We’ve known for a while now that animals can test positive for COVID-19, but according to the CDC, more investigation is needed into how different species can be affected by the virus. A recent Dutch study confirms that common household pets — specifically cats and dogs — can catch COVID-19 from their owners.
“About one out of five pets will catch the disease from their owners,” Dr. Els Broens, lead author of the study and associate professor at the Netherlands’ Utrecht University, told Reuters. “Luckily, the animals do not get very ill from it.”
According to the study, which was presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), a mobile veterinary clinic went to homes of human patients who have tested positive for COVID-19 in the last 200 days and tested their pets using nose-throat and rectal swabs, as well as blood samples. Out of 154 cats and 156 dogs tested from 196 households, six cats and seven dogs (4.2%) had positive PCR tests, showing that they had an active COVID-19 infection. 31 cats and 23 dogs (17.4%) additionally tested positive for antibodies, suggesting that they were previously infected.
Of the 13 pets that yielded positive PCR tests, 11 underwent a second round of testing one to three weeks following their first. All of them tested positive for antibodies, while three cats still had positive PCR tests and had to be tested for a third time. The animals reportedly had shown no or mild symptoms of COVID-19.
Can pets infect other pets with COVID-19?
Eight cats and dogs that resided with the PCR-positive pets were tested again during the second stage to determine if they had contracted the virus as well. According to results, none of these animals tested positive, suggesting there was no virus transmission between pets living in close contact with each other.
Results of the study reportedly show that humans passing COVID-19 to their pets is common. People who are sick with COVID-19 should avoid contact with their pets, as one would do with other people.
“The main concern, however, is not the animals’ health, but the potential risk that pets could act as a reservoir of the virus and reintroduce it into the human population,” Broens said in the study’s press release. “Fortunately, to date no pet-to-human transmission has been reported. So, despite the rather high prevalence among pets from COVID-19 positive households in this study, it seems unlikely that pets play a role in the pandemic.”
Cats are more prone to COVID-19 infection
Another study, this time from the University of Guelph in Canada — which was also released during the ECCMID — tested 48 cats and 54 dogs from 77 households for COVID-19 antibodies. The owners were asked in detail about their interactions with their pets, specifically whether they pet them, kissed them, or allowed them to sit on their lap or sleep with them in their beds. They were also asked how much time they spent with their pet each day and if their pets licked or kissed them on the face.
75 dogs and cats housed in an animal shelter, as well as 75 stray cats treated at a low-cost veterinary clinic, were also tested for COVID-19 antibodies. 32 of 48 (67%) of the owned cats and 23 of 54 (43%) of the owned dogs tested positive for antibodies, compared to only seven of 75 (9%) dogs and cats at the animal shelter and two of 75 (3%) of the stray cats that tested positive for antibodies.
11 (20%) of the 54 owned dogs showed COVID symptoms, primarily in the realm of low energy and loss of appetite. Some dogs had a cough or diarrhea, but all symptoms were mild and cleared up fairly quickly. 13 of the 48 (27%) owned cats also exhibited symptoms, the most common of which were a runny nose and difficulty breathing. Most of the cases were considered mild, but three were reportedly severe.
According to the study, the amount of time a dog owner spent with their pet and the extent of the contact shared did not affect the animal’s potential to contract COVID-19. The same could not be said about cats, however. Cats who spent more time with their previously infected owners showed a higher risk of infection, and this risk jumped even higher among cats who slept in their owners’ beds.
A cat’s biology, including its viral receptors, makes the species more susceptible to COVID-19 than dogs, according to the study’s authors. Cats are also more likely to sleep near their owners’ faces than dogs, heightening their exposure rate to infection.
The higher virus transmission rates in owned pets compared to strays and those in shelters, coupled with results from previous genetic studies, proves that the infection route is most likely from human to animal, as opposed to the reverse. This seems to back the Dutch study’s findings.
Dorothee Bienzle, a professor of veterinary pathology at the University of Guelph and lead author of the study, is advising people who have COVID-19 to keep their pets — particularly cats — off their beds and out of their bedrooms. It is important that they keep pets at a safe distance for the duration of their infection.
“I’d also recommend that you keep your pet away from other people and pets,” Bienzle said in a press release. “While the evidence that pets can pass the virus on to other pets is limited, it can’t be excluded. Similarly, although pets have not been shown to pass the virus back to people, the possibility can’t be completely ruled out.”
Sources: CDC, Reuters, AAAS [1, 2], University of Minnesota Center for Infectious Disease Research and Policy