Highly pathogenic H5N1 avian influenza infection and exposure in waterfowl and waterbirds of the Sacramento National Wildlife Refuge Complex, 2022-2025
5 affiliations
- 1U.S. Geological Survey, Eastern Ecological Science Center , , ,
- 2Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, The University of Georgia , , ,
- 3U.S. Geological Survey, Western Ecological Research Center , , ,
- 4U.S. Fish and Wildlife Service, Sacramento National Wildlife Refuge Complex , , ,
- 5California Waterfowl Association , , ,
Abstract
The introduction of clade 2.3.4.4b highly pathogenic avian influenza (HPAI) H5N1 into North America in 2021 marked a significant shift in disease dynamics for wild waterfowl populations. To assess infection and seroprevalence trends following this incursion, we leveraged ongoing capture efforts at the Sacramento National Wildlife Refuge Complex between October 2022 and July 2025 to conduct sampling for HPAI H5N1 prevalence and seroprevalence. Our efforts resulted in the analysis of 384 swab and 204 sera samples from assorted waterfowl and waterbird species. HPAI H5N1 infection was confirmed in only three individuals (two Snow Geese and one Greater White-fronted Goose), all asymptomatic at capture. Antibodies to influenza A viruses (IAVs) were detected in all duck and goose species with the majority of positive samples also testing positive for antibodies to both H5 and N1, demonstrating a relatively high population level of previous exposure and likely immunity that aligns with previous findings in these species. This study also reports the first known observation of H5 antibodies in American Coot, though both overall IAV seroprevalence and H5 specific antibodies were notably lower than in sympatric waterfowl. This disparity suggests that American Coot may have lower susceptibility to infection or exhibit behavior that limits exposure compared to sympatric waterfowl. Together these results underscore the value of serologic surveillance as a supportive surveillance strategy to better inform potential management strategies related to HPAI H5N1 risk in wild birds.
Related
- A caprine mammary infection model for highly pathogenic avian influenza H5N1
- Highly pathogenic avian influenza virus H5N1 infection in stranded porpoises and dolphins in Chile
- Inactivation of highly pathogenic avian influenza virus (H5N1) using a combination of Hatano-RCMF and naturally strongly acidic hot spring water
- Evidence of Exposure to Highly Pathogenic Avian Influenza H5 Viruses in East Greenland Polar Bears
- Intranasal and intramuscular H5-Matrix-M nanoparticle vaccines protects against highly pathogenic H5N1 influenza virus in mice
BibTeX
@article{sullivan2026highly,
title = {{Highly pathogenic H5N1 avian influenza infection and exposure in waterfowl and waterbirds of the Sacramento National Wildlife Refuge Complex, 2022-2025}},
author = {Jeffery D. Sullivan and Rebecca L. Poulson and Michael L. Casazza and Elliott L. Matchett and Michael D’Errico and Alisha Bundy and Jacob Chappell and Desmond Mackell and Andrea Mott and Cory T. Overton and David E. Stallknecht and Diann J. Prosser},
journal = {Frontiers in cellular and infection microbiology},
year = {2026},
month = oct,
doi = {10.3389/fcimb.2026.1993811},
url = {https://europepmc.org/article/PMC/PMC13724457},
note = {CC BY},
}
RIS
TY - JOUR
TI - Highly pathogenic H5N1 avian influenza infection and exposure in waterfowl and waterbirds of the Sacramento National Wildlife Refuge Complex, 2022-2025
AU - Jeffery D. Sullivan
AU - Rebecca L. Poulson
AU - Michael L. Casazza
AU - Elliott L. Matchett
AU - Michael D’Errico
AU - Alisha Bundy
AU - Jacob Chappell
AU - Desmond Mackell
AU - Andrea Mott
AU - Cory T. Overton
AU - David E. Stallknecht
AU - Diann J. Prosser
PY - 2026
DA - 2026/10/19
JO - Frontiers in cellular and infection microbiology
DO - 10.3389/fcimb.2026.1993811
UR - https://europepmc.org/article/PMC/PMC13724457
AB - The introduction of clade 2.3.4.4b highly pathogenic avian influenza (HPAI) H5N1 into North America in 2021 marked a significant shift in disease dynamics for wild waterfowl populations. To assess infection and seroprevalence trends following this incursion, we leveraged ongoing capture efforts at the Sacramento National Wildlife Refuge Complex between October 2022 and July 2025 to conduct sampling for HPAI H5N1 prevalence and seroprevalence. Our efforts resulted in the analysis of 384 swab and 204 sera samples from assorted waterfowl and waterbird species. HPAI H5N1 infection was confirmed in only three individuals (two Snow Geese and one Greater White-fronted Goose), all asymptomatic at capture. Antibodies to influenza A viruses (IAVs) were detected in all duck and goose species with the majority of positive samples also testing positive for antibodies to both H5 and N1, demonstrating a relatively high population level of previous exposure and likely immunity that aligns with previous findings in these species. This study also reports the first known observation of H5 antibodies in American Coot, though both overall IAV seroprevalence and H5 specific antibodies were notably lower than in sympatric waterfowl. This disparity suggests that American Coot may have lower susceptibility to infection or exhibit behavior that limits exposure compared to sympatric waterfowl. Together these results underscore the value of serologic surveillance as a supportive surveillance strategy to better inform potential management strategies related to HPAI H5N1 risk in wild birds.
SN - 2235-2988
ER -