Pets and COVID: What research shows about infection, spread

Dogs, cats can catch COVID from human companions, but pet cases tend to be mild

DETROIT – In the very beginning of the COVID-19 pandemic, there were sporadic reports of a dog or cat testing positive for the coronavirus -- SARS-CoV-2.

However, there was very little focus on how often it happened, which pets were at risk or if animals could spread the virus to humans. Local 4 News found an international expert to put that in perspective Tuesday.

“Most infectious diseases that cause outbreaks in people come from animals, and COVID-19, the disease caused by SARS-CoV-2, is no different -- it comes from a bat,” said Dr. Dorothee Bienzle, a professor of veterinary pathology at the University of Guelph in Ontario.

Bienzle has been studying the spread of the virus to animals since the start of the pandemic. She points out that given that it comes from an animal, it shouldn’t be surprising that SARS-CoV-2 can be spread to animals.

“During the past year we’ve found out that mink are highly infectious, and cats are relatively infectious. Dogs are also infectious and another number of other species are infectious,” she said.

More recently, her research group wanted to find out how frequently people with COVID pass the virus to their pets, so they tested a group of cats living with COVID-positive owners and compared them to a group of stray cats who did not have a known COVID exposure.

“We found a very big difference in the seroprevalence between the cats that lived in a household versus those that were admitted to an animal shelter,” said Bienzle.

The research showed:

  • 67 percent of cats exposed to COVID-positive owners had antibodies to SARS-CoV-2 compared to only 3 percent of stray cats, showing that a large number of cats were likely infected by their owners.
  • 43 percent of dogs that lived with a COVID-positive owner had evidence of an infection.

The study also identified risk factors putting cats at higher risk of becoming infected. In cats, seropositivity was associated with sleeping on a bed with the owner

“Cats tend to like sleeping close to the owners neck and face so they would be exposed to their breath potentially for a longer period of time and more frequently,” said Bienzle. “There also was a trend of the duration of the contact to be associated with a higher seropositivity in cats, so cats that spent 19 to 24 hours per day with their owner were more likely to have a positive test result than cats that spent less time with their owner.”

Often these infections probably went unnoticed by their owners.

“Cats and dogs seem to become infected and they clear infection after generally a short time. There are some exceptions in our hands as well as reported by others, some cats can be infected for prolonged periods of time, but in general they are infected for a short period of time,” said Bienzle.

In her study:

  • 27 percent of cats had symptoms, particularly a runny nose and difficulty breathing. Most cases were mild but three were severe.
  • 20 percent of dogs had symptoms, mainly a lack of energy and loss of appetite

Bienzle said pet owners who become infected with COVID should protect their furry companions.

“They should stay away from them as much as possible while they’re ill for at least two weeks,” she said.

She also pointed out that there have not been any well documented instances of cats or dogs infecting people, until we know more:

“I would treat an infected cat or dog or any other animal just like a person with SARS-CoV-2, and I would stay away from them,” she said.

If you have a pet with COVID, people around them should wear masks and be sure to wear gloves and wash your hands when cleaning up after them. There is a vaccine for animals but so far it is only being used to protect at-risk animals in zoos. Eventually there may be a vaccine available for house pets but it isn’t a priority since most pet infections tend to be mild, and since most pets get the infection from their owners.

The best way to protect your pet is to protect yourself from getting infected.

More: Pets headlines


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About the Author

Dr. McGeorge can be seen on Local 4 News helping Metro Detroiters with health concerns when he isn't helping save lives in the emergency room at Henry Ford Hospital.

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