Thursday, January 10, 2019

Human Diseases Cats Can Catch

Human Diseases Cats Can Catch

Some of the media hysteria around community cats focuses on diseases they could supposedly inflict upon the human population. But in reality, cats cannot transmit many diseases to fact, they are far more susceptible to being infected with human diseases than the other way around.

This recent article was far more balanced in its report of a cat diagnosed with bubonic plague in Wyoming. It stated, in part:

The cat fully recovered from the infection, according to a spokesperson for the Wyoming Department of Health, and with modern antibiotics and treatment, plague infections pose no major threat – certainly nothing close to the ‘Black Death’ which wiped out millions of people during the Middle Ages.

Well, that's certainly a relief!

What do we need to know about keeping our cats safe from human diseases, especially at the height of cold and flu season? Here's what we found:

Types of Infections

Our bodies and our cats' are both susceptible to invading pathogens that fall into five main classifications:
  • Bacteria - these include things like salmonella, listeria, e. coli, strep throat, tuberculosis, gonorrhea, and one form of meningitis.
  • Viruses - these are smaller than bacteria and cause diseases such as the common cold, AIDS, herpes, and shingles.
  • Fungal infections - These cause problems such as athlete's foot, ringworm, and jock itch.
  • Parasites - We mainly think of worms with these: hookworms, roundworms, and tapeworms, but animals such as fleas, ticks, and mosquitoes are also parasites that spread diseases.
  • Allergens -  While not technically pathogens, allergens could be any substance to which an individual has sensitivity. Certain foods, dust, dust mites, and pollen all fall into this causative category.
We (or our cats) can also become ill from a combination of two types of invaders. Only lab testing can determine the cause(s) of symptoms. Once that is determined, a course of treatment can be prescribed.

What Human Diseases Can Cats Catch?

When cats catch a disease from a human, it is known as zooanthroponosis or reverse zoonosis. A 2014 paper listed on the National Institutes of Health website commented that an increasing number of reports are emerging of animals being infected with human diseases. This makes sense, as our invasion of previously wild spaces for development means we are interacting more commonly with wild animals. Pet ownership keeps going up, which puts more people in close proximity to more domesticated animals. And more funding is being directed toward studying pet illnesses, so we're aware of many more connections than we used to be.

The main concern of the report listed above was animals in the food chain being infected. But since cats are obligate carnivores, it stands to reason that a threat to the health of animals raised to be meat would also threaten the cats that eat their meat.

Some of the diseases cats can catch from us are those that go both ways: we can infect each other with them. Here's a rundown of the most common zooanthroponotic diseases:

Bubonic plague

As the recent Wyoming cases illustrate, cats are mammals and can catch this disease that can infect all mammals. Luckily, it is easily treatable with antibiotics, but swift action is necessary to prevent death. If you suspect that your cat has been exposed to it, a visit to the veterinarian is in order.


While cancer itself is not transmitted between individuals, if you smoke and your cats are exposed to secondhand smoke, they can get cancer from it. Not only lung cancer, either: since cats groom all the time, it's even more common for them to develop oral cancers from licking all those carcinogens off their coats. Because cats are so much smaller than we are, secondhand smoke poses a far greater risk to them than it does to us humans. Proportionally, they are receiving a much higher dosage of the carcinogens in smoke.

Vaping is popular now as a less-stinky alternative to cigarettes, but even that involves carcinogens. It has not been around long enough for us to yet know the long-term consequences of vaping.


Depending on the virus that causes your symptoms we define as a cold, your cat may catch it from you. Exotic breeds such as Bengals seem to be at higher risk of this.

Several types of viruses can cause colds. Many come from the rhinovirus, which does not seem to affect cats. But they can catch to the coronavirus from humans, if that's what is causing you to sneeze.

Cold symptoms in cats, however, are most often caused by other viruses that are not the same as the human cold viruses. These include the feline herpes virus and the feline calicivirus.

E. coli (Escherichia coli)

This bacterial infection has been the subject of several pet food and meat recalls. If you happen to get it from eating or handling raw or undercooked meats, you can transmit it to your cats. And if you feed your cats a raw diet, there's always the risk that the meat could carry some contamination.

Giardia (giardiasis)

Contaminated water is typically the source of this bacterial infection. If your children have been playing in streams or rain puddles and come down with a case of diarrhea, it could be the cause. If your cats have been out there with them, both could become ill, or the sick children could infect the cats.

Influenza (the flu)

A cat in Oregon became infected with the H1N1 flu virus in 2009. This was the first recorded case of a cat catching the flu from a human. The poor kitty developed pneumonia secondary to the flu infection and died in the hospital. 

Because there are so many different strains of influenza virus -- they morph even within the same year, so that a vaccine never protects a human against every strain that may be circulating that year --cats may be more susceptible to some than to others. This susceptibility could differ based on each's cat's individual physiology, just as with humans.

Flu symptoms in cats are similar to those in human, mainly respiratory. As with most cats when they are sick, your cat may not want to eat. 

MRSA (methycillin-resistant staphylococcus aureus)

Cats who have contracted this strain of bacteria usually lived with healthcare workers who had contracted it in a hospital setting, or with people who had recently been in the hospital themselves. Symptoms of MRSA in a cat could include fever, no desire to eat, skin abscesses, infections in the eyes, ears, or respiratory system, skin lesions filled with pus, and itching.

Ringworm (dermatophytosis)

This may be called ringworm, but it is not actually a worm. It is a fungal infection that causes a little itchy, dotted red circle on the skin. A cat will likely lick off the hair in the itchy area and cause a bald patch. Cats can get this if they come into direct contact with a person who has the fungal infection. 


Cats are more resistant to this bacteria than are humans, but that doesn't make them immune to it. It attacks the digestive tract, where kitty's symptoms would be similar to yours: nausea, vomiting, diarrhea, fever, and stomach cramps.

Tuberculosis (TB, Myobacterium tuberculosis complex)

TB was commonplace in past generations, when people infected with it either died or were sent to a sanatorium to recuperate. If a person survived, they were usually immune to the disease for life. Fortunately, a vaccine virtually eradicated the disease. However, with the anti-vax movement in today's society, it is again a concern.

Symptoms of TB in cats are similar to those in humans: primarily coughing and unexplained weight loss that may be accompanied by lesions or abscesses. The possibility of cats contracting TB from humans is believed to be very slim.

Cats can catch TB from infected humans, but also by eating the meat of an animal that was infected with it or from drinking cow's milk that has not been pasteurized if the cow was infected. Since "raw" cow's milk is often sold at local green markets as a healthier alternative to that sold in grocery stores, your cat could be exposed if any of the dairy cows giving that milk had TB. (Cats should not really drink cow's milk, anyway, as they are not typically able to digest it well and it can lead to diarrhea, but some say their cats can drink whole cow's milk without incident.)

What to Do if You Suspect Your Cat Has Caught a Human Disease

Obviously, your first step would be a trip to the veterinarian to make sure. Tell the vet about your concern so it can be considered when assessing the cat's condition. And understand that many feline diseases can exhibit the same symptoms as human diseases caused by a different pathogen or condition.

We once had a cat who exhibited intestinal distress and would moan with it sometimes. My mother commented that he "sounded like he was lovesick." Our vet at the time diagnosed him with pancreatitis and treated him for that, putting him on a special diet he'd have to remain on for life. The truth was much worse: he was in the second stage of F.I.P., a fatal and mysterious virus that infects cats (but not people). Only once the third (final) stage arrived did we know this, since there was no reliable medical test or treatment for F.I.P. at that time.

Your vet can do the necessary lab work to verify what is affecting your cat, even if you're certain the symptoms look like a disease someone else in your family recently had. This is not the time to self-diagnose. Let your vet and the lab techs do what they were trained to do.

Once back home, make sure your kitty's bedding area and potty are kept clean. Make fresh water available to kitty and encourage drinking plenty of it by using a fountain to give it some motion. A lot of cats don't want to eat when they're sick, but encourage the cat to eat by serving kitty's favorite meal. If the air is dry, consider using a humidifier...but do not diffuse essential oils, as many of those can be harmful to a cat's liver; with the cat already fighting off one infection, compromising the liver could prove fatal. And give your cat plenty of time to sleep, as this helps the body heal.

Depending on the diagnosis, there may be some natural or homeopathic supplements to help your cat recover. Make sure you discuss these options with your vet, so they don't interfere with or amplify the effects of any prescribed medications. Some allopathic vets are skeptical of herbal and homeopathic remedies, so make sure you and your chosen vet see eye to eye on that issue if you like to use the natural supplements.

How to Protect Your Cat From Human Diseases

Obviously, those who work with cats in veterinary clinics, shelters, breeding facilities, or rescue groups must maintain the cleanliness of those facilities and refrain from being in contact with the cats if they have any of the above-listed illnesses. Most of these facilities keep wall dispensers of hand sanitizer nearby, but using this is no substitute for thorough hand washing when handling the cats or their waste.

If you have any of the diseases mentioned above, try to prevent your cat from sleeping in the bed with you. This is easier said than done, as our cats tend to want to give us their healing purrs when they sense that we are sick. Hopefully, you have other family members who can care for the cats and distract them while you recuperate.

If someone in your human family has developed symptoms of one of the intestinal infections listed above, wash your hands frequently and avoid touching your cat. Keep kitty out of the bathroom when you are in there...again, easier said than done, but try. Keep the cats clear of the infected human and make sure the person's hands are clean. Disinfect clothing and household surfaces.

To avoid giving your kitty tuberculosis, avoid giving your cat unpasteurized cow's milk and be careful of where you source any raw meat you feed your cats.

In general, the same hygiene practices that protect us from spreading diseases between humans also protect our cats: frequent and thorough hand washing and a little extra care taken when sick not to expose your cats to the disease. The same goes for if you visit a sick person in the hospital, are hospitalized yourself, or work in a hospital.

If your cat is under additional stress (from things like moves, construction noise, grief, or household changes), you may consider giving kitty an immune-boosting supplement. While this won't prevent your cat from being exposed to diseases, it can help minimize the impact of any infections, helping your cat recover more quickly and with less severe symptoms.

How to Protect Yourself from Feline Diseases

If you keep yourself healthy, there's less chance of your spreading any type of disease to your cats.

Obviously, if you're fostering or adding a new cat to your household, keep the newcomer separate from your other cats and avoid too much contact until the cat has a health check by your vet. This will protect both you and your other feline companions.

Whenever you handle cat waste or food, always wash your hands thoroughly with soap afterward. And don't just run them under the water, spend a little time rubbing the soap all over the palms and backs of your hands, between all your fingers, and around your nails, to get to all the pathogens that may be present. I have read that singing the song "Happy Birthday to You" through while you're washing will keep you at it for the recommended amount of time. Washing your hands will take care of 90% of the danger of any infection from any diseases your cat may have.

Keep your household clean, as well: vacuum frequently and disinfect food surfaces daily and floors periodically. Completely empty and disinfect the interiors of litter boxes monthly, and refill them with fresh, clean litter. You can scoop and replace litter in between times, but toss it all when you clean the inside of the box.

It seems like new human diseases are being discovered all the time these days. Knowing which of them pose a risk for our cats is important. Armed with that knowledge, we can take the appropriate steps to protect our feline companions from harm.

Sources: Bradley S. Schneider, editor, "Reverse Zoonotic Disease Transmission (Zooanthroponosis): A Systematic Review of Seldom-Documented Human Biological Threats to Animals" on PLoS One, February 28, 2014; Pete Wedderburn, "Eight diseases that pets can pick up from people" in The Telegraph, September 26, 2017; Sylvia Booth Hubbard, "5 Illnesses You Can Give to Your Pet" on Newsmax June 17, 2015; "Can Cats and Dogs Catch Cold From You?" in Reader's Digest Best Health magazine. 

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