Signs of deadly bird flu strain in seals on Australian sub-Antarctic Heard Island

Scientists have raised an alarm about the possibility of the H5 avian influenza (bird flu) strain being found on Heard Island after observing unusual levels of mortality in seals. Photo / 123rf

A deadly strain of bird flu has potentially reached one of Australia’s sub-Antarctic islands, sparking biosecurity fears and warnings of a “wake-up call”.

Australian scientists on board the RSV Nuyina raised the alarm of a possible H5 avian influenza (bird flu) strain being found on Heard Island after observing unusual levels of mortality in the seals while on an environmental management visit.

The animals are native to the external territory, which is located over 4000km southwest of Perth and 1700km north of Antarctica in the Southern Ocean.

No other unusual mortality levels were observed in other species, including penguins and seabirds.

In a joint statement, the federal departments of agriculture and environment reiterated this was not a confirmed detection.

“It reinforces the need for Australia to remain focused on preparing for an outbreak,” the statement said.

“Seeing signs consistent with H5 bird flu in wildlife on Heard Island is not unexpected.

“This virus has previously been found on the French Kerguelen and Crozet sub-Antarctic islands, which are less than 450km from Heard and McDonald Islands.”

Despite no official confirmation being made, the Invasive Species Council has slammed the news as being a “wake-up call” for the country’s “lacklustre environmental laws”.

“Many species already under enormous pressure from threats will be at grave risk from this deadly new disease,” the council’s policy director Dr Carol Booth said.

“We have campaigned to get Australia’s governments to prepare for the looming H5N1 catastrophe. But as well as the funding needed for Australia to properly prepare to do as much as we can to protect our precious wildlife from this one highly destructive disease, we need a system that is effective for other threats as well.”

Bird flu is a viral disease found across the globe that primarily affects birds, but can also affect other animals and humans on rare occasions.

Since arriving in South America in 2022, it has killed more than 30,000 South American sea lions, 17,000 southern elephant seal pups and at least 650,000 native birds, including 40% of Peru’s pelicans, according to the Invasive Species Council.

The H5 strain of bird flu – in particular the dangerous H5N1 clade 2.3.4.4b strain of the virus – has moved quickly around the world.

There have been 14 human infections, including eight deaths, reported in Cambodia this year.

Australia is the only continent free from this strain.

“Bird flu is just one of many looming threats,” Booth said.

“We need a system that spots danger early and acts fast. We also need a system that deals systematically with threats that can be eliminated or reduced to give wildlife the resilience to survive more challenging threats like bird flu.”

Samples have been collected and packaged and will be returned to the CSIRO Australian Centre for Disease Preparedness for confirmatory testing when RSV Nuyina returns to Australia in mid-November.

“It will take some weeks to get the results from these tests,” the departments of agriculture and environment both said.

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