Rapid expansion of genotype D1.1 A(H5N1) influenza viruses in wild birds across North America during the 2024 migratory season
In late 2021, high pathogenicity avian influenza A(H5N1) clade 2.3.4.4b viruses entered North America and reassorted rapidly with local avian influenza viruses. In September 2024, we detected a new reassortant later classified as genotype D1.1. Using active and passive avian influenza surveillance across Canada and the USA, we tracked the emergence and rapid spread of D1.1 viruses in wild birds during the 2024 fall migration. Phylodynamic analysis showed that D1.1 viruses formed a monophyletic group and displaced earlier A(H5) genotypes across several flyways. Their expansion coincided with detections in other hosts, including 17 human cases, 4 of which were severe or fatal. None of the mammalian-adaptive markers detected in human cases were found in wild bird viruses, and candidate vaccine viruses retained antigenic cross-reactivity with D1.1 strains.
Authors
- Cory J. Highway (ORCID: https://orcid.org/0009-0001-2609-3677)
- Jamie C. Feddersen
- Richard J. Webby (ORCID: https://orcid.org/0000-0002-4397-7132)
- Lisa Kercher (ORCID: https://orcid.org/0000-0001-6300-0452)
- Jolene A. Giacinti (ORCID: https://orcid.org/0000-0002-4843-599X)
- Jacqueline M. Nolting (ORCID: https://orcid.org/0000-0002-2705-4805)
- Mohammad Jawad Jahid
- Andrew M. Ramey (ORCID: https://orcid.org/0000-0002-3601-8400)
- Christina A. Ahlstrom (ORCID: https://orcid.org/0000-0001-5414-8076)
- Daniel Rejmanek
- Bradley S. Cohen (ORCID: https://orcid.org/0000-0001-5569-0684)
- Trushar Jeevan
- Ahmed Kandeil (ORCID: https://orcid.org/0000-0003-3253-6961)
- Anthony V. Signore (ORCID: https://orcid.org/0000-0002-0664-0864)
- Nicole M. Nemeth (ORCID: https://orcid.org/0000-0001-5931-175X)
- Walter N. Harrington (ORCID: https://orcid.org/0000-0003-3314-584X)
- Yohannes Berhane (ORCID: https://orcid.org/0000-0002-5958-3525)
- Dayna Goldsmith (ORCID: https://orcid.org/0000-0002-5619-4540)
- Deborah Carter (ORCID: https://orcid.org/0000-0001-6211-6584)
- Mia Kim Torchetti (ORCID: https://orcid.org/0000-0002-2649-0146)
- Thomas Fabrizio (ORCID: https://orcid.org/0000-0002-8960-0728)
- Krista E. Dilione (ORCID: https://orcid.org/0000-0001-6041-7877)
- Brian Stevens
- Lauren Smith (ORCID: https://orcid.org/0000-0001-9596-4897)
- Nathan J. Steelman
- Laura C. Scott
- John Franks
- Lance Miller
- David Stallknecht
- Rebecca Poulson
- Paul Link
- Trent Bollinger
- Madison Owsiany
- Evan J. Buck
- Chelsea Himsworth
- Beate Crossley
- Sarah Bevins
- Julianna Lenoch
- Claire Jardine
- Karlie Eure
- Lydia P. Holmes
- Christopher Sharp
Institutions
- Alberta Environment and Protected Areas (CA)
- United States Geological Survey (US)
- Animal and Plant Health Inspection Service (US)
- Canadian Food Inspection Agency (CA)
- Ministry of Health (CA)
- St. Jude Children's Research Hospital (US)
- Louisiana Department of Wildlife and Fisheries (US)
- California Department of Food and Agriculture (US)
- Tennessee Wildlife Resources Agency (US)
- Environment and Climate Change Canada (CA)
- University of Georgia (US)
- University of Calgary (CA)
- Canadian Science Centre for Human and Animal Health (CA)
- University of Saskatchewan (CA)
- Government of British Columbia (CA)
- National Research Centre (EG)
- National Laboratory for Agriculture and the Environment (US)
- The Ohio State University (US)
- Tennessee Technological University (US)
- University of Guelph (CA)
- University of California, Davis (US)
Publication Details
- Journal
- Nature Medicine
- Published
- 2026-04-15
- DOI
- https://doi.org/10.1038/s41591-026-04300-1
- Primary Topic
- Influenza Virus Research Studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- U.S. Department of Agriculture
- World Health Organization
- Environment and Climate Change Canada
- Canadian Wildlife Health Cooperative
- U.S. Fish and Wildlife Service
- U.S. Geological Survey
- National Institute of Allergy and Infectious Diseases