Australia has confirmed its first case of H5N1 bird flu in a mammal after testing of a long-nosed fur seal found in South Australia.

Federal agriculture minister Julie Collins on Sunday said that the first case in a mammal was recorded in a seal found at Beachport, 300km south of Adelaide.

“Although this is a concerning development, it is not unexpected for us to start to see infection in other wildlife, particularly in marine mammals, particularly in areas where there are high infection rates in wild birds,” she told reporters.

Australia ⁠has been grappling with rising cases of the highly pathogenic avian influenza after it landed in the country in June. The country’s first mass seabird deaths from the virus occurred this month, marking an escalation of ⁠the outbreak that began after the ​virus ⁠was first detected in migratory seabirds before spreading to native species.

The seal, one of an estimated population of 100,000 in the state’s waters, was found dead with no signs ‌of injury, the authorities said.

The minister said: “I have been advised that at this time the detection does not appear to be associated with other sick or dead marine mammals.An infection of this individual animal is likely to have occurred due to exposure to infected wild birds or the environment that they share.”

Ms Collins added: “Once the H5 bird flu is spreading in the ⁠natural environment, it is not possible to avoid significant losses.”

There have been 297 positive bird flu cases recorded in the island nation, with 194 of those being in South Australia, according to the Australian Broadcasting Corporation. “At this stage there is no evidence of infection in our poultry or agriculture systems,” Ms Collins said.

Officials in Australia earlier this month announced they would inoculate at-risk native bird populations against the lethal H5N1 strain of avian influenza. Government data shows that roughly 45 per cent of Australia’s 850 bird species are endemic, meaning they are entirely unique to the country and are not found anywhere else on the planet.

Australia was the last continent to report bird flu, although the virus was detected in late 2025 on the sub-Antarctic territory of Heard Island. More than 13,000 baby seals were killed by the virus on the island, according to local media.

Seals are at high risk of ‌contracting the virus, said South Australia’s chief veterinary officer, ​Skye Fruean, because they live very near wild birds ‌on rocky outcrops on the ⁠coast. “They would be coming across, no doubt, really high ⁠levels of the virus in their environment,” Ms Fruean said in televised remarks.