All dog owners are exposed to their pooch’s saliva at one time or another, either through affectionate licks or through a bite. The expression “a dog’s mouth is cleaner than a human’s mouth” quickly comes to mind. But is this really the case? According to scientists and canine experts, the answer is, unfortunately, no.
In fact, the mouths and saliva of dogs naturally contain a lot of bacteria. While these do not present a problem for the animal, they can, in some cases, be dangerous for humans when they come into contact with their blood. Find out what these bacteria are, what are the risks for humans, any aggravating factors, and the right actions to take if a wound gets infected.
Why Are Dogs’ Saliva Not Cleaner Than Ours?
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You know that your dog uses his tongue every day, either to communicate, explore his environment, or to lick himself. Licking is indeed essential for the animal because it participates in its mode of communication and understanding. However, dogs tend to lick a lot of things.
As a result, dog saliva contains a large number of bacteria. Of course, the body of every living being contains billions of bacteria: they contribute to the well-being, digestion, and the preservation of the immune system. But while some are used for the normal care of your pooch’s mouth and his entire body, others are potentially dangerous to humans.
The most famous bacteria that can be dangerous to humans and very common in dogs’ mouths is Capnocytophaga canimorsus. Naturally present in the saliva of doggies, but also cats and humans, it can cause severe infections in humans if it enters their bloodstream through a bite or licking a wound. The danger of this bacterium is zero for the animal because it comes naturally from its body. But, on the other hand, when it is taken out of this context, it presents a significant risk and can become a pathogen.
Researchers have also found that dogs have another type of bacteria called Porphyromonas gulae, which can cause periodontal disease. Humans have a different strain of this bacteria called Porphyromonas gingivalis.
In addition, other Harvard researchers have found more than 615 different bacteria in human mouths, compared to 600 in dogs. This slight difference may have reinforced the myth that dogs’ saliva is cleaner than ours, but that would be comparing apples to oranges. This is because the mouths of dogs and humans are full of germs, but these types of bacteria are different. So, in essence, you could say that a dog’s saliva is as dirty as ours.
What Are the Risks of Contracting Diseases from a Dog Kiss?
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As humans, our skin protects us from infections by forming a natural barrier against the vast majority of viruses, bacteria, and microorganisms of all kinds. However, bacteria can pass into our blood and spread throughout our bodies once we have a wound. The dog can therefore transmit it to us by a bite that crosses the skin, by scratches that cause bleeding, or even a lick on an unhealed wound.
The bacteria that is most commonly found in a dog’s mouth is Pasteurella canis. Also, as mentioned earlier, dogs can transmit the bacteria Capnocytophaga canimorsus through a bite, which can lead to severe bacterial infection in humans. Moreover, the rabies virus is the most serious infection that dogs can transmit through their saliva.
On the other hand, a dog can eat food contaminated with Salmonella or E. coli, and these pathogens could be passed to humans if the dog’s slime gets into your mouth.
Are There Any Aggravating Factors in Dog Saliva?
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It seems that certain factors are aggravating in the case of contact with certain bacteria through the saliva of a dog:
Being immunocompromised: A weakened organism will be less able to defend itself naturally against external attacks and will therefore be more vulnerable to bacteria.
Children under five or adults over 65: These groups of people are more vulnerable to infections.
Having wounds or lesions: Wounds and lesions are gateways for bacteria, which may enter the bloodstream through them.
What To Do if You Suspect an Infection?
The risk of contracting dangerous bacteria through a dog’s saliva is rather low in healthy individuals. However, if you get bitten deeply by a dog or licked on a wound, immediately wash the lesion with clean water and soap to disinfect it thoroughly. Then, seek medical attention, no matter how minor the wound may look.
Tips: To avoid any type of infection, wash your hands thoroughly after touching your dog, but also the parts of your body (arms, legs, face) that he has licked. Avoid touching a child, a weakened person, and food after such contact, without prior washing. Finally, don’t let your dog lick your face or any damaged skin.
How to Keep Your Dog’s Mouth Clean
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You can’t remove all bacteria from your dog’s mouth, but you can improve his oral hygiene with a few actions:
Brush your dog’s teeth at least twice a week.
Use toothpaste specially designed to reduce plaque.
Give food made to improve the dog’s dental health.
Your beloved dog’s saliva certainly isn’t cleaner than yours, but the bacteria it contains is generally not harmful to healthy people. However, in some cases, it is possible to contract serious illnesses through the saliva of dogs, but this risk remains low. Still, it’s best to avoid big kisses with your dog and to clean your hands after each handling. But, as dog lovers, we know that this is much easier said than done!
Genevieve is a biologist and science writer. Her deep love for capuchin monkeys, pumas, and kangaroos has taken her worldwide to work and volunteer for several wildlife rehabilitation centers in Bolivia, Guatemala, Canada, and Australia. As a Canadian expat, Genevieve now lives in Argentina, where she wakes up every morning to horses and cows saying hello from the vast plain next to her home office window. She is the proud mom of three rescued dogs, Lemmy, Nala, and Pochi, and a frisky kitten, Furiosa. Having the privilege of sharing her knowledge and passion for animals of all kinds is what makes her fulfilled and happy....Read more
