Are Dogs’ Mouths Cleaner Than Humans’?
For everyone who kisses their pup on the mouth 😘
If anyone has ever shamed you for letting your dog give you a kiss, you might have told them that dogs’ mouths are cleaner than humans’ mouths. But is that actually true, or is it just something obsessed dog parents made up to justify letting their dogs lick them?
The truth is that dogs’ mouths actually aren’t cleaner than human mouths — but they’re not really dirtier either. We just have different germs.
The Dodo spoke to Dr. Jonathan Roberts, a remote veterinarian with DoggieDesigner.com, to find out everything you need to know about dog saliva.
Why dogs’ mouths aren’t cleaner than human mouths
Your dog’s mouth isn’t exactly clean. Just like people have bacteria living in our mouths, dogs do too.
“Multiple studies have discovered that dogs have many unique and potentially dangerous bacteria and other parasites lurking in their mouths,” Dr. Roberts told The Dodo. “Around 600 different species of bacteria have been discovered in both canine and human mouths.”
The type and amount of bacteria living in a dog’s mouth depends on the level of periodontal (dental) disease present, which is determined by a number of factors, including:
- Breed (smaller dogs tend to be at greater risk because they have smaller teeth and mouths, leading to more food getting stuck, and they have less bone mass, leading to tooth loss)
- Frequency of teeth brushing
- Frequency of professional dental cleaning by a vet
What diseases can you get from dog saliva?
There are lots of bacteria in a dog’s mouth that are different from what humans have in our mouths. Some of these are harmless, but some could make you sick.
Some of the bacteria found in dogs’ mouths that can be dangerous to people include:
- E. coli, Clostridia, Salmonella and Campylobacter — “[These are] bacteria that can cause severe gastrointestinal illness in people,” Dr. Roberts said. “Dogs are often carriers of these bacteria, yet they do not become ill from them. They usually get these bacteria in their mouths through licking their anuses or ingesting other animals’ feces. Another common source of these illness-causing bacteria is from ingesting raw food.”
- Pasteurella — This can cause skin infections that can travel to your lymph nodes and cause severe disease, such as cellulitis or meningitis.
- Capnocytophaga canimorsus — “[This] enters the wounds in skin after being licked by a dog's tongue,” Dr. Roberts said. “Mostly only immune-compromised people are susceptible to this disease that develops into septicemia [blood poisoning].”
- Giardia and Cryptosporidium — These are actually protozoa, not bacteria, but they can still make you sick by your dog licking your face and can cause gastrointestinal illnesses.
- Parasites — If your dog has parasites, such as worms, and licks his anus and then your face, you could contract the parasite.
So what is the risk of getting sick from your dog licking you? Even with all those germs, if you’re healthy and don’t have a compromised immune system, the risk is luckily pretty low.
“Most human immune systems will neutralize these parasites before they can cause illness,” Dr. Roberts said. “Those with weakened immune systems, such as persons going through chemotherapy, persons with HIV, very young and very old people should be more careful around pets.”
Ultimately, it’s up to you to determine if it’s a risk you want to take.
But to be safe, you can follow these steps to avoid getting sick from dog saliva:
- Keep your dog up to date on his deworming medications and flea and tick medications.
- Get checked out by a doctor if you get bitten or scratched by a dog.
- Don’t let a dog lick your wounds.
- Frequently wash items that your dog’s mouth touches, like toys and food and water bowls.
- Don’t let your dog lick you if you’re immunocompromised, and don’t let him lick others who are immunocompromised.
Does dog saliva heal wounds?
It’s an old belief that dog saliva heals wounds. But is it actually true?
“There may be some truth to this after all,” Dr. Roberts said. “The action of licking helps to remove debris and necrotic tissue from the wound.”
Dog saliva also contains proteins that can be beneficial in healing.
“Mammal saliva contains a protein called histatin,” Dr. Roberts said. “This protein is able to kill bacteria before they can cause infection.”
Histatins have antimicrobial and antifungal properties and are part of the immune system. They have been found to play a role in wound closure.
But while it’s possible that dog saliva could help to heal a paper cut, you shouldn’t let your dog lick all of your cuts and scrapes — there are much better ways to take care of your injuries, and you always run the risk of infecting your wound instead of making it better.
“I would still not allow my dog to lick my wounds,” Dr. Roberts said. “We have excellent wound care products on the market these days that not only do a better job of keeping wounds clean but also come without the risk of introducing nasty infections or potential parasites.”
How to keep your dog’s mouth clean
If you do let your dog give you occasional kisses (and even if you don’t), you should try to keep his mouth as clean as possible since it’s also important for his health.
You can do this by regularly brushing his teeth and by providing toys that help clean his teeth.
Try this dog toothpaste from Chewy for $4.99.
“The most important way to keep your dog’s mouth clean and healthy is (just like humans) through regular teeth brushing and dental cleaning by a professional,” Dr. Roberts said. “Start introducing your dog to teeth brushing from a young age and aim to brush at least twice a week.”
So dogs’ mouths aren’t actually cleaner than people’s, and you shouldn’t let your dog lick your wounds. But if you keep your dog’s mouth and teeth clean, a kiss from your pup every now and then should be fine (if it’s something you’re comfortable with).
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