Abstract Title
Highly pathogenic avian influenza viruses in Mississippi Flyway dabbling ducks: a multi-season perspective
Abstract
Since its introduction to North America during 2021, highly pathogenic H5N1 (HP H5N1) influenza A virus (IAV) has been detected annually, but it is unknown if this virus will follow the same historic patterns observed with low pathogenic (LP) IAV in ducks. More than 5,000 dabbling ducks were sampled in the Mississippi flyway, prior to the detection of HP H5N1 through fall of 2024. Virologic results are consistent with historic seasonal and geographic patterns reported for LP IAV: peak HP H5N1 infections (53%) occurred in pre-migration staging areas in Minnesota during fall 2022 and HP H5N1 was detected, but at a lower prevalence (19%), on wintering areas in Louisiana/Texas during fall of that same year. These high rates of infection were followed by an increase in estimated antibody prevalence. HP H5N1 has not been detected in our collections in Minnesota since fall 2022, and only from a single bird in Louisiana in fall 2023. An increase in antibody prevalence, similar to 2022/2023, was observed during the winter/spring period of 2023/2024. Results support an initial high infection rate of HP H5N1 in ducks in the Mississippi flyway followed by a high prevalence of IAV, H5 and N1 subtype-specific antibodies, with limited detected infections since 2022. Observed patterns appear to be driven by population immunity during the migration cycle. Although HP H5N1 prevalence has been much reduced in following introduction, it is not known if this pattern will persist or affect subtype diversity in this wild bird reservoir.
Co-Author(s)
Rebecca L. Poulson1, Deborah L. Carter1, Lyndon Sullivan-Brugger1, Paul Link2, Emily Ferraro3, Ciara McCarty4, Bruce Davis4, Lynda Knutsen5, James Graham5, David E. Stallknecht1
1 Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, GA, USA
2 Louisiana Department of Wildlife and Fisheries, Grand Chenier, LA, USA
3 Louisiana State University Agricultural Center, School of Renewable Resources, Baton Rouge, LA, USA
4 Minnesota Department of Natural Resources, Wetland Wildlife Populations and Research Group, Bemidji, Minnesota, USA
5 Agassiz National Wildlife Refuge, U.S. Fish and Wildlife Service, Middle River, Minnesota, USA
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds