Maybe dogs – but only by a hair. The message from experts in zoonotic diseases – infections spread between animals and people – is that both dogs and cats are not only safe to live with, but actually enhance human health.
Many of the germs carried by pets are far more likely to be transmitted through contaminated food or water than from a pet, according to the federal Centers for Disease Control and Prevention. And the benefits of pet ownership are legion – lower blood pressure, reduced stress, even better social lives, says Dr. Lisa Moses, a veterinary internal medicine specialist at MSPCA Angell Animal Medical Center in Boston.
“The reality, fortunately, is that transmission of infectious diseases from pets to people is a relatively rare event,” agrees Dr. Ed Dubovi, a virologist at Cornell University College of Veterinary Medicine.
Dogs may have a slight safety advantage because they have no part in the zoonotic disease experts worry about most: toxoplasmosis, a parasite that pregnant women can pick up from cleaning cat boxes. The parasite can cause birth defects, but can also lie dormant for years; if it then becomes activated in the brain, it can cause blindness.
On the other hand, the bigger risk of “toxo” comes from contaminated meat or soil, which makes gardening while pregnant more risky than cleaning cat boxes.
Dogs are not entirely risk-free. The salmonella bacterium – present in some dog biscuits made with tainted peanut butter – can wind up in dog feces, just as it can with cats. So can campylobacter (a bacterium that causes diarrhea). Giardia in humans usually comes through exposure to contaminated water, but it does exist in dog and cat feces; and dog urine can contain leptospirosis (a bacterium that causes high fever and, potentially, kidney damage and meningitis).
As for bites, dogs are seen as the more frequent offender. But cat bites cause worse infections because cats have sharper teeth and their saliva contains more bacteria.
Bottom line? Pets are great. Just wash your hands after cleaning up.