The bird flu that is circulating affects birds and cattle, and even cats and dogs: shots

Avian flu grips dairy herds in California, a few people down seriously ill in North America and researchers have found that a single mutation could give the virus a better foothold in a person’s upper respiratory tract.

At the same time, bird flu trackers say most of us don’t need to worry about the virus as we go about our daily lives, at least for now.

“We are really on alert,” says Benjamin Andersenan infectious disease epidemiologist at the University of Florida. “It’s a difficult thing to communicate.”

Fears that H5N1 bird flu could trigger a pandemic go back decadesand earlier strains of the virus have proven quite lethal in humans. That has not been the case during this current outbreak. Most infections associated with the strain of bird flu that circulates globally in wild birds and U.S. dairy herds—technically known as draft 2.3.4.4b — have been mild.

But two recent cases are a reminder that this is not a given.

First, a teenager in Canada was hospitalized, as was a resident of Louisiana who was attacked by mobs in his backyard. In each, genetic analysis suggesting that mutations may have occurred as the virus replicated inside them. However, there is no evidence that any of this has led to human-to-human spread.

“The hard part is that it’s hard to know how much of a heads up we’re going to get that things will change,” says Richard Webbya virologist who studies bird flu at St. Jude Children’s Research Hospital.

Here’s what some experts are saying now.

Should I be worried about getting bird flu?

Despite its wide range, the strain of highly pathogenic avian influenza – so named because of its lethality in poultry – which is driving the current outbreak not adapted easily infect humans, meaning it’s still “essentially an avian virus,” Webby says.

Of the more than 65 human cases in the United States, almost all can be traced back to some form of close contact with infected poultry, wild birds, or dairy cattle. So if you do not have direct contact with any of these animals, the chance of catching the virus in its current form remains quite low.

Unlike seasonal influenza viruses, bird flu does not attack the cell receptors that predominate in a person’s upper respiratory tract. Instead, it prefers “avi-type receptors” deep in the lungs and i mucous membranes around the eyes, which seems to explain why many recent human cases have presented as conjunctivitis.

“It’s actually not very good at infecting people,” Anderson says. “What we’ve typically seen is a lot of viral exposure to get infected.”

A few cases have appeared of unexplained origin in California, Missouri and British Columbia. However, there is no indication that either person got the virus from another human or spread it to anyone else.

For now, the concern is more about what can happen as more animals and people become infected, says Kristen Colemanwho researches airborne infectious diseases at the University of Maryland. “It’s not an immediate risk, but that doesn’t mean it won’t be a risk in the near future.”

That’s because any spillover to mammals, including humans, puts extra pressure on the virus to adapt to its new host, raising the prospect of certain mutations emerging that, under the right circumstances, could allow the virus to replicate and infect humans more efficiently .

Scientists already have an idea of ​​what some of the most worrisome changes would look like (at least to some degree), and it doesn’t seem like they’ve caught on yet, based on tests done in poultry and cattle.

But it is clear that this particular strain of H5N1 is afflicting a much wider range of mammals than previously, says Seema Lakdawalaan influenza researcher at Emory University.

“We don’t know why yet, but it could be coincidence or a precise genetic trait,” she says.

What exactly does “close contact” with a bird look like?

During the current outbreak, poultry workers have generally caught the virus while culling infected flocks.

This is considered a high-risk activity because it can involve handling the animals and spending long stretches of time in facilities where virus particles in their saliva, mucus and feces can hang in the air and contaminate surfaces. For example, workers in Colorado were infected while depopulating birds in hot barns with industrial fans blowing. They struggled to wear personal protective equipment over their mouths, noses and eyes because of the heat.

Historically, human cases of highly pathogenic avian influenza H5N1 has often been traced back to live bird markets. In this context, people tend to handle, kill, slaughter and prepare the animals for sale.

High concentrations of viral particles can spew into the air and be inhaled, or coat surfaces and hands, and eventually end up in your eyes and nose, perhaps after you rub your face, Webby says. “If you just walk past an infected bird, it’s extremely unlikely you’ll get it that way.”

Coleman agrees. In a study conducted before this latest outbreak, she sampled the air of a massive live market in Vietnam and discovered that it was filled with aerosolized bird flu virus. They could even grow infectious viruses from their samples. Still, none of the people they tested there had active infections.

Okay, I don’t slaughter or touch any birds, but should I stop using my bird feeder? How about touching bird repellants?

For the average person, it’s unlikely you’ll get infected from a stray piece of bird poop or by touching your bird feeder, although there isn’t necessarily data on those specific scenarios, Anderson says.

How long H5N1 bird flu survives on objects depends on a number of factors. It can, for example, survive for days or even weeks during certain colder conditions and in water. Catching the virus from a contaminated surface is a legitimate concern for people who “handle animal care equipment on poultry or dairy farms,” ​​Lakdawala says, adding that people should also be careful around pets at zoos and agricultural fairs.

Bird droppings can harbor large amounts of the virus, possibly for long stretches of time, but Webby doubts that would be a concern for more than a few days after being exposed to the elements on your porch or deck.

“If you had things that had bird poop on them, yes, you would want to avoid that or disinfect it,” Anderson says.

You can do the same for your bird feeder. He says to just use common sense hygiene principles like washing your hands and avoiding touching your face before hand washing.

People who have backyard flocks should be especially aware of the risk, especially if they live in the path of migratory birds. Do your best to prevent your poultry from mixing with wild birds. If you are worried, you can wear an N95 mask around them.

What’s up with dairy cattle? Do I need to worry about milk?

Unless you spend time with dairy cattle or raw milk, there is no need to be concerned.

The spread of bird flu in dairy cattle surprised the researchers. The best guess is that a spillover from birds to dairy cattle in late 2023 was enough to trigger the nationwide outbreak in dairy cattle today.

The US Food & Drug Administration has found that pasteurizing milk can effectively inactivate the virus. The same applies to pasteurized egg products and whose eggs are cooked to 165 degrees

There is now “strong” evidence that contact with raw milk, loaded with high concentrations of virus, is how about 40 dairy workers has been infected, says Anderson. Most likely this happens in the milking parlor when people are sprayed in the face or virus particles are aerosolized and inhaled.

Research has shown that raw milk can “stabilize the virus on a variety of surfaces for long periods of time,” Lakdawala says. Therefore the warnings against drinking raw milk.

Even relatively small amounts can be lethal to mice, according to laboratory tests conducted by Peter Halfmann and his colleagues at the University of Wisconsin-Madison. “But we don’t know how exactly this would work in humans,” he says. “It’s still a big black box.”

While the exact risk is unknown, Lakdawala considers consuming raw milk a “high-risk activity,” especially in states like California, where bird flu has been found in some of these products.

Dr. Jürgen Richta veterinary microbiologist at Kansas State University, echoes that sentiment.

“Is the mouse a good model for humans? I don’t know,” says Richt. “But don’t become a guinea pig.”

What should I do to protect my pets?

The basic principles of protecting yourself from bird flu also apply to your pets.

Coleman’s advice: Give your cats a little more supervision when they’re outside. Keep them away from wild birds (dead or alive) and rodentsespecially if you live on a farm or have poultry in the garden.

Coleman recently reviewed the data, and found that this current strain of bird flu appears to be more lethal in felines than it is for H5N1 in general, although it’s hard to say because of limited data.

She says cats are widely infected with bird flu by consuming raw contaminated meat and by hunting wild birds, including during the current outbreak.

In Oregon, a house cat died after consuming raw pet food laced with the virus, leading to a nationwide recall. Contaminated meat may have been behind an outbreak that killed 20 cats at a wildlife sanctuary in Washington state. In Los Angeles is raw milk implicated by the death of several domestic cats.

Dogs are also susceptible. Last year, a dog in Canada died of the infection after it was found chew on a dead goose.

While pets can develop respiratory symptoms, the infection can manifest as a neurological illness that appears to mimic rabies, she says. “If your cat or dog starts acting funny, perhaps circling or acting rabid, make sure to contact a vet immediately.”

There have been few documented cases of cat-to-human transmission of avian influenza after humans caring for the animals had direct contact, but not during this current outbreak.

Anderson says “there’s no need to panic” that your pet will get H5N1 tomorrow, especially if you keep them away from these known sources of infection.

“It’s just about paying attention,” he says.