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H5N1 bird flu has been found in dead birds on Antarctica for the first time. The deadly strain of bird flu is currently spreading south along the Antarctic Peninsula and could spread around the continent, with devastating consequences for wildlife such as penguins.

“It’s scary. Fortunately, it’s affecting just a few [birds],” says at the Pontifical Catholic University of Chile in Santiago. “I hope it stays that way, but avian flu in Chile and Peru was a disaster. It killed thousands and thousands of seabirds and sea lions.”

Between November 2024 and January 2025, Vianna’s team surveyed 16 nesting sites of seabirds along the Antarctic Peninsula. The researchers found 35 dead skuas that had no signs of injury. Samples from 11 of the bodies were found to be positive for the highly pathogenic H5N1 bird flu virus that has been spreading around the world in recent years.

Skuas scavenge on corpses and predate on other birds, so they are particularly likely to become infected by feeding on infected birds. The skuas in this area are hybrids between south polar (Stercorarius maccormicki) and brown (Stercorarius antarcticus) skuas.

So far there are no confirmed cases in other kinds of birds, but Vianna says she was told on 9 March that dead penguins have now been found, too. “We just talked to the Chilean Antarctic Institute,” she says. “They saw dead skuas and penguins.”

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Because penguins breed in dense colonies, the fear is that H5N1 could spread among them rapidly and kill off a large proportion of some populations, many of which are already in decline because of climate change. The susceptibility of birds to H5N1 varies from species to species, however, so some penguin species may be resistant, Vianna says.

The highly pathogenic form of H5N1 bird flu has been circulating in Europe, Asia and Africa since 2020, killing many wild birds and causing outbreaks on poultry farms. In the UK, for instance, H5N1 killed in 2023.

In 2021, it reached North America, where it was later found to be infecting the udders of dairy cows and spreading among them. By the end of 2022, it had spread to the southern tip of South America, killing thousands of marine mammals as well as birds of many different species along the way.

Sick brown skuas and giant petrels on Bird Island, just off the larger island of South Georgia, tested positive for the virus in 2023. South Georgia is around 1500 kilometres from the Antarctic Peninsula.

In December 2023 and January 2024, Vianna’s team on the northernmost tip of the peninsula. Now the presence of the virus on the continent has been confirmed.

“The reported deaths of skuas is concerning,” says at Erasmus University Rotterdam in the Netherlands. Some species in the region are found only on small islands, and could be wiped out by bird flu, he says.

However, the tests described in Vianna’s study show only that the skuas were infected with H5 flu, Kuiken says, not whether it was the highly pathogenic form.

That is correct, says Vianna, but samples were sent off for additional testing not detailed in the paper. “So it is confirmed as highly pathogenic avian influenza,” she says.

On 25 February, another group of researchers reported in the Indian Ocean near Antarctica, where the virus has killed elephant seals as well as several species of birds. That means the virus has moved more than halfway around the Antarctic, towards Australia and New Zealand – the only major countries that remain free of the virus.