Deadly H5N1 avian influenza strain detected on mainland Antarctica for the first time – ABC News

The arrival of a devastating strain of avian influenza, which has killed millions of animalsglobally, to the Antarctic mainland makes Australia the last continent free of the virus.

The highly-contagious strain of bird flu, known as H5N1, was confirmed over the weekend in two brown skua, which are large seabirds that prey on fish, small mammals and other birds like penguin chicks.

Scientists from Spanish National Research Council tested the two dead birds, which were collected by Argentine researchers in early February.

The birds were found near Argentina's Primavera Base, which is on the western side of Antarctica, close to South America.

While avian influenza had previously been detected on islands between South America and Antarctica, this is the first confirmed detection on the mainland.

Scientists expected the flu to reach Antarctica's mainland this year or next, and are concerned it could lead to the deaths of thousands of the frozen land's unique animal species.

Here's five quick things to know about the virus and its likelihood of getting to Australia.

Different types of bird flu have been around as long as we've had birds.

Sometimes the viruses are not all that deadly and do not spread far.

But there are also strains of high-pathogenicity avian influenza, which can do a lot more damage.

In 1996 a strain of the flu, known as H5N1, was first detected in a goose in Guangdong, China.

This virus was able to kill domestic chicken flocks within a matter of days.

The strain was a precursor to the current outbreak known as H5N1 clade 2.3.4.4b,which started in Europe in 2020 when gene-swapping of the virus between wild and domestic birds created an even deadlier version.

That strain made its way to the shores of North America in 2021 thanks to trans-Atlantic migration pathways for shorebirds.

Since then some 81 million domestic birds have been killed or euthanised because of the virus.

The number of wild birds around the world that have succumbed to the disease is unknown, but it is believed to be in the millions.

H5N1 spread quickly around the rest of the world and rapidly made its way down the South America coastline to the subantarctic region at South Georgia and the Falkland Islands.

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So far Oceania, including Australia and New Zealand, has remained free of the virus.

The outbreak has been called a panzootic, which is like an animal version of a pandemic with a worldwide spread of an infectious disease.

About 600,000 wild birds died in South America between October, 2022, when the virus was first detected on the continent, up to November last year.

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The hardest hit species were cormorants and Peruvian boobies with a combined 504,000 deaths.

The virus has also killed different species of mammals around the world.

In South America, at least 50,000 mammals have died, most of these were sea lions.

At the other end of the world, the virus has affected mammals in the Arctic region andwas recently found in a dead polar bear.

Since 2020 there have been 26 cases of the virus in humans who have been infected by birds in Asia, Europe and the Americas.

Most recently there were four cases of the virus in people detected in Cambodia.

The detection of bird flu in the skuas potentially signals a serious event that could wipe out whole colonies of Antarctica's unique wildlife.

Australian Antarctic Division seabird ecologist Dr Louise Emerson recently visited the southern continent and subantarctic islands before the detection of avian flu at Primavera Base.

She said the concern about the virus being in Antarctica was because so many species from penguins to seals aggregated in large colonies.

"Which provides opportunity for the virus to spread between individuals," Dr Emerson said.

A recent study found about 70 per cent of elephant seal pups born at a high-density breeding site in Argentinalast year died from bird flu.

Dr Emerson said there were a lot of unknowns about what the virus would do in Antarctica and she hoped the harsh weather conditions would hinder the spread of the virus.

She also hoped the spread to East Antarctica, where Australia's research bases are, was slowed by the distance from West Antarctica.

"There's a lot we just don't know at the moment," Dr Emerson said.

"We don't know how the virus will cope with dry and cold Antarctic conditions... we don't know how close birds need to be to spread."

But University of Melbourne microbiologist Dr Michelle Wille believes the virus will cope well in Antarctic conditions.

Dr Wille is part of the Scientific Committee on Antarctic Research's wildlife health network and helps keep a database of avian influenza cases in the region.

"We know that [other]low pathogenic avian viruses are present in Antarctica," she said.

"If those viruses can survive fine, I'd suspect this one will do just fine."

Spread of avian influenza from Antarctica is one of three possible scenarios of how the virus could get to Australia suggested by the international expert group OFFLU, which provides animal influenza advice to the World Health Organization.

The transmission of the disease from Antarctica is seen as the least likely way for the virus to spread to Australia, althoughthere is a great deal of uncertainty because of a lack of tracking data.

OFFLU considered two possibilities for a spread from Antarctica.

First, a long-distance flying seabird, like the northern petrel or albatross, could make its way from a subantarctic island near South America to New Zealand.

An albatross could make the trip in just under six days and still be infectious when they arrive.

The second possibility could happen once the virus reached East Antarctica.

OFFLU suggested it could be possible for short-tailed shearwaters, which breed in South Australia, Victoria and Tasmania, to be exposed to the virus from other animals while foraging in the polar region for food.

Dr Wille said the spread of the virus from Antarctica to Australia was plausible, but not as likely as the spread byshorebirds making annual migrationssouth using theEast Asian-Australasian flyway.

Millions of birds use the flyway travelling from breeding grounds in places like Siberia and Alaska through Asia before arriving in Australia from about September.

The other most likely scenario would be the spread of the virus from waterfowl in the Papuan region.

If the virus reached Australia it could bring mass death for birds and other species.

Not only would poultry and egg industries be under pressure, but so too would wildlife with the potential for species like black swans to be wiped out.

Dr Wille and Deakin University ecology chair Marcel Klaassen have been testing migratory shorebirds that arrive in Australia each year.

Their latest season of testing which finished in December took them all over the country from west to east.

"All the migratory birds from the north have arrived now in Australia," Professor Klaassen said.

"None of those that we looked at had any signs of an infection or a past infection."

Testing of wild birds will continue next migration season and there is also ongoing testing of suspicious bird deaths in the different states and territories.

ADepartment of Agriculture, Fisheries and Forestry spokeswoman said Australia had a nationally-agreed response plan and cost-sharing arrangements if there did end up being an outbreak in the country.

"The department also participates in emergency management exercises to prepare for emergency animal disease outbreaks," she said.

A bird flu incursion was part of an animal health laboratory preparedness exercise last year by the federal government.

Dr Wille said Australia had been strengthening its systems wherever it could in preparation for the virus.

But the country was still very much in a wait-and-see situation.

Anyone who comes across dead birds or marine mammals is asked to contact the Emergency Animal Disease Hotline.

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Deadly H5N1 avian influenza strain detected on mainland Antarctica for the first time - ABC News