We all know that we share love with our dogs. But microbes?
Researchers at the University of Colorado Boulder have looked at the types and transfer modes of microbes from the guts, tongues, foreheads and palms (or paws) of members of 60 American families, including dogs. They found that humans shared more microbes with their dog than their own children.
The team swabbed various parts of the body to obtain microbial samples on couples, children and dogs. For humans, the team looked at the tongue, forehead, right and left palm and fecal samples to detect individual microbial communities. Dogs were sampled similarly, except that fur was sampled instead of skin on the forehead and all four paws were swabbed for bacteria in the absence of canine palms.
“One of the biggest surprises was that we could detect such a strong connection between their owners and pets,” said Associate Professor Rob Knight, the study’s leader.
The micro-organisms humans carry around have been linked to a broad spectrum of diseases ranging from malnutrition and obesity to diabetes, asthma and depression. “There is mounting evidence that exposure to a variety of environmental sources of microbes can affect long-term health, findings known as the ‘hygiene hypothesis,’ ” said doctoral student Se Jin Song.
Proposed by British epidemiologist Richard Strachen in 1989, the hypothesis is that children who have had a lack of exposure to bacteria and micro-organisms might be more prone to getting sick because many microbes have co-evolved with people to be beneficial.
Dogs were a key part of this research, said Knight. “Since so many people consider their pets truly a part of the family, it seemed appropriate to include them in a study involving family structure.”
The results of the study have been published in the journal eLIFE.