By Scott Weese
Does the SARS-CoV-2 virus (virus that causes COVID-19) infect animals?
…The virus likely originated in an animal of some kind and has since been found in a relatively healthy dog, but we don’t know much more than that. From a transmission standpoint, this is a human disease. Whether it’s purely human or predominantly human is a lingering question. If it’s purely a human disease, we can ignore the animal side (except for their potential to be contaminated fomites, more on that below). If it’s predominantly a human disease with minor animal involvement, the focus still needs to be on people, but there are some animal aspects worth considering.
What about that dog in Hong Kong that tested positive for the COVID-19 virus?
The dog was owned by an infected person and had a series of positive tests. That’s pretty convincing evidence that it was infected. However, the tests were reportedly “weak positives” and no detectable antibody response was detected in the dog (at least not yet), supporting that this was a pretty low-grade infection.
Infected vs infectious is the big question. An individual can be infected but not infectious if they’re not producing much virus and therefore unlikely to pass the infection along. The hope is that dogs are not a great host for the virus and if infected, that they’re not infected enough to pose a risk to others.
What about cats?
Cats are still a bigger concern in this scenario because they were able to be infected by the SARS virus and could infect other cats with SARS, and this virus is similar enough that it’s reasonable to be concerned that it could infect cats as well. However, there has been little testing (in fact none that we know of) of cats so far, though undoubtedly many cats have been exposed through their infected owners. Time will tell based on field study (hopefully) and probably experimental work.
Should I be worried about catching COVID-19 from my dog or cat?
No. As a disease that is at least predominantly if not purely transmitted by people, pets are going to get it from people, not the other way around. If your dog/cat is infected, it probably got it from you or one of your close contacts, and the infected person poses more of a risk to you than the dog/cat.
So, what should we think about with pets and COVID-19?
Common sense. If you’re infected, stay away from people and pets. If you’re infected and you’ve been with your pet, keep it away from others. If we keep pets from getting exposed and keep exposed pets away from people, then we reduce the risks – if there are in fact any – even further.
What about livestock?
This is another “we don’t know” topic. A recent study suggested that pigs, ferrets and cats may have cell receptors to which the COVID-19 virus can bind. The ability of the virus to infect livestock of various kinds is being investigated experimentally so more information will presumably be available in the near future. For now, the messaging is the same as for pets: if you’re infected, stay away from livestock. That means staying out of the barn, if at all possible, and having someone else care for your animals for a couple of weeks. If you are healthy but may have been exposed to COVID-19 (i.e. you are self-isolating), it is still best not to be in the barn at all, but if you must then avoid close/direct contact with the animals and practice good hygiene (e.g. covering coughs, hand hygiene) just as you would around other people.
Can pets transmit the COVID-19 virus via their haircoats?
Maybe. Haircoats are probably similar to other hand contact surfaces (but more mobile). If someone is infected and touches or coughs on their pet, it’s reasonable to assume the virus could be deposited on the coat. How long it survives there isn’t known, but it’s presumably going to be able to persist for hours, if not more. At this point, that’s one of the main reasons why we want infected people to limit contact with pets and use good hygiene.
Risk of infection to the owner during “hand-off” of the dog.
- This is low risk (assuming neither party has any clinical signs of illness), and keeping 2 meters (6 feet) apart during when the dog is picked up and dropped off would make that risk negligible (i.e. stay hands-off during the hand-off).
Potential contamination of the outside of the dog (e.g. fur).
- If the dog’s coat were to be contaminated with the virus, even if the dog isn’t infected it can still act as a fomite, just like a doorknob or any other hand contact surface.
- This would be a concern if the owner or walker was infected and shedding the virus. Making sure neither has signs of COVID-19 would be a good first step. It’s not a guarantee but if both are healthy, the risk that one is shedding the virus would be low.
- Focusing on good hand hygiene (as much as possible before and after touching the dog) would help too, in case either one is unknowingly shedding the virus but not sick.
- Personal protective equipment (e.g. masks, gloves) is probably of limited use in this scenario, and also a waste of what has become a very limited resource. Masks and gloves don’t do much in a lower risk situation like this, particularly since people tend to use them improperly. Even when used correctly, surgical masks mainly help prevent people from spreading the virus over short distances when they breathe or talk. They’re of limited benefit when you have a quick interaction at a reasonable distance between people who are apparently healthy. Masks are now also in short supply, so we want to save them for the situations when they’re really needed/can be of benefit.
Dr. Frank Richardson, DVM, MBA