A panzoonous disease (pandemic among animals) of avian influenza has occurred, affecting approximately 320 species of birds and mammals, including elephant seals.
Instead of the usual cacophony of guttural sounds that drown out the surf during breeding season, the eerie silence was broken only by the sounds of the few remaining elephant seal calls. He shakes his head, snot dripping from his namesake’s protruding nose.
“It felt like a bomb had gone off,” he said. Martín Méndez recalls what he witnessed during an annual survey of southern elephant seals along the Patagonian coast in October.
“This is devastating,” added a marine biologist with the New York-based nonprofit Wildlife Conservation Society. “This is the biggest extinction for the species.”
Last year, an estimated 17,000 elephant seal pups died there due to avian influenza, an unprecedented casualty. Panzootic (animal pandemic) is affecting approximately 320 species of birds and mammals.
Over the past few years, a powerful strain of H5N1 avian influenza has emerged. It has jumped between species and flourished in both domestic and wild animal populations. crisscrossing every continent except Australia and Antarctica A world along the migratory routes of birds.
So far, this strain of influenza has rarely caused serious illness in humans. But scientists fear the pathogen could develop into a new pandemic, as rapidly evolving influenza viruses can spread from mammal to mammal and eventually to humans. . “We’re lucky that something like this doesn’t happen every year,” Mendez said.
For poultry farmers, the outbreak has already caused significant economic losses, with tens of millions of birds affected in the United States. For wildlife, it can destroy ecosystems and push endangered animals closer to extinction.
Ron Foussier, a virologist at the Erasmus University Medical Center in the Netherlands, said: “We have never seen such a large-scale spread of a virus in wild birds, and we have never seen such a large-scale infection in wild mammals. No,” he said.
The trajectory of the virus, unprecedented in both its global spread and the number of species infected, shows how dependent and connected humans are to the natural world, and how agricultural practices that promote influenza can disrupt it. .
Scientists first spotted A precursor to this influenza strain was detected in commercial geese in southern China in 1996. Over the next few years, the infection spread to poultry farms in the area, occasionally appearing in wild birds within flight range of infected farms.
And in 2005, approximately 1,500 geese and gulls fell and died In a protected nature reserve in northwest China, far from the chicken coop. The virus was found to be invading wild bird populations.
From there, the virus spread rapidly to Asia, Africa, and Europe, causing seasonal epidemics. But it wasn’t until around 2021, after a genetic mutation that allowed the pathogen to spread among migratory birds, that the number of outbreaks exploded and the virus spread globally, starting in North America that year and then later. Established in South America.
since then, number of deaths It’s amazing.
There are approximately 5,200 cranes living in Israel. There are over 2,200 Dalmatian pelicans living in Greece. Approximately 40 percent of the species occurs in southeastern Europe, and there are approximately 20,000 sandwich terns in Europe, representing 17 percent of the breeding population in northwestern Europe. More than 18,000 barnacles have died in Scotland. And there are tens of thousands of gannets in Canada.
Last year, ornithologists discovered about 12,000 dead kittiwakes in Norway. By July, more than 500,000 birds had died in South America, including about 41 percent of all Peruvian pelicans.
Jonas Waldenström, a professor of disease ecology at Linnaeus University in Sweden, said influenza symptoms vary from bird to bird. Obvious signs include tilting their head, struggling to stand up, or rolling over while trying to take off. These are all signs that the virus is affecting the nervous system.
“Some species can be quite ugly,” he says.
The virus has literally reached the ends of the earth and is killing people. brown skua On islands near Antarctica, and for the first time this winter, polar bear in alaska. Scientists fear it is only a matter of time before the virus reaches penguins and other vulnerable populations in Antarctica itself.
“The situation in Antarctica is on the brink,” said Michelle Ville, a virus ecologist at the University of Melbourne. “Many of the animal species that live there are not found elsewhere in the world, and many are already facing significant pressures from fishing, climate change, and more.”
Scientists say the disease can jump between species when wild animals eat dead or dying birds, or when bird droppings get mixed into livestock feed. So far, avian influenza has infected Coyotes, lions, tigers, grizzly bears, raccoons, red foxes, and other land mammals occur, but only sporadically. They also attacked farms that collect mink and fox fur. in spain and Finland.
But mass die-offs of marine mammals that flock to beaches have biologists worried that the virus could evolve to transmit directly from mammal to mammal.
Last year there were over 5,000 sea lions. found dead In Peru. Additionally, more than 17,000 elephant seal pups in Argentina have died from the virus, representing at least 96 percent of the juvenile population. Nursing seal pups are less likely to get the flu from eating birds. Rather, Fouchier said, the infection could have come from contaminated milk, water, aerosols or feces.
Valeria Faravera, a marine biologist with the Wildlife Conservation Society who has studied Argentina’s elephant seals for decades, had only seen one adult elephant seal die before this flu outbreak. Seeing the beach where dozens of people had died was “absolutely shocking”.
“I wasn’t ready to see that,” Falabella said.
If avian influenza viruses evolved to spread among seals, they are likely to spread within other mammalian populations, such as humans. “There’s a long way from boobies to humans,” Waldenstrom said. “But from seals to humans, we are very similar.”
Tracking how viruses move between species is difficult. In the past, humans have contracted diseases from animals after working on farms (1918 influenza pandemic) probably started Kansas farmlands) or after entering the wilderness (HIV It is highly likely that he jumped off the chimpanzee. when a hunter kills a person for meat).
In the case of the latest influenza strains, “mammalian-to-mammal transmission is very difficult to prove,” Fouchier said, and genetic analysis of the virus found in dead seals could provide clues to transmission. he added.
So far, what we know about this strain of bird flu suggests that an epidemic among humans is not imminent. It appears that the virus has adapted to replicate in migratory birds, thereby spreading it around the world, thereby limiting its ability to infect humans, Fouchier said.
“At this point, it is of slightly less concern for human health than past influenza viruses,” he said. However, given the unprecedented nature of the ongoing outbreak, it is difficult to predict how it will develop. “A typical avian influenza virus never invades mammals on this scale,” he added.
The longer a virus persists in the environment, the more chance it has of starting a new pandemic. Influenza viruses evolve much faster than coronaviruses, behind the coronavirus pandemic and other pathogens.
At this time, little can be done to stop the spread of this influenza virus among wildlife. For example, the U.S. Fish and Wildlife Service cooperate with zoos Vaccinate the endangered California condor.
“It’s difficult to contain a virus that is currently spreading more or less across all continents,” Waldenström said. “You can’t put a lid on this. It’s going to be a given.”
But there are steps the poultry industry can take to reduce the risk of future outbreaks, said Jonathan Sleeman, scientific advisor for wildlife health at the U.S. Geological Survey. This includes monitoring, disinfecting equipment, and wearing protective clothing for workers. “Everyone recognizes this is a huge effort,” he says.
It may take years for Argentina’s remaining elephant seal population to return. “We may never recover to the same population levels as before,” Sleeman said. Biologists are working to determine how many adult seals died.
Biologist Mendez, who likened the seal extinction to a disaster movie, worries that the latest outbreak could undo decades of conservation efforts.
Now, the virus has completely changed their work. It’s not just about helping animals far away, it’s also about protecting people.
“We’re really trying to protect the very functioning of our planet,” Mendez said. “We’re looking at this disruption through the lens of wildlife, but it’s clearly very serious for humans as well.
This article is part of Animalia, a column that explores the strange and fascinating world of animals and the ways we appreciate, risk, and depend on them.