Zoonotic disease. Is that contagious to humans? With all the craziness going on right now with coronavirus, I get a lot of questions about things we can catch from our pets.
Although it isn’t very common and usually only an issue for someone with a compromised immune system (someone battling AIDS or on chemotherapy), there are things we can catch from our pets.
A zoonotic disease is something that can be passed to humans from another species. These diseases usually aren’t viral because viruses are usually species specific (meaning they are confined to one species and don’t jump over to a different species).
However, coronaviruses and influenza are two viruses that have evolved to jump species, and give them the ability to be pandemics (SARS, MERS, Influenza, HIN, and now Covid-19). This coronavirus probably started in bats, and then spread to birds and now humans.
Right now, there is no evidence that it has spread to dogs or cats.
So what is contagious? What do we, as owners need to worry about? The most common zoonotic diseases spread to us by cats and dogs are parasites. Again, this is going to be unlikely unless someone has a lowered immune system.
When cats and dogs have intestinal parasites, they pass eggs in their feces. If a child gets these eggs in their mouth, they can be infected by the parasite. We are not the preferred host, so these parasites will probably die, but there is a chance that the eggs will hatch and a larva can migrate to the eye or central nervous system. Hookworm eggs can hatch on the ground and the larvae can invade the skin if we are barefoot, and cause a red, migrating rash.
There are certain parasites called Coccidia that can infect us and cause diseases of the intestinal tract. These are found in feces from dogs, cats and chickens. Feces from chickens can also have bacteria that can affect our GI tract, causing severe diarrhea and vomiting, such as E-coli and salmonella.
Other bacteria called Bartonella can cause cat scratch disease. This can be passed on to humans with compromised immune systems by getting bitten or scratched by cats carrying these bacteria in their blood stream. This seems to be more common in kittens and is spread to the cats through fleas. The kitten will have no signs as a carrier, but humans will develop a fever, enlarged lymph nodes, fatigue, weight loss, headache, eye infections and a skin rash.
Cats can also spread Chlamydia, which causes an eye infection in cats and humans. As most cats aren’t tested when they get an eye infection, it is always a good idea to wash your hands after doing eye treatments. There are many other noncontagious reasons for eye infections, but since we don’t normally test for what the cause is, hand washing is always a good idea.
Most parasites on our pets’ skin (mites, fleas and ticks) are technically species specific, humans even have their own species of mites. However, if the preferred host is not available fleas, ticks and scabies mite will jump on humans and bite us. We can see fleas and ticks, but scabies is microscopic it causes an intensely itchy rash.
On our pets, there will be considerable hair loss and skin infections. Humans will get a red, pimply intensely itchy rash. They tend to like arms, legs (especially under the socks) and the bra and underwear lines. Treatment consists of permethrin cream, antihistamines and sometimes antibiotics.
Ringworm — which is actually not a worm— is another disease that can be spread by pets. It is a fungal infection called Tinea corporis. We actually get different subspecies of this fungal infection all the time. Tinea Cruris causes jock itch, Tinea pedis causes athletes foot and some dandruff is actually caused by Tinea Capitis. Most people have developed antibodies to “ringworm” as a child from playing outside in the grass and dirt, but if we catch it, it will cause a round, red itchy rash on the skin. Our pets will develop the same rash, but also have hair loss.
As stated before, most things that we can catch from our pets are usually a concern for those with an inadequate immune system or young children who haven’t developed their immunity yet.
However, it is always important to keep our pets free of parasites by using a preventative monthly and having the feces checked regularly at the vet’s office. And always pick up feces after they use the bathroom and wash your hands afterwards.
Dr. Lisa Silk is the owner and primary veterinarian at Isla Veterinary Clinic. Send feedback to firstname.lastname@example.org or call 477-7879