A new study is the latest to bring some mixed news when it comes to covid-19 and cats. The study found evidence that cats infected with the coronavirus that causes covid-19 can easily spread it to other cats within two days of exposure. However, none of these cats documented in the study become sick once infected, suggesting but not yet confirming that felines may be able to handle the virus better than people.
Veterinary researchers exposed six healthy cats that were less than six months old to the novel coronavirus, SARS-CoV-2, via the nose and mouth. Then a day later, they introduced two other cats to the group and let them socialise; another pair of cats served as the controls. The cats were watched for up to 21 days, with some euthanised and autopsied at various days to study the effects of infection on the body more closely.
All of the first group of cats became infected and tested positive for the virus within one to 10 days post-exposure. The two cats added later to the group also became infected within two days of co-mingling with them. In these infected cats, traces of viral RNA could be found in the nose, throat, lungs, and rectum within four days of infection, with relatively high levels in the nose and throat.
The findings were released this week on the preprint website biorxiv, meaning that they haven’t been formally published and peer-reviewed by other scientists yet, though the authors have submitted their work to a journal. Combined with other similar, published research, the authors wrote, the results “show that felines are susceptible to SARS-CoV-2 infection and could be potential virus reservoirs.”
The study also found that the cats didn’t develop any clinical symptoms while infected and only had minor, if any, bodily signs of anything being wrong, such as inflammation along the airways and lungs. All of the cats also developed specific antibodies to the virus as early as a week’s time post-exposure, indicating that they could have protection against reinfection.
The study’s findings support what vets are seeing in the real world. On Thursday, for instance, researchers at Texas A&M University reported that two pet cats in the state had tested positive for the virus, though both were asymptomatic. They had likely caught it from infected human family members.
There are still major questions about how covid-19 works in cats and other pets, according to study author Juergen Richt, a veterinary researcher at Kansas State University who specialises in viruses. More research has to be done before we can conclude that cats aren’t capable of getting severely sick from the coronavirus as people can, particularly older cats. We also need to study whether the virus undergoes any important genetic changes when infecting cats, if it can linger in a shared litterbox and infect others, and whether cats can get reinfected.
The fact cats can easily spread the virus to other cats, likely through the high levels of virus they shed from their nose and throat early into infection, is potentially worrying for both cats and humans, Richt added.
“The ease of transmission between domestic cats indicates a significant public health need to investigate the potential chain of human-cat-human transmission,” he said over email. “It is also critical that pet owners are educated on the risks and preventative measures in order to calm fears and discourage animal abandonment.”
Both the American Veterinary Medical Association and Centres for Disease Control and Prevention now advise that people who test positive for the virus avoid close contact with their pets as well as other human household members while sick, and to wear face masks around them when that isn’t possible.