Observance des mesures de biosécurité dans les élevages de volailles français : pratiques et attitudes

La biosécurité est l’un des principaux moyens de prévention des maladies en élevage. La bonne application des mesures de biosécurité (observance) constitue un enjeu majeur des filières de productions de volailles françaises, en particulier dans un contexte d’épidémies d’influenza aviaire depuis 2015. Ce manuscrit contribue à évaluer les mesures de biosécurité appliquées dans les élevages de volailles français, afin de mieux comprendre les facteurs, structurels et psycho-sociaux, à l’origine des variations d’observance. L’analyse est proposée à plusieurs échelles : (i) nationale, au moyen des rapports d’inspections de biosécurité menées par les directions départementales en charge de la protection des populations, (ii) de la filière des palmipèdes à foie gras du Sud-Ouest, au moyen d’une enquête menée dans 46 élevages représentant les différents modes de production afin de dresser un état des lieux des pratiques de biosécurité avant la survenue des crises influenza aviaire, (iii) d’un mode de production, les canards prêts-à-engraisser, au moyen d’une enquête menée chez 127 éleveurs afin d’évaluer les déterminants psychosociaux (connaissances, attitudes, traits de personnalité …) de l’observance de la biosécurité. Ces trois études ont permis de comparer différentes approches d’évaluation de la biosécurité, de dresser un état des lieux des pratiques, de mettre en évidence une hétérogénéité dans l’application des mesures et d’étudier l’effet de facteurs structurels (bassins de production, contraintes techniques des différents modes de productions de volailles) et psycho-sociaux (connaissance et compréhension de la biosécurité, caractère consciencieux des éleveurs, confiance en soi, pression sociale et perception de l’utilité de la biosécurité) sur les comportements de biosécurité. Les résultats de ces études offrent la possibilité de concevoir des interventions adaptées aux éleveurs

Inferring within-flock transmission dynamics of highly pathogenic avian influenza H5N8 virus in France, 2020.

Following the emergence of highly pathogenic avian influenza (H5N8) in France in early December 2020, we used duck mortality data from the index farm to investigate within-flock transmission dynamics. A stochastic epidemic model was fitted to the daily mortality data and model parameters were estimated using an approximate Bayesian computation sequential Monte Carlo (ABC-SMC) algorithm. The model predicted that the first bird in the flock was infected 5 days (95% credible interval, CI: 3-6) prior to the day of suspicion and that the transmission rate was 4.1 new infections per day (95% CI: 2.8-5.8). On average, ducks became infectious 4.1 h (95% CI: 0.7-9.1) after infection and remained infectious for 4.3 days (95% CI: 2.8-5.7). The model also predicted that 34% (50% prediction interval: 8%-76%) of birds would already be infectious by the day of suspicion, emphasizing the substantial latent threat this virus could pose to other poultry farms and to neighbouring wild birds. This study illustrates how mechanistic models can help provide rapid relevant insights that contribute to the management of infectious disease outbreaks of farmed animals. These methods can be applied to future outbreaks and the resulting parameter estimates made available to veterinary services within a few hours

Monitoring biosecurity in poultry production: an overview of databases reporting biosecurity compliance from seven European countries

Compliance with required on-farm biosecurity practices reduces the risk of contamination and spread of zoonotic and economically important diseases. With repeating avian influenza epidemics in the poultry industry, the need to monitor and improve the overall level of biosecurity is increasing. In practice, biosecurity compliance is assessed by various actors (e.g., academic, private and public institutions), and the results of such assessments may be recorded and gathered in databases which are seldom shared or thoroughly analyzed. This study aimed to provide an inventory of databases related to the assessment of biosecurity in poultry farms in seven major poultry-producing European countries to highlight challenges and opportunities associated with biosecurity data collection, sharing, and use. The institutions in charge of these databases were contacted and interviewed using a structured questionnaire to gather information on the main characteristics of the databases and the context of their implementation. A total of 20 databases were identified, covering the gamut of poultry species and production types. Most databases were linked to veterinary health authorities or academia, and to a lesser extent interbranch organizations. Depending on the institutions in charge, the databases serve various purposes, from providing advice to enforcing regulations. The quality of the biosecurity data collected is believed to be quite reliable, as biosecurity is mostly assessed by trained farm advisors or official veterinarians and during a farm visit. Some of the databases are difficult to analyze and/or do not offer information concerning which biosecurity measures are most or least respected. Moreover, some key biosecurity practices are sometimes absent from certain databases. Although the databases serve a variety of purposes and cover different production types, each with specific biosecurity features, their analysis should help to improve the surveillance of biosecurity in the poultry sector and provide evidence on the benefits of biosecurity

Pathobiology of highly pathogenic H5 avian influenza viruses in naturally infected Galliformes and Anseriformes in France during winter 2015-2016

In late 2015, an epizootic of Highly Pathogenic Avian Influenza (H5Nx) was registered in Southwestern France, including more than 70 outbreaks in commercial poultry flocks. Phylogenetic analyses suggested local emergence of H5 viruses which differed from A/goose/Guangdong/1/1996 clade 2.3.4.4b lineage and shared a unique polybasic cleavage site in their hemagglutinin protein. The present work provides an overview of the pathobiological picture associated with this epizootic in naturally infected chickens, guinea fowls and ducks. Upon necropsy examination, selected tissues were sampled for histopathology, immunohistochemistry and quantitative Real Time Polymerase Chain Reaction. In Galliformes, HPAIVs infection manifested as severe acute systemic vasculitis and parenchymal necrosis and was associated with endothelial expression of viral antigen. In ducks, lesions were mild and infrequent, with sparse antigenic detection in respiratory and digestive mucosae and leukocytes. Tissue quantifications of viral antigen and RNA were higher in chickens and guinea fowls compared to duck. Subsequently, recombinant HA (rHA) was generated from a H5 HPAIV isolated from an infected duck to investigate its glycan-binding affinity for avian mucosae. Glycan-binding analysis revealed strong affinity of rHA for 3'Sialyl-LacNAc and low affinity for Sialyl-LewisX, consistent with a duck-adapted virus similar to A/Duck/Mongolia/54/2001 (H5N2). K222R and S227R mutations on rHA sequence shifted affinity towards Sialyl-LewisX and led to an increased affinity for chicken mucosa, confirming the involvement of these two mutations in the glycan-binding specificity of the HA. Interestingly, the rHA glycan binding pattern of guinea fowl appeared intermediate between duck and chicken. The present study presents a unique pathobiological description of the H5 HPAIVs outbreaks that occurred in 2015-2016 in Southwestern France

Biosecurity compliance in French poultry farms : practices and attitudes

La biosécurité est l’un des principaux moyens de prévention des maladies en élevage. La bonne application des mesures de biosécurité (observance) constitue un enjeu majeur des filières de productions de volailles françaises, en particulier dans un contexte d’épidémies d’influenza aviaire depuis 2015. Ce manuscrit contribue à évaluer les mesures de biosécurité appliquées dans les élevages de volailles français, afin de mieux comprendre les facteurs, structurels et psycho-sociaux, à l’origine des variations d’observance. L’analyse est proposée à plusieurs échelles : (i) nationale, au moyen des rapports d’inspections de biosécurité menées par les directions départementales en charge de la protection des populations, (ii) de la filière des palmipèdes à foie gras du Sud-Ouest, au moyen d’une enquête menée dans 46 élevages représentant les différents modes de production afin de dresser un état des lieux des pratiques de biosécurité avant la survenue des crises influenza aviaire, (iii) d’un mode de production, les canards prêts-à-engraisser, au moyen d’une enquête menée chez 127 éleveurs afin d’évaluer les déterminants psychosociaux (connaissances, attitudes, traits de personnalité …) de l’observance de la biosécurité. Ces trois études ont permis de comparer différentes approches d’évaluation de la biosécurité, de dresser un état des lieux des pratiques, de mettre en évidence une hétérogénéité dans l’application des mesures et d’étudier l’effet de facteurs structurels (bassins de production, contraintes techniques des différents modes de productions de volailles) et psycho-sociaux (connaissance et compréhension de la biosécurité, caractère consciencieux des éleveurs, confiance en soi, pression sociale et perception de l’utilité de la biosécurité) sur les comportements de biosécurité. Les résultats de ces études offrent la possibilité de concevoir des interventions adaptées aux éleveurs.The spread of diseases between farms may be prevented with the application of adapted biosecurity measures. Compliance with on-farm biosecurity measures is a major challenge for the French poultry industry, considering the emergence of avian influenza outbreaks in 2015. This thesis proposes an assessment of biosecurity measures applied in French poultry farms, in order to better understand their structural and psycho-social determinants. The analysis was conducted at three different scales. Biosecurity measures were assessed at the national scale, using veterinary authorities inspection reports. At the scale of the ‘foie gras’ duck industry, 46 farm visits were conducted in various farm types, in order assess the biosecurity practices applied before the onset of avian influenza outbreaks. Finally, at the scale of duck grower farms, 127 farm visits were conducted in order to determine the psycho-social factors (knowledge, attitudes, personality traits) associated with biosecurity compliance. These three studies compared differents means to assess on-farm biosecurity compliance, described heterogeneous levels of adoption of biosecurity practices and proposed structural (production areas, production types and their technical constraints) and psycho-social factors associated with biosecurity compliance (knowledge and understanding of biosecurity measures, conscienciousness-related personality traits, social norm, auto-efficacy, perception of the benefits of biosecurity). These results provide valuable information for the conception of tailored interventions aiming at improving biosecurity in the long run

Etude épidémio-clinique des facteurs de risques des lésions cutanées infectées chez le poulet de chair

TOULOUSE-EN Vétérinaire (315552301) / SudocSudocFranceF

Low pathogenic avian influenza (H9N2) in chicken: Evaluation of an ancestral H9-MVA vaccine

International audienceModified Vaccinia Ankara (MVA) has proven its efficacy as a recombinant vector vaccine for numerous pathogens including influenza virus. The present study aimed at evaluating a recombinant MVA candidate vaccine against low pathogenic avian influenza virus subtype H9N2 in the chicken model. As the high genetic and antigenic diversity of H9N2 viruses increases vaccine design complexity, one strategy to widen the range of vaccine coverage is to use an ancestor sequence. We therefore generated a recombinant MVA encoding for the gene sequence of an ancestral hemagglutinin H9 protein (a computationally derived amino acid sequence of the node of the H9N2 G1 lineage strains was obtained using the ANCESCON program). We analyzed the genetics and the growth properties of the MVA vector virus confirming suitability for use under biosafety level 1 and tested its efficacy when applied either as an intra-muscular (IM) or an oral vaccine in specific pathogen free chickens challenged with A/chicken/Tunisia/12/2010(H9N2). Two control groups were studied in parallel (unvaccinated and inoculated birds; unvaccinated and non-inoculated birds). IM vaccinated birds seroconverted as early as four days post vaccination and neutralizing antibodies were detected against A/chicken/Tunisia/12/2010(H9N2) in all the birds before challenge. The role of local mucosal immunity is unclear here as no antibodies were detected in eye drop or aerosol vaccinated birds. Clinical signs were not detected in any of the infected birds even in absence of vaccination. Virus replication was observed in both vaccinated and unvaccinated chickens, suggesting the MVA-ancestral H9 vaccine may not stop virus spread in the field. However vaccinated birds showed less histological damage, fewer influenza-positive cells and shorter virus shedding than their unvaccinated counterparts. (C) 2016 Elsevier B.V. All rights reserved

Biosecurity risk factors for highly pathogenic avian influenza (H5N8) virus infection in duck farms, France

International audienceHighly pathogenic avian influenza (HPAI) subtype H5N8 outbreaks occurred in poultry farms in France in 2016-2017, resulting in significant economic losses and disruption to the poultry industry. Current evidence on associations between actual on-farm biosecurity risk factors and H5N8 occurrence is limited. Therefore, a retrospective matched case-control study was undertaken to investigate the inter-relationships between on-farm biosecurity practices and H5N8 infection status to provide new insights regarding promising targets for intervention. Data were collected on 133 case and 133 control duck farms (i.e. the most affected species) located in one area of the country that was mostly affected by the disease. Data were analysed using Additive Bayesian Networks which offer a rich modelling framework by graphically illustrating the dependencies between variables. Factors indirectly and directly positively associated with farm infection were inadequate management of vehicle movements (odds ratio [OR] 9.3, 95% credible interval [CI] 4.0-22.8) and inadequate delimitation of farm and units (OR 3.0, 95% CI 1.6-5.8), respectively. Inadequate disposal of dead birds was instead negatively associated with the outcome (OR 0.1, 95% CI 0.0-0.3). The findings highlight that reinforcing farm access control systems and reducing the number of visitors are key biosecurity measures to control farm vulnerability to H5N8 infection and could help setting priorities in biosecurity practices to prevent outbreaks' re-occurrence

Disclosing respiratory co-infections: a broad-range panel assay for avian respiratory pathogens on a nanofluidic PCR platform

<p>Respiratory syndromes (RS) are among the most significant pathological conditions in edible birds and are caused by complex coactions of pathogens and environmental factors. In poultry, low pathogenic avian influenza A viruses, metapneumoviruses, infectious bronchitis virus, infectious laryngotracheitis virus, <i>Mycoplasma</i> spp. <i>Escherichia coli</i> and/or <i>Ornithobacterium rhinotracheale</i> in turkeys are considered as key co-infectious agents of RS. <i>Aspergillus</i> sp., <i>Pasteurella multocida, Avibacterium paragallinarum</i> or <i>Chlamydia psittaci</i> may also be involved in respiratory outbreaks. An innovative quantitative PCR method, based on a nanofluidic technology, has the ability to screen up to 96 samples with 96 pathogen-specific PCR primers, at the same time, in one run of real-time quantitative PCR. This platform was used for the screening of avian respiratory pathogens: 15 respiratory agents, including viruses, bacteria and fungi potentially associated with respiratory infections of poultry, were targeted. Primers were designed and validated for SYBR green real-time quantitative PCR and subsequently validated on the Biomark high throughput PCR nanofluidic platform (Fluidigm©, San Francisco, CA, USA). As a clinical assessment, tracheal swabs were sampled from turkeys showing RS and submitted to this panel assay. Beside systematic detection of <i>E. coli</i>, avian metapneumovirus, <i>Mycoplasma gallisepticum</i> and <i>Mycoplasma synoviae</i> were frequently detected, with distinctive co-infection patterns between French and Moroccan flocks. This proof-of-concept study illustrates the potential of such panel assays for unveiling respiratory co-infection profiles in poultry.</p