STUDY WARNS THAT CATS MIGHT BE BIRD FLU CARRIERS

Imagine this: a healthy, playful cat suddenly falls ill with no clear explanation, only for the shocking culprit to be revealed—bird flu, a virus most people associate with poultry and wild birds. Now, scientists are warning that domestic cats could become an unexpected player in a potential public health crisis.

A recent study published on December 9 in Emerging Microbes & Infections suggests that domestic cats could play a role in the evolution and transmission of the H5N1 bird flu virus, potentially making it more dangerous.

The virus, which began circulating in dairy cattle earlier this year, has already claimed the lives of many cats, primarily on farms where herds were infected. At least 60 people have been sickened by the virus, most of whom had direct contact with infected dairy cows or poultry.

While H5N1 currently doesn’t spread easily between humans, scientists warn that just one or two key mutations could allow it to jump between people more easily.

Though there’s no evidence that cats have transmitted H5N1 to humans, researchers caution that these pets could still pose a risk. If a cat were to be infected with both H5N1 and a seasonal flu virus simultaneously, there is a possibility that the bird flu could acquire mutations that allow it to spread more widely among people.

Cats, which often come into contact with both wild animals and humans, could act as a bridge, facilitating the virus’s evolution.

While much of the attention has been on testing cows and humans for H5N1, no single agency has taken responsibility for tracking other animals like cats, as reported by the New York Times. However, the U.S. Department of Agriculture (USDA) has recently announced plans to begin testing the national milk supply to identify infected dairy herds.

The recent cat study highlights the urgent need for public health officials to increase surveillance for bird flu in cats, according to Dr. Suresh Kuchipudi, a veterinary microbiologist at the University of Pittsburgh and author of the study. In an interview with The Times, Kuchipudi warned that while attention has been focused on immediate concerns like dairy farms, milk safety, and human surveillance, a much larger and evolving issue may be slipping under the radar.

“In focusing on the immediate problems—like dairy farms, milk safety, and human monitoring—we might be overlooking a much bigger, evolving story,” Kuchipudi said. “This may already be happening right in front of us.”

Meanwhile, the Biden administration has stated that it has no immediate plans to authorize a bird flu vaccine for humans, as reported by NBC News, leaving that decision to the incoming Trump administration. This delay has sparked concerns about the government’s preparedness to tackle a potential outbreak.

In response, the U.S. Department of Agriculture (USDA) has ordered milk testing in six states, set to begin next week, to help reassure farmworkers about the safety of their animals and the steps they can take to prevent infection. The testing is also expected to provide valuable data for tracking the virus’s spread among herds.

The study itself focused on a case in South Dakota, where 10 outdoor cats, considered pets, died after exhibiting respiratory and neurological symptoms. The virus isolated from the cats was closely related to the strain found in cattle on a nearby dairy farm. Researchers believe the cats became infected after consuming wild birds that had contracted the virus from the farm.

Historically, scientists have been most concerned about pigs, which are considered ideal “mixing vessels” for flu viruses, as they can host both seasonal flu and H5N1, potentially allowing the viruses to swap genes.

According to Richard Webby, an influenza expert at St. Jude Children’s Research Hospital, many animals could potentially host both bird flu and seasonal flu viruses simultaneously. “Cats seem to be a pretty good candidate,” Webby said in an interview with The Times.

Since late 2022, the USDA has reported at least 53 domestic cats in the United States infected with H5N1.

What’s more, the current H5N1 strain has already infected an unusually broad range of species, including 90 types of birds and over 20 mammal species, said Tom Peacock, a virologist at the Pirbright Institute in the UK. “This virus is doing all sorts of unusual things we haven’t typically seen with flu viruses,” he added.

More information

The American Veterinary Medical Association (AVMA) has more on keeping pets safe from bird flu.