While pets bring their owners much joy, they can also pass on diseases, some with symptoms that might not be noticeable at first. More than 100 infections can be transmitted to humans from domestic pets. But taking precautions can help prevent many of those infections, including three of the most common.


About 14 percent of Americans are infected with Toxocara, or internal roundworms, which are transmitted by the feces of cats and dogs. See your vet if you notice worms in your pet’s stool or if your cat or dog develops a potbelly.

Your symptoms: Roundworm larvae that travel through your body can trigger fever, coughing or pneumonia.

Pet prevention: Follow your vet’s instructions for deworming kittens and puppies, since many are infected at birth or while nursing. Pick up dog droppings around your yard to keep worm eggs from accumulating in the soil, and wear gloves when gardening.


Don’t let the name fool you. Caused by a fungus, it’s reported to be the most common condition people contract from cats. It can also affect dogs. The fungus looks like dandruff on your pet’s fur.

Your symptoms: An itchy, circular rash with a reddish border will usually appear within a week or two of exposure, often on your hands or face. If the infection is on your scalp, you might lose some hair. Treatment calls for an oral or topical antifungal medication.

Pet prevention: If your cat or dog develops a bald spot or crusty skin, see your veterinarian for treatment.


Reptiles and amphibians are the riskiest pets to own because they naturally carry salmonella in their digestive tract.

Your symptoms: Abdominal cramps, diarrhea and fever. A salmonella infection can be life-threatening to children, the very old and those with weakened immune systems.

Pet prevention: Use bleach to disinfect the tub or sink after cleaning aquariums and supplies, and always wash your hands after touching those pets.

But wait, there’s more

Ticks can transmit dangerous blood-borne diseases to both pets and humans, according to Lynne White-Shim of the American Veterinary Medical Association. They include Lyme disease, Rocky Mountain spotted fever and babesiosis.

Fleas don’t tend to bite humans if there are animals around. In severe cases, fleas can suck enough blood from a cat or dog to cause anemia. And pets can get tapeworms if they swallow larvae-infected fleas during grooming.

How can you keep fleas off your cat or dog, and how can you tell if some have made their way on?

Animals often get fleas from one another, so pets that are out and about with other animals are at a higher risk than pets that hardly ever leave the house. There are many flea-prevention products on the market; your veterinarian can help you choose an appropriate one.

If you opt not to use a preventative, you need to check for fleas on your cat’s or dog’s belly. Obviously, if your pet starts to itch, that’s a bad sign. You may find “flea dirt” — flakes of flea excrement — on your pet’s fur or skin. To verify that it’s flea dirt, put some on a paper towel and moisten it. If it turns red – from the blood the flea sucked from the cat or dog – it’s a sign of fleas.

There are also tick preventatives, some in combination with flea preventatives; again, you need to talk to your vet about what might be appropriate for your pet. After walking your dog in the woods or high brush, closely examine the dog — and yourself — for ticks. If any have attached, use tweezers to grab the tick as close to the skin as possible, and pull it straight out without twisting. If you notice that your dog is limping or acting tired or weak after a tick bite, tell your vet about it. Note that outdoor cats can get ticks, too.

Copyright 2011. Consumers Union of United States Inc.