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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Gortázar C, Herskin M, Michel V, Miranda Chueca MÁ, Padalino B, Roberts HC, Spoolder H, Stahl K, Velarde A, Winckler C, Bastino E, Bortolami A, Guinat C, Harder T, Stegeman A, Terregino C, Aznar Asensio I, Mur L, Broglia A, Baldinelli F, Viltrop A. Vaccination of poultry against highly pathogenic avian influenza - part 1. Available vaccines and vaccination strategies. EFSA J 2023; 21:e08271. [PMID: 37822713 PMCID: PMC10563699 DOI: 10.2903/j.efsa.2023.8271] [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] [Indexed: 10/13/2023] Open
Abstract
Several vaccines have been developed against highly pathogenic avian influenza (HPAI), mostly inactivated whole-virus vaccines for chickens. In the EU, one vaccine is authorised in chickens but is not fully efficacious to stop transmission, highlighting the need for vaccines tailored to diverse poultry species and production types. Off-label use of vaccines is possible, but effectiveness varies. Vaccines are usually injectable, a time-consuming process. Mass-application vaccines outside hatcheries remain rare. First vaccination varies from in-ovo to 6 weeks of age. Data about immunity onset and duration in the target species are often unavailable, despite being key for effective planning. Minimising antigenic distance between vaccines and field strains is essential, requiring rapid updates of vaccines to match circulating strains. Generating harmonised vaccine efficacy data showing vaccine ability to reduce transmission is crucial and this ability should be also assessed in field trials. Planning vaccination requires selecting the most adequate vaccine type and vaccination scheme. Emergency protective vaccination is limited to vaccines that are not restricted by species, age or pre-existing vector-immunity, while preventive vaccination should prioritise achieving the highest protection, especially for the most susceptible species in high-risk transmission areas. Model simulations in France, Italy and The Netherlands revealed that (i) duck and turkey farms are more infectious than chickens, (ii) depopulating infected farms only showed limitations in controlling disease spread, while 1-km ring-culling performed better than or similar to emergency preventive ring-vaccination scenarios, although with the highest number of depopulated farms, (iii) preventive vaccination of the most susceptible species in high-risk transmission areas was the best option to minimise the outbreaks' number and duration, (iv) during outbreaks in such areas, emergency protective vaccination in a 3-km radius was more effective than 1- and 10-km radius. Vaccine efficacy should be monitored and complement other surveillance and preventive efforts.
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Schmidt CG, Herskin M, Michel V, Miranda Chueca MÁ, Pasquali P, Roberts HC, Sihvonen LH, Spoolder H, Stahl K, Calvo AV, Viltrop A, Winckler C, De Clercq K, Klement E, Stegeman JA, Gubbins S, Antoniou S, Broglia A, Van der Stede Y, Zancanaro G, Aznar I. Scientific Opinion on the assessment of the control measures of the category A diseases of Animal Health Law: Highly Pathogenic Avian Influenza. EFSA J 2021; 19:e06372. [PMID: 33488812 PMCID: PMC7812451 DOI: 10.2903/j.efsa.2021.6372] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
EFSA received a mandate from the European Commission to assess the effectiveness of some of the control measures against diseases included in the Category A list according to Regulation (EU) 2016/429 on transmissible animal diseases ('Animal Health Law'). This opinion belongs to a series of opinions where these control measures will be assessed, with this opinion covering the assessment of control measures for Highly Pathogenic Avian Influenza (HPAI). In this opinion, EFSA and the AHAW Panel of experts review the effectiveness of: (i) clinical and laboratory sampling procedures, (ii) monitoring period and (iii) the minimum radius of the protection and surveillance zone, and the minimum length of time the measures should be applied in these zones. The general methodology used for this series of opinions has been published elsewhere; nonetheless, specific details of the model used for the assessment of the laboratory sampling procedures for HPAI are presented here. Here, also, the transmission kernels used for the assessment of the minimum radius of the protection and surveillance zones are shown. Several scenarios for which these control measures had to be assessed were designed and agreed prior to the start of the assessment. In summary, sampling procedures as described in the diagnostic manual for HPAI were considered efficient for gallinaceous poultry, whereas additional sampling is advised for Anseriformes. The monitoring period was assessed as effective, and it was demonstrated that the surveillance zone comprises 95% of the infections from an affected establishment. Recommendations provided for each of the scenarios assessed aim to support the European Commission in the drafting of further pieces of legislation, as well as for plausible ad hoc requests in relation to HPAI.
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Cross-Protection by Inactivated H5 Prepandemic Vaccine Seed Strains against Diverse Goose/Guangdong Lineage H5N1 Highly Pathogenic Avian Influenza Viruses. J Virol 2020; 94:JVI.00720-20. [PMID: 32999029 DOI: 10.1128/jvi.00720-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/22/2020] [Indexed: 01/26/2023] Open
Abstract
The highly pathogenic avian influenza virus (HPAIV) H5N1 A/goose/Guangdong/1996 lineage (Gs/GD) is endemic in poultry across several countries in the world and has caused sporadic lethal infections in humans. Vaccines are important in HPAIV control both for poultry and in prepandemic preparedness for humans. This study assessed inactivated prepandemic vaccine strains in a One Health framework across human and agricultural and wildlife animal health, focusing on the genetic and antigenic diversity of field H5N1 Gs/GD viruses from the agricultural sector and assessing cross-protection in a chicken challenge model. Nearly half (47.92%) of the 48 combinations of vaccine and challenge viruses examined had bird protection of 80% or above. Most vaccinated groups had prolonged mean death times (MDT), and the virus-shedding titers were significantly lower than those of the sham-vaccinated group (P ≤ 0.05). The antibody titers in the prechallenge sera were not predictive of protection. Although vaccinated birds had higher titers of hemagglutination-inhibiting (HI) antibodies against the homologous vaccine antigen, most of them also had lower or no antibody titer against the challenge antigen. The comparison of all parameters and homologous or closely related vaccine and challenge viruses gave the best prediction of protection. Through additional analysis, we identified a pattern of epitope substitutions in the hemagglutinin (HA) of each challenge virus that impacted protection, regardless of the vaccine used. These changes were situated in the antigenic sites and/or reported epitopes associated with virus escape from antibody neutralization. As a result, this study highlights virus diversity, immune response complexity, and the importance of strain selection for vaccine development to control H5N1 HPAIV in the agricultural sector and for human prepandemic preparedness. We suggest that the engineering of specific antigenic sites can improve the immunogenicity of H5 vaccines.IMPORTANCE The sustained circulation of highly pathogenic avian influenza virus (HPAIV) H5N1 A/goose/Guangdong/1996 (Gs/GD) lineage in the agricultural sector and some wild birds has led to the evolution and selection of distinct viral lineages involved in escape from vaccine protection. Our results using inactivated vaccine candidates from the human pandemic preparedness program in a chicken challenge model identified critical antigenic conformational epitopes on H5 hemagglutinin (HA) from different clades that were associated with antibody recognition and escape. Even though other investigators have reported epitope mapping in the H5 HA, much of this information pertains to epitopes reactive to mouse antibodies. Our findings validate changes in antigenic epitopes of HA associated with virus escape from antibody neutralization in chickens, which has direct relevance to field protection and virus evolution. Therefore, knowledge of these immunodominant regions is essential to proactively develop diagnostic tests, improve surveillance platforms to monitor AIV outbreaks, and design more efficient and broad-spectrum agricultural and human prepandemic vaccines.
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Tatár-Kis T, Dán Á, Felföldi B, Bálint Á, Rónai Z, Dauphin G, Pénzes Z, El-Attrache J, Gardin Y, Palya V. Virus-Like Particle Based Vaccine Provides High Level of Protection Against Homologous H5N8 HPAIV Challenge in Mule and Pekin Duck, Including Prevention of Transmission. Avian Dis 2020; 63:193-202. [PMID: 31131577 DOI: 10.1637/11882-042718-reg.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 12/18/2018] [Indexed: 11/05/2022]
Abstract
The most recent pandemic clade of highly pathogenic avian influenza (HPAI) H5, clade 2.3.4.4, spread widely, with the involvement of wild birds, most importantly wild waterfowl, carrying the virus (even asymptomatically) from Asia to North America, Europe, and Africa. Domestic waterfowl being in regular contact with wild birds played a significant role in the H5Nx epizootics. Therefore, protection of domestic waterfowl from H5Nx avian influenza infection would likely cut the transmission chain of these viruses and greatly enhance efforts to control and prevent disease outbreak in other poultry and animal species, as well as infection of humans. The expectation for such a vaccine is not only to provide clinical protection, but also to control challenge virus transmission efficiently and ensure that the ability to differentiate infected from vaccinated animals is retained. A water-in-oil emulsion virus-like particle vaccine, containing homologous hemagglutinin antigen to the current European H5N8 field strains, has been developed to meet these requirements. The vaccine was tested in commercial Pekin and mule ducks by vaccinating them either once, at 3 wk of age, or twice (at 1 day and at 3 wk of age). Challenge was performed at 6 wk of age with a Hungarian HPAIV H5N8 isolate (2.3.4.4 Group B). Efficacy of vaccination was evaluated on the basis of clinical signs, amount of virus shedding, and transmission. Vaccination resulted in complete clinical protection and prevention of challenge virus transmission from the directly challenged vaccinated ducks to the vaccinated contact animals.
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Affiliation(s)
- Tímea Tatár-Kis
- Scientific Support and Investigation Unit, Ceva Phylaxia, Ceva Animal Health, Budapest, Hungary 1107
| | - Ádám Dán
- Veterinary Diagnostic Institute, National Food Chain Safety Office, Budapest, Hungary 1149
| | - Balázs Felföldi
- Scientific Support and Investigation Unit, Ceva Phylaxia, Ceva Animal Health, Budapest, Hungary 1107
| | - Ádám Bálint
- Veterinary Diagnostic Institute, National Food Chain Safety Office, Budapest, Hungary 1149
| | - Zsuzsanna Rónai
- Veterinary Diagnostic Institute, National Food Chain Safety Office, Budapest, Hungary 1149
| | - Gwenaelle Dauphin
- Science and Innovation Direction, Ceva Animal Health, 33500-Libourne, France
| | - Zoltán Pénzes
- Bio R&D, Ceva Phylaxia, Ceva Animal Health, Budapest, Hungary 1107
| | - John El-Attrache
- Scientific Support and Investigation Unit, Ceva Biomune, Ceva Animal Health, Lenexa, KS 66215
| | - Yannick Gardin
- Science and Innovation Direction, Ceva Animal Health, 33500-Libourne, France
| | - Vilmos Palya
- Scientific Support and Investigation Unit, Ceva Phylaxia, Ceva Animal Health, Budapest, Hungary 1107,
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Palya V, Tatár-Kis T, Walkóné Kovács E, Kiss I, Homonnay Z, Gardin Y, Kertész K, Dán Á. Efficacy of a Recombinant Turkey Herpesvirus AI (H5) Vaccine in Preventing Transmission of Heterologous Highly Pathogenic H5N8 Clade 2.3.4.4b Challenge Virus in Commercial Broilers and Layer Pullets. J Immunol Res 2018; 2018:3143189. [PMID: 30584541 PMCID: PMC6280313 DOI: 10.1155/2018/3143189] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/24/2018] [Accepted: 09/04/2018] [Indexed: 12/31/2022] Open
Abstract
Outbreaks caused by the highly pathogenic avian influenza virus (HPAIV) H5N8 subtype clade 2.3.4.4 were first reported in 2014 in South Korea then spread very rapidly in Asia, to Europe, and for the first time, to North America. Efficacy of a recombinant HVT-AI (H5) vaccine (rHVT-H5) to provide clinical protection as well as to significantly reduce the shedding of an H5N8 challenge virus has already been demonstrated in SPF chickens. The aim of our studies was to test the efficacy of the same rHVT-H5 vaccine in controlling the transmission of a recent Hungarian HPAIV H5N8 challenge virus in commercial chickens. Broilers and layers were vaccinated at day old according to the manufacturer's recommendation and then challenged with a 2017 Hungarian HPAIV H5N8 (2.3.4.4b) isolate at 5 or 7 weeks of age, respectively. Evaluation of clinical protection, reduction of challenge virus shedding, and transmission to vaccinated contact birds was done on the basis of clinical signs/mortality, detection, and quantitation of challenge virus in oronasal and cloacal swabs (regularly between 1 and 14 days postchallenge). Measurement of seroconversion to AIV nucleoprotein was used as an indicator of infection and replication of challenge virus. Our results demonstrated that rHVT-H5 vaccination could prevent the development of clinical disease and suppress shedding very efficiently, resulting in the lack of challenge virus transmission to vaccinated contact chickens, regardless the type of birds. Single immunization with the tested rHVT-H5 vaccine proved to be effective to stop HPAIV H5N8 (2.3.4.4b) transmission within vaccinated poultry population under experimental conditions.
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Affiliation(s)
- Vilmos Palya
- Scientific Support and Investigation Unit, Ceva-Phylaxia, Ceva Animal Health, Budapest 1107, Hungary
| | - Tímea Tatár-Kis
- Scientific Support and Investigation Unit, Ceva-Phylaxia, Ceva Animal Health, Budapest 1107, Hungary
| | - Edit Walkóné Kovács
- Scientific Support and Investigation Unit, Ceva-Phylaxia, Ceva Animal Health, Budapest 1107, Hungary
| | - István Kiss
- Scientific Support and Investigation Unit, Ceva-Phylaxia, Ceva Animal Health, Budapest 1107, Hungary
| | - Zalán Homonnay
- Scientific Support and Investigation Unit, Ceva-Phylaxia, Ceva Animal Health, Budapest 1107, Hungary
| | | | | | - Ádám Dán
- Veterinary Diagnostic Directorate, National Food Chain Safety Office (NEBIH), Budapest 1149, Hungary
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Lisovski S, van Dijk JG, Klinkenberg D, Nolet BA, Fouchier RA, Klaassen M. The roles of migratory and resident birds in local avian influenza infection dynamics. J Appl Ecol 2018; 55:2963-2975. [PMID: 30337766 PMCID: PMC6188652 DOI: 10.1111/1365-2664.13154] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 03/14/2018] [Indexed: 12/29/2022]
Abstract
Migratory birds are an increasing focus of interest when it comes to infection dynamics and the spread of avian influenza viruses (AIV). However, we lack detailed understanding migratory birds' contribution to local AIV prevalence levels and their downstream socio-economic costs and threats.To explain the potential differential roles of migratory and resident birds in local AIV infection dynamics, we used a susceptible-infectious-recovered (SIR) model. We investigated five (mutually non- exclusive) mechanisms potentially driving observed prevalence patterns: 1) a pronounced birth pulse (e.g. the synchronised annual influx of immunologically naïve individuals), 2) short-term immunity, 3) increase of susceptible migrants, 4) differential susceptibility to infection (i.e. transmission rate) for migrants and residents, and 5) replacement of migrants during peak migration.SIR models describing all possible combinations of the five mechanisms were fitted to individual AIV infection data from a detailed longitudinal surveillance study in the partially migratory mallard duck (Anas platyrhynchos). During autumn and winter, the local resident mallard community also held migratory mallards that exhibited distinct AIV infection dynamics.Replacement of migratory birds during peak migration in autumn was found to be the most important mechanism driving the variation in local AIV infection patterns. This suggests that a constant influx of migratory birds, likely immunological naïve to locally circulating AIV strains, is required to predict the observed temporal prevalence patterns and the distinct differences in prevalence between residents and migrants.Synthesis and applications. Our analysis reveals a key mechanism that could explain the amplifying role of migratory birds in local avian influenza virus infection dynamics; the constant flow and replacement of migratory birds during peak migration. Aside from monitoring efforts, in order to achieve adequate disease management and control in wildlife - with knock-on effects for livestock and humans, - we conclude that it is crucial, in future surveillance studies, to record host demographical parameters such as population density, timing of birth and turnover of migrants.
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Affiliation(s)
- Simeon Lisovski
- Deakin University, School of Life and Environmental Sciences, Centre for Integrative Ecology, Geelong, Australia
- Swiss Ornithological Institute, Seerose 1, CH-6204 Sempach, Switzerland
| | - Jacintha G.B. van Dijk
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), The Netherlands
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, SE-391 82 Kalmar, Sweden
| | - Don Klinkenberg
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Bart A. Nolet
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), The Netherlands
- Theoretical and Computational Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, The Netherlands
| | | | - Marcel Klaassen
- Deakin University, School of Life and Environmental Sciences, Centre for Integrative Ecology, Geelong, Australia
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Passive inhalation of dry powder influenza vaccine formulations completely protects chickens against H5N1 lethal viral challenge. Eur J Pharm Biopharm 2018; 133:85-95. [PMID: 30312742 PMCID: PMC7126314 DOI: 10.1016/j.ejpb.2018.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/01/2018] [Accepted: 10/08/2018] [Indexed: 11/30/2022]
Abstract
Bird to human transmission of high pathogenicity avian influenza virus (HPAIV) poses a significant risk of triggering a flu pandemic in the human population. Therefore, vaccination of susceptible poultry during an HPAIV outbreak might be the best remedy to prevent such transmissions. To this end, suitable formulations and an effective mass vaccination method that can be translated to field settings needs to be developed. Our previous study in chickens has shown that inhalation of a non-adjuvanted dry powder influenza vaccine formulation during normal breathing results in partial protection against lethal influenza challenge. The aim of the present study was to improve the effectiveness of pulmonary vaccination by increasing the vaccine dose deposited in the lungs and by the use of suitable adjuvants. Two adjuvants, namely, Bacterium-like Particles (BLP) and Advax, were spray freeze dried with influenza vaccine into dry powder formulations. Delivery of dry formulations directly at the syrinx revealed that BLP and Advax had the potential to boost either systemic or mucosal immune responses or both. Upon passive inhalation of dry influenza vaccine formulations in an optimized set-up, BLP and Advax/BLP adjuvanted formulations induced significantly higher systemic immune responses than the non-adjuvanted formulation. Remarkably, all vaccinated animals not only survived a lethal influenza challenge, but also did not show any shedding of challenge virus except for two out of six animals in the Advax group. Overall, our results indicate that passive inhalation is feasible, effective and suitable for mass vaccination of chickens if it can be adapted to field settings.
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Retkute R, Jewell CP, Van Boeckel TP, Zhang G, Xiao X, Thanapongtharm W, Keeling M, Gilbert M, Tildesley MJ. Dynamics of the 2004 avian influenza H5N1 outbreak in Thailand: The role of duck farming, sequential model fitting and control. Prev Vet Med 2018; 159:171-181. [PMID: 30314780 PMCID: PMC6193140 DOI: 10.1016/j.prevetmed.2018.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 09/15/2018] [Accepted: 09/15/2018] [Indexed: 11/29/2022]
Abstract
The Highly Pathogenic Avian Influenza (HPAI) subtype H5N1 virus persists in many countries and has been circulating in poultry, wild birds. In addition, the virus has emerged in other species and frequent zoonotic spillover events indicate that there remains a significant risk to human health. It is crucial to understand the dynamics of the disease in the poultry industry to develop a more comprehensive knowledge of the risks of transmission and to establish a better distribution of resources when implementing control. In this paper, we develop a set of mathematical models that simulate the spread of HPAI H5N1 in the poultry industry in Thailand, utilising data from the 2004 epidemic. The model that incorporates the intensity of duck farming when assessing transmision risk provides the best fit to the spatiotemporal characteristics of the observed outbreak, implying that intensive duck farming drives transmission of HPAI in Thailand. We also extend our models using a sequential model fitting approach to explore the ability of the models to be used in “real time” during novel disease outbreaks. We conclude that, whilst predictions of epidemic size are estimated poorly in the early stages of disease outbreaks, the model can infer the preferred control policy that should be deployed to minimise the impact of the disease.
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Affiliation(s)
- Renata Retkute
- School of Life Sciences and Institute of Mathematics, University of Warwick, UK.
| | - Chris P Jewell
- Faculty of Health and Medicine, Furness College, Lancaster University, UK
| | | | - Geli Zhang
- College of Land Science and Technology, China Agricultural University, Beijing 100193, China
| | - Xiangming Xiao
- College of Land Science and Technology, China Agricultural University, Beijing 100193, China
| | | | - Matt Keeling
- School of Life Sciences and Institute of Mathematics, University of Warwick, UK
| | - Marius Gilbert
- Biological Control and Spatial Ecology Universite Libre de Bruxelles, Belgium
| | - Michael J Tildesley
- School of Life Sciences and Institute of Mathematics, University of Warwick, UK
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9
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More S, Bicout D, Bøtner A, Butterworth A, Calistri P, Depner K, Edwards S, Garin-Bastuji B, Good M, Gortázar Schmidt C, Michel V, Miranda MA, Nielsen SS, Raj M, Sihvonen L, Spoolder H, Thulke HH, Velarde A, Willeberg P, Winckler C, Breed A, Brouwer A, Guillemain M, Harder T, Monne I, Roberts H, Baldinelli F, Barrucci F, Fabris C, Martino L, Mosbach-Schulz O, Verdonck F, Morgado J, Stegeman JA. Avian influenza. EFSA J 2017; 15:e04991. [PMID: 32625288 PMCID: PMC7009867 DOI: 10.2903/j.efsa.2017.4991] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Previous introductions of highly pathogenic avian influenza virus (HPAIV) to the EU were most likely via migratory wild birds. A mathematical model has been developed which indicated that virus amplification and spread may take place when wild bird populations of sufficient size within EU become infected. Low pathogenic avian influenza virus (LPAIV) may reach similar maximum prevalence levels in wild bird populations to HPAIV but the risk of LPAIV infection of a poultry holding was estimated to be lower than that of HPAIV. Only few non-wild bird pathways were identified having a non-negligible risk of AI introduction. The transmission rate between animals within a flock is assessed to be higher for HPAIV than LPAIV. In very few cases, it could be proven that HPAI outbreaks were caused by intrinsic mutation of LPAIV to HPAIV but current knowledge does not allow a prediction as to if, and when this could occur. In gallinaceous poultry, passive surveillance through notification of suspicious clinical signs/mortality was identified as the most effective method for early detection of HPAI outbreaks. For effective surveillance in anseriform poultry, passive surveillance through notification of suspicious clinical signs/mortality needs to be accompanied by serological surveillance and/or a virological surveillance programme of birds found dead (bucket sampling). Serosurveillance is unfit for early warning of LPAI outbreaks at the individual holding level but could be effective in tracing clusters of LPAIV-infected holdings. In wild birds, passive surveillance is an appropriate method for HPAIV surveillance if the HPAIV infections are associated with mortality whereas active wild bird surveillance has a very low efficiency for detecting HPAIV. Experts estimated and emphasised the effect of implementing specific biosecurity measures on reducing the probability of AIV entering into a poultry holding. Human diligence is pivotal to select, implement and maintain specific, effective biosecurity measures.
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Sitaras I, Rousou X, Peeters B, de Jong MC. Mutations in the haemagglutinin protein and their effect in transmission of highly pathogenic avian influenza (HPAI) H5N1 virus in sub-optimally vaccinated chickens. Vaccine 2016; 34:5512-5518. [DOI: 10.1016/j.vaccine.2016.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/29/2016] [Accepted: 10/03/2016] [Indexed: 10/20/2022]
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Dolka B, Żbikowski A, Dolka I, Szeleszczuk P. The response of mute swans (Cygnus olor, Gm. 1789) to vaccination against avian influenza with an inactivated H5N2 vaccine. Acta Vet Scand 2016; 58:74. [PMID: 27770803 PMCID: PMC5075189 DOI: 10.1186/s13028-016-0255-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 10/10/2016] [Indexed: 11/10/2022] Open
Abstract
Background Recent epidemics of highly pathogenic avian influenza (HPAI) produced an unprecedented number of cases in mute swans (Cygnus olor) in European countries, which indicates that these birds are very sensitive to the H5N1 virus. The HPAI outbreaks stirred a debate on the controversial stamping-out policy in populations of protected bird species. After preventive vaccination had been approved in the European Union, several countries have introduced vaccination schemes to protect poultry, captive wild birds or exotic birds in zoos against HPAI. The aim of this study was to investigate the immune response of wild mute swans to immunization with an inactivated AI H5N2 vaccine approved for use in poultry. The serological responses of mute swans were assessed by comparison with racing pigeons (Columba livia), a species which is characterized by different susceptibility to infection with the H5N1 HPAI virus and plays a questionable role in the ecology of influenza (H5N1) viruses. Results Swans were vaccinated once or twice at an interval of 4 weeks. The humoral immune response was evaluated by hemagglutination inhibition (HI) and NP-ELISA. The lymphocyte blast transformation test was used to determine the cell-mediated immune response. Higher values of the geometric mean titer (GMT) and 100 % seroconversion (HI ≥32) were noted in double vaccinated swans (1448.2) than in single vaccinated swans (128.0) or in double vaccinated pigeons (215.3). Significant differences in HI titers were observed between swans and pigeons, but no variations in ELISA scores were noted after the booster dose. Immunization of swans had no effect on the proliferative activity of lymphocytes. Conclusions The inactivated H5N2 vaccine was safe and immunogenic for mute swans and pigeons. Vaccination may have practical implications for swans kept in zoos, wildlife parks or rehabilitation centers. However, challenge studies are needed to prove the efficacy of the H5N2 AI vaccine.
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12
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Sitaras I, Rousou X, Kalthoff D, Beer M, Peeters B, de Jong MCM. Role of vaccination-induced immunity and antigenic distance in the transmission dynamics of highly pathogenic avian influenza H5N1. J R Soc Interface 2016; 13:20150976. [PMID: 26763336 DOI: 10.1098/rsif.2015.0976] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Highly pathogenic avian influenza (HPAI) H5N1 epidemics in poultry cause huge economic losses as well as sporadic human morbidity and mortality. Vaccination in poultry has often been reported as being ineffective in preventing transmission and as a potential driving force in the selection of immune escape mutants. We conducted transmission experiments to evaluate the transmission dynamics of HPAI H5N1 strains in chickens vaccinated with high and low doses of immune escape mutants we have previously selected, and analysed the data using mathematical models. Remarkably, we demonstrate that the effect of antigenic distances between the vaccine and challenge strains used in this study is too small to influence the transmission dynamics of the strains used. This is because the effect of a sufficient vaccine dose on antibody levels against the challenge viruses is large enough to compensate for any decrease in antibody titres due to antigenic differences between vaccine and challenge strains. Our results show that at least under experimental conditions, vaccination will remain effective even after antigenic changes as may be caused by the initial selection in vaccinated birds.
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Affiliation(s)
- Ioannis Sitaras
- Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Radix Building 107, Droevendaalsesteeg 1, Wageningen 6708 PB, The Netherlands Department of Virology, Central Veterinary Institute of Wageningen University and Research Centre, Houtribweg 39, Lelystad 8221 RA, The Netherlands
| | - Xanthoula Rousou
- Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Radix Building 107, Droevendaalsesteeg 1, Wageningen 6708 PB, The Netherlands
| | - Donata Kalthoff
- Institute of Diagnostic Virology, Friedrich-Löffler Institut, Südufer 10, Greifswald-Insel Riems 17493, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Löffler Institut, Südufer 10, Greifswald-Insel Riems 17493, Germany
| | - Ben Peeters
- Department of Virology, Central Veterinary Institute of Wageningen University and Research Centre, Houtribweg 39, Lelystad 8221 RA, The Netherlands
| | - Mart C M de Jong
- Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Radix Building 107, Droevendaalsesteeg 1, Wageningen 6708 PB, The Netherlands
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Hagenaars TJ, Fischer EAJ, Jansen CA, Rebel JMJ, Spekreijse D, Vervelde L, Backer JA, de Jong MCM, Koets AP. Modelling the Innate Immune Response against Avian Influenza Virus in Chicken. PLoS One 2016; 11:e0157816. [PMID: 27328069 PMCID: PMC4915690 DOI: 10.1371/journal.pone.0157816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 06/06/2016] [Indexed: 11/22/2022] Open
Abstract
At present there is limited understanding of the host immune response to (low pathogenic) avian influenza virus infections in poultry. Here we develop a mathematical model for the innate immune response to avian influenza virus in chicken lung, describing the dynamics of viral load, interferon-α, -β and -γ, lung (i.e. pulmonary) cells and Natural Killer cells. We use recent results from experimentally infected chickens to validate some of the model predictions. The model includes an initial exponential increase of the viral load, which we show to be consistent with experimental data. Using this exponential growth model we show that the duration until a given viral load is reached in experiments with different inoculation doses is consistent with a model assuming a linear relationship between initial viral load and inoculation dose. Subsequent to the exponential-growth phase, the model results show a decline in viral load caused by both target-cell limitation as well as the innate immune response. The model results suggest that the temporal viral load pattern in the lungs displayed in experimental data cannot be explained by target-cell limitation alone. For biologically plausible parameter values the model is able to qualitatively match to data on viral load in chicken lungs up until approximately 4 days post infection. Comparison of model predictions with data on CD107-mediated degranulation of Natural Killer cells yields some discrepancy also for earlier days post infection.
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Affiliation(s)
- T. J. Hagenaars
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands
- * E-mail:
| | - E. A. J. Fischer
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands
| | - C. A. Jansen
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - J. M. J. Rebel
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands
| | - D. Spekreijse
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - L. Vervelde
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - J. A. Backer
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands
| | - M. C. M. de Jong
- Quantitative Veterinary Epidemiology, Wageningen University, Wageningen, The Netherlands
| | - A. P. Koets
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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14
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Kilany WH, Safwat M, Mohammed SM, Salim A, Fasina FO, Fasanmi OG, Shalaby AG, Dauphin G, Hassan MK, Lubroth J, Jobre YM. Protective Efficacy of Recombinant Turkey Herpes Virus (rHVT-H5) and Inactivated H5N1 Vaccines in Commercial Mulard Ducks against the Highly Pathogenic Avian Influenza (HPAI) H5N1 Clade 2.2.1 Virus. PLoS One 2016; 11:e0156747. [PMID: 27304069 PMCID: PMC4909235 DOI: 10.1371/journal.pone.0156747] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/18/2016] [Indexed: 02/05/2023] Open
Abstract
In Egypt, ducks kept for commercial purposes constitute the second highest poultry population, at 150 million ducks/year. Hence, ducks play an important role in the introduction and transmission of avian influenza (AI) in the Egyptian poultry population. Attempts to control outbreaks include the use of vaccines, which have varying levels of efficacy and failure. To date, the effects of vaccine efficacy has rarely been determined in ducks. In this study, we evaluated the protective efficacy of a live recombinant vector vaccine based on a turkey Herpes Virus (HVT) expressing the H5 gene from a clade 2.2 H5N1 HPAIV strain (A/Swan/Hungary/499/2006) (rHVT-H5) and a bivalent inactivated H5N1 vaccine prepared from clade 2.2.1 and 2.2.1.1 H5N1 seeds in Mulard ducks. A 0.3ml/dose subcutaneous injection of rHVT-H5 vaccine was administered to one-day-old ducklings (D1) and another 0.5ml/dose subcutaneous injection of the inactivated MEFLUVAC was administered at 7 days (D7). Four separate challenge experiments were conducted at Days 21, 28, 35 and 42, in which all the vaccinated ducks were challenged with 106EID50/duck of H5N1 HPAI virus (A/chicken/Egypt/128s/2012(H5N1) (clade 2.2.1) via intranasal inoculation. Maternal-derived antibody regression and post-vaccination antibody immune responses were monitored weekly. Ducks vaccinated at 21, 28, 35 and 42 days with the rHVT-H5 and MEFLUVAC vaccines were protected against mortality (80%, 80%, 90% and 90%) and (50%, 70%, 80% and 90%) respectively, against challenges with the H5N1 HPAI virus. The amount of viral shedding and shedding rates were lower in the rHVT-H5 vaccine groups than in the MEFLUVAC groups only in the first two challenge experiments. However, the non-vaccinated groups shed significantly more of the virus than the vaccinated groups. Both rHVT-H5 and MEFLUVAC provide early protection, and rHVT-H5 vaccine in particular provides protection against HPAI challenge.
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Affiliation(s)
- Walid H. Kilany
- Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt
- * E-mail: (WHK); (FOF)
| | - Marwa Safwat
- Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt
| | - Samy M. Mohammed
- Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt
- Food and Agriculture Organization of the United Nations (FAO)–Emergency Center of Transboundary Animal Diseases (ECTAD), P.O. Box, 2223, Giza, Egypt
| | - Abdullah Salim
- Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt
| | - Folorunso Oludayo Fasina
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, South Africa
- * E-mail: (WHK); (FOF)
| | - Olubunmi G. Fasanmi
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, & Department of Animal Health, Federal College of Animal Health and Production Technology, Ibadan, Nigeria
| | - Azhar G. Shalaby
- Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt
| | - Gwenaelle Dauphin
- Food and Agriculture Organization (FAO) Viale delle Terme di Caracalla, 00153 Rome, Italy
| | - Mohammed K. Hassan
- Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt
| | - Juan Lubroth
- Food and Agriculture Organization (FAO) Viale delle Terme di Caracalla, 00153 Rome, Italy
| | - Yilma M. Jobre
- Food and Agriculture Organization of the United Nations (FAO)–Emergency Center of Transboundary Animal Diseases (ECTAD), P.O. Box, 2223, Giza, Egypt
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15
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Controlling highly pathogenic avian influenza outbreaks: An epidemiological and economic model analysis. Prev Vet Med 2015; 121:142-50. [PMID: 26087887 DOI: 10.1016/j.prevetmed.2015.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 06/02/2015] [Accepted: 06/04/2015] [Indexed: 11/23/2022]
Abstract
Outbreaks of highly pathogenic avian influenza (HPAI) can cause large losses for the poultry sector and for animal disease controlling authorities, as well as risks for animal and human welfare. In the current simulation approach epidemiological and economic models are combined to compare different strategies to control highly pathogenic avian influenza in Dutch poultry flocks. Evaluated control strategies are the minimum EU strategy (i.e., culling of infected flocks, transport regulations, tracing and screening of contact flocks, establishment of protection and surveillance zones), and additional control strategies comprising pre-emptive culling of all susceptible poultry flocks in an area around infected flocks (1 km, 3 km and 10 km) and emergency vaccination of all flocks except broilers around infected flocks (3 km). Simulation results indicate that the EU strategy is not sufficient to eradicate an epidemic in high density poultry areas. From an epidemiological point of view, this strategy is the least effective, while pre-emptive culling in 10 km radius is the most effective of the studied strategies. But these two strategies incur the highest costs due to long duration (EU strategy) and large-scale culling (pre-emptive culling in 10 km radius). Other analysed pre-emptive culling strategies (i.e., in 1 km and 3 km radius) are more effective than the analysed emergency vaccination strategy (in 3 km radius) in terms of duration and size of the epidemics, despite the assumed optimistic vaccination capacity of 20 farms per day. However, the total costs of these strategies differ only marginally. Extending the capacity for culling substantially reduces the duration, size and costs of the epidemic. This study demonstrates the strength of combining epidemiological and economic model analysis to gain insight in a range of consequences and thus to serve as a decision support tool in the control of HPAI epidemics.
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16
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Jonges M, van Leuken J, Wouters I, Koch G, Meijer A, Koopmans M. Wind-Mediated Spread of Low-Pathogenic Avian Influenza Virus into the Environment during Outbreaks at Commercial Poultry Farms. PLoS One 2015; 10:e0125401. [PMID: 25946115 PMCID: PMC4422664 DOI: 10.1371/journal.pone.0125401] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/23/2015] [Indexed: 02/06/2023] Open
Abstract
Avian influenza virus-infected poultry can release a large amount of virus-contaminated droppings that serve as sources of infection for susceptible birds. Much research so far has focused on virus spread within flocks. However, as fecal material or manure is a major constituent of airborne poultry dust, virus-contaminated particulate matter from infected flocks may be dispersed into the environment. We collected samples of suspended particulate matter, or the inhalable dust fraction, inside, upwind and downwind of buildings holding poultry infected with low-pathogenic avian influenza virus, and tested them for the presence of endotoxins and influenza virus to characterize the potential impact of airborne influenza virus transmission during outbreaks at commercial poultry farms. Influenza viruses were detected by RT-PCR in filter-rinse fluids collected up to 60 meters downwind from the barns, but virus isolation did not yield any isolates. Viral loads in the air samples were low and beyond the limit of RT-PCR quantification except for one in-barn measurement showing a virus concentration of 8.48 x 10(4) genome copies/m(3). Air samples taken outside poultry barns had endotoxin concentrations of ~50 EU/m(3) that declined with increasing distance from the barn. Atmospheric dispersion modeling of particulate matter, using location-specific meteorological data for the sampling days, demonstrated a positive correlation between endotoxin measurements and modeled particulate matter concentrations, with an R(2) varying from 0.59 to 0.88. Our data suggest that areas at high risk for human or animal exposure to airborne influenza viruses can be modeled during an outbreak to allow directed interventions following targeted surveillance.
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Affiliation(s)
- Marcel Jonges
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Jeroen van Leuken
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
- Institute for Risk Assessment Sciences, Faculty of Veterinary Sciences, Utrecht University, Utrecht, The Netherlands
| | - Inge Wouters
- Institute for Risk Assessment Sciences, Faculty of Veterinary Sciences, Utrecht University, Utrecht, The Netherlands
| | - Guus Koch
- Central Veterinary Institute, Wageningen University & Research Center, Lelystad, The Netherlands
| | - Adam Meijer
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Marion Koopmans
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
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17
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Cornelissen JBWJ, Post J, Peeters B, Vervelde L, Rebel JMJ. Differential innate responses of chickens and ducks to low-pathogenic avian influenza. Avian Pathol 2014; 41:519-29. [PMID: 23237364 DOI: 10.1080/03079457.2012.732691] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ducks and chickens are hosts of avian influenza virus, each with distinctive responses to infection. To understand these differences, we characterized the innate immune response to low-pathogenicity avian influenza virus H7N1 infection in chickens and ducks. Viral RNA was detected in the lungs of chickens from day 0.8 to 7, in ducks mainly at day 4. In both species, viral RNA was detected in the bursa and gut. Infection in chickens resulted in up-regulation of interferon (IFN)-α and IFN-β mRNA, while in the ducks IFN-γ mRNA was strongly up-regulated in the lung and bursa. In chickens and ducks, all investigated pathogen recognition receptor (PRR) mRNAs were up-regulated; however, in the chicken lung Toll-like receptor (TLR)7 and melanoma differentiation-associated protein (MDA)-5 mRNA were strongly induced. TLR3, TLR7 and MDA-5 responses correlated with IFN-α and IFN-β responses in chickens, but in ducks a correlation between IFN-α and TLR7, retinoic acid-inducible gene-I and MDA-5 was absent. We studied the responses of duck and chicken splenocytes to poly(I:C) and R848 analogues to analyse the regulation of PRRs without the interfering mechanisms of the influenza virus. This revealed IFN-α and IFN-γ responses in both species. MDA-5 was only strongly up-regulated in chicken splenocytes, in which time-related PRR responses correlated with the IFN-α and IFN-β response. This correlation was absent in duck splenocytes. In conclusion, chickens and ducks differ in induction of MDA-5, TLR7 and IFN-α mRNA after an influenza virus infection in vivo and after in vitro stimulation with TLR antagonists.
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Affiliation(s)
- J B W J Cornelissen
- Central Veterinary Institute of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, the Netherlands.
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18
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Antibody response and risk factors for seropositivity in backyard poultry following mass vaccination against highly pathogenic avian influenza and Newcastle disease in Indonesia. Epidemiol Infect 2014; 143:1632-42. [PMID: 25316261 DOI: 10.1017/s0950268814002623] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A large-scale mass vaccination campaign was carried out in Java, Indonesia in an attempt to control outbreaks of highly pathogenic avian influenza (HPAI) in backyard flocks and commercial smallholder poultry. Sero-monitoring was conducted in mass vaccination and control areas to assess the proportion of the target population with antibodies against HPAI and Newcastle disease (ND). There were four rounds of vaccination, and samples were collected after each round resulting in a total of 27 293 samples. Sampling was performed irrespective of vaccination status. In the mass vaccination areas, 20-45% of poultry sampled had a positive titre to H5 after each round of vaccination, compared to 2-3% in the control group. In the HPAI + ND vaccination group, 12-25% of the population had positive ND titres, compared to 5-13% in the areas without ND vaccination. The level of seropositivity varied by district, age of the bird, and species (ducks vs. chickens).
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19
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Peeters B, Tonnis WF, Murugappan S, Rottier P, Koch G, Frijlink HW, Huckriede A, Hinrichs WLJ. Pulmonary immunization of chickens using non-adjuvanted spray-freeze dried whole inactivated virus vaccine completely protects against highly pathogenic H5N1 avian influenza virus. Vaccine 2014; 32:6445-50. [PMID: 25285885 DOI: 10.1016/j.vaccine.2014.09.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 08/29/2014] [Accepted: 09/22/2014] [Indexed: 12/28/2022]
Abstract
Highly pathogenic avian influenza (HPAI) H5N1 virus is a major threat to public health as well as to the global poultry industry. Most fatal human infections are caused by contact with infected poultry. Therefore, preventing the virus from entering the poultry population is a priority. This is, however, problematic in emergency situations, e.g. during outbreaks in poultry, as there are currently no mass application methods to effectively vaccinate large numbers of birds within a short period of time. To evaluate the suitability of needle-free pulmonary immunization for mass vaccination of poultry against HPAI H5N1, we performed a proof-of-concept study in which we investigated whether non-adjuvanted spray-freeze-dried (SFD) whole inactivated virus (WIV) can be used as a dry powder aerosol vaccine to immunize chickens. Our results show that chickens that received SFD-WIV vaccine as aerosolized powder directly at the syrinx (the site of the tracheal bifurcation), mounted a protective antibody response after two vaccinations and survived a lethal challenge with HPAI H5N1. Furthermore, both the number of animals that shed challenge virus, as well as the level of virus shedding, were significantly reduced. Based on antibody levels and reduction of virus shedding, pulmonary vaccination with non-adjuvanted vaccine was at least as efficient as intratracheal vaccination using live virus. Animals that received aerosolized SFD-WIV vaccine by temporary passive inhalation showed partial protection (22% survival) and a delay in time-to-death, thereby demonstrating the feasibility of the method, but indicating that the efficiency of vaccination by passive inhalation needs further improvement. Altogether our results provide a proof-of-concept that pulmonary vaccination using an SFD-WIV powder vaccine is able to protect chickens from lethal HPAI challenge. If the efficacy of pulmonary vaccination by passive inhalation can be improved, this method might be suitable for mass application.
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Affiliation(s)
- Ben Peeters
- Central Veterinary Institute of Wageningen University and Research Centre, P.O. Box 65, 8200 AB Lelystad, The Netherlands.
| | - Wouter F Tonnis
- University of Groningen, Department of Pharmaceutical Technology and Biopharmacy, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Senthil Murugappan
- University of Groningen, Department of Pharmaceutical Technology and Biopharmacy, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Peter Rottier
- Virology Division, Department of Infectious Diseases and Immunology, Utrecht University, Faculty of Veterinary Medicine, Yalelaan 1, 3584 CL Utrecht, The Netherlands
| | - Guus Koch
- Central Veterinary Institute of Wageningen University and Research Centre, P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - Henderik W Frijlink
- University of Groningen, Department of Pharmaceutical Technology and Biopharmacy, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Anke Huckriede
- University Medical Center Groningen, Department of Medical Microbiology, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Wouter L J Hinrichs
- University of Groningen, Department of Pharmaceutical Technology and Biopharmacy, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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20
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Quantitative transmission characteristics of different H5 low pathogenic avian influenza viruses in Muscovy ducks. Vet Microbiol 2014; 168:78-87. [PMID: 24287046 DOI: 10.1016/j.vetmic.2013.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/21/2013] [Accepted: 10/24/2013] [Indexed: 11/23/2022]
Abstract
EU annual serosurveillance programs show that domestic duck flocks have the highest seroprevalence of H5 antibodies, demonstrating the circulation of notifiable avian influenza virus (AIV) according to OIE, likely low pathogenic (LP). Therefore, transmission characteristics of LPAIV within these flocks can help to understand virus circulation and possible risk of propagation. This study aimed at estimating transmission parameters of four H5 LPAIV (three field strains from French poultry and decoy ducks, and one clonal reverse-genetics strain derived from one of the former), using a SIR model to analyze data from experimental infections in SPF Muscovy ducks. The design was set up to accommodate rearing on wood shavings with a low density of 1.6 ducks/m(2): 10 inoculated ducks were housed together with 15 contact-exposed ducks. Infection was monitored by RNA detection on oropharyngeal and cloacal swabs using real-time RT-PCR with a cutoff corresponding to 2-7 EID50. Depending on the strain, the basic reproduction number (R0) varied from 5.5 to 42.7, confirming LPAIV could easily be transmitted to susceptible Muscovy ducks. The lowest R0 estimate was obtained for a H5N3 field strain, due to lower values of transmission rate and duration of infectious period, whereas reverse-genetics derived H5N1 strain had the highest R0. Frequency and intensity of clinical signs were also variable between strains, but apparently not associated with longer infectious periods. Further comparisons of quantitative transmission parameters may help to identify relevant viral genetic markers for early detection of potentially more virulent strains during surveillance of LPAIV.
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21
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Guan Y, Smith GJ. The emergence and diversification of panzootic H5N1 influenza viruses. Virus Res 2013; 178:35-43. [PMID: 23735533 PMCID: PMC4017639 DOI: 10.1016/j.virusres.2013.05.012] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 04/23/2013] [Accepted: 05/20/2013] [Indexed: 02/05/2023]
Abstract
The Asian highly pathogenic avian influenza H5N1 virus was first detected in the goose population of Guangdong, China in 1996. The viruses in this lineage are unique in their ecological success, demonstrating an extremely broad host range and becoming established in poultry over much of Asia and in Africa. H5N1 viruses have also diverged into multiple clades and subclades that generally do not cross neutralize, which has greatly confounded control measures in poultry and pre-pandemic vaccine strain selection. Although H5N1 viruses currently cannot transmit efficiently between mammals they exhibit high mortality in humans and recent experimental studies have shown that it is possible to generate an H5N1 virus that is transmissible in mammals. In addition to causing unprecedented economic losses, the long-term presence of the H5N1 virus in poultry and its frequent introductions to humans continue to pose a significant pandemic threat. Here we provide a summary of the genesis, molecular epidemiology and evolution of this H5N1 lineage, particularly the factors that have contributed to the continued diversification and ecological success of H5N1 viruses, with particular reference to the poultry production systems they have emerged from.
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Affiliation(s)
- Yi Guan
- State Key Laboratory of Emerging Infectious Diseases and Center of Influenza Research, The University of Hong Kong, Hong Kong SAR, China
- International Institution of Infection and Immunity, Shantou University Medical College, Shantou, China
| | - Gavin J.D. Smith
- Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857
- Duke Global Health Institute, Duke University, Box 90519, Durham, North Carolina 27708
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22
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Glycans from avian influenza virus are recognized by chicken dendritic cells and are targets for the humoral immune response in chicken. Mol Immunol 2013; 56:452-62. [DOI: 10.1016/j.molimm.2013.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 06/13/2013] [Accepted: 06/15/2013] [Indexed: 11/22/2022]
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23
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Pantin-Jackwood MJ, Suarez DL. Vaccination of domestic ducks against H5N1 HPAI: A review. Virus Res 2013; 178:21-34. [DOI: 10.1016/j.virusres.2013.07.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 05/21/2013] [Accepted: 07/18/2013] [Indexed: 01/08/2023]
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24
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Cha RM, Smith D, Shepherd E, Davis CT, Donis R, Nguyen T, Nguyen HD, Do HT, Inui K, Suarez DL, Swayne DE, Pantin-Jackwood M. Suboptimal protection against H5N1 highly pathogenic avian influenza viruses from Vietnam in ducks vaccinated with commercial poultry vaccines. Vaccine 2013; 31:4953-60. [PMID: 23994373 DOI: 10.1016/j.vaccine.2013.08.046] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 08/01/2013] [Accepted: 08/13/2013] [Indexed: 12/22/2022]
Abstract
Domestic ducks are the second most abundant poultry species in many Asian countries including Vietnam, and play a critical role in the epizootiology of H5N1 highly pathogenic avian influenza (HPAI) [FAO]. In this study, we examined the protective efficacy in ducks of two commercial H5N1 vaccines widely used in Vietnam; Re-1 containing A/goose/Guangdong/1/1996 hemagglutinin (HA) clade 0 antigens, and Re-5 containing A/duck/Anhui/1/2006 HA clade 2.3.4 antigens. Ducks received two doses of either vaccine at 7 and at 14 or 21 days of age followed by challenge at 30 days of age with viruses belonging to the HA clades 1.1, 2.3.4.3, 2.3.2.1.A and 2.3.2.1.B isolated between 2008 and 2011 in Vietnam. Ducks vaccinated with the Re-1 vaccine were protected after infection with the two H5N1 HPAI viruses isolated in 2008 (HA clades 1.1 and 2.3.4.3) showing no mortality and limited virus shedding. The Re-1 and Re-5 vaccines conferred 90-100% protection against mortality after challenge with the 2010 H5N1 HPAI viruses (HA clade 2.3.2.1.A); but vaccinated ducks shed virus for more than 7 days after challenge. Similarly, the Re-1 and Re-5 vaccines only showed partial protection against the 2011 H5N1 HPAI viruses (HA clade 2.3.2.1.A and 2.3.2.1.B), with a high proportion of vaccinated ducks shedding virus for more than 10 days. Furthermore, 50% mortality was observed in ducks vaccinated with Re-1 and challenged with the 2.3.2.1.B virus. The HA proteins of the 2011 challenge viruses had the greatest number of amino acid differences from the two vaccines as compared to the viruses from 2008 and 2009, which correlates with the lesser protection observed with these viruses. These studies demonstrate the suboptimal protection conferred by the Re-1 and Re-5 commercial vaccines in ducks against H5N1 HPAI clade 2.3.2.1 viruses, and underscore the importance of monitoring vaccine efficacy in the control of H5N1 HPAI in ducks.
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Affiliation(s)
- Ra Mi Cha
- Exotic and Emerging Avian Viral Diseases Unit, Southeast Poultry Research Laboratory, USDA-Agricultural Research Service, 934 College Station Road, Athens, GA 30605, USA
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25
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Niqueux E, Guionie O, Amelot M, Jestin V. Prime-boost vaccination with recombinant H5-fowlpox and Newcastle disease virus vectors affords lasting protection in SPF Muscovy ducks against highly pathogenic H5N1 influenza virus. Vaccine 2013; 31:4121-8. [PMID: 23845804 DOI: 10.1016/j.vaccine.2013.06.074] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/28/2013] [Accepted: 06/25/2013] [Indexed: 11/25/2022]
Abstract
Vaccination protocols were evaluated in one-day old Muscovy ducklings, using an experimental Newcastle disease recombinant vaccine (vNDV-H5) encoding an optimized synthetic haemagglutinin gene from a clade 2.2.1 H5N1 highly pathogenic (HP) avian influenza virus (AIV), either as a single administration or as a boost following a prime inoculation with a fowlpox vectored vaccine (vFP89) encoding a different H5 HP haemagglutinin from an Irish H5N8 strain. These vaccination schemes did not induce detectable levels of serum antibodies in HI test using a clade 2.2.1 H5N1 antigen, and only induced H5 ELISA positive response in less than 10% of vaccinated ducks. However, following challenge against a clade 2.2.1 HPAIV, both protocols afforded full clinical protection at six weeks of age, and full protection against mortality at nine weeks. Only the prime-boost vaccination (vFP89+vNDV-H5) was still fully protecting Muscovy ducks against disease and mortality at 12 weeks of age. Reduction of oropharyngeal shedding levels was also constantly observed from the onset of the follow-up at 2.5 or three days post-infection in vaccinated ducks compared to unvaccinated controls, and was significantly more important for vFP89+vNDV-H5 vaccination than for vNDV-H5 alone. Although the latter vaccine is shown immunogenic in one-day old Muscovy ducks, the present work is original in demonstrating the high efficacy of the successive administration of two different vector vaccines encoding two different H5 in inducing lasting protection (at least similar to the one induced by an inactivated reassortant vaccine, Re-5). In addition, such a prime-boost schedule allows implementation of a DIVA strategy (to differentiate vaccinated from infected ducks) contrary to Re-5, involves easy practice on the field (with injection at the hatchery and mass vaccination later on), and should avoid eventual interference with NDV maternally derived antibodies. Last, the HA insert could be updated according to the epidemiological situation.
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Affiliation(s)
- Eric Niqueux
- Anses (French Agency for Food, Environmental and Occupational Health Safety), Ploufragan/Plouzané Laboratory, Avian and Rabbit Virology Immunology and Parasitology Unit (VIPAC), B.P. 53, 22440 Ploufragan, France.
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Cornelissen JBWJ, Vervelde L, Post J, Rebel JMJ. Differences in highly pathogenic avian influenza viral pathogenesis and associated early inflammatory response in chickens and ducks. Avian Pathol 2013; 42:347-64. [PMID: 23782222 DOI: 10.1080/03079457.2013.807325] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We studied the immunological responses in the lung, brain and spleen of ducks and chickens within the first 7 days after infection with H7N1 highly pathogenic avian influenza (HPAI). Infection with HPAI caused significant morbidity and mortality in chickens, while in ducks the infection was asymptomatic. The HPAI viral mRNA load was higher in all investigated tissues of chickens compared with duck tissues. In the lung, brain and spleen of HPAI-infected chickens, a high, but delayed, pro-inflammatory response of IL-6 and IL-1β mRNA was induced, including up-regulation of IFN-β, IFN-γ, TLR3 and MDA-5 mRNA from 1 day post infection (p.i.). Whereas in ducks already at 8 h p.i., a quicker but lower response was found for IL-6, IL-1β and iNOS mRNA followed by a delayed activation of TLR7, RIG-I, MDA5 and IFN-γ mRNA response. Virus-infected areas in the lung of chickens co-localized with KUL-01⁺ (macrophages, dendritic cells), CD4⁺, and CD8α⁺ cells, during the first day after infection. However, only KUL-01⁺ cells co-localized with the virus after 1 day p.i. In ducks, CVI-ChNL-68.1⁺ (macrophage-like cells), CD4⁺ and CD8α⁺ cells and apoptosis co-localized with the virus within 8 h p.i. Apoptosis was detected in the brain and lung of HPAI-infected chickens after 2 days p.i. and apoptotic cells co-localized with virus-infected areas. In conclusion, excessive delayed cytokine inflammatory responses but inadequate cellular immune responses may contribute to pathogenesis in chickens, while ducks initiate a fast lower cytokine response followed by the activation of major pattern recognition receptors (TLR7, RIG-I, MDA5) and a persistent cellular response.
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Affiliation(s)
- J B W J Cornelissen
- Department of Infection Biology, Central Veterinary Institute of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands.
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Halbherr SJ, Brostoff T, Tippenhauer M, Locher S, Berger Rentsch M, Zimmer G. Vaccination with recombinant RNA replicon particles protects chickens from H5N1 highly pathogenic avian influenza virus. PLoS One 2013; 8:e66059. [PMID: 23762463 PMCID: PMC3677925 DOI: 10.1371/journal.pone.0066059] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 05/02/2013] [Indexed: 01/17/2023] Open
Abstract
Highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 not only cause a devastating disease in domestic chickens and turkeys but also pose a continuous threat to public health. In some countries, H5N1 viruses continue to circulate and evolve into new clades and subclades. The rapid evolution of these viruses represents a problem for virus diagnosis and control. In this work, recombinant vesicular stomatitis virus (VSV) vectors expressing HA of subtype H5 were generated. To comply with biosafety issues the G gene was deleted from the VSV genome. The resulting vaccine vector VSV*ΔG(HA) was propagated on helper cells providing the VSV G protein in trans. Vaccination of chickens with a single intramuscular dose of 2×10⁸ infectious replicon particles without adjuvant conferred complete protection from lethal H5N1 infection. Subsequent application of the same vaccine strongly boosted the humoral immune response and completely prevented shedding of challenge virus and transmission to sentinel birds. The vaccine allowed serological differentiation of infected from vaccinated animals (DIVA) by employing a commercially available ELISA. Immunized chickens produced antibodies with neutralizing activity against multiple H5 viruses representing clades 1, 2.2, 2.5, and low-pathogenic avian influenza viruses (classical clade). Studies using chimeric H1/H5 hemagglutinins showed that the neutralizing activity was predominantly directed against the globular head domain. In summary, these results suggest that VSV replicon particles are safe and potent DIVA vaccines that may help to control avian influenza viruses in domestic poultry.
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Affiliation(s)
- Stefan J Halbherr
- Institute of Virology and Immunology-IVI, Mittelhäusern, Switzerland
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28
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Walker PGT, Jost C, Ghani AC, Cauchemez S, Bett B, Azhar M, Murahman J, Widiastuti T, Daju D, Mariner J. Estimating the transmissibility of H5N1 and the effect of vaccination in Indonesia. Transbound Emerg Dis 2013; 62:200-8. [PMID: 23731554 DOI: 10.1111/tbed.12108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Indexed: 11/28/2022]
Abstract
The spread of H5N1 avian influenza continues to pose an economic burden and a public health risk worldwide. Despite this, estimates of the transmissibility of infection exist in only a handful of settings and vary considerably. Using final size methods and flock-level infection data from a field trial of mass vaccination, we obtained the first estimates of the transmissibility of infection between and within flocks in Indonesia. We also found that outbreaks in areas designated as vaccination zones were less transmissible than in non-vaccination zones. However, this reduction is only comparable with a limited degree of protective vaccination coverage. Quantifying the overall effect of vaccination in these zones remains challenging. However, this result would appear to imply that, although the interventions applied in vaccination zones were not sufficient to completely prevent transmission in all areas, when outbreaks occur, they are less transmissible than those in areas where vaccination was not applied. This could be either a direct or an indirect effect of vaccination. Given the dynamism of small-scale poultry production in Indonesia, more regular vaccination may be required to ensure that infection is fully controlled in vaccination zones.
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Affiliation(s)
- P G T Walker
- MRC Centre for Outbreak Analysis & Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
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29
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Oleson JJ, Wikle CK. Predicting infectious disease outbreak risk via migratory waterfowl vectors. J Appl Stat 2013. [DOI: 10.1080/02664763.2012.750286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Jansen CA, de Geus ED, van Haarlem DA, van de Haar PM, Löndt BZ, Graham SP, Göbel TW, van Eden W, Brookes SM, Vervelde L. Differential lung NK cell responses in avian influenza virus infected chickens correlate with pathogenicity. Sci Rep 2013; 3:2478. [PMID: 23963354 PMCID: PMC3748423 DOI: 10.1038/srep02478] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 07/31/2013] [Indexed: 01/22/2023] Open
Abstract
Infection of chickens with low pathogenicity avian influenza (LPAI) virus results in mild clinical signs while infection with highly pathogenic avian influenza (HPAI) viruses causes death of the birds within 36-48 hours. Since natural killer (NK) cells have been shown to play an important role in influenza-specific immunity, we hypothesise that NK cells are involved in this difference in pathogenicity. To investigate this, the role of chicken NK-cells in LPAI virus infection was studied. Next activation of lung NK cells upon HPAI virus infection was analysed. Infection with a H9N2 LPAI virus resulted in the presence of viral RNA in the lungs which coincided with enhanced activation of lung NK cells. The presence of H5N1 viruses, measured by detection of viral RNA, did not induce activation of lung NK cells. This suggests that decreased NK-cell activation may be one of the mechanisms associated with the enhanced pathogenicity of H5N1 viruses.
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Affiliation(s)
- Christine A Jansen
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
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31
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New DIVA vaccine for the protection of poultry against H5 highly pathogenic avian influenza viruses irrespective of the N-subtype. Vaccine 2012; 30:7078-83. [DOI: 10.1016/j.vaccine.2012.09.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/06/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022]
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Avian influenza transmission risks: analysis of biosecurity measures and contact structure in Dutch poultry farming. Prev Vet Med 2012; 109:106-15. [PMID: 22998848 DOI: 10.1016/j.prevetmed.2012.09.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 08/30/2012] [Accepted: 09/03/2012] [Indexed: 11/22/2022]
Abstract
In the 2003 epidemic of highly pathogenic avian influenza in Dutch poultry, between-farm virus transmission continued for considerable time despite control measures. Gaining more insight into the mechanisms of this spread is necessary for the possible development of better control strategies. We carried out an in-depth interview study aiming to systematically explore all the poultry production activities to identify the activities that could potentially be related to virus introduction and transmission. One of the between-farm contact risks that were identified is the movement of birds between farms during thinning with violations of on-farm biosecurity protocols. In addition, several other risky management practices, risky visitor behaviours and biosecurity breaches were identified. They include human and fomite contacts that occurred without observing biosecurity protocols, poor waste management practices, presence of other animal species on poultry farms, and poor biosecurity against risks from farm neighbourhood activities. Among the detailed practices identified, taking cell phones and jewellery into poultry houses, not observing shower-in protocols and the exchange of unclean farm equipment were common. Also, sometimes certain protocols or biosecurity facilities were lacking. We also asked the interviewed farmers about their perception of transmission risks and found that they had divergent opinions about the visitor- and neighbourhood-associated risks. We performed a qualitative assessment of contact risks (as transmission pathways) based on contact type, corresponding biosecurity practices, and contact frequency. This assessment suggests that the most risky contact types are bird movements during thinning and restocking, most human movements accessing poultry houses and proximity to other poultry farms. The overall risk posed by persons and equipment accessing storage rooms and the premises-only contacts was considered to be medium. Most of the exposure risks are considered to be similar for layer and broiler farms. Our results, including those on farmer opinions, are relevant for the communication with farmers and poultry-related businesses about practices and risks. We conclude by providing recommendations for improvement of control strategies.
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Cagle C, Wasilenko J, Adams SC, Cardona CJ, To TL, Nguyen T, Spackman E, Suarez DL, Smith D, Shepherd E, Roth J, Pantin-Jackwood MJ. Differences in Pathogenicity, Response to Vaccination, and Innate Immune Responses in Different Types of Ducks Infected with a Virulent H5N1 Highly Pathogenic Avian Influenza Virus from Vietnam. Avian Dis 2012; 56:479-87. [DOI: 10.1637/10030-120511-reg.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Spekreijse D, Bouma A, Koch G, Stegeman A. Quantification of dust-borne transmission of highly pathogenic avian influenza virus between chickens. Influenza Other Respir Viruses 2012; 7:132-8. [PMID: 22487257 PMCID: PMC4986625 DOI: 10.1111/j.1750-2659.2012.00362.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Please cite this paper as: Spekreijse et al. (2013) Quantification of dust‐borne transmission of highly pathogenic avian influenza virus between chickens. Influenza and Other Respiratory Viruses 7(2) 132–138. Background Understanding the transmission of highly pathogenic avian influenza virus (HPAIv) between poultry flocks is essential to prevent and control epidemics. Dust, produced in infected chicken flocks, has been hypothesized to be an important mechanical vector for between‐flock transmission of HPAIv. Objectives The aim of our study was to quantify the amount of virus shed by infected birds and its relation to deposition of virus in the environment and the rate of dust‐borne transmission between groups of chickens. Methods Four replicate experiments were performed, each replicate with two groups of 14 chickens housed in two separate rooms. In one group, chickens were inoculated with HPAIv. Ventilation forced the air from that room to the second (recipient) group through a tube. Deceased birds in the inoculated group were replaced with new susceptible birds up to day 10 p.i. Dust samples were collected daily. Trachea and cloaca swabs were collected daily to determine virus shedding and virus spread to the recipient group. Results The amount of virus detected in dust samples in the recipient room was, on average, 103·7 EID50/m3. Virus transmission from the inoculated to the recipient group occurred in two experiments. The transmission rate parameter for dust‐borne transmission was estimated at 0·08 new infections/infectious chicken/day. Conclusions The results of this study are a first step to elucidate the importance of dust‐borne transmission of HPAIv between flocks and help interpret environmental samples.
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Affiliation(s)
- Dieuwertje Spekreijse
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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35
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Post J, Burt DW, Cornelissen JBWJ, Broks V, van Zoelen D, Peeters B, Rebel JMJ. Systemic virus distribution and host responses in brain and intestine of chickens infected with low pathogenic or high pathogenic avian influenza virus. Virol J 2012; 9:61. [PMID: 22390870 PMCID: PMC3314540 DOI: 10.1186/1743-422x-9-61] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 03/06/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Avian influenza virus (AIV) is classified into two pathotypes, low pathogenic (LP) and high pathogenic (HP), based on virulence in chickens.Differences in pathogenicity between HPAIV and LPAIV might eventually be related to specific characteristics of strains, tissue tropism and host responses. METHODS To study differences in disease development between HPAIV and LPAIV, we examined the first appearance and eventual load of viral RNA in multiple organs as well as host responses in brain and intestine of chickens infected with two closely related H7N1 HPAIV or LPAIV strains. RESULTS Both H7N1 HPAIV and LPAIV spread systemically in chickens after a combined intranasal/intratracheal inoculation. In brain, large differences in viral RNA load and host gene expression were found between H7N1 HPAIV and LPAIV infected chickens. Chicken embryo brain cell culture studies revealed that both HPAIV and LPAIV could infect cultivated embryonic brain cells, but in accordance with the absence of the necessary proteases, replication of LPAIV was limited. Furthermore, TUNEL assay indicated apoptosis in brain of HPAIV infected chickens only. In intestine, where endoproteases that cleave HA of LPAIV are available, we found minimal differences in the amount of viral RNA and a large overlap in the transcriptional responses between HPAIV and LPAIV infected chickens. Interestingly, brain and ileum differed clearly in the cellular pathways that were regulated upon an AI infection. CONCLUSIONS Although both H7N1 HPAIV and LPAIV RNA was detected in a broad range of tissues beyond the respiratory and gastrointestinal tract, our observations indicate that differences in pathogenicity and mortality between HPAIV and LPAIV could originate from differences in virus replication and the resulting host responses in vital organs like the brain.
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Affiliation(s)
- Jacob Post
- Central Veterinary Institute of Wageningen UR. P.O. Box 65, 8200 AB Lelystad, The Netherlands.
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36
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Effects of infection-induced migration delays on the epidemiology of avian influenza in wild mallard populations. PLoS One 2011; 6:e26118. [PMID: 22028812 PMCID: PMC3196538 DOI: 10.1371/journal.pone.0026118] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 09/19/2011] [Indexed: 11/23/2022] Open
Abstract
Wild waterfowl populations form a natural reservoir of Avian Influenza (AI) virus, and fears exist that these birds may contribute to an AI pandemic by spreading the virus along their migratory flyways. Observational studies suggest that individuals infected with AI virus may delay departure from migratory staging sites. Here, we explore the epidemiological dynamics of avian influenza virus in a migrating mallard (Anas platyrhynchos) population with a specific view to understanding the role of infection-induced migration delays on the spread of virus strains of differing transmissibility. We develop a host-pathogen model that combines the transmission dynamics of influenza with the migration, reproduction and mortality of the host bird species. Our modeling predicts that delayed migration of individuals influences both the timing and size of outbreaks of AI virus. We find that (1) delayed migration leads to a lower total number of cases of infection each year than in the absence of migration delay, (2) when the transmission rate of a strain is high, the outbreak starts at the staging sites at which birds arrive in the early part of the fall migration, (3) when the transmission rate is low, infection predominantly occurs later in the season, which is further delayed when there is a migration delay. As such, the rise of more virulent AI strains in waterfowl could lead to a higher prevalence of infection later in the year, which could change the exposure risk for farmed poultry. A sensitivity analysis shows the importance of generation time and loss of immunity for the effect of migration delays. Thus, we demonstrate, in contrast to many current transmission risk models solely using empirical information on bird movements to assess the potential for transmission, that a consideration of infection-induced delays is critical to understanding the dynamics of AI infection along the entire flyway.
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Gonzales JL, Elbers ARW, Bouma A, Koch G, de Wit JJ, Stegeman JA. Transmission characteristics of low pathogenic avian influenza virus of H7N7 and H5N7 subtypes in layer chickens. Vet Microbiol 2011; 155:207-13. [PMID: 21982127 DOI: 10.1016/j.vetmic.2011.09.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Revised: 09/06/2011] [Accepted: 09/12/2011] [Indexed: 12/01/2022]
Abstract
Low pathogenic avian influenza virus (LPAIv) infections of H5 and H7 subtypes in poultry are notifiable to the OIE, hence surveillance programmes are implemented. The rate at which LPAIv strains spread within a flock determines the prevalence of infected birds and the time it takes to reach that prevalence and, consequently, optimal sample size and sampling frequency. The aim of this study was to investigate the transmission characteristics of an H7N7 and an H5N7 LPAIv in layer chickens. Two transmission experiments were performed, which consisted of 30 (first experiment) and 20 (second experiment) pairs of conventional layers, respectively. At the start of the experiments, one chicken per pair was inoculated with LPAIv and the other chicken was contact-exposed. Occurrence of infection was monitored by regularly collecting tracheal and cloacal swab samples, which were examined for the presence of virus RNA by RT-PCR. The results of the test were used to estimate the transmission rate parameter (β), the infectious period (T) and the basic reproduction ratio (R(0)). In addition, egg production and virus shedding patterns were quantified. For the H7N7 virus, the β, T and R(0) estimates were 0.10 (95% confidence interval (CI): 0.04-0.18) day(-1), 7.1 (95% CI: 6.5-7.8) days and 0.7 (95% CI: 0.0-1.7), respectively. With the H5N7 virus, only a few inoculated chickens (5 out of 20) became infected and no transmission was observed. This study shows that transmission characteristics of LPAIv strains may vary considerably, which has to be taken into account when designing surveillance programmes.
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Affiliation(s)
- J L Gonzales
- Department of Epidemiology, Crisis organization and Diagnostics, Central Veterinary Institute, P.O. Box 65, 8200 AB Lelystad, The Netherlands.
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De Leo GA, Bolzoni L. Getting a free ride on poultry farms: how highly pathogenic avian influenza may persist in spite of its virulence. THEOR ECOL-NETH 2011. [DOI: 10.1007/s12080-011-0136-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Pekin and Muscovy ducks respond differently to vaccination with a H5N1 highly pathogenic avian influenza (HPAI) commercial inactivated vaccine. Vaccine 2011; 29:6549-57. [DOI: 10.1016/j.vaccine.2011.07.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 06/27/2011] [Accepted: 07/04/2011] [Indexed: 01/18/2023]
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40
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Magor KE. Immunoglobulin genetics and antibody responses to influenza in ducks. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:1008-16. [PMID: 21377488 DOI: 10.1016/j.dci.2011.02.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/23/2011] [Accepted: 02/25/2011] [Indexed: 05/24/2023]
Abstract
The role of the duck as the natural host and reservoir of influenza and efforts to vaccinate ducks during recent outbreaks of avian influenza has renewed interest in the duck antibody response. Ducks have unique antibody structures and expression, with consequences for their function. Aspects of immunoglobulin genetics, gene expression, and antibody function will be reviewed in the context of the duck immune response to influenza. Ducks have three immunoglobulin isotypes, IgM, IgA and IgY in translocon arrangement. The order of heavy chain genes in the locus is unusual, IGHM, IGHA and IGHY, with IGHA in inverse transcriptional orientation. IgH and IgL gene rearrangement in ducks involves limited V, (D) and J element recombination and diversity is generated by gene conversion from pseudogenes. IgY, the functional equivalent of IgG, is produced in two secreted forms, a full-length form and one lacking the third and fourth C region domains, which predominates later in the immune response and lacks the biological effector functions of IgG. The unusual features of duck antibodies may contribute to weak antibody responses and the perpetuation of the virus in this animal reservoir.
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Affiliation(s)
- Katharine E Magor
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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41
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Maas R, Rosema S, van Zoelen D, Venema S. Maternal immunity against avian influenza H5N1 in chickens: limited protection and interference with vaccine efficacy. Avian Pathol 2011; 40:87-92. [PMID: 21331952 DOI: 10.1080/03079457.2010.541226] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
After avian influenza (AI) vaccination, hens will produce progeny chickens with maternally derived AI-specific antibodies. In the present study we examined the effect of maternal immunity in young chickens on the protection against highly pathogenic AI H5N1 virus infection and on the effectiveness of AI vaccination. The mean haemagglutination inhibition antibody titre in sera of 14-day-old progeny chickens was approximately eight-fold lower than the mean titre in sera of vaccinated hens. After H5N1 infection at the age of 14 days, chickens with maternal antibody titres lived a few days longer than control chickens. However, only a low proportion of chickens with maternal immunity survived challenge with H5N1. In most progeny chickens with maternal immunity, high virus titres (>10(4) median embryo infective dose) were present in the trachea during the first 4 days after H5N1 infection. In the cloaca, only low virus titres were present in most chickens. In 14-day-old progeny chickens with maternal immunity, the induction of antibody titres by vaccination was severely inhibited, with only a few chickens showing responses similar to the control chickens. It is concluded that high maternal antibody titres are required for clinical protection and reduction of virus titres after infection of chickens, whereas low antibody titres already interfere with vaccine efficacy.
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Affiliation(s)
- Riks Maas
- Central Veterinary Institute of Wageningen UR, The Netherlands, Lelystad, The Netherlands.
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42
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Airborne transmission of a highly pathogenic avian influenza virus strain H5N1 between groups of chickens quantified in an experimental setting. Vet Microbiol 2011; 152:88-95. [PMID: 21565455 DOI: 10.1016/j.vetmic.2011.04.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 03/31/2011] [Accepted: 04/14/2011] [Indexed: 01/12/2023]
Abstract
Highly pathogenic avian influenza (HPAI) is a devastating viral disease of poultry and quick control of outbreaks is vital. Airborne transmission has often been suggested as a route of transmission between flocks, but knowledge of the rate of transmission via this route is sparse. In the current study, we quantified the rate of airborne transmission of an HPAI H5N1 virus strain between chickens under experimental conditions. In addition, we quantified viral load in air and dust samples. Sixteen trials were done, comprising a total of 160 chickens housed in cages, with three treatment groups. The first group was inoculated with strain A/turkey/Turkey/1/2005 H5N1, the second and third group were not inoculated, but housed at 0.2 and 1.1m distance of the first group, respectively. Tracheal and cloacal swabs were collected daily of each chicken to monitor virus transmission. Air and dust samples were taken daily to quantify virus load in the immediate surroundings of the birds. Samples were tested by quantitative RRT-PCR and virus isolation. In 4 out of 16 trials virus was transmitted from the experimentally inoculated chickens to the non-inoculated chickens. The transmission rate was 0.13 and 0.10 new infections per infectious bird at 0.2m and 1.1m, respectively. The difference between these estimates was, however, not significant. Two air samples tested positive in virus isolation, but none of these samples originated from the trials with successful transmission. Five dust samples were confirmed positive in virus isolation. The results of this study demonstrate that the rate of airborne transmission between chickens over short distances is low, suggesting that airborne transmission over a long distance is an unlikely route of spread. Whether or not this also applies to the field situation needs to be examined.
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Hsu SM, Chen THH, Wang CH. Efficacy of avian influenza vaccine in poultry: a meta-analysis. Avian Dis 2011; 54:1197-209. [PMID: 21313840 DOI: 10.1637/9305-031710-reg.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
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.
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Affiliation(s)
- Shu-Mei Hsu
- School of Veterinary Medicine, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
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44
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Single dose of oil-adjuvanted inactivated vaccine protects chickens from lethal infections of highly pathogenic H5N1 influenza virus. Vaccine 2011; 29:2178-86. [DOI: 10.1016/j.vaccine.2010.12.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 11/29/2010] [Accepted: 12/05/2010] [Indexed: 11/20/2022]
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45
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Rebel JMJ, Peeters B, Fijten H, Post J, Cornelissen J, Vervelde L. Highly pathogenic or low pathogenic avian influenza virus subtype H7N1 infection in chicken lungs: small differences in general acute responses. Vet Res 2011; 42:10. [PMID: 21314972 PMCID: PMC3037890 DOI: 10.1186/1297-9716-42-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 09/24/2010] [Indexed: 02/01/2023] Open
Abstract
Avian influenza virus can be divided into two groups, highly pathogenic avian influenza virus (HPAI) and low pathogenic avian influenza virus (LPAI) based on their difference in virulence. To investigate if the difference in clinical outcome between LPAI and HPAI in chickens is due to immunological host responses in the lung within the first 24 hours post infection (hpi), chickens were infected with LPAI or HPAI of subtype H7N1. Virus was found in the caudal and cranial part of the lung. With LPAI, virus was localised around the intrapulmonary bronchus and secondary bronchi. In sharp contrast, HPAI was detected throughout the whole lung. However, based on viral RNA levels, no quantitative difference was observed between LPAI and HPAI infected birds. In infected areas of the lungs, an influx of CD8α+ cells as well as KUL01+ macrophages and dendritic cells (DC) occurred as fast as 8 hpi in both infected groups. No major difference between LPAI and HPAI infected birds in the induction of cytokines and interferons at mRNA level in lung tissue was found.In conclusion, the differences in lethality for chickens infected with LPAI or HPAI could be ascribed to difference in location of the virus. However similar amounts of viral RNA, similar cytokine mRNA levels, and similar influxes of CD8α+ and KUL01+ macrophages and DC were found between HPAI and LPAI in the lungs. A cytokine storm at mRNA level as described for mammals was not observed in the lungs of HPAI infected birds within 24 hpi.
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Affiliation(s)
- Johanna M J Rebel
- Central Veterinary Institute, PO box 65, 8219 PH Lelystad, The Netherlands.
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46
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Eggert D, Swayne DE. Single Vaccination Provides Limited Protection to Ducks and Geese Against H5N1 High Pathogenicity Avian Influenza Virus. Avian Dis 2010; 54:1224-9. [DOI: 10.1637/9410-052810-reg.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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47
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Yao Q, Fischer KP, Li L, Agrawal B, Berhane Y, Tyrrell DL, Gutfreund KS, Pasick J. Immunogenicity and protective efficacy of a DNA vaccine encoding a chimeric protein of avian influenza hemagglutinin subtype H5 fused to CD154 (CD40L) in Pekin ducks. Vaccine 2010; 28:8147-56. [PMID: 20937323 DOI: 10.1016/j.vaccine.2010.09.081] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 09/23/2010] [Accepted: 09/26/2010] [Indexed: 11/24/2022]
Abstract
The potential of CD154 (CD40L) as a powerful immunological adjuvant has been shown in various strategies. In this study we examine the immunogenicity and protective efficacy of a CD40-targeting avian influenza hemagglutinin (HA) subunit DNA vaccine in ducks. DNA constructs encoded the ectodomain of the HA protein of LPAI A/mallard/BC/373/2005 (H5N2) with or without fusion to the ectodomain of duck CD154. CD40-targeting significantly accelerated and enhanced humoral responses to the vector-encoded HA protein. In viral challenge experiments with A/chicken/Vietnam/14/2005 (H5N1), DNA immunization conferred partial protection against the genetically distant HPAI. The observed improved kinetics and magnitude of immune induction suggest that CD40-targeting holds promise for influenza A vaccine development.
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Affiliation(s)
- Qingxia Yao
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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48
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Terregino C, Toffan A, Cilloni F, Monne I, Bertoli E, Castellanos L, Amarin N, Mancin M, Capua I. Evaluation of the protection induced by avian influenza vaccines containing a 1994 Mexican H5N2 LPAI seed strain against a 2008 Egyptian H5N1 HPAI virus belonging to clade 2.2.1 by means of serological and in vivo tests. Avian Pathol 2010; 39:215-22. [PMID: 20544428 DOI: 10.1080/03079451003781858] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Since 2006 Egypt has been facing an extensive epidemic of H5N1 highly pathogenic avian influenza (HPAI) with a huge number of outbreaks both in rural and intensively reared poultry areas. The use of efficacious vaccines in this country has been, and still remains, essential for the control and possible eradication of HPAI. The present study was performed to establish whether the administration of inactivated vaccines containing an H5 virus belonging to a different lineage to the Eurasian H5N1 HPAI viruses guarantees protection from clinical signs, provides significant immune response and is able to achieve a reduction of viral shedding in the face of a challenge with a contemporary H5N1 virus isolated in Egypt. Despite the genetic and antigenic differences between the vaccine strain (H5N2/Mexico) and the challenge strain (H5N1/Egypt), confirmed by molecular and serological (haemagglutination inhibition) tests, it was established that the immune response induced by these conventional vaccines is sufficient to prevent infection in the majority of birds challenged with a contemporary H5N1 Egyptian strain. The data reported in this study also indicate that there may be a low degree of correlation between haemagglutination inhibition titres, clinical protection and reduction of shedding.
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Affiliation(s)
- Calogero Terregino
- OIE/FAO and National Reference Laboratory for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, Legnaro, Padua, Italy.
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49
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Spekreijse D, Bouma A, Stegeman JA, Koch G, de Jong MCM. The effect of inoculation dose of a highly pathogenic avian influenza virus strain H5N1 on the infectiousness of chickens. Vet Microbiol 2010; 147:59-66. [PMID: 20619974 DOI: 10.1016/j.vetmic.2010.06.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 06/01/2010] [Accepted: 06/14/2010] [Indexed: 11/27/2022]
Abstract
Highly pathogenic avian influenza is of major concern for the poultry industry, as the virus can spread rapidly in and between flocks, causing high mortality and severe economic losses. The aim of this study was to determine the probability of infection and to determine dose-dependent virus transmission (direct transmission) for various inoculation doses. Two transmission experiments with pair-wise housed layer type chickens were performed, in which one bird per pair was inoculated with an HPAI H5N1 virus and the other contact-exposed. Various inoculation doses were used to determine the susceptibility (ID(50)), and possible relation between ID(50), and infectiousness, expressed as the amount of virus shedding and the probability of contact birds becoming infected. The infectious H5N1 dose (CID(50)) in this study was an estimated 10(2.5) egg infectious dose (EID(50))(.) Increasing the dose increased the probability of infection but survival from infection was independent of dose. In addition, increasing the dose decreased the mean latent period in the inoculated chickens significantly. This could be important for determining the time of onset of infection in a flock and thus allowing more accurate identification of the source of infection. Moreover, the amount of virus shed in trachea and cloaca by the inoculated chickens in the time between inoculation and contact infection, also differed between the various dose groups. Despite differences in latent period and virus shedding, the transmission rate parameter β and reproduction ratio R(0) did not differ significantly between the various dose groups. This implies that in this experiment the amount of virus shedding is not a measure to predict transmission or the infectiousness of chickens.
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Affiliation(s)
- D Spekreijse
- Department of Farm Animal Health, Faculty of Veterinary Medicine, University of Utrecht, P.O. Box 80151, 3508 TD Utrecht, The Netherlands.
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50
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Species-specific contribution of the four C-terminal amino acids of influenza A virus NS1 protein to virulence. J Virol 2010; 84:6733-47. [PMID: 20410267 DOI: 10.1128/jvi.02427-09] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Large-scale sequence analyses of influenza viruses revealed that nonstructural 1 (NS1) proteins from avian influenza viruses have a conserved C-terminal ESEV amino acid motif, while NS1 proteins from typical human influenza viruses have a C-terminal RSKV motif. To test the influence of the C-terminal domains of NS1 on the virulence of an avian influenza virus, we generated a wild-type H7N1 virus with an ESEV motif and a mutant virus with an NS1 protein containing a C-terminal RSKV motif by reverse genetics. We compared the phenotypes of these viruses in vitro in human, mouse, and duck cells as well as in vivo in mice and ducks. In human cells, the human C-terminal RSKV domain increased virus replication. In contrast, the avian C-terminal ESEV motif of NS1 increased virulence in mice. We linked this increase in pathogenicity in mice to an increase in virus replication and to a more severe lung inflammation associated with a higher level of production of type I interferons. Interestingly, the human C-terminal RSKV motif of NS1 increased viral replication in ducks. H7N1 virus with a C-terminal RSKV motif replicated to higher levels in ducks and induced higher levels of Mx, a type I interferon-stimulated gene. Thus, we identify the C-terminal domain of NS1 as a species-specific virulence domain.
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