First Death From H5N5 Avian Influenza
A Washington State resident has become the first documented human fatality associated with the H5N5 avian influenza virus, a subtype not previously confirmed to cause disease in people. The case represents an unprecedented zoonotic event and marks the first known instance of H5N5 infection in humans worldwide.
The individual, an older adult (75-year-old woman) with multiple underlying medical conditions, was admitted to hospital earlier this month after developing a high fever, progressive respiratory distress, and acute confusion. Despite intensive clinical management, the patient’s condition deteriorated rapidly. Laboratory testing performed by state and federal health authorities subsequently identified H5N5 as the causative agent. As of 14 November 2025, the US CDC have reported 71 human cases with avian influenza A(H5).
