Cats infected with SARS-Cov-2, the virus that causes Covid-19, appear to be able to transmit the virus to other felines, often without presenting symptoms or other signs of illness, new research confirms.
Previous reports presented evidence of SARS-CoV-2 transmission from humans to pets when a cat in Belgium became the first known case. In the weeks that followed, multiple tigers and large cats at a zoo in New York also contracted the virus and two cats in New York tested positive for the disease, one of which only showed mild signs of respiratory illness.
“It’s something for people to keep in mind,” said Peter Halfmann, a research professor at the University of Wisconsin School of Veterinary Medicine, in a statement. “If they are quarantined in their house and are worried about passing COVID-19 to children and spouses, they should also worry about giving it to their animals.”
To determine whether the virus can be transmitted between cats, researchers from the US and Japan isolated and administered the virus taken from a human patient to three cats. The following day, nasal swabs indicated that the virus was present in two of the animals. Within three days, all cats tested positive for the virus. A fourth, uninfected cat was placed in a cage near the three infected cats and, within two days, was shedding the virus. In six days, the virus was present in nasal swabs of each animal though there was no presence in rectal samples. Every cat shed the virus from their nasal passages for up to six days, but the virus was not lethal and the cats were largely asymptomatic. Each cat successfully cleared the virus.
The findings build on a study published earlier this year that found cats and ferrets could become infected with, and potentially transmit, the virus between members of their own species. The data shows the “ease of transmission between domestic cats” and represents a “public health need to recognize and further investigate the potential chain of human-cat-human transmission.” It appears that cats may be capable of becoming infected with the virus when exposed to other people or animals who are, suggesting that the animals could become “silent intermediate hosts” because they do not necessarily exhibit recognizable symptoms.
Still, the researchers caution that there is no evidence that cats can transmit the virus back to humans nor are there any documented cases of feline-to-human transmission. Experts add that cats are “still much more likely to get Covid-19 from you, rather than you get it from a cat.”
“Animal welfare organizations are working very hard in this crisis to maintain the human-animal bond and keep pets with their people,” said Sandra Newbury, director of the UW-Madison Shelter Medicine Program. “It’s a stressful time for everyone, and now, more than ever, people need the comfort and support that pets provide.”
Researchers recommend keeping animals in mind when planning for emergencies, including having a two-week supply of food and medicine.
“Preparations should also be made for the care of animals should you need to be quarantined or hospitalized due to illness,” said Ruthanne Chun, associate dean for clinical affairs at UW Veterinary Care.
If a person is exhibiting symptoms of Covid-19, the researchers say to avoid contact with cats and to always keep their animals indoors to limit exposure with other cats and people. If concerned, pet owners are encouraged to contact a veterinarian, particularly as testing kits for pets are now available on a case-by-case basis. It is okay to cuddle and interact with an animal as usual if they live indoors and do not come into contact with infected individuals. Additional guidance is available from the American Veterinary Medical Association and Centers for Disease Control and Prevention.