Human bird flu case: Washington state has confirmed a human case of bird flu in an older adult with underlying conditions, the first US case since February, state health officials said. The patient remains hospitalised.
Laboratory testing identified the virus as H5N5, a subtype not previously seen in a human infection. State and federal officials said the case does not appear to pose a greater risk to the public than H5N1, the strain behind roughly 70 US human infections reported in 2024–2025, most of them mild and linked to dairy or poultry work.
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The CDC said there is no evidence that the risk to public health has increased and is conducting additional testing on a specimen from Washington.
Experts noted H5N5 and H5N1 are closely related; differences lie in a viral protein that helps the virus exit infected cells and spread, which may influence which bird species each strain infects most readily. Health authorities said the Grays Harbor County patient kept a backyard flock that had been exposed to wild birds, and that contact with domestic or wild birds is the most likely source. An investigation into the exposure and any close contacts is ongoing.
