World's First H5N5 Avian Influenza Human Death Confirmed in Washington State

A resident of Washington state has died after contracting the H5N5 avian influenza, marking the first recorded human infection with this variant globally. The Washington State Department of Health (DOH) reported that the deceased was an older adult with pre-existing health conditions, who had been hospitalized in King County since early November and died on November 21.

The patient was identified as a resident of Grays Harbor County. The UW Medicine Clinical Virology Lab initially identified the virus as H5N5, a result subsequently confirmed by the Centers for Disease Control and Prevention (CDC). Although the H5N5 strain has been reported in animals previously, this incident represents the first time it has infected a person worldwide.

While the H5N5 fatality is rare, it is the second human fatality linked to a bird flu virus reported in the United States since 2024, though the prior case was linked to the H5N1 strain.

Health officials believe the most probable source of the infection was the deceased individual's exposure to domestic poultry, their environment, or wild birds. The resident maintained a backyard flock of mixed domestic birds, and DOH sampling confirmed the presence of the avian influenza virus in the flock’s environment.

The patient's identity, including name, age, and gender, was withheld by the DOH to respect the family’s privacy.

Despite this unprecedented case, public health officials have reassured the community that the risk to the general public remains low. The DOH confirms that no other individuals who had contact with the patient or the flock have tested positive for avian influenza.

Officials are currently monitoring contacts of the patient and the flock for any symptoms to prevent potential transmission. Crucially, there is currently no evidence of human-to-human transmission of the H5N5 virus. Transmission of avian influenza between humans is described as extremely rare, having never been documented in the United States.

The CDC has recorded 71 human cases of bird flu nationwide as of November 23rd, though the majority are tied to the H5N1 strain. Most human cases of bird flu occur in people exposed to sick or infected animals, with symptoms similar to the common flu, such as fever, body aches, and fatigue. Health experts advise individuals with backyard poultry to avoid contact with sick or dead birds and recommend a seasonal flu vaccine for those potentially exposed to domestic or wild birds.

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🔖 Sources

World's First Death From H5N5 Bird Flu Strain Reported in US

Washington state resident dies after rare bird flu strain infection

Bird flu: Washington state resident believed to be first to die from rare strain of H5N5

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Keywords:   H5N5 Avian Influenza

 H5N5 Avian Influenza

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