Bird flu has reached the Antarctic region for the first time, and scientists are filled with dread about what could be in store for its unique wildlife.
But there’s another worry too. Could the presence of the virus in the frigid wilderness help it reach Australia?
For the past two years, highly pathogenic avian influenza has been sweeping the world, killing poultry and wild birds en masse.
But increasingly mammals are being affected, from domestic cats, dogs and farm animals, to bears and leopards, dolphins, seals and sea lions.
Even humans are not immune, although cases are rare.
The rise of the virus in marine mammals has scientists fearful for much of the wildlife in the Antarctic region, species that until now have largely escaped exposure to previous iterations of bird flu.
The epicentre of the regional outbreak is Bird Island in South Georgia and the South Sandwich Islands, a sub-Antarctic British territory due east of South America’s southern tip.
In October, after reports of sick birds and unexplained deaths on the island, researchers from the British Antarctic Survey took samples and confirmed the presence of the highly pathogenic H5N1 strain in brown skuas.
It’s likely the seabirds picked up the virus while migrating back to the island from South America, where case numbers are high.
In Chubut in southern Argentina, about 2200km northwest of Bird Island, authorities have reported the mass deaths of baby elephant seals, with the adult population also affected.
In some colonies, 90 per cent of pups have perished.
Confronting images of their decaying bodies littering the province’s shores have left scientists including Australia’s Meagan Dewar anxious about what might unfold in Antarctica in coming months.
Dr Dewar is chair of the Antarctic Wildlife Health Network, which is part of the international Scientific Committee on Antarctic Research.
In December, she’s due to travel to South Georgia and the Antarctic continent.
So far there’s been no confirmation that the virus has spread from the sub-Antarctic zone to mainland Antarctica.
But given Bird Island is a mere 1500km from the nearest mainland point in West Antarctica, the fear and the expectation is that won’t last.
“As the season progresses, we do expect it to hit the peninsula (on the mainland),” she said.
“It’s very, very concerning, and I don’t know what I’ll see.”
There are already signs bird flu may be spreading to other species in South Georgia but test results are still pending.
“We have a range of species that are showing up – more skuas, into kelp gulls now, but we are also seeing big mass mortality events in elephant seals as well.”
Penguins are susceptible too.
So if bird flu reaches West Antarctica – below South America – what are the prospects of it spreading across the continent to East Antarctica, below Australia?
“It is expected that once it gets on to the peninsula, it will slowly do that movement around the continent, but exactly how fast that will be and whether that will be this year or not? We need to wait and see,” Dr Dewar said.
Australia, and for now Antarctica, are the only continents that are yet to be hit by the latest deadly strain.
But Australia is on high alert and preparing for its arrival.
Dr Dewar believes the virus is most likely to reach Australia from migratory birds that come down from Asia.
“But if it got around to places like East Antarctica, Macquarie Island, we would definitely see it moving up that way to Australia as well,” she said.
“A lot of the short-tailed shearwaters that we have currently breeding in Australia, they come down to the Antarctic polar front to feed. If there were infected individuals, they could be interacting at foraging grounds.”
Dr Dewar says there’s a fair chance any infected birds might die before they can return to Australia.
But sick birds dropping dead doesn’t extinguish the risk because predators can be infected by eating their carcasses.
Australia has been lucky in the past with outbreaks of highly pathogenic avian influenza affecting poultry, but not wild birds.
Invasive Species Council biologist and policy anaylst Carol Booth is nervous about a possible outbreak given so many bird and mammal species are already in deep strife from other pressures.
She says the federal government must urgently establish a national taskforce to deal with impacts on Australian wildlife.
She is also seeking the immediate release of a risk assessment, commissioned by the agriculture department, on the likelihood and consequences of high pathogenicity bird flu establishing in Australia’s wild birds.
“There is stuff happening but we’re not in any position to make a judgement as to how adequate it is because it hasn’t been released,” Dr Booth said.
“We haven’t been privy to exactly what has been going on.”
The department, which is managing Australia’s response, says the assessment is complete and concludes the nation is at higher risk than its historical baseline of low risk.
It’s been shared with key stakeholders and will be publicly released in the “near future”.
“Australia has an active surveillance program in wild birds, as well as general surveillance in poultry, wild birds, and wild mammals,” the department said.
The federal environment department says it’s working closely with the agriculture department, which leads Australia’s biosecurity responses.
As Dr Dewar prepares for her trip, she says the focus must be on charting where the virus is confirmed and suspected, and on strict biosecurity protocols to ensure scientists and Antarctic tourists don’t aid the spread of the virus.
“Probably within the next month, we would potentially start to see things happening,” she said.
“Then how quickly it will spread throughout the continent is unknown.”