A resident of Washington state has been diagnosed with bird flu, marking the first confirmed human case in the U.S. since February. State health officials announced the identification of the H5N5 strain of the virus, distinct from the previously rampant H5N1 variant. The affected individual, an older adult with underlying health conditions, is currently hospitalized but is reported to be receiving care.
Health officials confirmed that this is the first known human infection with the H5N5 bird flu virus. Although this strain has not been linked to a higher risk to public health compared to H5N1, which saw a spike of 70 reported infections in the U.S. in 2024 and 2025, experts are monitoring the situation closely. Most H5N1 cases have been mild and primarily impacted workers in environments like dairy and poultry farms.
Richard Webby, a flu researcher at St. Jude Children’s Research Hospital, characterized the two viruses as behaving similarly, suggesting that H5N5 does not present a significant additional threat to humans. The Centers for Disease Control and Prevention (CDC) echoed this sentiment, stating that there is currently no evidence to indicate an increased public health risk stemming from this new case. They are working with state officials to conduct more tests on samples from the infected person.
The individual has a backyard flock of domestic poultry that may have been exposed to wild birds, indicating a probable source of exposure, although investigations are ongoing.
As health officials navigate this new case, they stress the importance of public health monitoring and keeping the public informed about the situation. This case underscores the ongoing need to be vigilant regarding zoonotic diseases, especially as wildlife interacts closely with domestic birds.