Australia confirms first H5N1 bird flu case on sub-Antarctic Macquarie Island

SYDNEY, Oct 17 (Reuters) – Australia on Saturday confirmed its first case of H5N1 bird flu on the sub-Antarctic Macquarie Island, with the deadly virus found in the remote territory’s vulnerable elephant seal population.

• Australia’s Chief Veterinary Officer Beth Cookson said official testing confirmed the highly pathogenic virus strain “in samples collected from an elephant seal and a kelp gull on Macquarie Island, marking the first H5 event on this island”.

• Australia in June became the last continent to report bird flu, although the virus was detected in late 2025 on another of its sub-Antarctic territories, Heard Island, where more than 13,000 ​baby seals were ⁠killed by the virus, according to local media.

• Like Heard Island, Macquarie Island, a UNESCO World Heritage-listed territory located in the Southern Ocean halfway between Australia’s Tasmania state and Antarctica, is a key breeding ground for southern elephant seals.

• The mammals, which can weigh up to 3,600 kg (7,936 pounds), are particularly susceptible to H5 bird flu, with pup mortality rates in some cases of more than 90%, according to the federal government.

• In August, Australia’s environment department said it would withdraw personnel from a research station on Macquarie Island due to the “psycho-social risk to expeditioners of a potential H5 avian influenza outbreak”.

• Expert assessments predicted the virus would likely cause a significant elephant seal mortality event during the upcoming breeding season, the environment department said.

(Reporting by Sam McKeith in Sydney; Editing by Sam Holmes)