New research suggests that human-to-pet COVID transmission occurs more frequently than once believed.
A team led by Dr. Dorothee Bienzle, professor of veterinary pathology at the University of Guelph in Ontario, Canada, examined potential COVID infection in 198 cats and 54 dogs. All of the dogs and 48 of the cats lived in households where at least one person had COVID. The remaining cats came from an animal shelter or neuter clinic.
The study found that 67 percent of household cats and 40 percent of household dogs whose owners had COVID carried the antibodies indicating that they, too, were infected with COVID. Less than 10 percent of pets in shelters and 2.6 percent of neuter clinic animals carried the antibodies.
Between 20 and 30 percent of the animals in the household group developed COVID symptoms including loss of energy and appetite, coughing, diarrhea, runny nose and respiratory problems. Symptoms were generally mild and short-term, though three cases were severe and prolonged. According to behavioral surveys conducted by the research team, the risk of infection was higher in cats cuddled by their owners. The cuddling correlation was not observed in dogs.
Els Broens, DMV, of Utrecht University, Netherlands, and her colleagues studied 156 dogs and 154 cats from 200 households with at least one human COVID patient. Twenty percent of companion animals in these households became infected with COVID per Polymerase chain reaction (PCR) or antibody tests. Gastrointestinal and respiratory symptoms were most prominent in this sampling, though symptoms again were generally mild.
Results of these studies were presented at the 2021 European Congress of Clinical Microbiology and Infectious Diseases. Respective papers are pending publication in scientific journals.
These conclusions don’t surprise Sarah Hamer, a veterinary epidemiologist at Texas A&M University who is currently conducting similar studies in the U.S.
The results makes sense given the physical closeness between humans and their animal companions, Hamer told Spektrum der Wissenschaft. “It’s just not that hard for these animals to get infected.”
Beyond these studies looms concern for mutations. COVID’s Delta variant, which has shown to be more transmissible between humans than its predecessor, may also be more easily transmissible to pets where it could further mutate.
“The main concern is . . . the potential risk that pets could act as a reservoir of the virus and reintroduce it into the human population,” Broens said, noting that there is currently no evidence of COVID retransmission from pets back to humans.
True, few things are more comforting during an illness than cuddling with a furry family member. However, people contracting the Delta variant, particularly the unvaccinated, are getting sicker. It isn’t a huge epidemiological leap to think that exposed pets may get sicker as well.
Those testing positive should take measures to protect their pets. Isolate. Ask a friend or family member to care for your pet’s daily needs until you recover. Visit at a safe distance so your pet(s) know you haven’t disappeared. If you’re the only one at home, avoid cuddling — especially with cats.
As of press time, about 53 percent of Americans are fully vaccinated against COVID-19. However, this is far short of the minimum 70 percent of the U.S. population required to achieve herd immunity. Vaccine resistance is not just prevalent among those espousing “personal liberty.” It runs freely in our inner cities and even among some educators and health care workers.
The consequences speak for themselves: 99 percent of new COVID cases are among the unvaccinated. The chances of being hospitalized and dying from COVID among the vaccinated are virtually nil.
Please get vaccinated. If not for your fellow humans, then for those who ask for nothing — and give everything.
Portions of this piece originally appeared in Spektrum der Wissenschaft and Scientific American with additional reporting by Tess Joosse.