Oh No, I’m Sick! Could I Infect My Pets?

Sometimes yes, sometimes no. Here’s what diseases may spread from you to Fido.

Table of Contents

· In most cases, feel free to cough around Fido ∘ For dogs ∘ For cats · What about zoonotic diseases, though? Isn’t that how COVID got started? · In summary: You and your pet are able to commiserate together when sick

Normally, I love my cat, but he can be quite the nuisance when I get sick. I’m over on the sofa, hacking up a lung and blasting gallons of snot into tissues, and he’s meowing angrily at me because it’s only forty minutes until his dinnertime, and what if I somehow forget he exists?

“You’re lucky,” I snarl at him through my congestion. “You don’t feel like death right now.”

But as I haul my aching body up and trudge to the kitchen to feed the little king his nightly meal of meat goop, I wonder if I should be more careful about him. Do I need to concern myself with not sneezing directly on my cat? Is it possible for him to catch my illness?

Similarly, if a dog comes home from the park with a cough, should his owners be worried about the disease spreading through the whole family?

Let’s talk cross-species transmission, and see whether we should worry!

In most cases, feel free to cough around Fido

Thankfully, before we dive into specific diseases and details, we can quickly share the general consensus: cross-species transmission is usually fairly rare. There are a class of diseases that are known for crossing the species barrier, called zoonotic diseases, but most of the everyday commonplace diseases we pick up aren’t going to easily cross to your pet.

Why not? You’re both mammals, both breathing the same air, both living in the same space… why wouldn’t a pet get your diseases, and vice versa?

The answer comes down to specificity, and whether the payoff of “going wide” is worth the risk.

Many of the diseases that we catch — the common colds, the yearly flu, the hand, foot, and mouth disease that my young son is at risk of bringing home from his daycare — have all spent many years circulating in humans. These diseases are passed from one person to another, constantly evolving through Nature’s trial-and-error process to find new variations that evade our immune system without losing their potency and ability to quickly replicate and spread.

But a human system, while overall pretty similar to a dog, is not identical. Human and dog immune systems will respond slightly differently, will look for different markers on the virus. And humans and dogs don’t interact at the same frequencies; a human may have twenty face-to-face interactions a day, but a dog has only two or three face-to-face interactions.

For dogs

Colds: Dogs do get colds, but the viruses that cause the common cold in dogs are different from the ones that cause the cold in humans, and so you cannot give your dog your cold.

Flu: Again, human-flu viruses and dog-flu viruses are similar but not identical, and they don’t work interchangeably. Your dog is safe from your flu.

Stomach illness: Potentially. Dogs carry a bacterium called Campylobacter jejuni in their feces, which can cause stomach pains/food poisoning in humans. Dogs have occasionally picked up norovirus from sick humans, but it’s uncommon (4/92 tested animals in a Finland study).

COVID: Yes, but it’s rare (only a handful of documented human->dog COVID cases), and pets seem to have very mild symptoms.

Chicken pox: No.

Herpes: There is a dog strain of herpes, but it’s species-specific; you won’t give your pet herpes through kisses, and vice versa.

For cats

Colds: Again, while cats can get their own colds, the virus is species-specific and your cat won’t get your cold.

Flu: Yes, it’s semi-common for cats to pick up a human influenza virus. However, it’s rarer for a human to get the flu from a sick cat, and influenza in cats is usually fairly mild.

Stomach illness: Yes, cats can commonly pick up Rotavirus from humans, which causes stomach pains and severe diarrhea. Again, it’s less likely for you to get a stomach bug from your cat as long as you maintain good hygiene, especially after cleaning their feces/litterbox.

COVID: Yes, there have been recorded cases of cats getting COVID from their owners, but the rate is very low and the illness is mild in the cat.

Chicken pox: No.

Herpes: Similar to dogs, cats have their own specific strain of herpes and it doesn’t jump from cats to humans or humans to cats.

What about zoonotic diseases, though? Isn’t that how COVID got started?

In many cases, we can continue relying on our pets for love and comfort when we’re sick, but there are still plenty of diseases that have shown the ability to cross the species barrier.

Earlier, I talked about why it’s risky to jump species, for a disease — you will have to evolve to be more general to infect the new species (which means easier for the immune system to catch), you don’t know about the population density of the new species, and you may not be able to evade the new creature’s immune system.

But there are also benefits to hopping into multiple different species: there are more total creatures to infect. Many times, the initial hop is random, occurring when humans and an infected creature are in close proximity.

Most zoonotic diseases that can infect both us and our pets tend to be parasites, or carried by parasites. These include:

• Worms, like roundworms, ringworms, hookworms, and tapeworms
• Mites and scabies
• Giardia (a parasite found in infected water, and why you shouldn’t drink from those “pure” mountain streams in the wilderness)
• Bacteria associated with food poisoning, like Salmonella, Campylobacter, and Leptospira
• Rabies

Despite there being a number of zoonotic diseases, most of us with pets are not at a high risk of having any of those diseases jump to us — or even get into our pet, as long as we both practice reasonable hygiene.

Regular baths, avoiding contaminated water, and maintaining good hygienic habits will help both us and our pets avoid picking up these parasites. For cats, especially, keeping cats fully indoors is the best move (both for parasite avoidance, and to help protect the populations of local wildlife!).

In summary: You and your pet are able to commiserate together when sick

When we’re sick, we feel terrible, and a bit of “fur therapy” can sometimes help us temporarily forget about the sniffles, runny nose, head congestion, rough and itchy throat, and any other symptoms we may be feeling.

Overall, don’t worry about potentially infecting your pet if you’re suffering from a fairly common ailment, like a cold or the flu! There is a small chance of passing a flu virus onto your pet, especially if you are suffering from COVID and if you have a cat. However, even if you do infect your pet, the disease tends to be fairly mild in pets (and they won’t hold you to blame for getting them sick!).

The most common diseases that are zoonotic, meaning that they can cross between different species, are parasites. It’s highly unlikely that we’re going to pick up the next COVID or HIV from associating with a pet, especially if we practice good hygiene for both ourselves and our animal companion.

(Additionally, our pets are not reservoirs of disease in the same way as bats and some other wild animals.)

So go ahead! Hug your dog, stroke your cat, and focus on recovery, without worrying about giving them your diseases!

Up next, read about how we’re vaccinating bees — no tiny needles needed.

Enjoyed the story? Consider sharing it on Twitter — you can tag me @swestreich with your thoughts.

Not yet a paid Medium member? Consider joining: you can read unlimited articles, and you can earn money if you try publishing your own articles. Use my referral link and you support my writing, at no additional cost to you: