Decoding Wild Bird Immune Response: A Transcriptomic and Immunological Assessment of H5N1 in Lesser Scaups

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 Hospital Diann J. Prosser- U.S. Geological Survey, Eastern Ecological Science Center Nichola J. Hill- Biology Department, University of Massachusetts Boston Ahmed Kandeli- Department of Infectious Diseases, St Jude Children’s Research Hospital Patrick Seiler- Department of Infectious Diseases, St Jude Children’s Research Hospital Jeri Carol Crumpton- Department of Infectious Diseases, St Jude Children’s Research Hospital Sharon L. Johnson- U.S. Geological Survey, Eastern Ecological Science Center Jeffrey D. Sullivan- U.S. Geological Survey, Eastern Ecological Science Center Lisa Kercher- Department of Infectious Diseases, St Jude Children’s Research Hospital Matthew B. Gonnerman- Department of Environmental Science and Technology, University of Maryland Joshua. Cullen- U.S. Geological Survey, Eastern Ecological Science Center Shenglai Yin- School of Biological Sciences, University of Oklahoma Cody Kent- Department of Biology, Frostburg State University Jonathan B. Dain- Biology Department, University of Massachusetts Boston Jennifer M. Mullinax- Department of Environmental Science and Technology, University of Maryland Richard Webby- Department of Infectious Diseases, St Jude Children’s Research Hospital

Transmission pathways, pathobiology, immune responses