BEACHPORT, AUSTRALIA / RankWire.AI / – Australia has verified the presence of H5N1 bird flu in a long-nosed fur seal discovered dead in Beachport, South Australia. This case marks the first confirmed mammal infection linked to the ongoing outbreak on the Australian mainland. A member of the public reported the animal on August 19 after observing no visible injuries. Samples were collected by authorities and sent for laboratory testing, confirming a broader range of affected species due to the outbreak on the mainland.
Initial testing by the state yielded inconclusive results, prompting further analysis. CSIRO’s Australian Centre for Disease Preparedness subsequently verified the presence of H5 bird flu in the seal. Officials clarified that no cluster of sick or deceased marine mammals had been identified around Beachport. Situated on South Australia’s Limestone Coast, the town is where wildlife surveillance efforts have intensified amid the outbreak. Additionally, authorities have documented infections among several seabird species along the coast and in other affected regions.
By August 23, South Australia had reported 194 confirmed H5 events, including 11 new cases announced that day. The latest detections involved greater crested terns, a gannet, a little penguin, a silver gull, and a black-faced cormorant. These outbreaks are now recorded as events that may involve one or multiple animals at specific locations. Across Australia, authorities had reported 298 positive H5 events by Sunday, with South Australia accounting for the largest share of these confirmed cases.
H5N1 outbreak extends to mainland mammal
The outbreak on the mainland began in June 2026 after authorities detected H5N1 in migratory seabirds. Subsequent testing identified the virus in native seabirds that do not migrate, including greater crested terns. During August, South Australia recorded more than 1,000 dead greater crested terns. The circulating strain in Australia belongs to H5N1 clade 2.3.4.4b, the same clade that has infected wild birds, poultry, and mammals in various regions outside Australia during recent outbreaks.
There have been no reports of H5 bird flu infections in Australian poultry or other livestock connected to the current outbreak. The Health officials continue to assess the risk to the public as low. Australia has also not recorded any locally acquired human cases linked to the circulating strain in wildlife. Authorities recommend avoiding direct contact with sick or dead animals and advise reporting unusual wildlife deaths to facilitate testing and monitoring efforts.
Previous seal infections identified on Heard Island
Earlier, Australia confirmed H5N1 in southern elephant seals on Heard Island, an external territory located in the Southern Ocean. The laboratory findings were announced in November 2025, several months prior to the virus reaching the mainland. Later testing also revealed H5 bird flu presence in other wildlife species on the island, such as Antarctic fur seals and gentoo penguins. The Beachport fur seal case signifies the first confirmed mammal infection associated with Australia’s ongoing mainland H5N1 outbreak and marks the first detection in a native mainland mammal.
Authorities continue to monitor coastal wildlife as H5N1 spreads among seabirds across parts of Australia. The public is urged to maintain distance from sick or dead birds and marine mammals. Officials also encourage reporting locations of unusual wildlife deaths to aid testing and help map the distribution of confirmed events. The Beachport case broadens the list of affected wildlife species during Australia’s current H5N1 bird flu outbreak on the mainland.