Local transmission of H5N1 declared as alarm sounds for local birds, sea lions

Dreaded local transmission of the deadly H5N1 bird flu has been declared in South Australia, sounding the alarm for avian species around the country and sparking fears for a colony of endangered sea lions, which are also susceptible to the virus.

The South Australian government said on Wednesday that 11 new cases of the virus had been detected among greater crested terns, a local species that does not leave the country.

CSIRO national laboratory testing underway is expected to confirm the SA results. It is likely that migratory seabirds from the Antarctic brought the virus to Australia and it then spread among terns.

Seven detections were made on South Australia’s south-east coast, and four on Kangaroo Island.

SA Primary Industries Minister Clare Scriven said results showed it was “very, very likely” the birds were infected with H5N1 virus.

Federal Agriculture Minister Julie Collins said the virus was believed to be spreading in terns and that with the onset of local transmission, it would spread in local populations.

“We do expect with this local transmission there will be further transmission in Australian wildlife,” Collins said.

Australia’s chief veterinary officer, Dr Beth Cookson, said little could be done to stem the virus moving around the country.

“In the natural environment there are limited feasible actions to contain the spread,” Cookson said.

Bird flu viruses have circulated around the globe for decades. H5N1 is a particularly deadly variant and has killed hundreds of millions of birds around the world. It is believed that an outbreak in Australia could spark an environmental disaster, risking extinction of dozens of species including marine mammals such as dolphins and seals that also suffer from infection.

Scriven said popular beach tours to the colony of about 1000 sea lions at Seal Bay on Kangaroo Island had been halted. The virus has not been detected among the marine mammals, but tours were halted to stop any potential disturbances that could harm the colony.

There are also about 100,000 long-nosed fur seals on or around Kangaroo Island. These animals can also contract the virus.

“Everyone knows how susceptible the [sea lion] population is, and they are an endangered species,” Scriven said.

H5N1 arrived in South America in 2022 and killed more than 30,000 South American sea lions, 17,000 southern elephant seal pups and unknown numbers of porpoises, dolphins and otters, as well as at least 650,000 native birds.

More than 13,000 seal pups were killed by the virus on Australia’s sub-Antarctic Heard Island territory, which was more than three-quarters of new births on the island.

Conservation groups are calling for the immediate deployment of a $200 million fund to boost wildlife resilience. They argue that while the virus cannot be stopped from spreading among wildlife, investment in habitat restoration and programs to cull feral predators can help native animals survive the outbreak.

“With only 12,000 individuals left, the Australian sea lion simply cannot absorb the kind of losses we have seen bird flu inflict on marine mammals overseas,” said Australian Marine Conservation Society campaign director Alexia Wellbelove.

“Every colony, every pup, every individual matters when a population is this small. We cannot afford to wait.”

Invasive Species Council senior advocate James Johnston said emergency wildlife funds were critical.

“We can’t stop bird flu reaching every corner of Australia, but we can give our wildlife a much better chance of surviving it,” he said.

The Albanese government committed $113 million to preparations to deal with an H5N1 incursion, with an emphasis on planning to identify an outbreak swiftly and a response to limit its spread.

This includes funding to prepare biosecurity officers to respond to an outbreak in farmed poultry, which may involve quarantining farms or districts and restricting transport between locations.

Tens of millions of dollars have also been committed to environmental measures such as building pup shelters on Kangaroo Island to help reduce infant mortality in sea lions, removing weeds from islands to improve habitat for seabirds, and funding pre-existing captive breeding programs for endangered species such as the Tasmanian devil, orange-bellied parrot and regent honeyeater.

The funds would also pay for teams to remove carcasses of infected animals swiftly to prevent further spread and limit contact between wild and farmed birds.

Australia’s unique wildlife, which has evolved in isolation for millions of years, could be particularly vulnerable to H5N1. But little is known about native species’ vulnerability.

There have been no detections of the virus in farmed poultry. An outbreak would cause a significant impact on chicken meat and egg production. H5N1 in the United States has caused more than 170 million birds to be culled since 2022, while egg prices had tripled by 2025.

H5N1 is not considered a significant risk to human health. However, pet birds and cats usually become extremely ill and die when infected.

Dogs are more resistant to the virus and rarely die or become severely ill. The same is believed to be true for rabbits and guinea pigs as well as cows, sheep, pigs and horses.

People are encouraged to look out for possible infections in birds and marine mammals. Signs include sudden death or difficulty breathing, standing, walking or flying. Sick animals should not be touched, but their location should be noted, with photos and videos, before calling the bird flu hotline on 1800 675 888.

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