FRIDAY, April 23, 2021 (HealthDay News) -- Not even your beloved feline is safe from COVID-19.
Using in-depth genetic analyses, a new investigation in the United Kingdom suggests that people can pass COVID-19 on to their cats.
"We identified two cats that tested positive," said study lead author Margaret Hosie. "Both of them were from suspected COVID-19 households."
One case involved a 6-year-old female Siamese. Last May, the cat had notable nasal and eye discharge. Swab samples were taken from the affected areas and tested for signs of respiratory infection.
Genetic sequencing of the virus found in those samples revealed "that it was very similar to the sequences of isolates from (COVID-19-)infected people in the same region of the U.K.," said Hosie, a professor of comparative virology with the MRC-University of Glasgow Centre for Virus Research, in Scotland.
The other case involved a 4-month-old Ragdoll kitten who succumbed to severe respiratory illness in April 2020. A post-mortem exam revealed the kitten had contracted COVID-19 after exposure to human SARS-CoV-2, the virus that causes the illness.
So how common is human-to-cat transmission?
It's pretty common, said Dorothee Bienzle, a professor of veterinary pathology at the University of Guelph in Ontario, Canada. But the variability of cases may depend on the proximity of the COVID-19 patient and the pet.
If your cat does get infected following exposure to human COVID-19, is serious illness a given? No, said Keith Poulsen, director of the University of Wisconsin Veterinary Diagnostic Laboratory, in Madison.
"Clinical disease with COVID for domesticated pets is very uncommon," Poulsen said. "We don't test all of our animals, but we have collaborated in studies with the U.S. Centers for Disease Control and Prevention and know that pets in households with COVID have a good chance of testing positive for COVID. But they rarely show any clinical signs and do not require veterinary intervention, in our data. The only outlier here are ferrets and mink. They get sick with COVID."
As for whether the transmission dynamic might go the other way, Hosie said that, for the moment, "we cannot rule out the possibility that the virus could be transmitted from cats to humans."
And it's going to be a difficult question to answer, she added, "as we could never expose an uninfected person to an infected cat to determine whether cat-to-human transmission would occur."
Still, Poulsen suggested that while the possibility cannot be ruled out, it is not overly concerning.
"We have no evidence that any companion animals play a significant role in transmission back to people," he said, "with the exception of ferrets and mink. The chances of this happening to a significant, or intervention-requiring rate, are low, but not zero."
His bottom line: "We still do not believe that cats, or dogs, are significant players in the disease ecology of COVID-19 in people, animals or the environment," Poulsen stressed.
Maybe so, but the study authors concluded that "it will be important to monitor for human-to-cat, cat-to-cat and cat-to-human transmission."
As for canines, both Hosie and Poulsen agreed dogs appear to have the upper hand over their feline friends when it comes to human coronavirus vulnerability.
"Dogs are infectable, but less frequently than cats," Hosie said.
Poulsen agreed, noting that "the science points to the fact that cats likely replicate more virus than dogs."
The study was published April 22 in the Veterinary Record.
There's more on pet health at the U.S. Centers for Disease Control and Prevention.
SOURCES: Margaret J. Hosie, PhD, professor, comparative virology, MRC-University of Glasgow Centre for Virus Research, Bearsden, Glasgow, U.K.; Dorothee Bienzle, DVM, professor, veterinary pathology, University of Guelph, Ontario, Canada; Keith Poulsen, DVM, PhD, DACVIM, clinical associate professor, large animal internal medicine, and director, Wisconsin Veterinary Diagnostic Laboratory, University of Wisconsin, Madison; Veterinary Record, April 22, 2021