Rob Dunn is a professor in the Department of Applied Ecology at North Carolina State University and in the Natural History Museum of Denmark at the University of Copenhagen. His new book is Never Home Alone: From Microbes to Millipedes, Camel Crickets, and Honeybees, the Natural History of Where We Live.From the transcript of Dunn's Fresh Air interview with Terry Gross:
GROSS: Cats and dogs. So many people have pets. What kind of microbiology do they introduce into our homes?--Marshal Zeringue
DUNN: So cats and dogs - and especially dogs - have a huge impact on what's in your home. And so if we were to swab your computer screen, Terry, and then look at look at which microbes were on the computer screen, about half of the variation between what's on your computer screen and somebody else's computer screen is whether or not there has been a dog in that room. And so they affect the microbes everywhere in the house. Their microbes drift up and around all over the place.
And so we can actually identify whether or not there's a dog in the house just based on the microbes 99 percent of the time. And cats have an effect, too, but it's more subtle. They seem to bring both bacteria and some fungi, and they make some things more rare. And it's hard to know just exactly which effect, what sort of effects the dogs and cats and their microbes are having. And they can be very complex. But one of the things we see is that people, especially in urban environments with dogs, tend to have kids who are less prone to allergy and asthma.
And one of the things that we think may be happening is that the dogs are actually a vehicle for the connection of those kids to just a little bit of nature, that in these environments in which we've isolated ourselves so much from the rest of the world, that the dirt on a dog's paw may be enough connection to forestall allergy and asthma, at least a little bit. We don't see that effect with cats. But with dogs, it's pretty strong. And by the same token, dogs in rural environments seem to have less effect on allergy and asthma, and we think that's because in rural environments, you're getting so many other exposures to nature that the dog matters...[read on]