Health officials in Washington state have confirmed the first known human infection with the H5N5 strain of bird flu, marking a rare development in the ongoing spread of avian influenza across the U.S. The patient, an older adult with underlying health conditions, has died, authorities announced late Friday.
The Washington State Department of Health said the individual kept a backyard flock of mixed domestic birds. No additional personal details were released out of respect for the family, News.Az reports, citing ABC News.
While H5N5 has been detected in animals before, this is the first time the strain has ever been confirmed in a human, according to state health officials.
The case comes amid continued detection of avian influenza in birds and mammals across the country. However, authorities emphasized that the public risk remains low:
No other people connected to the case have tested positive.
There is no evidence of human-to-human transmission of H5N5 or any major shift in the virus's behavior.
Bird flu, or avian influenza, has circulated in birds for decades. But the virus has increasingly spilled over into other species, including cattle and mammals, raising concern among health experts.
Over the past 18 months, the U.S. has recorded around 70 human cases of avian influenza -- all involving the H5N1 strain, not H5N5. Most infections have been linked to:
Culling operations or contaminated environments
Most human cases have caused mild symptoms such as red eyes and fever, though severe illness has been reported, including the first H5N1-related U.S. death earlier this year in an older patient with underlying conditions.
The CDC and state authorities stress that there is currently no evidence of bird flu spreading between humans. They say the risk to the general public remains low, though investigations are ongoing.