 8 December 2021, 867 highly pathogenic avian influenza (HPAI) virus detections were reported in 27 EU/EEA countries and the UK in poultry (316), in wild (523) and in captive birds (28). The detections in poultry were mainly reported by Italy (167) followed by Hungary and Poland (35 each). Tha majority of the detections in wild birds were reported by Germany (280), Netherlands (65) and United Kingdom (53). The observed persistence and continuous circulation of HPAI viruses in migratory and resident wild birds will continue to pose a risk for the poultry industry in Europe for the coming months. The frequent occurrence of HPAI A(H5) incursions in commercial farms (including poultry production types considered at low avian influenza risk) raises concern about the capacity of the applied biosecurity measures to prevent virus introduction. Short-term preparedness and medium- and long-term prevention strategies, including revising and reinforcing biosecurity measures, reduction of the density of commercial poultry farms and possible appropriate vaccination strategies, should be implemented. The results of the genetic analysis indicate that the viruses characterised during this reporting period belong to clade 2.3.4.4b. Some of the characterized HPAI A(H5N1) viruses detected in Sweden, Germany, Poland and United Kingdom are related to the viruses which have been circulating in Europe since October 2020; in North, Central, South and East Europe novel reassortant A(H5N1) virus has been introduced starting from October 2021. HPAI A(H5N1) was also detected in wild mammal species in Sweden, Estonia and Finland; some of these strains characterised so far present an adaptive marker that is associated with increased virulence and replication in mammals. Since the last report, 13 human infections due to HPAI A(H5N6) and two human cases due to LPAI A(H9N2) virus have been reported from China. Some of these A(H5N6) cases were caused by a reassortant virus of clade 2.3.4.4b, which possessed an HA gene closely related to the A(H5) viruses circulating in Europe. The risk of infection for the general population in the EU/EEA is assessed as low, and for occupationally exposed people, low to medium, with large uncertainty due to the high diversity of circulating viruses in the bird populations.
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