It's like “a dead bird flying”: how bird flu is spreading in the wild

About a year ago, Marcela Uhat was walking along the beaches of Punta Delgada, Argentina. It was a peak breeding session on the peninsula known for its rich marine wildlife. Usually, a salty breeze brought it, bringing the sound of a baby elephant seal calling the mother with a high-pitched cry.

“This time I was silent,” Uhart recalls. “The beach was packed with corpses. I basically saw everything. [elephant seal] The puppy is dead. It estimates seals from around 18,000 dead baby elephants. ”

He died from the bird flu.

And it wasn't just the elephant seal. I had a tern with a yellow beak and a black head, and was stumbling over having a seizure in the sand. The scene repeated many times up and down the coastline for the following weeks. “It was like a bird fell out of the sky and died,” she says.

Uhart veterinarian and director of Latin America Program at Karen C. Dreyer Wildlife Health Center at the University of California, Davis. She arrived in October 2023 at Punta Delgada Beach, wearing a suit with a white dangerous material suit, gloves and goggles, ready to take samples and document the decimation. She tracks bird flu from one bird species to another, from waterfowl to bird species, from sea lions to dolphins to marine mammals and sometimes back to birds.

“It's just like a wildfire. I mean it killed everything I encountered,” she speaks to NPR from Argentina.

In the US, avian flu headlines are An unprecedented number of American cases And the effects of the virus Dairy cow And on Poultry farm. But wildlife researchers like Uhart say the dramatic scene in Argentina is evidence that new and ominous things continue to happen with the virus that causes avian flu. And ignoring it puts human health at risk.

“Relay Race” began in 2020 and 2021

“I've been studying the flu virus in detail since 1980, and there are days when I wake up feeling like I don't know much about the flu more than I did ten years ago.” Michael Osterholmdirector of the Center for Infectious Disease Research and Policy at the University of Minnesota. That's especially about the avian flu.

Certain viruses that cause avian flu – H5N1 – That in itself is not new. It was a disease that occurred in East Asia and was first detected in China in 1996. This virus is mainly Fearful Poultry Farm This led to a large-scale selection. It sometimes spills on humans, causing about 400 deaths over decades, but the spread from human to human is rare. And it has regularly jumped on wild birds, but in many places it killed many birds – it never took off globally.

Then came 2020 and 2021, versions of the current outbreaks emerged.

As the virus has evolved, some wild birds can move far enough to reach another bird community or mammal population to pass the virus before they die.

“What you see here is like a relay race,” Uhart says. “We were all skeptical that this could be possible, but somehow this started to happen.”

“From this concept of dead birds, we should not fly to this new virus that appears to be flying dead birds.” Eric Carlsondean of the Department of Virus at Pasteur de Cambodge, Cambojji Institute of Camboj, and director of the Cambodia National Influenza Centre.

This means that the virus can not only stick to poultry farms and jump into the wildlife regularly, but also endure wild birds and move from one flock to the next flock without burning out.

Scientists are trying to understand exactly how the virus spreads between animals. One theory is that a scavenger bird east feasts a mammalian body, “clogged with a virus” and becomes apparently infected, and can easily be spread across its legs and beak,” Uhart says. Another theory, she states: [animals] Poo in the water and other animals drink [that water]. ”

Valeria Falabella/Wildlife Conservation Society Argentina
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How far can a dead bird fly?

Wild birds are particularly suitable for globally ingesting this virus.

“If this virus's natural reservoir is more of a species than a bird, then it may be expected that it will only be located on a certain continent, as the animals do not swim in the ocean. It is a bird,” Osterholm said. says.

Travelling infected wild birds, The virus has taken off It jumped over to North America in the second half of 2021. From there they set out for South America, which was then destroyed.

“In South America, we moved 6,000 kilometers of spine in about six months,” he says. Michelle WillSenior Research Fellow at the Center for Pathogen Genomics at the University of Melbourne. “So this is a virus that has not been helped by plane. This is a virus that moves after mass death after mass death after mass death.” Not only do mass birds, but elephant seals and sea lions. They also kill mammals such as dolphins, dolphins and otters.

South America has been much quieter this year. “Amazingly, Brazil does not have these recent cases of wild birds,” he says. Helena Rage Ferreiraveterinary biologist at the University of Sao Paulo, studying avian influenza. Her team tried to determine if the bird had gained immunity. So far, the results were unknown. “It's very difficult to understand,” she says.

Meanwhile, new parts of the planet are at risk. Researchers have noticed that the virus is currently plaguing Antarctica.

They are concerned about this trend as Antarctica is a particularly difficult place to study. Many of the animals that live there do not live anywhere else in the world. Even if there are researchers on the ground to collect samples, “We have to wait several months for these samples to actually reach the lab. And by that time, she said Speculation, the virus is already spreading much further.

This adds to the broader problem. Globally, no one knows how many wild animals the virus has killed.

“No one counts. We don't know,” Will says. “It's a global catastrophe.”

Wildlife with viruses is bad news for humans

Researchers say the rapid spread is devastating for animal species that are being hit hard. For example, in PeruThousands of Peruvian Pelicans have passed away. “In a few weeks, almost one in two species that completely disappeared,” Will says. And she adds, it's still too early to know how these massive die-offs affect ecosystems, but that's likely to be important.

Plus, this is important for human health.

Will and other team of wildlife experts estimate Millions of birds have been infected and killed, and tens of thousands of marine mammals have been killed. Each infected animal, especially mammal, may be suitable for the virus to evolve and infect people.

This rapid evolution was revealed earlier this year. Our first person – From Louisiana – Died of bird flu. When scientists sequence viruses from different organs from the body, “the virus is changing internally,” Uhart says. This patient Uhaat says he didn't hand the virus to anyone else. This case says it shows how quickly the virus changes.

There is another element in this genetic game. If one animal is infected with multiple influenza viruses, the virus can mix and match the gene with the local influenza virus. When this very deadly avian influenza virus arrives at a new location, it can interact with a large pool of deadly influenza-low viruses and create a new “Frankenstein” virus, explains Will. .

And each genetic change can make the virus even more serious.

At this point, the virus can infect humans, but it has not yet evolved to easily jump from one human to another. That could change.

And without catching up with the virus journey in wildlife, experts are worried.

“Since H5N1 [bird flu] “I tend to sleep with one eye open,” says Osterholm.

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