Washington Confirms First Human H5N5 Case, Patient Dies

Washington state health authorities announced that a resident who was being treated for H5N5 avian influenza has died, underscoring the rare but serious risk posed when bird influenza viruses infect people. State officials said this is the first confirmed human H5N5 infection in Washington and that public health teams are investigating the patient’s recent exposures and identifying contacts for monitoring and follow up.

The case has prompted increased surveillance and guidance for clinicians across the state as health officials work to limit further spread and understand how the infection occurred. Federal and state public health entities are coordinating laboratory testing and epidemiologic inquiries to determine whether the infection resulted from direct contact with infected birds, contact with contaminated environments, or an alternate exposure pathway. Genetic sequencing of the virus will be a central part of the investigation to assess whether the virus carries mutations that could affect transmissibility or severity in humans.

Public health authorities emphasized that human infections with H5N5 remain rare even as avian influenza circulates widely among wild and domestic birds in many regions. Most bird influenza viruses do not transmit easily between people, but sporadic spillover events have occurred in the past with several avian strains, producing severe illness in some individuals. The death of the Washington resident brings renewed attention to testing, early detection, and hospital preparedness for influenza strains that fall outside the seasonal viruses clinicians typically see.

Health officials said they are tracing contacts of the patient to provide monitoring and to recommend testing or medical evaluation if symptoms develop. Clinicians have been advised to consider testing for avian influenza in patients with severe respiratory illness and relevant exposure histories, and laboratories have been alerted to prioritize confirmatory testing and sequencing as part of the public health response. The objective is to detect any additional human cases quickly and to limit potential chains of transmission.

The case also has implications for animal health and the poultry industry, which can be affected by outbreaks of avian influenza among domestic flocks. State animal health authorities are likely to increase surveillance in commercial and backyard flocks in affected areas to identify infected birds and reduce the risk of further spillover to humans. Effective coordination between animal health and human health agencies will be essential to control the outbreak among birds and to reduce human exposure.

While public concern may grow following the announcement, experts note that the overall risk to the general public remains low when prompt public health measures are implemented. The coming days of contact tracing, laboratory analysis, and field investigation will be critical to clarifying the source of the infection and any public health implications. State officials have said they will provide updates as new information becomes available and as investigations progress.