'Highly pathogenic' bird flu found in Puget Sound seals for first time

PORTLAND, Ore. (KOIN) — A “highly pathogenic” strain of bird flu capable of spreading to humans and their pets was detected in harbor seals in the Puget Sound between Aug. 18 and 25, marking the first time that a marine mammal has tested positive for the virus on the West Coast, the National Marine Fisheries Service warns.

NOAA Fisheries published the U.S. Department of Agriculture’s findings on Sept. 8, stating that three adult harbor seals on Marrowstone Island tested positive for H5N1 — a virus that has plagued 58.7 million poultry and more than 7,100 wild birds in the U.S. since 2013.

“This marks the first incidence of [bird flu] in marine mammals on the West Coast,” NOAA Fisheries stated. “This discovery follows an ongoing [bird flu] outbreak affecting seabirds on Rat Island and Marrowstone Island since mid-summer. The outbreak resulted in the death of approximately 1,700 birds.”

Although the current strain is thought to pose little risk to humans, the CDC continues to monitor people exposed to the virus as “concerns around bird flu are growing rather than diminishing.” The ongoing outbreak has cost the U.S. government an estimated $661 million and spiked grocery store prices after more than 58 million birds were slaughtered to limit the spread of the virus.

In 2022, a person working in a Colorado slaughterhouse became the first person in the U.S. to test positive for the bird flu strain. The patient said that they suffered from fatigue for several days before recovering from the illness. Researchers are actively working to determine if a mutated version of the virus could produce a deadlier, more infectious disease with higher rates of spread between humans and animals.

People in the Puget Sound and their pets are advised to keep 100 yards away from any sick or dead wildlife. The prevalence of bird flu among harbor seals and gray seals in Maine caused a rapid spike in seal deaths in 2022. The die-off prompted NOAA Fisheries to declare an “unusual mortality event” to investigate the issue. 

Oregon Department of Fish and Wildlife Wildlife Veterinarian Julia Burco told KOIN 6 News that no harbor seals have been tested for bird flu at this time. However, two dozen California sea lions were recently tested for the illness in Astoria.

“We are working with the Oregon stranding network to make sure we have the ability to test any dead seals that arise for avian influenza,” Burco said. “We also recently captured and released 24 California sea lions in Astoria that were screened for avian influenza in addition to other diseases as part of the Eastern Pacific Marine One Health Coalition project.  These were clinically healthy sea lions and results are still pending.”

Beachgoers who encounter any potentially sick or dead seals are asked to keep a safe distance and call the West Coast Region Stranding Hotline.