U.S. scientists are testing the spread of the coronavirus not only in humans, but in their pets as well. At least 2,000 animals in America have been tested by veterinarians and other researchers to find out how the disease affects other species. Besides domestic animals, farmed minks, zoo cats, and even armadillos have been examined for COVID-19.

According to CNN and Kaiser Health News, cats and dogs exposed to infected owners tested positive 80% of the time. Recently, thousands of minks at fur farms in Utah and Wisconsin died from coronavirus infections that veterinarians said were spread from workers.

In late July, a pet cat in the U.K. was reportedly infected by the virus. A few days later, Buddy, a 7-year-old German shepherd became the first dog to die from the virus. In April, the Centers for Disease Control and Prevention announced that two domestic cats developed a mild respiratory illness and tested positive for the virus. In one case, the owner was diagnosed with COVID-19 prior to the cat exhibiting symptoms, according to The Blaze.

The first COVID-19 case of a big cat contracting the virus was reported in April at the Bronx Zoo. Staff reported that a 4-year-old female Malayan tiger tested positive for COVID-19 and that subsequently more sick animals were tested, bringing the total of cats infected to eight, including five tigers and three lions.

Dr. Casey Behravesh, a CDC official, said in a statement, according to The Blaze: “We don’t want people to be afraid of pets. There’s no evidence that pets are playing a role in spreading this disease to people.”

According to CNN, neither the CDC nor the U.S. Department of Agriculture recommends routine testing for pets. But Dr. Douglas Kratt, president of the American Veterinary Medical Association, said that owners are concerned.

“The questions have become a little more consistent in my practice,” he said. “People do want to know about COVID-19 and their pets. Can their pet pick it up at a clinic or boarding or in doggie day care?”

Experts say it’s unlikely, as humans have been found to be the primary source of infection. But since coronaviruses infects many species, mostly mammals, “it makes sense to take a species-spanning approach and look at a wide spectrum,” noted Dr. Peter Rabinowitz, director of the Human Animal Medicine Project at the University of Washington School of Public Health.

Texas A&M University researchers have been tracking the spread of the disease in pets since June, swabbing dogs, cats, pet hamsters, and guinea pigs. According to The Hill, the researchers, headed by Dr. Sarah Hamer, are conducting investigations on how SARS-CoV-2 infects pets and if can they spread the virus to other animals or humans.

“By actively screening pets who may not be symptomatic and who are living with people who have tested positive for COVID-19, Dr. Hamer’s project provides important new information about the transmission pathways of the virus,” said Dr. John August, interim dean of the College of Veterinary Medicine and Biomedical Sciences at Texas A&M.

So far, most of the animals tested have shown no symptoms, according to CNN, but cats appear to be more susceptible than dogs to the virus. Experts caution that pet owners should exercise the same safety protocols as humans, keeping their four-legged companions away from unfamiliar animals and washing their own hands frequently.