Wed Nov 19 07:33:02 UTC 2025: Summary:
A Washington State resident has been diagnosed with a novel strain of bird flu, H5N5, marking the first confirmed human infection with this particular virus. The patient, an older adult with underlying health conditions, is hospitalized. While the CDC and leading flu researchers suggest the H5N5 strain doesn’t appear to pose a greater threat to human health than the H5N1 strain, which caused a significant number of human infections in the recent past, further testing is underway to fully assess the risk. The individual likely contracted the virus from domestic poultry exposed to wild birds.
News Article:
New Bird Flu Strain Detected in Washington State Resident
NEW YORK, NY – November 19, 2025 – A resident of Washington State has been diagnosed with the first known human case of the H5N5 bird flu virus, state health officials confirmed on November 15. The individual, an older adult with pre-existing health conditions, is currently hospitalized.
This marks the nation’s first human bird flu case since February. The infected individual resides in Grays Harbor County and had contact with a backyard flock of domestic poultry exposed to wild birds, believed to be the source of infection.
While the H5N5 strain is new to humans, experts, including Richard Webby of St. Jude Children’s Research Hospital, suggest it may not be a significantly greater threat than the H5N1 virus that led to 70 reported human infections in the U.S. in 2024 and 2025. “These viruses behave similarly,” Webby stated, adding, “My gut instinct is to consider it the same as H5N1 from a human health perspective.”
The Centers for Disease Control and Prevention (CDC) echoed this sentiment, stating that available information does not suggest an increased risk to public health. The CDC is awaiting a specimen from Washington for further testing and analysis.
According to experts, the key difference between H5N5 and H5N1 lies in a protein involved in the virus’s release and spread. The ongoing investigation aims to determine the specific characteristics of the H5N5 strain and its potential impact.
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