One confirmed human infection with avian influenza A(H5N1) virus was reported to CDC this week. To date, human-to-human transmission of influenza A(H5) virus has not been identified in the United States.

The case was reported by the Washington State Department of Health and occurred in a worker aged ≥18 years at a commercial dairy cattle farm where highly pathogenic avian influenza (HPAI) A(H5N1) virus has been detected in cows. This individual developed eye irritation and upper respiratory symptoms, which they reported to the local health department. Specimens were collected from the individual and tested at the state public health laboratory using the CDC influenza A(H5) assay during the week ending October 17, 2026 (Week 41). Influenza A(H5) virus was confirmed by the state public health laboratory. Additional testing conducted by CDC determined this was an influenza A(H5N1) virus. This is the first influenza A(H5) case associated with a dairy worker in Washington.