Pets Can Share More Than Their Love With You

Cats, dogs, chickens, snakes, can transmit all sorts of bacteria to humans. Children and older adults are more susceptible to complications

By Eva Briggs, M.D.

Last summer I attended a canine carnival event at Jamesville Beach. One of the exhibits was a snake. To the dismay of the snake handler, I declined to pet her beautiful beast. Not because I am afraid of snakes, but because I’m aware that reptiles can carry the bacteria salmonella.

Salmonella infections aren’t fun. At best, it causes abdominal cramps, severe diarrhea, fever and sometimes vomiting. The acute illness lasts for several days but infected people can spread the germs for months afterward. People — especially kids under 5 and adults over 65 — can wind up dehydrated and hospitalized. At worst, the infection can invade the bloodstream, bones, joints, brain or nervous system.

More than 1 million people in the U.S. develop salmonella every year and 450 die of complications related to it. To be fair, most of those cases arise from contaminated food. And you can also catch salmonella, as well as the diarrheal illness campylobacter, from your pet chicken.

As much as I love pets, there are a few diseases you can catch from your companion animals. Two common illnesses transmitted by cats are toxoplasmosis and cat-scratch disease.

“The most important ways to keep from catching an illness from your pets is to keep your animals current on veterinary care.”

Toxoplasmosis is a single-celled parasite. Infected cats secrete oocysts that contaminate cat litter. A person who inadvertently gets the cysts on her hands, touches her mouth and swallows can be infected. Other ways to catch toxoplasmosis are eating contaminated food or undercooked meat. Most people never develop symptoms, or develop a flu-like illness with muscle aches and swollen glands lasting up to a month. A few people, often but not always patients who are immunocompromised, can develop infections of the brain or eyes. The unborn can be infected though the placenta by an infected mother. These fetuses may die, or develop permanent damage to the brain, or eyes.

Cat-scratch disease is caused by the bacteria Bartonella henselae. This bacterium is spread by cat claws contaminated with flea feces. Symptoms include fever and enlarged lymph nodes days to weeks after a cat scratch.

Dogs, my personal favorite pet, can spread infections too. Ringworm, a fungal infection, can be spread by direct contact with infected pets. Affected animals usually have patches of hair loss with redness, itchiness, scaling or scabs. People develop ring-like red scaly spots. Dogs can also have mange caused by the mite Sarcopties scabiei var canis. This is the dog form of scabies, and the mites can cause human scabies.

Fortunately, dog scabies mites prefer to live on dogs, and treating the dog will cure humans infected with the canine version of the scabies mite.

Your dog or cat can bring home ticks. There is the small chance that a tick harboring a disease will crawl from your pet onto you, or fall off your pet onto the floor where you will pick it up. But most ticks are acquired from the outdoor environment. Even if your pet becomes infected with a tick-borne disease, he or she probably won’t spread the disease to you. And there are products available to reduce your pet’s chances of acquiring fleas and ticks.

Leptospirosis, a bacterial illness spread through urine, can infect individuals exposed to the urine of infected dogs and wildlife (especially rodents), or from contaminated water. Symptoms include fever, chills, muscle aches, headaches, nausea, and vomiting. Fortunately, infected dogs usually don’t spread the illness to household human contacts. If your dog’s leptospirosis vaccination is up-to-date, he’ll be less likely to shed the bacteria in his urine if infected.

The most important ways to keep from catching an illness from your pets is to keep your animals current on veterinary care, to keep your animals and their environment clean, and to wash your hands with soap and water.

Eva Briggs is a medical doctor who works at two urgent care centers (Central Square and Fulton) operated by Oswego Health.