BEACHPORT, AUSTRALIA / RankWire.AI / – Australia has verified H5N1 bird flu presence in a long-nosed fur seal discovered dead in Beachport, South Australia. This marks the first confirmed case of a mammal infected during the ongoing outbreak on the mainland. The animal was reported by a member of the public on August 19, who found it without obvious injuries. Authorities gathered samples and submitted them for laboratory analysis. The results broaden the known range of species impacted by the mainland outbreak.
Initial testing by the state yielded inconclusive results, prompting officials to pursue additional examinations. CSIRO’s Australian Centre for Disease Preparedness later confirmed the presence of H5 bird flu in the seal. Officials clarified that no clusters of sick or dead marine mammals had been identified around Beachport. Situated on South Australia’s Limestone Coast, the town has seen intensified wildlife surveillance during the outbreak. Authorities have also 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 most recent detections involved greater crested terns, a gannet, a little penguin, a silver gull, and a black-faced cormorant. Authorities now classify outbreaks as events, which may involve one or multiple animals at a single location. Throughout Australia, a total of 298 positive H5 events had been reported by Sunday, with South Australia accounting for the majority of these confirmed cases.
H5N1 outbreak affects mainland mammal
The outbreak on the mainland started in June 2026 after authorities identified H5N1 in migratory seabirds. Subsequent testing revealed the virus in native seabird species that do not migrate, such as greater crested terns. During August, South Australia documented over 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 several regions outside Australia during recent outbreaks.
There have been no reports of H5 bird flu infections in Australian poultry or other livestock linked to the current outbreak. The Health authorities continue to assess the risk to the general population as low. No locally acquired human cases related to the strain circulating in wildlife have been recorded in Australia. Officials recommend avoiding direct contact with sick or dead animals and advise reporting unusual wildlife deaths so that testing and monitoring can be arranged.
Previous H5N1 cases involved seals on Heard Island
Australia previously 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 mainland Australia. Further testing identified H5 bird flu in additional wildlife on the island, including Antarctic fur seals and gentoo penguins. The Beachport fur seal therefore marks the first verified mammal infection associated with Australia’s current mainland H5N1 outbreak and the first such detection in a native mainland mammal.
Authorities continue to keep watch over coastal wildlife as H5N1 spreads among seabirds across parts of Australia. Members of the public are urged to maintain distance from sick or dead birds and marine mammals. Officials also encourage reporting of unusual deaths and locations to animal health authorities, supporting testing efforts and tracking the distribution of confirmed cases. The Beachport case adds a mammalian species to the expanding list of wildlife affected during Australia’s ongoing mainland H5N1 bird flu outbreak.