Covid-19 is common in cats and dogs that live in households with people who have the virus, according to a new study.
Cases of pets becoming infected from their owners have been documented before.
But researchers in the Netherlands were keen to know how often that happened, and whether pets posed a risk in transmitting the virus.
So they took blood and swab samples from more than 300 cats and dogs belonging to people who had tested positive in the previous two to 200 days.
No evidence of pets passing on virus to human beings
The results showed that a fifth had contracted the virus, demonstrating it is “highly prevalent” in pets of people who have had the disease.
Experts believe the most likely route of transmission is from human to animal, and not from pet to owner.
"If you have Covid-19, you should avoid contact with your cat or dog, just as you would do with other people,” said Dr Els Broens, who led the study at Utrecht University, Utrecht.
"The main concern, however, is not the animals' health – they had no or mild symptoms of Covid-19 – but the potential risk that pets could act as a reservoir of the virus and reintroduce it into the human population.
"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."
There were 156 dogs and 154 cats from 196 households tested as part of the study.
Six cats and seven dogs, a rate of 4.2 per cent, had positive PCR tests, while 31 cats and 23 dogs, 17.4 per cent of the total, tested positive for antibodies.
Eleven of the 13 owners of pets who returned positive PCR tests agreed for them to undergo further screening three weeks later. All of them tested positive for antibodies, confirming they had Covid-19.
The research is being presented at the European Congress of Clinical Microbiology & Infectious Diseases, which will also hear about results from a similar study in Canada, which found that cats are more easily infected with the virus if they sleep on their owners’ beds.
Domestic pets face higher risk of infection
Researchers at the University of Guelph, Ontario, Canada, tested 48 cats and 54 dogs for signs of past infection. All were owned by people who had had Covid-19.
The owners were asked whether they had petted them or allowed their pet to lick them on the face and sleep in their bed. They were also asked whether they became ill around the time they had Covid-19, and what symptoms they had.
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The antibody results were compared to samples taken from 75 dogs and cats living in an animal shelter and 75 stray cats.
They revealed 67 per cent, or 32 of the 48 of the pet cats and 43 per cent, 23 of the 54 pet dogs tested positive for antibodies, showing they had had Covid-19.
But just 9 per cent, or 7 of 75 shelter dogs and cats and 3 per cent, or two of 75 stray cats, had antibodies, demonstrating transmission was more common from people to animals, rather than the other way round.
Cats that spent more time with their owners seemed to be at higher risk of infection. And cats that slept on their owner's bed were the most likely to have Covid-19.
The lead researcher, Dorothee Bienzle, a professor of veterinary pathology, said the results show there is a “surprisingly high chance” an infected person will pass the virus on to their pet.
“Cats, especially those that sleep on their owner's bed, seem to be particularly vulnerable. So, if you have Covid-19, I'd advise that you keep your distance from your pet - and keep it out of your bedroom,” she said.
"I'd also recommend that you keep your pet away from other people and pets. 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."