H5N5 Bird Flu Confirmed in Washington State as Global Avian Influenza Monitoring Continues Amid Emerging Challenges

Bird Flu Bulletin: Daily H5N1 Update Wednesday, November 19, 2025 This is Bird Flu Bulletin: Daily H5N1 Update. It’s Wednesday, November 19, 2025. Here are the top stories shaping the global response to avian influenza in the last 24 hours. Top stories: First, the Washington State Department of Health has confirmed the first known human infection with the H5N5 strain of avian flu in the United States. This follows a nine-month period with no reported human bird flu cases in the country. The patient is an older adult from Grays Harbor County and remains hospitalized with severe symptoms. The likely source was a mixed backyard flock exposed to wild birds, though investigations are ongoing. According to Washington state officials, human-to-human transmission has not been documented and no additional cases have been identified. Second, Highly Pathogenic Avian Influenza H5N1 continues to impact commercial poultry across the United Kingdom. In the last 24 hours, H5N1 was confirmed at a fourth large commercial poultry site near Milford Haven, Pembrokeshire, Wales, as well as in a small backyard flock in Lawshall, Suffolk. Protective zones up to 10 kilometers have been established around each site, and culling is underway to limit further spread. UK authorities note a significant rise in confirmed cases since last week, reflecting what they describe as a very high risk environment for commercial and backyard flocks. Third, California continues to grapple with the impact of H5N1 on its dairy sector. The California Department of Food and Agriculture reports 766 infected dairies to date, with new cases declining but not eliminated. Enhanced bi-monthly surveillance and new genotype detections in Nevada are keeping the region on alert for possible changes in the virus’s behavior and risk. Comparing to yesterday, human case counts remain stable in the US, with just the single new case identified in Washington. In the UK and EU, poultry cases have risen by two since the last update, with additional backyard and commercial sites now under protective measures. No additional human cases have been reported globally today. Health authorities in both the US and UK are emphasizing strict biosecurity for commercial and backyard flock owners. CDC officials stress that while human risk remains low, those working directly with poultry or dairy cattle, as well as individuals with backyard flocks, should take extreme precautions. The UK Department for Environment, Food & Rural Affairs continues to urge bird keepers, especially in risk zones, to monitor for symptoms and report any suspicion promptly. A brief interview with Dr. Maria Patel, infectious disease specialist at Seattle’s Harborview Medical Center: “While the emergence of H5N5 in humans is concerning, we see no indication yet of efficient person-to-person transmission. The key is rapid containment, ongoing genetic surveillance, and targeted risk communication, especially for those with backyard or comme This content was created in partnership and with the help of Artificial Intelligence AI.