Two confirmed human infections with avian influenza A(H5) virus were reported to CDC this week, including one death. To date, human-to-human transmission of avian influenza A(H5) virus has not been identified in the United States.
Both cases were reported by the Washington State Department of Health and occurred in adults aged ≥18 years who worked at commercial dairy cattle farms where highly pathogenic avian influenza (HPAI) A(H5N1) virus has been detected in cows.
One individual developed respiratory symptoms during the week ending October 24, 2026 (Week 42). The patient presented to an emergency department the following week, was hospitalized, and has died. A respiratory specimen collected at the healthcare facility tested positive for influenza A and was presumptive positive for influenza A(H5) at the University of Washington. The specimen was sent to the Washington State Public Health Laboratory where influenza A(H5) was confirmed using the CDC influenza A(H5) assay. Additional testing conducted by the University of Washington determined this was an avian influenza A(H5N1) virus.
The second individual developed conjunctivitis and sought healthcare. 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 31, 2026 (Week 43). Influenza A(H5) virus was confirmed by the state public health laboratory. The specimen has been shipped to CDC for additional testing.
There has been a total of three influenza A(H5) cases in dairy workers in Washington.