Standardizing the Response: A practical decision tool for marine bird mortality assessments

Worldwide, highly pathogenic avian influenza (HPAI) outbreaks have severely affected wild bird populations. The currently H5N1 clade 2.3.4.4b has spread extensively through migratory birds, yet the roles of wild bird species play in HPAI transmission, and their susceptibility remain poorly. In a recent study, we synthesized current knowledge of HPAI and identify knowledge gaps. One such gap is a high-resolution understanding of the wild bird immune response to H5N1 clade 2.3.4.4b. To begin to address this knowledge gap we holistically characterize the host immune response by integrating transcriptomic data, a diverse suite of immunological assays, and viral titers across the infection period conducting a challenge study. We challenged four-week old, captive bred Lesser Scaups (Aytha affinis) with H5N1, A/redhead duck/North Carolina/W24-83A/2024 at a dose of 6 log10 EID50 via the intra-choanal route. We used the diving duck, Lesser Scaup, as a non-traditional model to characterize the host disease response to H5N1 infection. Our objective was to identify transcriptomic markers verified using immunoassays, to more robustly characterize the host response to HPAI infections. The transcriptomic data will inform the identification of differentially expressed genes and characterization of molecular pathways and regulatory networks involved in gene expression. This study aims to identify the genetic and adaptive mechanisms underlying host disease response, contributing to a deeper understanding of HPAI dynamics in wild bird populations.

Walter N. Harrington- Department of Infectious Diseases, St Jude Children’s Research HospitalDiann J. Prosser- U.S. Geological Survey, Eastern Ecological Science CenterNichola J. Hill- Biology Department, University of Massachusetts BostonAhmed Kandeli- Department of Infectious Diseases, St Jude Children’s Research HospitalPatrick Seiler- Department of Infectious Diseases, St Jude Children’s Research HospitalJeri Carol Crumpton- Department of Infectious Diseases, St Jude Children’s Research HospitalSharon L. Johnson- U.S. Geological Survey, Eastern Ecological Science CenterJeffrey D. Sullivan- U.S. Geological Survey, Eastern Ecological Science CenterLisa Kercher- Department of Infectious Diseases, St Jude Children’s Research HospitalMatthew B. Gonnerman- Department of Environmental Science and Technology, University of MarylandJoshua. Cullen- U.S. Geological Survey, Eastern Ecological Science CenterShenglai Yin- School of Biological Sciences, University of OklahomaCody Kent- Department of Biology, Frostburg State UniversityJonathan B. Dain- Biology Department, University of Massachusetts BostonJennifer M. Mullinax- Department of Environmental Science and Technology, University of MarylandRichard Webby- Department of Infectious Diseases, St Jude Children’s Research Hospital

Transmission pathways, pathobiology, immune responses