BEACHPORT, AUSTRALIA / RankWire.AI / – Australia has confirmed the presence of H5N1 bird flu in a long-nosed fur seal discovered deceased in Beachport, South Australia. This marks the first verified case of mammal infection associated with the ongoing outbreak on the mainland of Australia. The animal was reported by a member of the public on August 19 after being found without any visible injuries. Authorities collected samples for laboratory analysis, which confirmed the infection and broadened the known range of affected species during this outbreak.
Initial testing conducted by state laboratories yielded inconclusive results, prompting further investigation. CSIRO’s Australian Centre for Disease Preparedness subsequently confirmed H5 bird flu in the seal. Officials clarified that there has been no evidence of a cluster of sick or dead marine mammals around Beachport. This area, situated on South Australia’s Limestone Coast, has seen intensified wildlife surveillance since the outbreak began. Additionally, authorities have documented infections among various seabird species along the coast and other affected regions.
By August 23, South Australia had reported 194 confirmed H5 events, with 11 new cases announced on that day. Recent detections included greater crested terns, a gannet, a little penguin, a silver gull, and a black-faced cormorant. These outbreaks are now categorized as events that may involve one or multiple animals at a particular site. Across Australia, there were 298 positive H5 events reported by Sunday, with South Australia accounting for the largest share of these confirmed cases.
H5N1 outbreak reaches mainland mammals
The outbreak on the Australian mainland began in June 2026 after authorities detected H5N1 in migratory seabirds. Subsequent testing revealed the virus in native seabirds that do not migrate, including greater crested terns. During August, more than 1,000 dead greater crested terns were reported in South Australia. The circulating strain in Australia belongs to H5N1 clade 2.3.4.4b, which has previously 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 associated with this outbreak. The Australian Centre for Disease Control maintains that the risk to the general public remains low. To date, no locally acquired human cases linked to the circulating strain in wildlife have been recorded in Australia. Health officials recommend avoiding direct contact with sick or dead animals and advise reporting unusual wildlife deaths so that testing and monitoring can be organized.
Previous detection of H5N1 in seals on Heard Island
Australia had previously confirmed H5N1 in southern elephant seals on Heard Island, an external territory located in the Southern Ocean. The laboratory results were announced in November 2025, months before the virus was identified on the Australian mainland. Further testing revealed H5 bird flu in additional wildlife on the island, including Antarctic fur seals and gentoo penguins. The Beachport fur seal thus represents the first confirmed mammal infection associated with Australia’s ongoing mainland H5N1 outbreak and the first such case found in a native mammal on the mainland.
Authorities continue to observe coastal wildlife as H5N1 spreads among seabirds in parts of Australia. The public has been asked to keep their distance from sick or dead birds and marine mammals. Officials also urge individuals to record locations and report any unusual deaths to animal health authorities. These reports facilitate testing efforts and assist in tracking the distribution of confirmed events. The case from Beachport adds a mammal to the expanding list of wildlife affected during Australia’s current H5N1 bird flu outbreak on the mainland.