A new kind of death is coming Antarctica, scientists fear. The harsh environment is filled with everyday anguish: predation, hunger, chicks lost to the sea when their frozen shore melts. Now, a new pathogen threatens to devastate colonies of marine mammals and birds, potentially including penguins. If the worst happens, ghosts of entire species could appear, and there’s little scientists can do but wait.
TO deadly strain of avian influenza H5N1 has been devastating poultry farms and flocks of wild birds around the world, infecting mammals and even killing at least one polar bear. Now it’s knocking on Antarctica’s doors, just as dozens of species that have likely never experienced any strain of bird flu are congregating to raise their next generation. Currently, avian influenza is causing large outbreaks on islands around the southern tip of South America, about 1,000 miles from the Antarctic Peninsula. The virus has caused clusters of illness in gentoo penguins on the Falkland Islands in January and in fur seals, elephant seals and other animals on South Georgia Island last December. Scientists fear that it will only take a small leap for the virus to reach the Antarctic Peninsula and spread to the rest of the continent.
“We are prepared for the impact. We’ve been like this basically since the end of (last) year,” says Marcela Uhart, a wildlife veterinarian at the University of California, Davis, who is currently monitoring the outbreak in Patagonia. “It’s unlikely that (bird flu) won’t get there simply because of how connected the species are,” as animals often travel long distances across the Southern Ocean to find food.
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avian flu They come in two varieties. Wild birds typically contract mild cases of what scientists call “low-pathogenic” flu, while poultry species, such as chickens and ducks, can develop much more serious infections with “high-pathogenic” strains. . These different flavors can mix, creating more infectious viruses like the one currently ravaging South America. That combination, a substrain called clade 22.214.171.124b that developed in the last decade, comes from a lineage identified in China in the mid-1990s that has caused occasional outbreaks around the world. But clade 126.96.36.199b has now become a Frankenstein virus that combines the severe disease of poultry strains with a particular affinity for infecting wild birds. In addition to affecting South America, the virus has devastated seabird colonies in Europe, followed migratory birds to southern Africa and jumped the Atlantic Ocean to infects even the majestic California condor.
“Avian influenza is nothing new; it’s been around for a long, long time,” says Christian Walzer, wildlife veterinarian and executive health director for the nonprofit Wildlife Conservation Society. But this Bird flu is different. “What’s important to understand is that the whole dynamic has changed,” she says.
Despite the rapid spread of this strain, scientists are not sure how it is transmitted between animals, particularly how it spreads between birds and mammals. Many infected species are scavengers, suggesting that consumption of infected carcasses could contribute to transmission; Healthy animals can also contract the virus from the feces of those infected, researchers say. Some species appear to be resistant to disease, although they could still be contributing to transmission. “The big problem we have is that we don’t really understand how some birds can be infected with this virus and not get sick, but it’s clear that happens,” says Ashley Banyard, a virologist at the UK’s Animal and Animal organisation. Plant Health Agency.
By late 2022 and early 2023, the brutal clade 188.8.131.52b virus in South America had killed at least 600,000 birds and 50,000 mammals, and probably many more, scientists say. “We’ve never had anything of this magnitude in the southern hemisphere,” Uhart says.
Antarctica and Australia are currently the only continents where this bird flu has not yet reached, as far as scientists can tell. In the case of Antarctica in particular, the virus may simply be spreading undetected. “There’s no way to know for sure,” says Michelle Wille, a viral ecologist at the University of Melbourne in Australia who specializes in avian viruses. “One of the big challenges is that it could already be there, in a place where few people visit.”
Detecting any wildlife infection in a remote location is a difficult job, but that’s especially true when most of the victims are ocean-dwelling species. “It’s really hard to detect anything in the sea,” says Amandine Gamble, an ecologist at Cornell University. “This is probably a huge underestimate of the actual number of deaths.”
Scientists fear that if the virus takes hold in Antarctica, casualties on the continent could be particularly high. “Highly pathogenic avian influenza has never been recorded there before,” says Thijs Kuiken, a pathologist at the Erasmus University Medical Center in the Netherlands. “Most of the 48 species of birds and 26 species of marine mammals present in Antarctica are likely susceptible to infections and diseases caused by this virus.”
These animals are not only immunologically vulnerable, but also have lifestyles that expose them to additional risk of infection. “You have these huge, densely populated bird colonies and some of these mega-charismatic, highly endangered species, which are all clustered down there,” such as penguinssays Walzer. “If (the virus) comes, the impacts will potentially be really devastating.”
“Entire populations can disappear,” Wille says of a possible outbreak in Antarctica. “This would be a catastrophe.”
It could be a catastrophe for species beyond those directly affected, and even beyond those that call Antarctica home, Uhart says. For example, if mass die-offs occur on the continent and these bodies become encased in ice rather than sinking into the ocean, the deaths could potentially affect the global carbon cycle and nutrient flow. “I don’t think anyone can even imagine what the potential loss of this huge biomass of wildlife would mean to the ocean,” Uhart says. “I don’t think we understand what this means.”
Timing could influence the severity of a bird flu outbreak in Antarctica, experts say. The continent is currently in the peak of its summer, and many species are still busy raising their young, whose new immune systems could be more susceptible to bird flu or more likely to spread it, scientists say. “We are now at a critical stage,” says Gamble.
“If it really arrives now, its spread can be very, very rapid,” he says. “If we can keep the virus from reaching the Antarctic continent for a few more weeks, we could be safe this year.” Most species will disperse out of tightly packed colonies until the next breeding season, making them less likely to encounter other animals and therefore the virus. Still, Gamble and others fear it is likely only a temporary suspension, given how aggressively the virus is circulating globally. Antarctica may dodge the crisis this year, only to suffer during the coming southern hemisphere spring and summer.
As with so many ecological disasters, the story of avian influenza highlights the consequences of human alteration of the natural world, scientists say. modern poultry farming, where birds are even more crowded than the most populated penguin colony, encourages the spread of disease. And although several avian influenza vaccines exist, countries around the world have generally opted to kill the entire population of any farm after exposure. Tens of millions of chickens have died or been culled in the U.S. alone since 2022. That decision was driven by fears that vaccinated chickens would interfere with international trade because the tests cannot distinguish between infected and vaccinated birds. Countries that do not vaccinate will not import poultry that tests positive for bird flu.
And now, Uhart says, it’s sea lions and elephant seals, cormorants and pelicans and, yes, even penguins that are suffering from this cruel virus. “These poor animals are dying without a voice,” he says. “Unless we tell their story, it very well may not be told.”