Are beards dirtier than dogs? 'Significantly' more germs hide in men's beards, study finds

Man's best friend might have a thing or two to teach us about cleanliness: The beards covering men's faces hide "significantly higher" amounts of bacteria than found on dogs, a recent study suggests.

The research, published in February in the peer-reviewed journal European Radiology, compared bacteria samples from 18 hairy men with those from 30 dogs, including border collies, dachshunds and German shepherds. 

The conclusion? "On the basis of these findings, dogs can be considered as 'clean' compared with bearded men," the Switzerland-based researchers noted.

Twenty-three of the 30 dogs showed high microbial counts; all 18 of the bearded men did. Disease-causing bacteria showed up more frequently on the beards, too, including bugs causing urinary tract infections, though that difference was not deemed significant.

Researchers took bacterial samples from the dogs' necks, between the shoulder blades, which veterinarians suggest is "particularly unhygienic" and where most canine skin infections occur, the study says. The dogs were 3 months to 13 years in age.

The men, ages 18 to 76, gave samples from beard hair below the mouth. Researchers noted the length of each beard "by gently pulling on the beard hair and measuring the length in centimeters with a ruler."

"The beards of men harbor significantly more microbes than the neck fur of dogs and these microbes were significantly more pathogenic to humans," per the study.

Authors acknowledged limitations of the study, including its size. They said similar research could be done with hair samples from women’s heads, which could carry just as much bacteria as men’s beards.

The research, which occurred at three radiology departments in Europe, arose from a technological question.

Only a few veterinary clinics in the continent had MRI scanners reserved solely for animals, the authors said, prompting a question: Is it safe for dogs and humans to use the same MRI machine?

That prompted the study from Switzerland's Hirslanden Clinic, which, in addition to examining beards, tested the cleanliness of MRIs used by both dogs and men. 

The study's conclusion: "Dogs are no risk to humans if they use the same MRI."

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