First Human Death Linked to Rare H5N5 Bird Flu Strain in Washington State
The risk to the general public remains low, according to health officials.
A man in Washington state is believed to be the first person to die from infection with the H5N5 strain of avian influenza, state health authorities announced Friday. The individual, an older adult with pre-existing health conditions from Grays Harbor County – approximately 78 miles southwest of Seattle – had been receiving treatment for the virus after being identified as the first known human case of this particular strain. This marks the nation’s first human case of bird flu since February.
Initial Case and Public Health Response
The deceased man owned a small flock of domestic poultry that had been exposed to wild birds, prompting concerns about potential transmission. However, officials were quick to reassure the public. “The risk to the public remains low,” a statement from the Washington State Department of Health affirmed. “No other people involved have tested positive for avian influenza.”
Health authorities are actively monitoring individuals who had close contact with the man, but, as of Friday, “there is no evidence of transmission of this virus between people.” Earlier this month, the Centers for Disease Control and Prevention (CDC) released a statement indicating that this single case did not suggest an increased risk to public health.
H5N5 vs. H5N1: Understanding the Threat
While this is the first confirmed human death linked to H5N5, experts emphasize that it is not currently considered a greater threat to human health than the more prevalent H5N1 virus. A wave of approximately 70 reported human infections with H5N1 have been recorded in the U.S. since 2024, with the majority resulting in mild illnesses among workers on dairy and poultry farms.
The key difference between H5N5 and H5N1 lies in a protein crucial for viral release and spread. This subtle distinction is currently being investigated to understand potential implications for transmissibility and severity.
Broader Bird Flu Concerns and Transmission Risks
Bird flu has been circulating in various bird populations globally since January 2022. In March of last year, the virus was detected in dairy cows for the first time, expanding the scope of the outbreak. The virus is known to infect not only birds but also mammals, including pigs, cattle, and even domestic cats.
Human infection typically occurs through close contact with infected animals, making farm workers particularly vulnerable. This highlights the importance of preventative measures and vigilant monitoring within agricultural settings.
The situation remains fluid, and public health officials will continue to assess the evolving risk posed by both H5N5 and H5N1 strains.
