Pet owners recently browsing the Internet may have gotten the impression that cuddling with Rover could cause mortal danger: “Letting Sleeping Dogs Lie in Your Bed Can Kill You” and “Sleeping with Pets Brings Risk of Serious Disease” are just two examples of sensationalized headlines splashed around the web. “I knew it was going to be controversial, but it’s my job as a public health researcher to warn people about the risks,” said Bruno Chomel, a veterinary zoonoses expert at the University of California-Davis and co-author of the paper that caused all the fuss.
Many of those scare headlines, however, missed the main point of Chomel’s work: For most people, the risks are minimal, and there are easy ways to go about preventing pet-to-owner disease sharing.
While cat-napping with kitties or stealing a kiss with puppies, pet owners can expose themselves to a whole cornucopia of nasty ailments — from plague to parasites, rabies to Chagas disease — according to the article that appeared January in the journal Emerging Infectious Diseases. An estimated 62 percent of American households have pets, researchers say; that adds up to 60 million dogs and 75 million cats. Of these, approximately 27 percent of dogs and 60 percent of cats have “conquered our bedrooms.” At first glance, the potential for a mass epidemic instigated by our furry friends seems like a real-life Hollywood nightmare scenario. But before bullying your pet with a harsh “Get off the bed, I mean it this time!” as one hysterical news story suggests, take a step back. First consider whether your pet could even be guilty of the disease charges, since some are so rare that they exclude the vast majority of pets.
First, there’s plague. That’s right, plague: the infamous Black Death of fourteenth century Europe that claimed about 75 million lives. As any high school student knows, plague is transmitted from the bites of infected fleas that normally live on rats. What most people do not know, though, is that plague can still be found in rodent populations in the western United States, like Colorado, New Mexico, and Arizona. Although rats are the fleas’ preferred hosts, when plague begins to decimate rodent populations, fleas will settle for a substitute mammal host. This is where the cats and dogs come into play, explains Kevin Griffith, a medical epidemiologist at the Centers for Disease Control and Prevention.
Plague-carrying fleas prefer rodents and are not happy feeding on cats and dogs, Griffith says, so when a pet brings a plague-carrying flea into a home, the fleas tend to be mobile, abandoning the pet in search of their preferred host. If owners are spending six to eight hours sleeping with a pet, this gives the fleas an opportunity to move and potentially infect the other occupant of the bed.
Griffith reports that only about seven cases of plague have occurred per year between 2005 to 2010, making it a rare disease that most people don’t have to worry about. This is roughly equivalent to the chance of getting struck and killed by lightening. In contrast, about 850 people die per year from intestinal infections caused by Escherichia coli in undercooked hamburgers or salmonella in runny eggs.
And if you live on the East Coast, none of this even applies since plague-carrying fleas don’t live there. For those who reside in the Western United States, though, it seems owning pets could put them more at risk. Interviews with nine people who contracted the disease revealed that eight of them had dogs, and of those eight, four slept with their animals, Griffith says.
But the chance of being one of the unfortunates who receive plague from a pet is more minuscule than a flea. Out of the 135 million dogs and cats installed in the sanctum sanctorum of American homes, perhaps 0.0000075 percent might have been associated with plague. These statistics don’t exactly call for a mass exodus of pets from the bedroom, and simple flea control and veterinary care can minimize this already microscopic risk.
The article further describes a case of methicillin-resistant Staphylococcus aureus, or MRSA, which repeatedly affected a couple until they realized the family’s dog — which reportedly often licked their faces and slept in their bed — was carrying the MRSA bug and re-infecting its owners. MRSA, an aggressive bacterium that typically proves tricky to eradicate, gained fame several years ago with a similar media pet-panic campaign.
Almost invariably, however, MRSA originates in humans, not pets, says Scott Weese, a veterinarian specializing in microbiology at the University of Guelph in Ontario, Canada. Rather than MRSA cropping up in pets, Weese says, it’s often the human owner who transmits the infection to their pet, which then becomes a reservoir for the disease, re-infecting the owner and potentially circulating the infection to other animals during vet visits. What’s important to keep in mind is that every household is not the same, Weese says, and that for the average person these risks are very low. Like plague, reducing the risk for MRSA contraction from pets comes down to basic hygiene and veterinary care.
Finally, the relevance of why some diseases appeared in the article seems downright questionable. Chagas disease, for example, is an inspect-spread illness most common to South America. Kissing bugs — the culprits that transmit the disease to humans — hide in the mud and thatch of rural South American homes, emerging at night to feed on sleeping human hosts and thus transmit the Chagas parasite. Though the disease sometimes occurs in the southern Unites States, in order for Chagas to be spread, infected kissing bugs must be present in a person’s home.
The article warns that dogs and cats infected with the Chagas parasite increase the risk for human infection, but the study cited occurred in Argentina and isn’t even applicable to the United States. The vast majority of American homes do not provide the necessary conditions for kissing bugs to live, says Patricia Dorn, a microbiologist and Chagas expert at Loyola University in New Orleans, so even if a dog is infected with Chagas, a person cannot contract the parasite without the insect vector. “The article is really misleading about Chagas,” says Dorn.
With all the hype over the life-threatening ailments pets can introduce to owners, it seems only fair to discuss the benefits that pets can bring to their owners. “The interaction with another special being provides so much,” says Carole Fudin, a clinical social worker based in New York who specializes in veterinary medicine and the human-animal bond. The “extraordinary” benefits that “these little fuzzballs” bring to their owners’ lives, she says, include acting as antidepressants, encouraging exercise, helping with high blood pressure and alleviating loneliness.
Fudin says that the issues pointed out in the paper are real and worthy of concern but should not cause alarm. Fudin’s dog, for example, recently came down with a case of giardia — the intestinal infection that causes traveler’s diarrhea in humans — but as soon as she noticed blood in the dog’s stool, she brought him to the vet for treatment. “We got on it right away,” she said, “and nothing happened.” Chomel agrees that basic hygiene rules and common sense should greatly reduce the risk of transmission of the diseases cited in his paper.
Luckily, most online readers seem to get the point, too. In reply to an article titled “Humans beware: Pet kisses can lead to diseases called ‘zoonoses,’” one reader commented, “Yeah, right. Is your dog covered in fleas and has never been wormed? Maybe then I’d worry about the possibility [of disease].” Cats and dogs still seem to have the run of the bedroom, according to general reader consensus, and the “fur babies” may be “a pack of crotch and butt sniffers, but it’s no big deal.”
Nevertheless, Chomel says, we live in a society where we are surrounded by pets, so caution should be applied, especially for sick or elderly people and children. Keeping these concerns in context maintains the practical message this paper delivers: that risks exist but are easily preventable. “I can’t think of any close relationship that doesn’t involve some risk of catching something,” Fudin said. “Do you stay away from human companions because you might catch the flu?”