Patient With Novel Strain of Avian Influenza Dies

A Grays Harbor County, WA resident who was undergoing treatment for H5N5 (avian influenza) died on November 21, the Washington State Department of Health reported. Interestingly, testing at the University of Washington Medicine Clinical Virology Lab identified the virus as H5N5, making this the first recorded infection with this variant in a person globally. The result was confirmed by the Centers for Disease Control and Prevention (CDC).¹

Not much is known of the patient or the circumstances surrounding the individual’s illness, and authorities did not release the person’s name, gender, or age. What is known is the person was an older adult with underlying health conditions. The person had been hospitalized in King County since early November.¹

The person had a backyard flock of mixed domestic birds. DOH sampling identified avian influenza virus in the environment of the flock, making exposure to the domestic poultry, their environment, or wild birds the most likely source of exposure for this patient. People who had exposure to the backyard flock and environment are also being monitored for symptoms.¹

Important to note, health officials said the risk to the public remains low. They report that no other people involved have tested positive for avian influenza, and public health officials will continue to monitor anyone who was in close contact with the patient for symptoms to ensure that human-to-human spread has not occurred. There is no evidence of transmission of this virus between people.¹

This Avian Influenza Season’s Predictions

This is the first case of avian influenza reported since last February. In a recent interview with Contagion, Richard Webby, PhD, director of the World Health Organization Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds and Department of Host-Microbe Interactions, Division of Virology, St. Jude Children's Research Hospital said he is predicting a milder H5N1 influenza season.²

“I think it's clear now that the H5 virus has settled into a bit more of a seasonal pattern where we see this increased activity, increased spillover to poultry to wild mammals, as the migratory birds fly south,” Webby said. “And this time last year, we saw the emergence of what was quite a fit virus, and it spread very widely and infected a lot of birds. And so essentially, that's what that prediction is based on.”²

And he says the primary vector, wild birds, have likely built immunity.²

Check out the full interview with Webby below.

What is Avian Influenza

Avian influenza is caused by influenza type A viruses, which naturally occur in wild aquatic birds around the world. These viruses can infect other bird species, and occasionally mammals, and can be deadly to domestic birds such as chickens and turkeys. On rare occasions, avian influenza viruses can infect people.¹

The H5N5 variant is a sub-type of avian influenza and not expected to be a greater threat to human health than the H5N1 virus, which has infected 70 people since 2024. The distinction between H5N5 and H5N1 lies in a protein involved in releasing the virus from an infected cell and promoting spread to surrounding cells.³

References
1. Grays Harbor County resident dies from complications of avian influenza. Washington Department of Health. November 21, 2025. Accessed November 25, 2025.
https://doh.wa.gov/newsroom/grays-harbor-county-resident-dies-complications-avian-influenza

2. Parkinson J. A Mild Avian Influenza Season Ahead? Contagion. October 31, 2025. Accessed November 25, 2025.
https://www.contagionlive.com/view/a-mild-avian-influenza-season-ahead-

3. Burke K. Washington state resident dies after H5N5 infection. Deutsche Welle. November 22,2025. Accessed November 25, 2025.
https://www.dw.com/en/washington-state-resident-dies-after-h5n5-infection/a-74847177