Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Pets Pose Health Hazards, Experts Warn

CATV, 11/27/2006

Few other relationships feature such a high degree of physical contact. Slobbering kisses. Frequent caresses. Sometimes even the sharing of a pillow at bedtime.

But chances are you don't let your toddler scarf back dog dung on a trip to the park, your husband doesn't shed Salmonella bacteria and your wife doesn't lap water from the toilet bowl before settling down beside you in bed.

There are some health perils to owning pets -- a fact many pet owners seem to prefer to ignore, often choosing unbridled affection over hygiene.

"People treat them like kids," says Dr. Bruno Chomel, an expert in zoonoses -- the diseases that pass from animals to humans -- in the school of veterinary medicine at the University of California at Davis.

"A healthy pet is a good pet. And I think the message here is that if you are taking good care of your pet, if it's regularly checked by a veterinarian, the risks are pretty low."

"On the other hand, yes, you are dealing with live organisms here. And they may bring back and carry home dirty stuff."

The list is impressive, ranging from skin conditions like ringworm to diarrhea-causing bugs like Salmonella, Campylobacter and maybe C. difficile to more exotic and health-threatening ailments like leptospirosis, toxoplasmosis and monkeypox, an animal cousin of smallpox.

"There's a litany of diseases that can affect people and pets," says Dr. Scott Weese, a veterinarian and scientist at the Ontario Veterinary College in Guelph.

"And they don't happen very often. But they do happen enough."

Weese specializes in the spread of antibiotic-resistant bacteria between humans and animals. He has just published a report of a domestic cat in California found to be carrying a dangerous strain of the superbug MRSA, short for methicillin-resistant Staphylococcus aureus. The cat's owner was colonized with identical bacteria from the sometimes fatal strain, called USA300.

Despite the fact he researches -- and gives talks on -- the health risks associated with companion animals, Weese if very pro-pet. "In the cost-benefit analysis, I think the benefit greatly exceeds the cost in the vast, vast majority of situations," he says.

But he and other veterinarians are also realistic about what their charges can carry. And they think pet owners -- or would-be pet owners -- should know which animals spread what and to whom, and tailor their pet choices accordingly.

Stop that slobbering dog

Some also think humans ought to impose a few limits on their interactions with their pets.

"I'm not a big advocate for dogs licking faces. That's just not appropriate," says Dr. Jeff Bender, director of the program for veterinary population medicine in the school of veterinary medicine at the University of Minnesota.

Chomel cites a report in the medical literature of a woman who developed septicemia, a blood infection, after allowing her dog to lick her surgical incision. Apparently, there are people who believe dog saliva has curative properties.

Chomel isn't one of them. "I don't think that being licked by a pet is the best thing. That's all I can say."

Pregnant women need to be careful around cat droppings, which can carry toxoplasmosis, a parasite that can infect the fetus, causing birth defects or triggering a miscarriage.

Reptiles, notorious for shedding Salmonella, aren't a good choice for households with young children, notorious for putting dirty fingers -- and many other things -- into their mouths.

Likewise, reptiles are a health risk in long-term care facilities. As with most pathogens, Salmonella exposure is most likely to lead to illness in the young, the old and people whose immune systems have been weakened by chemotherapy, HIV or some other medical conditions.

Just as young children can be potent incubators for bacteria and viruses, puppies and kittens seem to shed more germs when they become infected - making them a questionable pet choice for young children or the elderly.

"In households where you have concern about disease transmission, it might not fit to bring those animals in," Bender says.

"But who wants those animals, those puppies and kittens? It's young kids. So you have to kind of weigh the risks and the benefits."

Exotic pets a problem

The more exotic the pet, the more exotic the things you can catch from it, as shown in 2003 by an outbreak of monkeypox in the United States. Pet prairie dogs became infected in the pet distribution chain when they came in contact with imported Gambian rats. The prairie dogs in turn infected about 70 people in six states.

"When you look at a dog and a cat and probably a rabbit, we know about them pretty much. We know what infectious diseases they carry.... When you get farther from them, the risks get greater," Weese says.

He is no fan of a hedgehogs, a recent fad pet. "They've got obscene rates of carriage of certain zoonotic bacteria. Really high rates of salmonella shedding. They can get ringworm. They can carry the plague. Really nasty things."

Many of the more serious diseases are rare in domestic animals. And it is rarer still for pets to pass them to their humans.

But it does happen. A woman in Rhode Island died last year from lymphocytic choriomeningitis caught from a hamster. The tragedy was compounded when three people who received organs from the dead woman also contracted the disease and died.

And just recently, Quebec City veterinarian Dr. Lucie Paradis asked her staff to take antibiotics as a precautionary measure after a dog her clinic was caring for that was found to be sick with leptospirosis.

The disease is caused by bacteria found in the urine of infected animals; pets can become sick by drinking contaminated water. Left untreated, leptospirosis can be fatal - to both people and pets.

This dog pulled through, but in the process Paradis feared her staff could have been exposed - hence the antibiotics.

"He was hospitalized here for a week," she notes. "My staff had to clean the dog which was urinating maybe 10 times more than normal. So he was always in his urine."

Interestingly, the dog's owners' doctor didn't advise the same course of action for them. Paradis doesn't question that decision, pointing out the dog was in the animal hospital during the worst of its illness.

But the different calls made by the physician and the veterinarian point to a problem those on the animal health side of the ledger see. Too often, the health of the whole household - human and animal - isn't taken into account when diseases crop up.

"There's very poor communication in general between the veterinarian and human (medicine) sides," Weese notes.

Chomel agrees. "When it happens in a family environment (it's important that) the pets not be forgotten. They will look at the humans and then they sometimes don't think to ask the question: 'Well, do you have pets? Let's test the pets.' "

Tips for pet owners

Pets are an endless source of affection, but they can also spread illness in a household. Experts offer the following tips for keeping interactions with your pets a source of pleasure, not disease:

No licking: Veterinarians say kissing your pets or allowing them to lick you isn't a great idea. Pets eat, drink and lick things that can contain pathogens they can pass to you.

No raw meat: Some pet owners are strong advocates for feeding dogs and cats raw meat. But veterinarians say that can lead to infection with Salmonella, Campylobacter and other bugs your pets can then spread around the household.

Careful with the pet chews: Dried pig ears, often used as a pet chew for dogs, are also often contaminated with Salmonella. You can pick up the bug by handling the chew, or cleaning up after the dog if it develops Salmonella-induced diarrhea.

Choose appropriate pets: Consider the age and health status of people in your household when choosing a pet.

Keep sandboxes covered: Kitty can't tell a sandbox from a litter box. Enough said.

Stick to traditional pets: The further you get from household standards like dogs, cats, hamsters and rabbits, the more risk you run of picking up weird diseases.

Wild animals don't make good pets: The baby raccoon may look precious now, but he's not going to be a good pet. Don't do it.

Wash your hands: Pets can carry a variety of bugs on their coats, in their mouths and can shed many in their droppings. Take precautions when cleaning up after them, especially if they have diarrhea. And if you are handling pets -- especially reptiles -- wash your hands afterwards.