Pathobiology of highly pathogenic H5 avian influenza viruses in naturally infected Galliformes and Anseriformes in France during winter 2015\u20132016

Nicolas Gaide,Iwan A Gagarinov,Roosmarijn Van Der Woude,Robert P De Vries,Romain Volmer,Andreas Papanikolaou,Jean-Luc Guérin,Guillaume Croville,Timothée Vergne,Marie-Noëlle Lucas,Guillaume Le Loc’H,Kim M Bouwman,Mattias Delpont,Céline Bleuart,Geert-Jan Boons,Maxence Delverdier,Angélique Teillaud

doi:10.1186/s13567-022-01028-x

Abstract

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.

Highlights

Avian influenza is a highly contagious infectious disease caused by Influenza A viruses belonging to the Orthomyxoviridae family [1]
The present study aims to characterize the pathobiology of naturally infected Galliformes and Anseriformes originating from H5 HPAIV reassortants that emerged locally in France during winter 2015–2016
During winter 2015–2016, an epizootic involving several H5 HPAIVs was registered in commercial poultry flocks located in the South-West of France

Summary

Introduction

Avian influenza is a highly contagious infectious disease caused by Influenza A viruses belonging to the Orthomyxoviridae family [1]. Between November 2015 and January 2016, an epizootic of Highly Pathogenic Avian Influenza (HPAI) H5 (N1, N2 and N9) was registered in commercial poultry flocks in France, with more than 70 confirmed cases distributed in the South-West of the country [4]. Free-range, mule duck farms, dedicated to foie-gras production, comprised more than 80% of identified cases, while 20% of cases were registered in chicken and guinea fowl flocks. Genetic analysis revealed that the HPAI viruses isolated from infected birds belonged to a monophylogenic group of Eurasian lineage and shared the same original hemagglutin cleavage site (HQRRKR/GLF). These findings suggested the emergence of different H5Nx reassortants from a locally circulating H5 AIV ancestor [4]

Methods

Results

Conclusion