For me, there are few things in life that can beat the comfort of snuggling with my pet cats—and I’m not alone in feeling that way. At least 30% of US households have at least one kitty roaming through it. They’re cute and can have a therapeutically calming effect on us.

But there are also risks—big risks—to sharing space with cats. Richard O’Brien, MD, an emergency physician based in Scranton, Pennsylvania, admits that he loves cats and has had a few himself, but he’s also seen firsthand how dangerous they can be. How can your own pet cat hurt you? Dr. O’Brien and I tallied up the six ways your cat can make you sick—or even kill you—and what you and your family need to know to protect yourselves.

By mouth and teeth.

A cat’s mouth is a literal reservoir of bacteria, and you might have had firsthand experience of how very sharp the slender pointy teeth of a cute little cat are. If you’ve been bitten by a cat and didn’t get a raging infection, consider yourself lucky. Puncture wounds from cat bites usuall arey very deep, sending bacteria deep into human flesh as if by needle injection. “Because of the shape of the cat’s teeth, the deepest part of the wound also is7 the narrowest, so it’s virtually impossible to clean the wound before it starts closing up,” said Dr. O’Brien. “It’s the perfect set-up for a nasty infection.”

Because about 90% of cats carry a type of infectious bacteria called Pasteurella multocida, which can cause severe skin infections that can even spread to the heart (endocarditis) or protective tissue of the brain (meningitis), Dr. O’Brien treats every cat bite he sees with antibiotics—and a tetanus shot, too, if the bitten person hasn’t had one in the past 10 years.

Many people who have been bitten by cats wait until redness and swelling start to appear before they decide to seek treatment, but by then it may be too late. P. multocida infections can worsen and spread very fast—within 24 hours. The hand is particularly vulnerable because of how many bones and tendons are in it—all within easy striking range of little kitty. “You can be bitten on Tuesday and by Thursday, already have a severe enough infection that hand function is compromised,” said Dr. O’Brien. Bottom line: When a cat bites, see a doctor right away for appropriate treatment.

A note about rabies…Although it’s reassuring to know that the rabies virus, which is transmitted in the saliva of an infected animal, is rare in domesticated cats, all bets are off for feral or stray cats. This makes bites from strays, or just outdoor cats, a medical urgency—meaning you don’t need an ambulance or emergency room visit, but you do need to get to a doctor as soon as possible. If you’ve been bitten by a cat and are not absolutely sure that it has been vaccinated against rabies, thoroughly wash the area with lots of soap and water and contact animal control, which will try to locate the cat and find out whether it’s healthy or rabid. If there’s any doubt about the creature, you’ll need to be vaccinated for rabies within 10 days after the bite. “Untreated rabies is fatal, period,” Dr. O’Brien said, so it’s wise to take any cat bite very seriously.

By claws and paws.

As you know from watching cats preen, they always have their paws in their mouths. A cat scratch can transmit bacteria that was originally in the cat’s mouth to your skin. Usually, superficial love-tap scratches can be successfully cleaned with soap and water and then covered with antibiotic ointment for good measure. But a puncture wound from a cat’s claw should be treated with prescription oral antibiotics for many of the same reasons mentioned above.

A note about cat scratch fever…About 40% of cats carry Bartonella henselae, the bacteria that causes cat scratch fever, which can be transmitted to humans not only by cat scratch but by a cat or flea bite as well. Common symptoms include bumps or blisters and/or swollen glands around the wound and, as the name suggests, fever. Although antibiotics are sometimes used to treat cat scratch fever, it often goes away on its own, but why not do what you can to avoid it altogether by remembering to thoroughly wash even simple cat scratches and daub them with a basic antibiotic ointment, such as bacitracin or bacitracin/polymyxin (Polysporin).

By fleas and ticks.

Both fleas and ticks can transmit nasty bacteria, viruses and even parasite larva, but only if they’ve bounced off an infected animal and onto you. “The biggest risk from fleas,” said Dr. O’Brien, “is a very itchy rash from a mass of flea bites. If your cat has fleas, then your house has fleas, and they’re very hard to get rid of because they breed abundantly, frequently and exponentially. If they are left unchecked, you could have many thousands of them in your home and yard. Avoiding them in the first place is much easier than trying to rid your carpet, upholstery and bedding of them, which might require the services of a professional exterminator to be sure that you’re safely rid of them. So garland kitty with a flea collar and examine the cat regularly, especially outdoor cats, to make sure fleas aren’t hitching a ride on them.

As for ticks, you know they can carry Lyme disease—among other diseases that can infect humans—and they can take a ride from your outdoor cat to you. Doing what you can to protect your cat from ticks by, for example, using a flea and tick collar is good for your health and safety, too.

A note about tapeworms…You can be infected with a tapeworm from a cat if a flea that’s got tapeworm larvae attached to it ends up inside you. Yuck! How’s that going to happen? Well, since tiny fleas can be missed by the naked eye and are always jumping into airborne flight, they can end up wafting into a person’s mouth—usually that of a child—where they are unwittingly swallowed, allowing tapeworm larva to travel through the digestive tract to set up camp in the intestines.

As gross as it sounds, the type of tapeworm infecting most cats in the US, Dipylidium caninum, generally doesn’t cause sickness in humans if ingested via an infected flea but just passes out in stool. If there are symptoms, they include stomach pain, diarrhea and anal itch. Fortunately, the tapeworm infection is easily treated with the prescription antiparasitic medication praziquantel. (The human formulation of this drug is marketed as Biltricide and the cat formulation as Droncit.) So for the health of your cat and home and for peace of mind, get your cat to a vet for treatment if it has symptoms of tapeworm infection, such as gassiness or passing tiny worms in the stool. And if you want to be really careful, have your cat examined for tapeworm during an annual vet exam.

By poop.

Up to 40% of domestic cats host a tiny parasite called Toxoplasma gondii, responsible for a flulike infection in humans called toxoplasmosis, which can lead to very serious complications in certain people. One way that humans are exposed to T. gondii is by cleaning cat litter boxes, as the parasite passes out of kitty in its feces.

The good news is that, if your body has already encountered T. gondii and fought it off, as is the case with about one-third of Americans, you’re immune to it and probably never knew that you came across the critter in the first place. The bad news is that it can do damage in people with compromised immune systems, such as transplant patients or people with cancer or HIV infection, so they should steer clear of litter box areas. And as you probably already know, pregnant women are warned to stay away from cat litter because, if they become infected, the infection can cross the placenta and cause neurological and eye problems in the baby.

But T. gondii isn’t the only disease-causing nasty thing in cat poop. Cat feces also harbors infectious bacteria such as Salmonella and Campylobacter, most famous for causing stomach and intestinal infections. Although getting these kinds of infections from cats is uncommon, Dr. O’Brien suggests that animal waste be handled like any hazardous waste. “Ideally, use gloves when cleaning the litter box. If you can’t bother with this, at least wash with soap and water immediately afterward.” Because cats—including strays over which you have no control—are also doing their business outdoors, you ought to also wear gloves when doing yard work and thoroughly wash your hands right after, he added.

By dander.

About 10 million Americans, including some cat lovers and owners, are allergic to cat dander, the tiny flecks of skin shed by the animal. Allergic reactions can range from watery eyes to severe breathing difficulty. It’s virtually impossible to remove cat dander from a home that a cat lives in, so cats should never be allowed in a home with someone who is allergic to them. You also can never know where you will encounter cat dander, so if you’re allergic to cats, it might be a good idea to carry an antihistamine with you and, if you have asthma, make sure you have your inhaler within reach.

By cuddling.

Yep, even cuddling with your cat can be hazardous to your health, believe it or not. For one, cats can harbor fungi that cause ringworm and can do so whether they themselves have symptoms of ringworm or not. Ringworm symptoms in both humans and cats include an itchy, scaly, bumpy rash that spreads with a ringlike formation at the borders. Cats also can easily pick up ringworm from infected people, so to keep ringworm from spreading if someone in the family has it, treat your cat as well. Also, if the ringworm in a pet or person is severe or keeps coming back, you’ve got to treat your house for ringworm, too. Tips to get the fungus out of your house include…

• Vacuuming daily (throw out the vacuum cleaner bag after each vacuum).
• Washing hard surfaces and cat-grooming equipment with diluted bleach (1.5 cups bleach per gallon of water)
• Steam cleaning carpets and soft furnishings
• Using disinfecting cleaners for bedding (yours and kitty’s) and kennels.

Another cuddling hazard is bed-sharing with a cat. Dr. O’Brien was very firm about this danger—never let a cat sleep with you or a child, he said. It isn’t because you or your child will be smothered, as folk wisdom tells us (although this has happened). The risk is simpler—the cat might scratch or bite while you’re sleeping. Why would your darling kitty do such a thing? A sleeping cat might startle and reflexively extend its claws when you turn over in your sleep. If you’re sleeping face-to-face with a cat, you could even end up with a corneal abrasion and infection that threatens your eyesight.


Despite all these dangers associated with cats, Dr. O’Brien is certainly not suggesting we banish our furry friends from our homes. First, remember that they’re animals uniquely made to react to stimuli in certain ways—usually to protect themselves. Respect that, and don’t test a cat’s limits of composure (or let a visitor do so). Also, protect your pet, yourself and your household by controlling for fleas, ticks and infections…setting boundaries about contact (such as keeping cats out of your bed)…and keeping up with vaccinations for a long, happy life with your animal companion.