Officials have reported that the lethal and highly transmissible H5 avian influenza has been detected in a sparsely populated Australian territory for the first time.

During an environmental monitoring expedition to Heard Island in October, Australian researchers observed an unusually high death rate among elephant seals. This island is located approximately 4,000 kilometers southwest of Perth and 1,700 kilometers north of Antarctica.

Researchers noted that other wildlife on the island, such as penguins and seabirds, appeared unaffected.

Subsequent testing of deceased elephant seal samples has confirmed the presence of the H5 avian influenza virus.

Agriculture Minister Julie Collins remarked that the positive test was anticipated due to ongoing outbreaks on nearby sub-Antarctic islands. She emphasized that this discovery does not significantly alter the risk level to the Australian mainland.

She said the detection does, however, reiterate the importance of Australia’s biosecurity.

“While this detection of H5 bird flu on Heard Island does not substantially increase risks to Australia, it does reinforce the ongoing need for Australia to remain focused on preparing for a potential outbreak,” she said.

Environment Minister Murray Watt said the confirmation “reinforces the importance and urgency of the work currently underway across Australia to protect threatened species and priority biodiversity, and build resilience of our most at risk species in nature”.

Australian scientists are on a second voyage to Heard Island to gather more information about wildlife health.

They are scheduled to arrive in late December and return to Hobart in February.

Australia has been the only continent free from the virus, which has spread across the US, Europe, Asia and Antarctica and caused serious illness and deaths in millions of wildlife.

The H5 bird flu only reached mainland Antarctica for the first time in February 2024, which caused experts to warn that it would almost certainly reach Australia. 

Australia has been preparing for an outbreak, with the federal government throwing more than $100 million at strengthening the nation’s measures and responses and researchers monitoring the global spread of the virus.

States and territories are also helping the most threatened and vulnerable species to build resilience to the virus. 

Springtime is a particularly precarious time, with birds migrating from the south arriving in Australia.

H5 bird flu would have a devastating effect on Australia’s wildlife population and agricultural industries.

Threatened Species Commissioner Fiona Fraser has said the spread of the virus cannot not be able to be stopped or eradicated once it reaches Australia.