Many dog owners enjoy getting affectionate licks from their furry companions, but some have concerns about the germs that dogs can carry in their saliva. According to the American Kennel Club, a dog’s mouth contains around 600 types of bacteria, some of which are unique to canines and can be harmful to humans. The risks of transmission from dog saliva are relatively small, but not non-existent.
A 2022 genetic study, published in Antibiotics, found that canine saliva has plenty of bacteria containing transferable antimicrobial resistance genes, which may promote antibiotic resistance in humans. However, bacteria from dogs have a very low chance of penetrating intact skin, but they can get into the human system through broken skin and mucus membranes like the eyes, nose, and mouth.
So, what are the most harmful organisms in dog saliva? Veterinarian Heather Berst warns that some of the microorganisms to be most concerned about are Clostridium, E. coli, salmonella, and campylobacter. These organisms are zoonotic, meaning they can jump between species and cause infections.
In addition, dogs can also have intestinal parasites like heartworm that they can spread by licking. However, Dr. Berst says parasites are more likely to spread through dog poop than by oral transmission. It's also worth mentioning that coprophagia, or the habit of eating poop, is gross and can introduce harmful bacteria into a dog's mouth, but the risk of transmission to humans from a dog's lick is still relatively low.
It is important to note that the most critical things to consider are the dog's health status and the person's overall health. People with compromised immune systems should avoid having their dog lick them on the face. Elderly individuals and children should also show added caution.
While there are risks associated with dog saliva, many pet owners allow their dogs to lick their faces as a sign of affection. Heather Berst, a veterinarian and dog mom, allows her highly affectionate rescue Chinese crested dog to give her kisses on the face. She advises pet owners to talk to their physicians and veterinarians if their dog licks their face regularly, as there can be some risks.
To protect oneself from dog germs, regular veterinary care for pets is a must. This should include preventatives, like vaccines, that decrease the chance of transmitting zoonotic diseases to humans. Dr. Berst also recommends that pet owners make sure their pet is tested for parasites and is on a parasite preventative. Additionally, dogs should be vaccinated for diseases such as rabies and have their teeth cleaned regularly.
Another consideration is a dog's diet. Raw food diets have become popular, but many veterinarians, including Dr. Berst, discourage their use. "Raw food diets increase the risk of transmitting food-borne illnesses. If I was around a dog and the owner fed the dog raw food, I would be cautious about that dog licking my face," Dr. Berst says.
Finally, if a dog licks an open wound or bites a person, they should contact their healthcare provider right away. Signs of infection like redness, swelling, or pus-like discharge require medical attention as soon as possible.