Australian authorities confirmed on Sunday (August 23) that the highly pathogenic H5N1 avian influenza virus has been discovered for the first time in a mammal in the country.
According to reports from Reuters, in the coastal town of Beachport in South Australia, a long-nosed fur seal was tested positive for the H5N1 virus.
This marks the first time in Australia that the virus has been identified as spreading from wild birds to native mammals since the outbreak of highly pathogenic avian influenza.
The South Australian government stated that the fur seal was found dead with no apparent external injuries. Beachport is located about 310 kilometers south of Adelaide, the capital of South Australia. Authorities estimate that there are around 100,000 long-nosed fur seals in the coastal waters of South Australia.
Julie Collins, the Minister for Agriculture, Fisheries, and Forestry of the Australian federal government, stated that there is currently no evidence linking the death of this seal to any other diseased or deceased marine mammals.
She said, “Once H5 avian influenza spreads in the natural environment, significant losses become unavoidable.”
Australia has been experiencing a growing outbreak of highly pathogenic avian influenza recently, with cases continuing to rise. This month, a large-scale event of seabird deaths was reported for the first time locally, indicating further expansion of the epidemic. The virus was initially discovered in migrating seabirds and subsequently spread to native Australian bird species.
South Australia’s Chief Veterinary Officer, Skye Fruean, pointed out that fur seals have a higher risk of H5N1 infection due to their frequent habitat in coastal rocky areas, which are close to the territories where wild birds are active, potentially exposing them to a high concentration of the virus over the long term.
Australia is one of the regions where the H5N1 epidemic emerged relatively late. It wasn’t until the end of 2025 that the virus was first discovered on Heard Island in the country’s sub-Antarctic territory. Local media reported that over 13,000 juvenile seals have died from virus infection on the island.
The Australian federal government stated that the H5N1 virus has not yet been detected in poultry farms or agricultural systems. As of August 21, a total of 297 cases of highly pathogenic avian influenza have been confirmed nationwide.