Australia has been grappling with rising cases of the highly pathogenic avian influenza after it landed in the country in June

Australia on Sunday confirmed its first ​case of H5N1 bird flu in a mammal, with the deadly virus found in a long-nosed fur seal in South Australia state.

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. 

South Australian authorities confirmed the nation’s first mammalian detection in the seal, found at the coastal town of Beachport, about 310 km (190 miles) south of Adelaide, the ​state capital. 

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.

Its death “does ​not appear to be associated with other sick or dead marine mammals,” federal Agriculture Minister Julie Collins said in televised remarks. “Once the H5 bird flu is spreading in ‌the natural environment it is ​not possible to avoid significant losses.” 

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,” Fruean said in televised remarks. 

H5N1 has not shown up in Australia’s poultry or agriculture, according to the federal government, which said on Friday that 297 cases have been confirmed nationwide.