Bird flu is spreading. Which American animals have contracted the disease?

Over the past year, bird flu has spread far beyond American bird species. The disease is largely concentrated among farm animals, but also affects zoos, pets and even humans.

The risk to public health remains very low. But experts are closely monitoring the disease as it spreads and adapts among animals, in case changes occur that improve its ability to infect humans.

What is bird flu?

Bird flu, also known as bird flu, belongs to a group of influenza viruses known as H5. The disease has become widespread in wild birds around the world in recent years, with outbreaks in poultry and cows bringing the disease closer to humans.

In birds, the disease causes symptoms such as swelling of the head, watery eyes and unusual movements. It can kill the disease and is thought to have caused 280 million deaths since 2021. An estimated 127,470,312 poultry in 50 states are affected by the disease.

Cows have also been seriously affected by bird flu. Nearly 900 herds of livestock in 16 states have suffered bird flu infections, according to the U.S. Department of Agriculture.

The virus is not well adapted to humans and therefore usually results in mild illness in humans. The number of cases is still very low, with 66 human infections reported in the US so far this year. The disease cannot pass between people, and most cases are linked to animal exposure.

Bird flu has been found in raw milk samples, leading to recalls of the product due to public health concerns. Officials say pasteurized milk is still safe to drink because the process kills the virus.

What other animals have contracted bird flu?

In addition to wild birds, poultry and cows, bird flu has infected countless other animals. Earlier this week, a Washington shelter announced that the disease had killed 20 big cats that died at a Washington shelter — more than half of the animals it cares for.

The sanctuary lost one Bengal tiger, four pumas, one African caracal, two Canada lynx, one Geoffroy cat, one Bengal cat, one Eurasian lynx, four bobcats and five African servals. Infections have previously been reported in other large and wild cat species, including Asian golden cats, Amur leopards and clouded leopards.

“Cats are particularly vulnerable to this virus, which can cause subtle initial symptoms but quickly worsen, often resulting in death within 24 hours from pneumonia-like conditions,” the vet said. Wild Felid Advocacy Center of Washington wrote on his Facebook page.

Domestic cats can also contract the disease, with an Oregan domestic cat recently dying after eating raw, frozen cat food contaminated with bird flu. Cases have also been reported in dogs, goats and alpacas Centers for Disease Control and Prevention and the United States Department of Agriculture. Bird flu was also responsible for the death of a polar bear in Alaska.

Over the years, American wild mammals, including mountain lions, bears, dolphins, seals, coyotes, foxes, martens, American mink, fishermen, otters, raccoons, skunks, opossums, squirrels, mice, cottontail mice and prairie voles have all contracted bird flu.

The disease is prominent around the world, even spreading to Antarctica, where it kills it significant numbers of penguins, elephant seals and fur seals.

What is the risk of bird flu for humans?

Special proteins on the bird flu virus allow it to bind to sugars on the surface of the host animal’s cells. The sugars from different animals have different forms, some of which match the virus better than others.

These bird flu proteins are well adapted for birds and cows, whose sugars are relatively similar in shape. The human equivalent has a very different shape, making it more difficult for the virus to gain traction. This generally results in milder illness and stops the transmission of bird flu between people.

Experts are closely watching the virus as it spreads and mutates, to see if it develops adaptations that can help it better bind to human cells.

Scientists at the Centers for Disease Control and Prevention announced this week that they have found “low-frequency mutations” in some of the proteins involved in binding in a US Public Health sample. first serious case in humans.

Evidence shows the virus likely mutated in the Louisiana patient, who developed a severe illness from his bird flu infection earlier this month. While still “concerning,” the CDC states that it would be more concerning if this change had occurred before this specific infection. There is no evidence that the infection has spread to anyone other than this one patient.

Experts say the mutation is also not enough to allow person-to-person transmission. “Is this an indication that we are getting closer to seeing an easily transmissible virus between humans? No,” said Michael Osterholm, an infectious disease researcher at the University of Minnesota. “Right now, this is a key that’s in the lock, but it doesn’t open the door.”

Mutations are a normal part of the spread of a virus, which replicates itself imperfectly, resulting in small changes. Most mutations will have little impact on how a virus is transmitted. Avian flu may never adapt in the way it needs to pass between people.

But just in case that does happen, countries such as the US and Britain have already ordered millions of doses of an H5 bird flu vaccine.