Can I get sick from my pet?

There are many benefits to having a pet in the home, but it’s important to understand the risks pets can bring in certain environments, including the potential – although rare – of getting sick from them. People should consider if having a pet is right for them and their environment before taking the plunge.

“There is not necessarily a category of pets that are safe or unsafe, but it’s important to remember where you’re getting your pet from and also have some awareness of the different types of organisms that might be associated with different animals,” said Dr. Stacey Rose, associate professor of infectious diseases and internal medicine. “It not only has to do with exposures, but also the host.”

Those with a weakened immune system should be more thoughtful about the potential exposures that are introduced by a pet, according to Rose. Household pets might harbor microorganisms that can potentially harm those at risk. Toxoplasma is an organism that can be found in cat feces, and some groups are at higher risk of infection: pregnant women, people with compromised immune systems related to HIV or people who have had an organ transplant and take medications to suppress the immune system. Hookworm can spread through dog stool, so it’s important to practice good hygiene by picking up after your dog and washing your hands.

The adage that human mouths are dirtier than dogs’ mouths might be true, but people frequently encounter bites and scratches from animals, which is a potential risk factor for the spread of infection as both dogs and cats carry bacteria in their mouths. A classic organism associated with bites, particularly from cats, is a bug called Pasteurella multocida. A less common organism called Capnocytophaga canimorsus is a bacteria found in the mouths of dogs. Those with a compromised immune system (usually related to liver disease or a dysfunctional spleen) can get into trouble with this organism and infections can even be fatal.

If your pet picks up a dead animal like a rat or opossum, oral contamination is not a big worry. The issue with pets spending a lot of time outdoors with other rodents or animals is not only the contact between animals, but also the small things like fleas and other insects that may feed off both the rodents and your household pets. This can lead to human exposures to infections such as Murine typhus, Rose said.

“You don’t have to have direct exposure with a rodent to be at risk; if your pets are galivanting with those other animals and the fleas are transferred from the rodent to your pet, then your pet can help transmit that disease.”

Bartonella henselae is another pet-borne bacteria that is the cause of cat scratch disease. The disease is mostly associated with kittens. If the kitten’s fleas are carrying the bacteria and the kitchen scratches you, the flea feces can be deposited into your skin. In kids or adults with a normal immune system, one might develop a big lymph node that will go away on its own. With a compromised immune system, that same bug can lead to far reaching diseases including bloodstream infections or infections of the heart or heart valves, or the eye, liver or spleen.

Some animals, such as reptiles, might carry salmonella. This can spread to humans if you don’t practice good hygiene. Young children, adults over 65 and people with compromised immune systems are at risk for severe infection.

Household pets also bring advantages to the home. Children with pets are less likely to have allergies because the continuous exposure trains the immune system to not stress so much when experiencing potential environmental allergens. Pet ownership also provides health benefits in regard to blood pressure and depression, playing a role in helping people self-soothe from daily stressors.

“There are plenty of reasons why we can and should have pets, but you just need be aware of your own immune system and the potential risks. Taking good care of your pets also matters, like keeping their environment clean and using flea prevention. We have to be conscientious pet owners for our own health and the health of our families and neighbors,” Rose said.

Learn more about Baylor Medicine Infectious Diseases. 

By Homa Warren