Why do dogs heal faster than humans

Is dog saliva curative or dangerous?

The phrase "licking one's wounds" is no coincidence: dogs instinctively lick their own, but also infected parts of the human body. The associated idea of ​​the healing properties of dog saliva persists to this day. The fact is: As early as the early 20th century, researchers B. L. Hart and K. L. Powell from the University of California's Faculty of Veterinary Medicine discovered that the saliva of dogs can prevent infection by certain bacteria. Bacteria in the wound are greatly diluted by the saliva and most of them are licked out.

Jörg Jores from the University of Bern also knows about the antibacterial components of dog saliva. “Saliva contains lysozyme, which attacks certain bacteria such as staphylococci and streptococci. We also find immunoglobulins there, i.e. antibodies that play an important role in the defense against pathogens, ”explains the head of the Institute for Veterinary Bacteriology.

Microorganisms are constantly changing
Our medieval ancestors probably just ignored the often strong smell. "Tartar, infections in the throat or organic complaints such as those of the kidneys can be the cause of bad-smelling dog saliva and breath," says Jores. The normal flora of the bacteria present in the saliva does not cause an unpleasant odor. It is difficult to say which bacteria this can be. All you know is that there is an incredibly large amount of bacteria in dog saliva, an estimated several million. "Only very few do we know how to cultivate them."

The sources of the bacteria, however, are known. According to Jores, there is a high level of bacterial transmission from the bitch to the puppies. In addition, numerous bacteria enter the saliva through food, the environment and, of course, diseases. The so-called microbiome (the entirety of the settled bacteria and other microorganisms) are constantly changing in their composition: the dog drinks, eats, licks or licks something and the microbiome is already different. “Antibiotics, feed changes, conspecifics and changes in the environment also play a role here,” says Jores. Although most of the bacteria are harmless, bacteria that cause infections can also colonize dog saliva. "Since the dog is busy with his personal hygiene, licking the body parts of others, you can sometimes find bacteria such as E. coli in the saliva." Escherichia coli can lead to gastrointestinal flu or urinary tract infections.

Dangerous, but don't panic
Despite antibacterial and wound-healing components, Jores warns of the dangers that can lurk in dog saliva. Resistant bacteria could also be found there, which could become a problem for humans if transmitted. The transmission of rabies viruses is also still an important topic in certain areas - even if not in Switzerland.

A certain bacterium can also be dangerous for us: If a person becomes infected with a "dog bite" (Capnocytophaga canimorsus), blood poisoning can spread rapidly. "Over a quarter of all dogs carry this bacterium in their saliva." The veterinary bacteriologist therefore advises caution. "Bacteria like this can be transmitted through saliva through open wounds."

However, there is no reason to panic. Jores - like many other dog owners - will continue to be gobbled up by his beloved four-legged friend. However, he strongly advises elderly and immunocompromised people against being licked by a dog. Such a pathogen could have devastating consequences for them. And in principle you shouldn't let dogs lick your wounds.