Humans and animals share many diseases. And as dramatically shown by the tigers that tested positive in the Bronx Zoo, the coronavirus is one of them. As three veterinary epidemiologists who study infectious disease, we have been asked a lot questions about if and how the coronavirus SARS-CoV-2 affects pets.
Can my pet get the coronavirus?
When talking about a virus, the words "get" or "catch" are vague. A more precise question is: Can my cat or dog become infected with SARS-CoV-2?
The answer is yes. There is evidence from real-world cases as well as laboratory experiments that both cats and dogs can become infected with coronavirus.
In Hong Kong, health officials have tested 17 dogs and eight cats living with COVID-19 patients for the coronavirus. They found evidence of the virus in two dogs: a Pomeranian and a German shepherd, though neither became sick.
None of the eight cats were infected or had been sick. However, there is a separate report of an infected cat from Hong Kong.
Another case of an infected cat was reported in Belgium. Again, the owner of the cat had COVID-19, but unlike the infected cat in Hong Kong, this one had become sick with respiratory problems as well as diarrhea and vomiting.
The final evidence comes from Wuhan, where researchers tested 102 cats and released a pre-print study of the results. Fifteen of those cats tested positive for the antibodies to the virus - meaning the cats been exposed in the past. As the researchers say in the paper, the coronavirus has "infected cat populations in Wuhan, implying that this risk could also occur at other outbreak regions." This study tested cats from owners with COVID-19, veterinary hospitals and even some strays. Three of the infected cats were owned by COVID-19-affected patients which explains their exposure; for the other 12 it is unclear how they were infected.
Can my pet spread the virus to another animal?
If cats or dogs can spread the coronavirus, health agencies and the public would need to incorporate these animals into their planning to contain and slow the pandemic. It is very important to know how easily the coronavirus replicates in pets and whether they can transfer it to other animals. A group of researchers in China set out to answer these questions.
To do this, they inoculated - that is, directly exposed - a number of cats and dogs with the coronavirus by deliberately placing large doses of live SARS-CoV-2 into their noses. The scientists then put some of these inoculated animals next to uninfected control animals to see if the exposed animals got sick, could spread the virus to the uninfected animals, or both.
The researchers found that kittens and adolescent cats can become infected when given a large dose of the virus. All five of the kittens who were inoculated became sick and two died, but all of the adolescent cats were able to fight off the infection without becoming seriously ill.
They also found that cats can spread the coronavirus to other cats. After a week, one-third of the uninfected cats that were placed next to the inoculated cats tested positive for the coronavirus.
These results provide evidence that SARS-CoV-2 can replicate in cats and can make them sick. It also shows that cats can transfer the virus through the air to other cats.
The same researchers also looked at dogs and found them to be much more resistant to the virus and unable to transmit it to other animals.
This is important information, but the conditions of the experiment were very unnatural. There are no studies about transmission of the virus between cats and dogs in the real world so it remains unclear whether natural transmission is occurring. While this experiment shows that cats and dogs are not totally immune to the coronavirus, the lack of a pandemic among household pets provides some evidence that they are more resistant than people are.
Can I get the coronavirus from my cat?
While we can't say it would be impossible to catch the coronavirus from a cat or dog, the research suggests this is extremely unlikely. There are currently no reported cases of people catching the coronavirus from animals.
The World Health Organization says that "based on current evidence, human to human transmission remains the main driver" of the COVID-19 pandemic, but that "further evidence is needed to understand if animals and pets can spread the disease."
The Centers for Disease Control and Prevention says that there is no evidence pets can spread COVID-19 to people.
While your cat can get infected, according to the science, it is extremely unlikely they could pass it to you. In fact, if your cat is infected, the chances are your cat caught the coronavirus from you.
Should I keep my cat inside or change my dog's behavior?
Although the chances of your pet catching the coronavirus from another animal are low, if you take your dog or cat outside, have your pets follow the same rules as everyone else - keep them away from other people and animals.
If a dog approaches you, there is no need to be scared of getting sick from virus on the dog's fur. But avoid approaching dogs on leashes - not because of the dog, but because there is usually a human on the other end.
If you become ill with COVID-19, the CDC recommends that you isolate yourself from your pets and have someone else care for them. If that isn't possible, continue to wash your hands frequently and avoid touching your face.
Also remember: If your pet needs medical care, make sure you inform your veterinarian if you or a household member is ill with COVID-19. That information will allow your veterinarian to take adequate precautions.
The evidence around pets and the coronavirus is changing rapidly and our team is keeping an updated review about how cats, dogs, ferrets, other less common pets and livestock are affected by the new coronavirus. But where the science stands today, there is little to worry about with regards to your cat or dog. In rare cases, they might become infected with the virus, but the chances of them getting sick from the infection or passing it on to you or another animal are extremely low.
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Annette O'Connor, Professor of Veterinary Epidemiology, Michigan State University; Jan Sargeant, Professor of Veterinary Epidemiology, University of Guelph, and Sarah Totton, Research Assistant, University of Guelph