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Volume 31, Number 12—December 2025

Dispatch

Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus Infection in Poultry Farm Workers, Washington, USA, 2024

Yasuko Hatta1, Juan A. De La Cruz1, Theresa Murray, Brian Hiatt, Yunho Jang, Julia C. Frederick, Kristine A. Lacek, Juliana C. DaSilva, Dan Cui, Paul Carney, Jimma Liddell, Kay W. Radford, Natasha Burnett, Sabrina Schatzman, Pauline Trinh, Anna Unutzer, Elizabeth A. Pusch, Monique Johnson, Ha T. Nguyen, Benjamin L. Rambo-Martin, Larisa Gubareva, James Stevens, C. Todd Davis, Marie K. Kirby, Allison Black, and Han DiComments to Author 
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA (Y. Hatta, J.A. De La Cruz, Y. Jang, J.C. Frederick, K.A. Lacek, J.C. DaSilva, D. Cui, P. Carney, J. Liddell, K.W. Radford, N. Burnett, S. Schatzman, E.A. Pusch, M. Johnson, H.T. Nguyen, B.L. Rambo-Martin, L. Gubareva, J. Stevens, C.T. Davis, M.K. Kirby, H. Di); Washington State Department of Health, Shoreline, Washington, USA (T. Murray, B. Hiatt, P. Trinh, A. Unutzer, A. Black)

Main Article

Figure 1

Neighbor-joining phylogenetic trees of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b viruses isolated from poultry farm workers, Washington, USA, 2024. A) Hemagglutinin gene segment; B) neuraminidase gene segment. Green font indicates influenza A(H5N1) D1.1 viruses from Washington human cases; red font indicates prepandemic candidate vaccine virus A/Ezo red fox/Hokkaido/1/2022. Bootstrap values >50, generated from 1,000 replicates, are labeled on branch nodes. Scale bars indicate nucleotide substitutions per site.

Figure 1. Neighbor-joining phylogenetic trees of highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b viruses isolated from poultry farm workers, Washington, USA, 2024. A) Hemagglutinin gene segment; B) neuraminidase gene segment. Green font indicates influenza A(H5N1) D1.1 viruses from Washington human cases; red font indicates prepandemic candidate vaccine virus A/Ezo red fox/Hokkaido/1/2022. Bootstrap values >50, generated from 1,000 replicates, are labeled on branch nodes. Scale bars indicate nucleotide substitutions per site.

Main Article

1These authors contributed equally to this article.

Page created: November 20, 2025
Page updated: January 01, 2026
Page reviewed: January 01, 2026
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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