H5N1 bird flu spreads to sea otters and sea lions along San Mateo coast, wildlife experts say

Researchers accidental the H5N1 vertebrate flu outbreak successful California elephant seals has dispersed to different marine mammals, including a oversea otter and oversea lion.

However, wildlife officials are cautiously optimistic the outbreak volition stay contained. It has truthful acold lone been detected connected beaches successful San Mateo County, though investigating is being conducted on the coastline.

The strain of vertebrate flu recovered successful these animals contains a mutation that allows it to much easy transmit betwixt mammals. It is besides a antithetic saltation than the ones recovered successful dairy cows and commercialized poultry. This 1 is Eurasian successful origin, and was archetypal seen successful 2022. It has been detected successful birds that alert on the Pacific Flyway, and is liable for a wide mortality lawsuit successful 2023 successful bluish fur seals connected an land successful eastbound Russia, said Christine Johnson, the manager of UC Davis’ Center for Pandemic Insights, during a property league Thursday morning.

Johnson said researchers deliberation this is the archetypal detection of the A3 saltation of the microorganism connected the Pacific Coast and truthful apt a caller instauration into North America, she said.

In precocious February, a squad of researchers from UC Davis, UC Santa Cruz, California Department of Fish and Wildlife and the Marine Mammal Center announced they had recovered the microorganism successful 7 dormant elephant seal pups collected from the formation astatine Año Nuevo State Park. That fig is present 16, but Johnson said apt much volition beryllium confirmed successful the weeks to come.

“This number reflects lone the animals that person gone done sampling and confirmatory investigating successful aggregate labs,” she said. “We cognize determination are much animals with signs of corruption that we person sampled that are being tested crossed the antithetic laboratory systems.”

She said nary different otters person been found, but a “handful” of California oversea lions are “in the queue.” This benignant of spillover, she said, is not unusual.

“Outbreaks impact a wide scope of birds and mammals, and these animals each stock the adjacent enactment ecosystem,” she said, though it’s “especially tragic erstwhile infections interaction little communal taxon successful the confederate oversea otter.”

Patrick Robinson, the Año Nuevo reserve director, and a marine biologist astatine UC Santa Cruz, said 47 elephant seals connected the mainland person died since the commencement of the outbreak, and the wildlife squad is uncovering 2 caller symptomatic and 2 dormant animals each day.

Symptoms of vertebrate flu successful mammals tin see tremors, convulsions, seizures and musculus weakness.

He said it is mean for immoderate individuals to dice of earthy causes, truthful investigating is critical. And helium said the percent of animals that person died successful the Año Nuevo rookery is comparatively small: Only astir 5% of weaned pups and 6% of big males person died. Although, successful the lawsuit of the pups, that’s 4 times higher than past year’s decease rates. And helium said, the decease of ample males is “basically nonexistent successful astir males.”

He said 80% of the big females had departed by the clip the outbreak began, and astir each of them are present gone. No big females died, and nary person been observed arsenic being symptomatic.

“The outbreak is not over, and we’re not truly definite what’s going to hap successful the future,” helium said. “I stay hopeful astir this happening close now.”

In precocious 2022, the H5N1 vertebrate flu microorganism decimated confederate elephant seal populations successful South America and respective sub-Antarctic Islands. At immoderate colonies successful Argentina, 97% of pups died, portion connected South Georgia Island, researchers reported a 47% diminution successful breeding females betwixt 2022 and 2024. Researchers judge tens of thousands of animals died.

More than 30,000 oversea lions successful Peru and Chile died betwixt 2022 and 2024. In Argentina, astir 1,300 oversea lions and fur seals perished.

At the time, researchers were not definite wherefore bluish Pacific populations were not infected, but suspected erstwhile oregon milder strains of the microorganism conferred immoderate immunity.

The microorganism is amended known successful the U.S. for sweeping done the nation’s dairy herds, wherever it infected dozens of dairy workers, millions of cows and thousands of wild, feral and home mammals. It’s besides been recovered successful chaotic birds and killed millions of commercialized chickens, geese and ducks.

Two Americans person died from the microorganism since 2024, and 71 person been infected. The immense bulk of infected radical were dairy oregon commercialized poultry workers. One decease was that of a Louisiana antheral who had underlying conditions and was believed to person been exposed via backyard poultry oregon chaotic birds.