A deadly new bird flu is infecting wild birds and it may not go away: NPR


Waterfowl and the birds of prey that feed on them, such as this bald eagle and snow goose, have been killed by the new bird flu virus.

Jeff Goulden/Getty Images


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Jeff Goulden/Getty Images


Waterfowl and the birds of prey that feed on them, such as this bald eagle and snow goose, have been killed by the new bird flu virus.

Jeff Goulden/Getty Images

AN newly arrived avian flu is wiping out wild bird populations in the United States, and that may spell trouble for poultry farmers who have been doing everything they can to control this flu outbreak in their flocks.

Some 24 million poultry such as chickens and turkeys have already been lost, either because they died from the virus or were culled to prevent its spread. But unlike a similar outbreak of bird flu seven years ago, this one is unlikely to burn itself out.

This is because this particular flu virus appears capable of remaining in wild bird populations, potentially transmitting the virus to poultry farms. While chickens and turkeys with the virus get sick and die quickly, some waterfowl can remain healthy with the virus and carry it long distances.

Scientists believe that wild migratory birds brought this virus to North America a few months ago. Since then, more than 40 Wild bird species in more than 30 states have tested positive. This strain of bird flu virus has shown up in everything from ravens to pelicans to bald eagles.

“It’s kind of amazing how widespread it is already in North America,” he says. jonathan runstadler, an influenza researcher at Tufts University. “It’s clearly capable of persisting and transmitting from year to year in parts of Asia, Europe, Africa, and I don’t think we should be surprised if that’s going to be the case here.”

As the virus moves across the country, and potentially takes hold for the long term, it will encounter new species of animals that could become infected. This pathogen will also have a chance to genetically mix with flu viruses already circulating in the US.

“What that means for the virus in terms of how it evolves, how it changes, we just don’t know,” he says. richard webbyflu researcher at St. Jude Children’s Research Hospital.

There has only been one known human case.

So far, the risk to humans appears low.

But since related bird flu viruses have repeatedly jumped to people in the past, public health experts are watching for any signs of genetic changes that could make the virus jump to humans.

“We are concerned about any avian influenza viruses that are circulating in domestic or wild birds,” he says. Todd Davis, animal-to-human disease expert at the Centers for Disease Control and Prevention (CDC). “Because humans have no prior immunity to these viruses, if they were to become infected and spread the virus to other humans, then we could have another pandemic virus on our hands.”

This virus does not have genetic characteristics previously associated with the related bird flu that has infected humans. and the only person acquaintance Contracting this particular bird flu virus was an elderly person in the UK who lived indoors with ducks; while some of the ducks got sick and died, their owner never had any symptoms.

The CDC has been monitoring the health of more than 500 people in 25 states who were exposed to infected birds, Davis says. Although a few dozen people developed flu-like symptoms, all were tested and none tested positive for this virus.

The Raptors could be especially affected

Wildlife experts have long known that highly pathogenic avian flus like this one circulated in Europe and Asia. and they have worried the possible threat these viruses could represent for American birds.

Then, in December 2021, chickens and other birds got sick and began to die on a farm on the island of Newfoundland, Canada. Tests He showed this deadly bird flu virus had crossed the Atlantic.

“The first time it came to North America, it was a heads up for us,” says bryan richardsthe coordinator for emerging diseases at the US Geological Survey’s National Center for Wildlife Health.

In January, government officials announced their arrival in the US after a wigeon duck in South Carolina tested positive. The last time a dangerous avian flu entered the country, Richards says, “the number of instances where we detected that particular virus in wild birds was very, very limited.”

Instead, this latest avian flu virus is being detected in sick and dying birds far and wide.

“This outbreak in the wild bird population is much more extensive than what we saw in 2014 and 2015,” he says. David Stallknecht, an avian influenza researcher at the University of Georgia. “Just a lot more birds seem to be affected.”

Waterfowl and raptors that eat their carcasses are the most affected.

In Florida, for example, more than 1,000 lesser scaup ducks have succumbed to the virus. In New Hampshire, about 50 Canada Geese were killed in a single event. In the Great Plains states, wildlife experts have seen mass die-offs of white geese.

“In addition, there are a host of other species, including black vultures and bald eagles and some of the other scavenger species, that probably got infected by consuming the carcasses of those waterfowl,” says Richards.

How much this virus will affect American bird species remains to be seen.

In Israel, when this virus reached an area where some 40,000 whooping cranes had gathered for the winter, “8,000 of these birds were lost over the course of a couple of weeks,” says Richards. “So when you start thinking about losing 20% ​​of a specific population of wild birds, that’s a pretty substantial impact.”

Poultry farmers slaughter their flocks

Chickens and turkeys raised by the poultry industry have suffered the most deaths, and farmers are bracing for even more.

The bird flu that hit in 2014 and 2015 killed more than 50 million birds and cost the industry billions of dollars. At that time, the largest number of cases occurred in the month of April.

“So I think I’m holding my breath this month,” he says. denise listeneddirector of research programs for the US Poultry and Egg Association

The virus has several ways of moving from wild birds to poultry, Heard says. Since the last outbreak, the industry has worked to educate farmers on how to protect their herds.

“Wild migratory waterfowl always fly overhead and when they poop, that poop falls to the ground,” he says, explaining that the virus can then be traced to bird houses by wearing boots or inadvertently moving from one place to another. farm to farm in vehicles.

Heard says there currently appears to be less spread of the virus from farm to farm than was seen during the last major outbreak. Instead, more isolated cases are emerging, perhaps because wild birds are bringing the viruses to farms and backyard flocks.

If this virus persists in wild bird populations, which some scientists believe is likely, poultry farmers may need to learn to live with this problem.

“I hope this is not the case. I hope that in the US this infection will go away soon and the virus will go away again like it did in 2014,” she says. Rum Fouchier, a virologist at the Erasmus Medical Center in the Netherlands. “But there is no guarantee of that, as we have seen in Europe now that this virus has been around for several years in a row.”

Since December, farmers in Europe have had to slaughter more than 17 million birds. “So that’s very similar to the situation in the US,” says Fouchier. “And we’re seeing massive die-offs of wild birds.”

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