Many of us have done it, or know someone who has: kiss and get kissed by a dog on the face. Sometimes, this even happens mouth-to-mouth. This may seem appalling to many folks who don’t own dogs (and even to some who do), especially given what we all know about how and where dogs groom themselves. Nonetheless, many people share smooches with their pooches. This interaction (on both sides of the equation) can be friendly, sweet, loving and irresistibly adorable. But is it safe? Or sensible? May it actually benefit the dog or its owner in some way? There hasn’t been a lot of research to support complete and thoughtful answers to these questions. However, there has been some. Hopefully, this overview will help dog owners and non-owners separate fact from fiction and provide a framework for evaluating the fuzzy issues in between.
Why Do Dogs Lick?
In the most general terms, dogs lick to communicate and to keep clean. This behavior has been ingrained in them for generations, reinforced by interactions with dogs they grow up with, live with and meet. Licking is natural for dogs. From the day they are born, puppies are licked by their mothers to keep them clean, provide comfort and help her differentiate them by smell. As they age, pups learn that if they lick their mom or other older dogs, a few morsels of “real food” may magically drop from their mouths. Eventually, puppies start licking themselves, their littermates, other animals and people. They learn from and adapt to the responses they get to this behavior.
Licking has been present since the time dogs were wolves (or, more accurately, since the time wolves lived as the ancestors of today’s domesticated dogs). When wolves or wild dogs return from a hunt, subordinate pack members typically meet and greet the hunters but wait for their own turn to eat. They cower and lick the mouths of more dominant pack members to show contentment and submission. One dog licking the face of another is considered to be a fairly universal doggie message: “I’m really friendly and happy to make your acquaintance” or “I submit.” Dogs may express anxiety or submissiveness by licking their lips and smacking them together, which most other dogs seem to recognize.
It is normal for dogs to lick themselves as part of self-grooming. This is similar to people brushing their teeth or taking a shower. Still, some owners don’t want to be licked in the face after their dog has groomed its private parts. Dogs instinctively lick open wounds to keep them clean, whether the sores are their own or on other animals or people. Some people think that a dog’s saliva has disinfectant properties, but this hasn’t been proven. Given where most dogs’ tongues have been, it probably isn’t wise to let them lick your open wounds.
To summarize, a dog’s licking behavior typically indicates something about its desire for cleanliness, general mood and comfort level, degree of submissiveness and affection for the subject of its licking. Usually, it isn’t difficult to teach a dog when licking is inappropriate. If an owner doesn’t want her dog to lick, she should not reinforce that behavior by paying attention to the dog when it happens.
Let’s Discuss and Dispel Some Myths…
There are several myths surrounding smooches between pooches and people. One of these is that a dog’s mouth is cleaner than a person’s. Consider how, where and what a dog’s mouth comes into contact with: their paws (who knows what they’ve walked on?); their external genitalia with all its assorted excretions; rotting garbage; dead rodent and bird carcasses; feces; and any number of other things likely to harbor parasites or other unhealthy infectious organisms. This, together with scientific evidence, confirms that dogs’ mouths are not “cleaner” than people’s. Infectious organisms can remain and replicate in a dog’s mouth, or they can be swallowed and settle in other places. Many of these organisms (and their eggs or larvae) are eventually expelled in feces, where they can infect other animals. Fortunately, most infectious organisms in a dog’s mouth are processed by its digestive system fairly rapidly and don’t remain in the mouth for very long. In addition, most of them are species-specific, which means that they can infect dogs but not people.
Another myth is that kissing a dog is extremely dangerous, because of where its mouth has been. This is the flip side of the myth that dog’s mouths are cleaner than ours. Humans and dogs have many of the same types of bacteria, viruses and other microscopic organisms in their mouths. This makes “kissing on the lips” not that much different, in terms of infectious potential, when it happens between pets and people, or between people and people. Most infectious organisms don’t cross between dogs and people.
Can I Catch Diseases From My Dog?
Illnesses can be transmitted between animals and humans; these are called “zoonotic diseases”. Less than half of all reported zoonotic diseases have been found in North America. Among those, only a fraction can be transferred from dogs to people; this is an uncommon phenomenon, especially in the United States. Diseases transmitted from dogs to humans by oral contact are even rarer.
Some of the infectious organisms that dogs reportedly may transmit to people (not necessarily by oral contact) are listed below:
Brucella canis: Brucellosis is a bacterial disease uncommonly associated with dogs.
- Campylobacter: Campylobacteriosis is a bacterial disease found in dogs, cats and farm animals. Campylobacter pass in fecal matter and can cause diarrhea.
- Cryptosporidium: Cryptosporidiosis is a parasitic disease that can affect dogs (especially puppies), cats, farm animals and people.
- Tapeworm: This parasitic worm can cause disease in dogs, cats and people. It commonly carried by fleas.
- Giardia: Giardiasis is a parasitic disease that affects many animals, including dogs and humans. Giardia are frequently found in water.
- Hookworms: Hookworms are commonly found in dogs and cats. They also can infect people.
- Leishmania: Leishmaniasis is a parasitic disease found in dogs and sand flies, primarily outside the United States.
- Leptospira: Leptospirosis is a bacterial disease associated with wild and domestic animals, including dogs and people, in both urban and rural areas.
- Lyme Disease: This bacterial disease can affect people and dogs and is mainly transmitted by ticks. It is caused by infection with Borrelia burgdorferi in the United States, and Borrelia afzelii and garinii in Europe.
- Poison Ivy: Although dogs rarely are affected by poison ivy, they can carry toxic oils from the plant on their hair and skin. People can develop an intense, itchy rash by petting, “kissing” or otherwise touching affected areas of their pet.
- Rabies: Rabies is a fatal viral disease that can affect various animals, including dogs and people. Because of current vaccination protocols, rabies in dogs is extremely uncommon in the United States. According to one report, more people die each year from infections associated with in-grown toenails than they do from rabies. However, certain wild animals remain reservoirs for the rabies virus here and elsewhere, including the skunk, fox, bat and raccoon.
- Ringworm: Ringworm is a fungal disease that can affect dogs, people and other animals.
- Rocky Mountain Spotted Fever: : This bacterial disease can occur in dogs and people. It is associated with tick bites.
- Toxocara: Toxocariasis is a parasitic disease that affects dogs, cats and sometimes people, among other animals. It is commonly called “roundworm.” When roundworm eggs are ingested by children, they can hatch in the digestive tract, burrow through the intestinal wall and migrate almost anywhere in the body.
Can I Get Sick From Kissing My Dog, Or Letting It Kiss Me?
Zoonotic diseases transmitted orally from dogs to people are highly uncommon, although they have been reported. One study found that dogs and humans share several types of disease-causing oral bacteria that may be able to be transferred by direct contact. As adorable as pooches’ smooches may be, in rare cases they may give you more than you bargained for. People who are unusually cautious in terms of health, germs, disease transmission and cleanliness, and those who are immunocompromised (very young, very old, very sick, HIV positive, recipient of an organ transplant, taking immunosuppressive drugs or going through chemotherapy) may want to kiss dogs somewhere other than on the mouth. Otherwise, the chances of “catching something” by smooching a pooch are extremely low - substantially less, for example, than the chances of being hit by a car when walking across the street.
Who Should Be Worried?
The immune systems of healthy people help them fend off many infectious diseases. The risk of people in this group getting sick from kissing (or being kissed by) a dog is extremely low. Unfortunately, some folks aren’t so lucky. Those with underdeveloped, weak or otherwise compromised immune function should be particularly careful when they interact with any animals – especially ones known to be ill. This includes the very young, the elderly, those with cancer or other serious diseases, organ transplant recipients, people taking immunosuppressive drugs, people going through chemotherapy and people with diseases that compromise the immune system, such as HIV and AIDS. These people should wash their hands with warm soapy water after they touch any dog or cat and should vigilantly avoid contact with their saliva, urine or feces.
Some people think that exposing children to a wide range of immunological novelties can enhance their body’s ability to process and respond successfully to immunological insults. The debate continues about whether this is true, including whether kisses from a dog may be beneficial to development of a child’s immune system.
Are There Any Benefits From The Occasional Pooch Smooch?
Most American households have at least one pet. Owners usually get great satisfaction from petting and snuggling with their animals, which often includes giving and getting “kisses.” Well-socialized dogs also seem to enjoy being loved-on by people. Pet ownership and close physical interactions between people and animals reportedly have many potential benefits. Pets can:
- - lower their owners’ blood pressure, cholesterol level and triglyceride levels
- - relieve or reduce feelings of loneliness and depression
- - provide companionship and protection
- - enhance a positive outlook and improve the owner’s overall quality of life
- - increase people’s opportunities for exercise, social contact with other people and engagement in outdoor activities
- - teach children responsibility and respect for living things.
While it is important to think about health and the likelihood of disease transmission between pets and people, the risk of “catching something” from a dog is extremely low. Most people consider that slight risk to be outweighed by the abundant benefits of dog ownership. Any risk can be further reduced if the owner uses common sense, practices good environmental hygiene and keeps his dog well-fed, happy, healthy and clean.
What Should I Do About Kissing (Or Being Kissed By) My Dog?
The most practical advice on this subject is for owners to use common sense. Good environmental and oral hygiene, regular grooming, routine veterinary examinations, effective parasite control and attention to the health of all household members will reduce the risk of any disease passing from a dog to people.
- - Keep your dog healthy. Healthy pets pose fewer risks to their owners, because they are less likely to develop infectious diseases. Take your dog to the veterinarian for annual check-ups, vaccinations, de-worming and overall health management. Keeping your dog free of fleas, ticks and other parasites is critical to its health. Don’t acquire a dog if it looks sick.
- - Keep your dog clean. Despite the unlikelihood of a disease being spread from dogs to people, it still is best to keep pets clean and well-groomed. Any urine or fecal matter that collects around the external genitalia should be gently removed using warm soapy water. Scissors or clippers should only be used by experienced people.
- - Clean up after your pet. Keep poop picked up from the yard, and keep the litter box or other areas for indoor elimination clean and well-disinfected.
- - Avoid touching your animal’s feces or urine. Some owners wear disposable gloves (or rubber gloves that are easy to disinfect) when they clean the cat box or pick up and dispose of fecal matter. A long-handled pooper scooper is useful, especially for routine yard clean-up. A plastic grocery bag is handy in a pinch. Commercial pet-poop-picker-upper bags are available at most well-stocked pet supply stores.
- - Wash your hands. A thorough hand-washing with warm soapy water, followed by application of a hand sanitizer, are easy ways to reduce the risk of getting or spreading infection. Do this after yard or litter box cleaning, changing a pet’s bedding or handling any unfamiliar or sick animal. Always wash your hands before eating. Teach children to wash their hands after touching any animal. Veterinarians and physicians are taught to wash their hands and use hand sanitizer after every contact with a patient.
- - Practice good pet oral hygiene. Oral infections usually can be prevented by routine brushing, use of oral rinses made specifically for animals and regular veterinary dental cleanings. The process is essentially the same as that required for good human dental health.
- - Don't let your pets (or children) come in contact with stray or wild dogs, cats or other animals. They are much more apt to carry diseases that can infect pets and people.
- Keep people in your household healthy. This will reduce the risk of them becoming ill, even if a pet does.
- - It is probably safest not to let your pets lick you on or in the mouth. Children should not put their mouth on animals or put any part of an animal's body inside their mouth. They should keep their hands out of their mouth after touching an animal. If nothing else, try to keep your mouth closed when you smooch a pooch!