Bird flu is not a direct threat to humans, experts say, but they’re watching the virus closely

CNN
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infected with bird flu record number With studies of birds and some mammals across the United States, scientists are watching closely.

Director-General of the World Health Organization Tedros Adhanom Ghebreyesus said on thursday It said the risk to humans remains low, but added, “I can’t imagine it will continue.”

The coronavirus that causes Covid-19 is believed to have started in animals before it spread to humans, but some animal viruses mutate, jump species, make humans sick, and spread rapidly around the world. There is a possibility.

However, highly pathogenic avian influenza is not Covid-19. Scientists have reassured the public that, with a few rare exceptions, the virus has not infected humans on a large enough scale to cause an outbreak.

But it extends far beyond birds, and has recently spread among members of another species, making some experts concerned about how the virus is mutating.

Avian influenza is a type A influenza virus. Origin with a bird. The version that causes problems mainly in the US and Europe is called H5N1. There are several subtypes, and his H5N1 bird flu virus, now in common circulation, is genetically different from previous versions of the virus, according to the U.S. Centers for Disease Control and Prevention.

After late 2022, scientists will Detected this virus Among more than 100 kinds of wild birds such as ducks, seagullUS geese, hawks and owls.

Globally, the virus strain has actually been around longer, he said. Richard Webbyan infectious disease researcher at St. Jude Children’s Research Hospital in Memphis, Tennessee, and director of the WHO Collaborative Center for Research on the Ecology of Animal and Avian Influenza.

“We’ve been following the evolution and changes since we saw the virus’ great-great-grandchildren in Southeast Asia in the late 1990s,” said Webby.

By the 2000s, it had spread to parts of Europe and Africa and was carried around the world via infected migratory birds. It recently came to the Americas, he said, Webby.

The first infection with this version of the virus was reported in January 2022 in wild birds in the United States. According to the CDC. The following month, the U.S. Department of Agriculture announced a turkey outbreak at a commercial facility.

Research Shows Bird flu can be transmitted to songbirds, but birds that typically flock to feeding grounds such as cardinals, sparrows, and blue jays, and birds that are found on the roads, such as pigeons and crows, usually carry the threatening avian influenza virus. I don’t own it. to humans, According to the CDC.

Ducks and geese can carry the virus without getting sick. poultry Not always lucky.

Transmits highly pathogenic avian influenza ‘Extremely high mortality rate’ Between chicken and turkey. The disease affects multiple internal organs and can kill 90% to 100% of chickens within 48 hours of infection, according to the CDC.

It can spread rapidly, so farmers usually need to kill uninfected birds along with infected birds to prevent a wider outbreak. is considered one of the Biggest Known Threat to the house bird.

as of wednesday, 6,111 cases It has been detected in wild birds in all 50 states, according to the U.S. Department of Agriculture. The virus has affected more than 58.3 million poultry in 47 states. According to the CDC.

Experts say the sheer number of cases means the virus is likely to spread to other species.

Avian influenza is transmitted through feces and saliva. It can also be spread by contact with contaminated surfaces.

The virus has infected many mammals in the United States, primarily in the West and Midwest, as part of recent outbreaks.

Cases have been reported among bears and foxes in Alaska. Department of AgricultureThe virus has also been found in bobcats in California, skunks in Colorado, raccoons in Washington, possums in Illinois and Iowa, mountain lions and grizzly bears in Nebraska, and seals. maine Even bottlenose dolphins in Florida.

In total, 17 non-avian species are affected in 20 states.

Scientists believe that all these sick mammals They probably contracted the virus when they ate or otherwise interacted with infected birds.

But in a disturbing development last fall, the virus appeared to have spread among mammals, perhaps for the first time, at a mink farm in Spain, some say. study It was published in the journal Eurosurveillance.

According to scientists, Mink had a nosebleed, had tremors, lost his appetite, and appeared depressed, so he had to be killed to curb the threat.

The virus did not infect humans working on mink farms, but scientists were concerned by multiple mutations found in the virus that were distinct from sequences found in birds. rice field. One mutation improved replication in mammals, but it’s not clear if the mutation was in the virus before it reached farms.

“But that’s when an infection starts to spread from one mammal to the next to the next. It’s the environment and environment that seems most likely to pick up these changes that allow them to switch hosts.” , that’s why we’re concerned,” said Webby.

Since December 2021, there have been fewer than 10 known cases of avian influenza in humans, and none have been transmitted by human-to-human transmission. CDC says.

The most recent U.S. case was a Colorado man who became ill after culling an infected bird in April. They were quarantined and treated with antivirals, according to the CDC.

Officials said at the time that the threat to public health remained low, but urged people exposed to any kind of bird to take precautions.

“People who get sick in general are one of those individuals who have very strong interactions with wildlife, whether living or dead,” he said. Dr. W. Ian Lipkin, Director of the Center for Infectious Diseases and Immunity, and Jon Snow Professor of Epidemiology at Columbia Mailman School of Public Health. “I wouldn’t say we have another pandemic because we don’t. We’re not there.

“What we have to do now is keep a close eye on how this spreads. We need to contain it in farms and wildlife wherever possible,” he added.

Although the threat to humans is low, the CDC suggests avoiding direct contact with wild birds.

Webby says he uses gloves and a mask if he has to handle dead birds, such as removing them from feeders. Always wash your hands after touching birds or feeders.

Properly handled and cooked poultry and eggs are safe to eat, the CDC says. Bird flu is not a foodborne illness and the poultry industry is closely monitored and has strict health standards, including bird flu surveillance and control.

Cook poultry and eggs to 165 degrees, a temperature that kills bacteria and viruses such as bird flu.

In the very rare case that someone gets sick, the CDC recommends immediate medical attention. Most bird flu infections can be treated with currently available flu antiviral drugs, officials say.

The US government also has a stockpile of vaccines, including one against bird flu viruses. CDC says.

“The chances of getting this are not zero. Anything you can do to further reduce that risk is a good thing,” said Webby. “But you’ll probably have to work really hard to catch this virus.”