Current Situation
There are several strains of bird flu that wild birds carry worldwide. The most widely circulating, or common, strain in the United States today is H5N1. This strain was first detected in the U.S. in wild birds in January 2022. In Washington state, H5N1 was first identified in a backyard flock in May 2022.
H5N1 has since spread to domestic birds, including commercial poultry and backyard flocks, and to mammals, such as wild and domestic cats. In some states, dairy cattle have been infected.
The first human H5N1 case in Washington state was identified in October 2024 and was linked to a close contact during a commercial poultry outbreak. In 2025, Washington also reported a human infection with H5N5, a strain not previously seen in humans. Other subtypes that have infected humans are H6, H7, H9, and H10. CDC’s Avian Influenza Type A as more information on influenza virus subtypes.
| Case Classification | Known Exposure | 2024* | 2025 | 2026 | Total |
|---|---|---|---|---|---|
| Confirmed | Poultry | 11 | 1 | 0 | 12 |
| Probable | Poultry | 3 | 0 | 0 | 3 |
| Total | 14 | 1 | 0 | 15 |
*Washington residency could not be confirmed for one case in 2024.
View bird flu case data on Zoonotic and Vector-Borne Disease Dashboard.
Public Risk and Monitoring
The bird flu virus changes, or mutates, easily. Each time a person or animal is infected, the virus can mutate in ways that make it easier to spread. If a person becomes infected with more than one influenza A virus at the same time, such as with human seasonal flu and bird flu, a new strain that easily spreads from person to person could develop.
CDC currently considers the risk to the general public to be low. To date, there is no evidence of person-to-person transmission of any bird flu strain in Washington state or the United States. See CDC's Global Human Cases with Avian Influenza A (H5N1), 1997-2026.
Public health officials work closely with local, state, and federal partners across human and animal health to monitor bird flu activity in Washington. They provide prevention and response guidance, identify and monitor people exposed to infected birds and other animals, and provide testing and treatment when needed.