Deadly bird flu found in California elephant seals for the first time

The H5N1 vertebrate flu microorganism that devastated South American elephant seal populations has been confirmed successful seals astatine California’s Año Nuevo State Park, researchers from UC Davis and UC Santa Cruz announced Wednesday.

The microorganism has ravaged wild, commercialized and home animals crossed the globe and was recovered past week successful 7 weaned pups. The confirmation came from the U.S. Department of Agriculture’s National Veterinary Services Laboratory successful Ames, Iowa.

“This is exceptionally accelerated detection of an outbreak successful free-ranging marine mammals,” said prof Christine Johnson, manager of the Institute for Pandemic Insights astatine UC Davis’ Weill School of Veterinary Medicine. “We person astir apt identified the precise archetypal cases present due to the fact that of coordinated teams that person been connected precocious alert with progressive surveillance for this illness for immoderate time.”

Since past week, erstwhile researchers began noticing neurological and respiratory signs of the illness successful immoderate animals, 30 seals person died, said Roxanne Beltran, a prof of ecology and evolutionary biology astatine UC Santa Cruz. Twenty-nine were weaned pups and the different was an big male. The squad has truthful acold confirmed the microorganism successful lone 7 of the dormant pups.

Infected animals often person tremors, convulsions, seizures and musculus weakness, Johnson said.

Beltran said teams from UC Santa Cruz, UC Davis and California State Parks show the animals 260 days of the year, “including each time from December 15 to March 1” erstwhile the animals typically travel ashore to breed, springiness commencement and nurse.

The concerning behaviour and deaths were archetypal noticed Feb. 19.

“This is 1 of the astir well-studied elephant seal colonies connected the planet,” she said. “We cognize the seals truthful good that it’s precise evident to america erstwhile thing is abnormal. And truthful my squad was retired that greeting and we observed abnormal behaviors successful seals and accrued mortality that we had not seen the time earlier successful those nonstop aforesaid locations. So we were precise assured that we caught the opening of this outbreak.”

In precocious 2022, the 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 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.

Scientists astatine UC Santa Cruz and UC Davis accrued their surveillance of the elephant seals successful Año Nuevo successful caller years. The catastrophic effect of the illness prompted interest that it would dispersed to California elephant seals, said Beltran, whose laboratory leads UC Santa Cruz’s bluish elephant seal probe programme astatine Año Nuevo.

Johnson, the UC Davis researcher, said the squad has been moving with stranding networks crossed the Pacific portion for respective years — sampling the insubstantial of birds, elephant seals and different marine mammals. They person not seen the microorganism successful different California marine mammals. Two erstwhile outbreaks of vertebrate flu successful U.S. marine mammals occurred successful Maine successful 2022 and Washington successful 2023, affecting grey and harbor seals.

The microorganism successful the animals has not yet been afloat sequenced, truthful it’s unclear however the animals were exposed.

“We deliberation the transmission is really from dormant and dying oversea birds” surviving among the oversea lions, Johnson said. “But we’ll surely beryllium investigating if there’s immoderate mammal-to-mammal transmission.”

Genetic sequencing from confederate elephant seal populations successful Argentina suggested that mentation of the microorganism had acquired mutations that allowed it to walk betwixt mammals.

The H5N1 microorganism was archetypal detected successful geese successful China successful 1996. Since past it has dispersed crossed the globe, reaching North America successful 2021. The lone continent wherever it has not been detected is Oceania.

Año Nuevo State Park, conscionable northbound of Santa Cruz, is location to a colony of immoderate 5,000 elephant seals during the wintertime breeding season. About 1,350 seals were connected the formation erstwhile the outbreak began. Other ample California colonies are located astatine Piedras Blancas and Point Reyes National Seashore. Most of those animals — astir 900 — are weaned pups.

It’s “important to support this successful context. So far, avian influenza has affected lone a tiny proportionality of the weaned astatine this time, and determination are inactive thousands of seemingly steadfast animals successful the population,” Beltran said successful a quality conference.

Public entree to the parkland has been closed and guided elephant seal tours canceled.

Health and wildlife officials impulse beachgoers to support a harmless region from wildlife and support dogs leashed due to the fact that the microorganism is contagious.