The feather epithelium contributes to the dissemination and ecology of clade 2.3.4.4b H5 high pathogenicity avian influenza viruses in ducks

Immature feathers are known replication sites for high pathogenicity avian influenza viruses (HPAIVs) in poultry. However, it is unclear whether feathers play an active role in viral transmission. This study aims to investigate the contribution of the feather epithelium to the dissemination of clade 2.3.4.4b goose/Guangdong/1996 lineage H5 HPAIVs in the environment, based on natural and experimental infections of domestic mule and Muscovy ducks. During the 2016–2022 outbreaks, H5 HPAIVs exhibited persistent and marked feather epitheliotropism in naturally infected commercial ducks. Infection of the feather epithelium resulted in epithelial necrosis and disruption, as well as the production and environmental shedding of infectious virions. Viral and feather antigens colocalized in dust samples obtained from poultry barns housing naturally infected birds. In summary, the feather epithelium contributes to viral replication, and it is a likely source of environmental infectious material. This underestimated excretion route could greatly impact the ecology of HPAIVs, facilitating airborne and preening-related infections within a flock, and promoting prolonged viral infectivity and long-distance viral transmission between poultry farms.This study was performed in the framework of the “Chaire de Biosécurité et Santé Aviaires”, hosted by the National Veterinary College of Toulouse (ENVT) and funded by the Direction Generale de l’Alimentation, Ministère de l’Agriculture et de la Souveraineté Alimentaire, France. The animal experiment was partially funded by the Veterinary Biocontained facility Network (VetBioNet) [EU Grant Agreement INFRA-2016-1 N°731014].info:eu-repo/semantics/publishedVersio

The feather epithelium contributes to the dissemination and ecology of clade 2.3.4.4b H5 high pathogenicity avian influenza viruses in ducks

Immature feathers are known replication sites for high pathogenicity avian influenza viruses (HPAIVs) in poultry. However, it is unclear whether feathers play an active role in viral transmission. This study aims to investigate the contribution of the feather epithelium to the dissemination of clade 2.3.4.4b goose/Guangdong/1996 lineage H5 HPAIVs in the environment, based on natural and experimental infections of domestic mule and Muscovy ducks. During the 2016-2022 outbreaks, H5 HPAIVs exhibited persistent and marked feather epitheliotropism in naturally infected commercial ducks. Infection of the feather epithelium resulted in epithelial necrosis and disruption, as well as the production and environmental shedding of infectious virions. Viral and feather antigens colocalized in dust samples obtained from poultry barns housing naturally infected birds. In summary, the feather epithelium contributes to viral replication, and it is a likely source of environmental infectious material. This underestimated excretion route could greatly impact the ecology of HPAIVs, facilitating airborne and preening-related infections within a flock, and promoting prolonged viral infectivity and long-distance viral transmission between poultry farms

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

Tropism of high pathogenicity avian influenza viruses in poultry : diagnostic applications an new insights into viral ecology

Les virus de l'influenza aviaire hautement pathogènes (VIAHP) ont eu un impact considérable sur l'industrie avicole et les populations d'oiseaux sauvages au cours des dernières années, provoquant l'abattage de millions de volailles et la mort massive d'espèces en danger. Le tropisme viral, qui désigne l'ensemble des espèces hôtes, des organes et des types cellulaires réceptifs et permissifs à l'infection virale, constitue un déterminant majeur de la pathologie et de l'écologie virales. Il influence tant les tableaux lésionnels observés, que l'expression clinique de la maladie et les paramètres d'excrétion environnementale. Ces virus sont extrêmement évolutifs : cette diversification génotypique conduit donc à une modification substantielle et régulière des présentations clinico-pathologiques, ce qui requiert une adaptation constante et proportionnée des moyens de diagnostic et de contrôle mis en place. Ce travail de thèse s'appuie sur quatre études, combinant analyses rétrospectives et prospectives, infections expérimentales et spontanées de volailles, par les VIAHP de sous-type H5 ayant affectés la France entre 2015 à 2022. A titre diagnostic, nous avons montré que les plumes en croissance constituent une matrice biologique de choix pour le diagnostic moléculaire des VIAHP H5 de clade 2.3.4.4b, chez les canards et les oies domestiques. Nous avons en parallèle validé une nouvelle méthode de détection de ces virus par hybridation in situ RNAscope ciblant le gène M, démontrant une sensibilité supérieure à l'immunohistochimie anti-nucléoprotéine virale influenza A. Dans une troisième étude, nous avons caractérisé, pour la première fois, la pathobiologie des VIAHP H5 issues d'une émergence locale et unique au cours de l'hiver 2015-2016 ayant affecté les élevages de canards, de poules et de pintades. Enfin, au travers d'une analyse du tropisme plumeux des VIAHP H5 de clade 2.3.4.4b de 2016 à 2022, nous avons montré que l'épithélium plumeux constitue une voie alternative de diffusion du virus dans l'environnement. L'ensemble de ces résultats souligne que l'étude du tropisme viral peut contribuer in fine à l'adaptation des méthodes de surveillance, de diagnostic et de contrôle des VIAHP, ainsi qu'à une meilleure connaissance de l'écologie virale.High Pathogenicity Avian Influenza Viruses (HPAIV) have had a significant impact on the poultry industry and wild bird populations in recent years, resulting in the culling of millions of poultry and the substantial death of endangered species. Viral tropism, which refers to the range of host species, organs, and receptive and permissive cell types susceptible to viral infection, is a major determinant of viral pathology and ecology. It influences both pathological pictures, the clinical expression of the disease, as well as excretion parameters. These viruses are highly evolutive: genomic diversification leads to substantial modification of clinico-pathological profiles, necessitating constant adaptation of diagnostic and control measures. This work is based on four studies that combine retrospective and prospective analyses conducted on poultry, both experimentally and naturally infected with H5 HPAIVs, from 2015 to 2022 in France. In terms of diagnostics, we have demonstrated that growing feathers are suitable and sensitive biological matrices for the molecular diagnosis of Clade 2.3.4.4b H5 HPAIVs in domestic ducks and geese. Meanwhile, we have validated a new technique for the tissue detection of AIV by in situ hybridization RNAscope targeting the AIV Matrix gene. It demonstrated superior sensitivity to anti-nucleoprotein influenza A immunohistochemistry. In a third study, we have characterized, for the first time, the pathobiology of H5 HPAIVs arising from a unique emergence in France during the winter of 2015-2016, affecting domestic ducks, chickens, and guinea fowls. Finally, through an analysis of feather tropism of Clade 2.3.4.4b H5 HPAIVs, we have demonstrated in domestic ducks that feather epithelium represents an alternative route of diffusion in the environment. Altogether, these results emphasize that the study of viral tropism ultimately contributes to the adaptation and improvement of methods for monitoring, diagnosing, and controlling HPAIVs

Tropisme des virus influenza aviaires hautement pathogènes chez les volailles : applications diagnostiques et nouvelles perspectives sur l'écologie virale

High Pathogenicity Avian Influenza Viruses (HPAIV) have had a significant impact on the poultry industry and wild bird populations in recent years, resulting in the culling of millions of poultry and the substantial death of endangered species. Viral tropism, which refers to the range of host species, organs, and receptive and permissive cell types susceptible to viral infection, is a major determinant of viral pathology and ecology. It influences both pathological pictures, the clinical expression of the disease, as well as excretion parameters. These viruses are highly evolutive: genomic diversification leads to substantial modification of clinico-pathological profiles, necessitating constant adaptation of diagnostic and control measures. This work is based on four studies that combine retrospective and prospective analyses conducted on poultry, both experimentally and naturally infected with H5 HPAIVs, from 2015 to 2022 in France. In terms of diagnostics, we have demonstrated that growing feathers are suitable and sensitive biological matrices for the molecular diagnosis of Clade 2.3.4.4b H5 HPAIVs in domestic ducks and geese. Meanwhile, we have validated a new technique for the tissue detection of AIV by in situ hybridization RNAscope targeting the AIV Matrix gene. It demonstrated superior sensitivity to anti-nucleoprotein influenza A immunohistochemistry. In a third study, we have characterized, for the first time, the pathobiology of H5 HPAIVs arising from a unique emergence in France during the winter of 2015-2016, affecting domestic ducks, chickens, and guinea fowls. Finally, through an analysis of feather tropism of Clade 2.3.4.4b H5 HPAIVs, we have demonstrated in domestic ducks that feather epithelium represents an alternative route of diffusion in the environment. Altogether, these results emphasize that the study of viral tropism ultimately contributes to the adaptation and improvement of methods for monitoring, diagnosing, and controlling HPAIVs.Les virus de l'influenza aviaire hautement pathogènes (VIAHP) ont eu un impact considérable sur l'industrie avicole et les populations d'oiseaux sauvages au cours des dernières années, provoquant l'abattage de millions de volailles et la mort massive d'espèces en danger. Le tropisme viral, qui désigne l'ensemble des espèces hôtes, des organes et des types cellulaires réceptifs et permissifs à l'infection virale, constitue un déterminant majeur de la pathologie et de l'écologie virales. Il influence tant les tableaux lésionnels observés, que l'expression clinique de la maladie et les paramètres d'excrétion environnementale. Ces virus sont extrêmement évolutifs : cette diversification génotypique conduit donc à une modification substantielle et régulière des présentations clinico-pathologiques, ce qui requiert une adaptation constante et proportionnée des moyens de diagnostic et de contrôle mis en place. Ce travail de thèse s'appuie sur quatre études, combinant analyses rétrospectives et prospectives, infections expérimentales et spontanées de volailles, par les VIAHP de sous-type H5 ayant affectés la France entre 2015 à 2022. A titre diagnostic, nous avons montré que les plumes en croissance constituent une matrice biologique de choix pour le diagnostic moléculaire des VIAHP H5 de clade 2.3.4.4b, chez les canards et les oies domestiques. Nous avons en parallèle validé une nouvelle méthode de détection de ces virus par hybridation in situ RNAscope ciblant le gène M, démontrant une sensibilité supérieure à l'immunohistochimie anti-nucléoprotéine virale influenza A. Dans une troisième étude, nous avons caractérisé, pour la première fois, la pathobiologie des VIAHP H5 issues d'une émergence locale et unique au cours de l'hiver 2015-2016 ayant affecté les élevages de canards, de poules et de pintades. Enfin, au travers d'une analyse du tropisme plumeux des VIAHP H5 de clade 2.3.4.4b de 2016 à 2022, nous avons montré que l'épithélium plumeux constitue une voie alternative de diffusion du virus dans l'environnement. L'ensemble de ces résultats souligne que l'étude du tropisme viral peut contribuer in fine à l'adaptation des méthodes de surveillance, de diagnostic et de contrôle des VIAHP, ainsi qu'à une meilleure connaissance de l'écologie virale

Tropisme des virus influenza aviaires hautement pathogènes chez les volailles : applications diagnostiques et nouvelles perspectives sur l'écologie virale

High Pathogenicity Avian Influenza Viruses (HPAIV) have had a significant impact on the poultry industry and wild bird populations in recent years, resulting in the culling of millions of poultry and the substantial death of endangered species. Viral tropism, which refers to the range of host species, organs, and receptive and permissive cell types susceptible to viral infection, is a major determinant of viral pathology and ecology. It influences both pathological pictures, the clinical expression of the disease, as well as excretion parameters. These viruses are highly evolutive: genomic diversification leads to substantial modification of clinico-pathological profiles, necessitating constant adaptation of diagnostic and control measures. This work is based on four studies that combine retrospective and prospective analyses conducted on poultry, both experimentally and naturally infected with H5 HPAIVs, from 2015 to 2022 in France. In terms of diagnostics, we have demonstrated that growing feathers are suitable and sensitive biological matrices for the molecular diagnosis of Clade 2.3.4.4b H5 HPAIVs in domestic ducks and geese. Meanwhile, we have validated a new technique for the tissue detection of AIV by in situ hybridization RNAscope targeting the AIV Matrix gene. It demonstrated superior sensitivity to anti-nucleoprotein influenza A immunohistochemistry. In a third study, we have characterized, for the first time, the pathobiology of H5 HPAIVs arising from a unique emergence in France during the winter of 2015-2016, affecting domestic ducks, chickens, and guinea fowls. Finally, through an analysis of feather tropism of Clade 2.3.4.4b H5 HPAIVs, we have demonstrated in domestic ducks that feather epithelium represents an alternative route of diffusion in the environment. Altogether, these results emphasize that the study of viral tropism ultimately contributes to the adaptation and improvement of methods for monitoring, diagnosing, and controlling HPAIVs.Les virus de l'influenza aviaire hautement pathogènes (VIAHP) ont eu un impact considérable sur l'industrie avicole et les populations d'oiseaux sauvages au cours des dernières années, provoquant l'abattage de millions de volailles et la mort massive d'espèces en danger. Le tropisme viral, qui désigne l'ensemble des espèces hôtes, des organes et des types cellulaires réceptifs et permissifs à l'infection virale, constitue un déterminant majeur de la pathologie et de l'écologie virales. Il influence tant les tableaux lésionnels observés, que l'expression clinique de la maladie et les paramètres d'excrétion environnementale. Ces virus sont extrêmement évolutifs : cette diversification génotypique conduit donc à une modification substantielle et régulière des présentations clinico-pathologiques, ce qui requiert une adaptation constante et proportionnée des moyens de diagnostic et de contrôle mis en place. Ce travail de thèse s'appuie sur quatre études, combinant analyses rétrospectives et prospectives, infections expérimentales et spontanées de volailles, par les VIAHP de sous-type H5 ayant affectés la France entre 2015 à 2022. A titre diagnostic, nous avons montré que les plumes en croissance constituent une matrice biologique de choix pour le diagnostic moléculaire des VIAHP H5 de clade 2.3.4.4b, chez les canards et les oies domestiques. Nous avons en parallèle validé une nouvelle méthode de détection de ces virus par hybridation in situ RNAscope ciblant le gène M, démontrant une sensibilité supérieure à l'immunohistochimie anti-nucléoprotéine virale influenza A. Dans une troisième étude, nous avons caractérisé, pour la première fois, la pathobiologie des VIAHP H5 issues d'une émergence locale et unique au cours de l'hiver 2015-2016 ayant affecté les élevages de canards, de poules et de pintades. Enfin, au travers d'une analyse du tropisme plumeux des VIAHP H5 de clade 2.3.4.4b de 2016 à 2022, nous avons montré que l'épithélium plumeux constitue une voie alternative de diffusion du virus dans l'environnement. L'ensemble de ces résultats souligne que l'étude du tropisme viral peut contribuer in fine à l'adaptation des méthodes de surveillance, de diagnostic et de contrôle des VIAHP, ainsi qu'à une meilleure connaissance de l'écologie virale

Tomodensitometric and histological age‐related changes in the normal feline middle and inner ear

International audienceDeafness in cats may be due to acquired causes such as aging. Similar age‐related morphological changes in the cochlea have been noted in several animal species. However, little is known about the effects of age on the morphology of the middle and inner ear in cats. The aim of the present study was to compare these structures in middle‐aged and geriatric cats using computed tomography and histological morphometric analysis. Data were obtained from 28 cats, aged 3–18 years, with no hearing or neurological disorders. Computed tomography showed an increase in tympanic bulla (middle ear) volume with aging. Histological morphometric analysis revealed thickening of the basilar membrane and atrophy of the stria vascularis (inner ear) in older cats, similar to what has been observed in older humans and dogs. Nevertheless, histological procedures could be improved to provide more data for comparison with different forms of presbycusis in humans

Causes of Mortality and Pathological Findings in European Hedgehogs (Erinaceus europaeus) Admitted to a Wildlife Care Centre in Southwestern France from 2019 to 2020

International audienc