Australia Confirms First H5N1 Bird Flu Case in Mammal

Australia has confirmed its first case of H5N1 bird flu in a mammal, after the deadly virus was found in a long-nosed fur seal in South Australia. The confirmation comes as the country faces a rise in highly pathogenic avian influenza (HPAI) cases since the virus was first detected there in June.

South Australian authorities confirmed the first detection of the virus in a mammal in the state. The seal was found in the coastal town of Beachport, about 310 kilometres south of Adelaide, the state capital. According to local authorities, the dead seal was part of a population estimated at 100,000 in the state’s waters. No signs of injury were found on the carcass.

Australian Agriculture Minister Julie Collins said the seal’s death did not appear to be linked to other sick or dead marine mammals in the area. She added that once H5 bird flu spreads in the natural environment, significant losses are difficult to avoid.

Australia this month also reported its first mass death of seabirds from the virus, marking an escalation of an outbreak that began when the virus was first detected in migratory seabirds before spreading to local species. To date, the virus has not been found in poultry or the agricultural sector. The federal government said on Friday that 297 cases had been confirmed nationwide.

Australia became the last continent to report bird flu cases, although the virus had been detected in late 2025 on Heard Island, a sub-Antarctic territory under Australian administration. According to local media, more than 13,000 seal pups died from the virus on Heard Island.