A common dolphin in South Australia has tested positive for the H5N1 strain of bird flu, marking a new development in the spread of the virus in the region. The dolphin was found dead on a beach near Goolwa, with preliminary lab results showing high levels of the virus in its brain, according to South Australia’s chief veterinary officer, Skye Fruean. Full post-mortem analyses are still underway.

This recent detection comes amid a surge in H5N1 infections across South Australia, where 46 new cases were reported since Thursday. Most cases have been identified in migratory greater crested terns, with additional infections confirmed in native species such as brown falcons, black-faced cormorants, and little penguins. A red fox in the state has also tested positive for the virus.

Officials noted that while bird flu cases among marine mammals like dolphins are rare, there have been documented instances overseas involving dolphins and porpoises. Dr. Fruean said dolphins usually consume fish rather than birds, so the exact cause of the infection remains unclear. She suggested the animals might have been exposed through incidental contact, such as playing with infected birds or contaminated materials in the water.

Despite the detection of the virus in the dolphin, authorities do not expect a large-scale die-off among dolphin populations. Concerns are higher for other marine mammals such as seals and sea lions, which tend to gather in large groups near shorelines, potentially facilitating widespread transmission.

Since June, South Australia has recorded a total of 249 bird flu cases, the highest number among Australian states and territories. The ongoing outbreak has prompted precautionary measures beyond the mainland. Authorities are preparing to evacuate around two dozen personnel stationed on Macquarie Island—a remote outpost located roughly 1,500 kilometers southeast of Tasmania—due to concerns over a potential outbreak on the island. The group includes tradespeople, scientists, and support staff.

The H5N1 bird flu virus continues to pose a risk to wildlife populations in the region, with state officials closely monitoring developments and coordinating response efforts to prevent further spread.