When your Labrador is playful and salivates all over you, you may wonder whether Labrador saliva is harmful to your health.
Saliva is a unique clear fluid, composed of electrolytes, immunoglobulins, proteins and enzymes mostly secreted from different salivary glands.
Its main role is to protect the oral mucosa and teeth through lubrication, buffering and clearance action, and antibacterial and antiviral activity, and it is also involved in taste and digestion.
Canine and human saliva contain proteins. These proteins play an important role in the biological process that takes place in the mouth.
Research showed that a human’s, as well as a dog’s mouth, contains more than 2500 different proteins. Proteins that help with natural cell death and biological adhesion were predominant in dog saliva.
The proteins also fight tumor-forming, inflammation, and microbial processes. Dog saliva has 79 proteins that humans do not possess.
Dog saliva is antibacterial which protects newborn puppies from diseases.
Wound licking cleans wounds from bacterial infections such as Streptococcal infections and E. coli which also occur in humans.
Saliva and wound healing
Oral wounds heal faster than skin wounds and the reason lies in saliva.
Saliva enhances wound healing for the following reasons:
- Saliva creates a humid environment which promotes the survival of inflammatory cells,
- Saliva contains several proteins that are needed in the healing process of wounds,
- Saliva contains tissue factor which accelerates blood-clotting,
- Saliva contains epidermal growth factor, a protein that stimulates cell growth, promotes the growth of epithelial cells (cells that line the surface of the body),
- Saliva contains SLPI which is an enzyme that enhances the immune response of the body,
- Salivary histatins protect against fungi such as Candida and enhance cell spreading (it is researched in the search for wound healing medication).
Who has the most mouth bacteria, dogs, cats or humans?
Bacteria growth in saliva samples from the mouth of 10 cats, 10 dogs, and 10 human subjects placed in
nutrient dishes was measured to see if dogs, cats, or humans have the most bacteria in their mouths (pdf).
The expectation was that dogs would have the most bacteria because dogs lick where humans and cats do not.
The bacteria growth was checked every three days and finally after 9 days.
Bacteria colonies deferred from animal to animal. Dogs had an average of 53 bacteria colonies, cats had an average of 16 and humans had an average of 5 bacteria colonies.
In two test dishes, humans had more bacteria than the cats and in some cases, no bacteria grew.
The test results confirmed the expectations presumably because humans brush their teeth while pets do not get their teeth cleaned daily.
The cats had cleaner mouths after they had water to drink but more after eating.
The researcher theorizes that dogs had more bacteria because they tend to eat a variety of substances that humans and cats would not eat, including their own and other animals’ feces (coprophagy).
We must keep in mind that much research still needs to be done on dogs’ mouths. Eighty percent of the bacterial content of the canine oral cavity has not been identified.
Dog oral bacteria have been found in human skin samples. But we know little about the differences in mouth cavity bacteria and how they cross-influence humans and dogs.
How can your Labrador’s saliva transfer diseases to you?
Organisms that cause diseases (pathogens) can be transferred from dogs to humans in a number of ways, but this usually surfaces in people who are immunocompromised.
Healthy people are immunocompetent and would not become sick.
Getting a disease or damaging bacteria from your Labrador’s lick will rarely happen.
There are probably many more things you could worry about if you are looking for something to worry about.
However, there are knowledgeable people who advise against dogs licking your face or wounds.
The CDC promotes a view of general care and advises against the intake of dog saliva (unintentional or otherwise), especially by people with compromised immune systems.
Saliva intake can happen when an excited dog licks your lips, nose and skin around the mouth.
Because of increased contact between humans and animals, the One Health Approach was developed.
This approach will assist in the management of cross-specie contamination although we can expect that cross-contamination between healthy humans and animals will not be a threat.
The saliva of dogs is different from those of humans, so treating its influence on humans as the same as human saliva would not be correct, although not necessarily dangerous.
Diseases transmitted from dogs to humans
Humans have kept dogs for around 1500 years and more than 60% of Western households have a dog.
Pets, especially dogs, have many advantages for humans, but they also carry threats to the health of humans.
Diseases that are transmitted from animals to humans are called Zoonoses and can be transmitted either by domestic pets or by wildlife animals.
Bacterial and viral infections transmitted by dogs
Infections can be transmitted by contact with contaminated feces or urine, direct contact with an animal and dried saliva on the fur which becomes airborne when dry.
Dogs can transmit viral infections such as rabies and norovirus, a stomach virus that causes serious vomiting and diarrhea.
There are no known cases of transmission of norovirus from dogs to humans, so it isn’t something that should be overly concerned with.
They can also transmit a long list of bacterial infections.
Dander from dog fur is usually blamed for creating allergic reactions in people but research indicates that dog saliva is often the cause of the allergic reactions.
Who is most at risk of disease because of dog saliva?
People who are vulnerable are most at risk of bacterial contamination by dog saliva. These include:
- People who have low immunity such as diabetics, cancer sufferers and the elderly.
- Pregnant women.
- People with open sores on their skin including pimples and scratches.
Defence against catching diseases from your Labrador
- Raw meat and eggs should not be fed to dogs due to the higher risk of infection.
- Owners must consider Rabies vaccination for their dogs.
- Wash hands well after touching your dog and coming into contact with your dog’s saliva.
Dog saliva is more good than bad
We know that saliva has good properties. Just observe how wounds inside your mouth heal much faster than wounds on the skin.
I had the experience with my dentist who once complained that cuts he made in the gums, were closing up so fast he had difficulty finishing what he had to do.
Dog saliva has similar properties but it may be safer to lick your lips than have your dog do it. This is because dog saliva is less acidic than human saliva.
The reason for this is that dog saliva is not part of the digestive process but only makes it possible for the dog to swallow its food.
In humans, saliva is more acidic to start the digestive process while a person chews the food.
People also need to chew their food well to break it down for swallowing. Dogs do not need to chew their food.
The saliva found in the mouths of dogs is better suited to prevent cavities in comparison to human saliva. That is why dogs get fewer cavities while humans with more acidic saliva do.
Human saliva has a PH of 6.5 to 7, dogs have a PH of 7.5 to 8.
Should you stop exchanging kisses with your Labrador because of fear of the saliva being harmful?
The answer is probably “No”, as long as you are healthy, and do not have a compromised immune system or open wounds or scratches around or in your mouth.
Just keep in mind where that nose may have been!