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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Exotic & Emerging Avian Viral Diseases Research » Research » Publications at this Location » Publication #401808
Research Project: Control Strategies to Prevent and Respond to Diseases Outbreaks Caused by Avian Influenza Viruses

Location: Exotic & Emerging Avian Viral Diseases Research

Title: Diverse infectivity, transmissibility and pathobiology of clade 2.3.4.4 H5Nx highly pathogenic avian influenza viruses in chickens

Author
item KWON, JUNG-HOON - Kyungpook National University
item BERTRAN, KATERI - Institute De Recerca I Tecnologia Agroalimentaries (IRTA)
item LEE, DONG-HUN - Konkuk University
item CRIADO, MIRIA - Auburn University
item Killmaster, Lindsay
item Pantin Jackwood, Mary
item Swayne, David

Submitted to: Emerging Microbes & Infections
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2023
Publication Date: 6/12/2023
Citation: Kwon, J., Bertran, K., Lee, D., Criado, M.F., Killmaster, L.F., Pantin Jackwood, M.J., Swayne, D.E. 2023. Diverse infectivity, transmissibility and pathobiology of clade 2.3.4.4 H5Nx highly pathogenic avian influenza viruses in chickens. Emerging Microbes & Infections. 12:2218945. https://doi.org/10.1080/22221751.2023.2218945.
DOI: https://doi.org/10.1080/22221751.2023.2218945

Interpretive Summary: Highly pathogenic avian influenza viruses (HPAIVs) of the Eurasian subtype H5Nx clade 2.3.4.4 are a major threat to poultry and are disseminated by wild birds. These viruses have spread globally since 2014 and have evolved into different H5 genetic subgroups. In this study, chickens were inoculated with one of seven different H5Nx viruses from subgroups 2.3.4.4a, b, c, and e to determine the infectivity, transmissibility, and pathobiology of these HPAIVs. All the viruses caused high mortality in infected chickens, but the levels of infectivity and transmissibility of the viruses varied. Viruses from subgroup 2.3.4.4e had 100% transmissibility in chickens. However, viruses from subgroups 2.3.4.4a and c showed 67% transmissibility, and 2.3.4.4b viruses showed no transmission. Understanding the pathogenicity of novel HPAIVs in poultry is important to predicting disease outbreak patterns and establishing effective control strategies.

Technical Abstract: Clade 2.3.4.4 Eurasian lineage H5Nx highly pathogenic avian influenza virus (HPAIV) has become the globally dominant clade and caused global outbreaks since 2014. The clade 2.3.4.4 viruses have evolved into eight hemagglutinin subgroups (2.3.4.4a-h). In this study, we evaluated the infectivity, pathobiology and transmissibility of seven clade 2.3.4.4 viruses (two 2.3.4.4a, two 2.3.4.4b, one 2.3.4.4c and two 2.3.4.4e) in chickens. The two clade 2.3.4.4e viruses caused 100% mortality and transmissibility in chickens. However, clade 2.3.4.4a and c viruses showed 80–90% mortality and 67% transmissibility. Clade 2.3.4.4b viruses showed 100% mortality, but no transmission to co-housed chickens was observed based on lack of seroconversion. All the infected chickens died showing systemic infection, irrespective of subgroup. The results highlight that all the clade 2.3.4.4 HPAIVs used in this study caused high mortality in infected chickens, but the transmissibility of the viruses in chickens was variable in contrast to that of previous Eurasian-lineage H5N1 HPAIVs. Changes in the pathogenicity and transmissibility of clade 2.3.4.4 HPAIVs warrant careful monitoring of the viruses to establish effective control strategies.