First Human Case of Bird Flu in Washington State
NEW YORK — A resident of Washington state has been diagnosed with bird flu, marking the first human case of its kind in the United States since February, according to state health officials.
The patient, an older adult with pre-existing health conditions, is currently hospitalized. Initial reports of the diagnosis were announced on Thursday, but it was confirmed on Friday.
Officials stated that the individual contracted a variant known as H5N5, and this incident appears to be the first recorded human infection with this specific strain. While it differs from the more commonly known H5N1 virus, experts suggest it doesn’t pose a higher risk to human health than H5N1, which was linked to 70 reported human cases in the U.S. during 2024 and 2025, most of which have been mild and involved workers in the dairy and poultry industries.
Richard Webby, a noted flu researcher at St. Jude Children’s Research Hospital, expressed that the two viruses behave similarly. “From a human health perspective, I’d say consider it comparable to H5N1,” he said.
The Centers for Disease Control and Prevention echoed this sentiment, indicating that this recent case hasn’t increased public health risks. They are currently awaiting a specimen from Washington for additional tests.
The main difference between H5N5 and H5N1 involves a protein essential for the virus’s release from infected cells, which affects how it spreads. Webby likened the situation to different brands of car tires, suggesting that while they all serve the same purpose, each brand may perform better under specific conditions that aren’t fully understood yet. He also noted that H5N5 might prefer certain bird types for infection.
The unidentified resident has a backyard flock that was exposed to wild birds, raising the likelihood that domestic poultry or wild birds are the sources of infection, although officials continue to investigate.
