NEW YORK — A Washington state man has bird flu and it's a different type than what has been seen in previous infections, state health officials said Friday.
This is the first case of bird flu among humans in the country since February. An elderly person with underlying health conditions remains hospitalized.
State health officials announced preliminary diagnosis of bird flu on Thursday. On Friday they said it was confirmed.
The man was infected with a bird flu called H5N5, government officials said. State and federal health officials said this appears to be the first known human infection with the H5N5 avian influenza virus.
The variant is believed to pose no greater threat to human health than the H5N1 virus, which caused a wave of 70 reported human cases in the United States in 2024 and 2025. Most of them were mild illnesses in dairy and poultry workers.
“These viruses behave in a similar way,” said Richard Webby, a renowned influenza researcher at St. Jude Children's Research Hospital in Memphis, Tennessee. “My gut feeling is that from a human health perspective it's the same as H5N1.”
The Centers for Disease Control and Prevention issued a similar statement Friday, saying the lack of information suggests “the risk to public health has increased as a result of this case.”
The agency is awaiting a sample from Washington for further testing.
The difference between H5N5 and H5N1 is a protein that is involved in the release of the virus from an infected cell and helps it spread to surrounding cells.
“Think about different brands of car tires. They both do the same job, they're just each better tuned for specific conditions that we don't fully understand,” Webby wrote in an email.
H5N5 may have different preferences for which bird species it infects most easily, he added.
An unidentified Grays Harbor County resident has a flock of poultry in his backyard that was exposed to wild birds, health officials said. They believe the most likely source of contamination is poultry or wild birds, but say the investigation is still ongoing.
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