As we cope with the ever-changing landscape of what is known and not known about the COVID-19 pandemic and the coronavirus that has caused it, one question being asked is whether the virus can be transferred to or from our pets.
Can animals get coronaviruses?
The answer is yes. Although there are only seven coronaviruses known to affect humans, there are hundreds of different coronaviruses circulating in various animal species. Via mutation, coronaviruses have adapted over thousands of years so that nearly every species on earth, including humans, is susceptible to certain of them.1
In general, coronaviruses are species specific, and rarely jump from one animal species to another. And rarely is there crossover from animals to humans because the virus must evolve and overcome multiple barriers to affect humans.
Lions and tigers and housecats, oh my!
Can cats get COVID-19? What I might have answered a few weeks ago is not what I would answer today – and perhaps what I answer today will change in the next few weeks as we learn more about this specific virus and how it is transmitted. For up-to-the-minute reports, check the CDC website.
To show how fast things are evolving, on April 21 the U.S. Department of Agriculture (USDA) reported that two pet cats from different areas of New York State tested positive for the coronavirus responsible for COVID-19 (SARS-CoV-2).2 Although there had been unconfirmed reports of cats and dogs acquiring the virus from their owners in other parts of the world, these are the first confirmed human-to-pet transmissions reported in the United States.
One cat was tested by a veterinarian after showing mild respiratory symptoms about a week after a human member of the household had mild respiratory symptoms not confirmed to be COVID-19. The pet owner also thought the cat might have acquired the virus by going outside and being exposed to an infected person.
The second cat showed signs of respiratory illness a week after its owner had tested positive for COVID-19. Another cat in the household remained healthy and tested negative. Both COVID-positive cats had mild respiratory symptoms and are expected to make a full recovery.
These housecat reports followed on the heels of the report in early April that Nadia, a Malayan tiger at the Bronx Zoo in New York City, had tested positive for COVID-19 after being exposed to a handler who was asymptomatic but later tested positive.3
On April 22nd, NBC NewYork and other news outlets reported that, according to the Wildlife Conservation Society that runs the Bronx Zoo, four more tigers and three lions had tested positive. The zoo animals have since recovered from dry coughs and other mild symptoms.
Can cats give coronavirus to humans?
Cats have coronaviruses that are specific to their species. Feline coronavirus (FCoV) is somewhat ubiquitous in housecats, particularly felines from shelters or catteries.
In fact, in a study on feline viral spread in a shelter setting, as many as one-third of healthy cats and 90 percent of kittens and young cats tested positive for FCoV on admittance to the shelter.4 Although it’s typically asymptomatic or causes mild diarrhea, FCoV can mutate and cause the deadly feline infectious peritonitis (FIP).5 Humans can’t contract this virus.
Although cats appear mildly susceptible to the coronavirus that causes COVID-19, there is no evidence of the reverse occurring – cats transferring the virus to humans.2
What about other pets?
Like cats, dogs have their own species-specific coronaviruses – canine respiratory coronavirus (CRCoV) and canine enteric coronavirus (CECoV). On April 28th, the first case of a dog to test positive for the virus causing COVID-19 was reported in North Carolina by Duke Health.
The dog’s family was part of a Duke University study on how infections affect the body. Other family pets – a cat and another dog – tested negative. The dog – a pug named Winston – was sick for a few days and has since recovered.6
A recent study in China determined the susceptibility of various animal species inoculated with the COVID-19 virus – SARS-CoV-2.7 Dogs were shown to have very low susceptibility, while pigs, ducks, and chickens showed no susceptibility to the virus.
On the other hand, the virus did easily replicate in cats, with younger cats being more susceptible; and they showed airborne cat-to-cat spread. Ferrets were also found to be susceptible to the virus, which manifested mainly in the upper respiratory tract but not in the lungs.
Why does the virus affect some animals and not others? It is theorized that it has to do with what is called the ACE2 receptor. Among other functions, it turns out in humans that the ACE2 receptor appears to be the key that unlocks the cell, thus allowing the virus to enter.8 And, guess what? Cats and ferrets have these receptors, too.7,9
Recommendations from the CDC and the USDA
Currently, testing of animals is not recommended. A report on animals that have tested positive is posted at the USDA website.
According to the USDA:
Public health officials are still learning about SARS-CoV-2, but there is no evidence that pets play a role in spreading the virus in the United States. Therefore, there is no justification in taking measures against companion animals that may compromise their welfare. Further studies are needed to understand if and how different animals, including pets, could be affected.2
This conclusion bears repeating: “Therefore, there is no justification in taking measures against companion animals that may compromise their welfare.”
The CDC has made the following recommendations to pet owners:
Until we learn more about how this virus affects animals, treat pets as you would other human family members to protect them from a possible infection.
- Do not let pets interact with people or other animals outside the household.
- Keep cats indoors when possible to prevent them from interacting with other animals or people.
- Walk dogs on a leash, maintaining at least 6 feet (2 meters) from other people and animals.
- Avoid dog parks or public places where a large number of people and dogs gather.
Talk to your veterinarian if your pet gets sick or if you have any concerns about your pet’s health.
If you have pets, then it is advised to regularly check with the CDC for updates in this rapidly changing environment.
References
- Can pets contract coronavirus from humans or vice versa? https://www.vetmed.ucdavis.edu/news/can-pets-contract-coronavirus-humans-or-vice-versa [Accessed 4.23.20]
- Confirmation of COVID-19 in two pet cats in New York. https://www.aphis.usda.gov/aphis/newsroom/news/sa_by_date/sa-2020/sars-cov-2-animals [Accessed 4.23.20]
- USDA statement on the confirmation of COVID-19 in a tiger in New York. https://www.aphis.usda.gov/aphis/newsroom/news/sa_by_date/sa-2020/ny-zoo-covid-19 [Accessed 4.23.20]
- Pedersen N, Sato R, Foley JE, Poland A. Common virus infections in cats, before and after being placed in shelters, with emphasis on feline enteric coronavirus. J Feline Med Surg 2004;6(2):83-88.
- Feline coronavirus (FCoV) RT-PCR. https://www.vet.cornell.edu/animal-health-diagnostic-center/veterinary-support/disease-information/feline-coronavirus [Accessed 4.23.20]
- North Carolina pet believe to be first dog in the U.S. to test positive for virus that causes COVID-19 in humans. https://time.com/5828413/dog-coronavirus/ [Accessed 4.28.20]
- Shi J, WenZ, Zhong G, et al. Susceptibility of ferrets, cats, dogs, and other domesticated animals to SARS-coronavirus 2. Science 2020 Apr 8. pii: eabb7015. doi: 10.1126/science.abb7015. [Epub ahead of print]
- Coronaviruses often start in animals – here’s how those diseases can jump to humans. https://www.discovermagazine.com/health/coronaviruses-often-start-in-animals-heres-how-those-diseases-can-jump-to [Accessed 4.23.20]
- Summerstein R, Kochen M, Messerli F, Grani C. Coronavirus disease 2019 (COVID-19): Do angiotensin-converting enzyme inhibitors/angiotensin receptor blockers have a biphasic effect? J Am Heart Assoc 2020 Apr 7;9(7):e016509. doi: 10.1161/JAHA.120.016509. Epub 2020 Apr 1. https://www.ahajournals.org/doi/10.1161/JAHA.120.016509 [Accessed 4.23.20]
