My voracious reader wife loves Rob Dunn's science books. He's professor of ecology and his new book, Never Home Alone, is so fascinating he ended up on Fresh Air, being interviewed by Terry Gross. We sat mesmerized by the interview.
He loves studying microbes and his career began by going where he thought he'd find undiscovered ones—in faraway jungles. But it turns out we've created new environments in our homes that never existed before: in hot water heaters, in chlorinated water, on the handles of antibacterial soap dispensers.
We fear the 200,000 species of microbes that live in our homes so we've tried to kill them all and the unintended consequence is we've given rise to harmful ones.
People who are on municipal water supply — cities like Philadelphia and New York — that are heavily chlorinated, that chlorine seems to kill most of the bacteria in the water system. But it leaves nontuberculous mycobacteria alone because they're chlorine-tolerant. So it kind of creates a world in which they can live happily without much competition. On the other hand, in well water (from rural environments or municipal water from some of the European cities that don't treat their water with chlorine), the mycobacterium seems very, very rare. And so we're accidentally making them common by trying to kill everything.
👆 The nontuberculous mycobacteria that live on your showerhead, and other bacteria that live on the handles of your antibacterial soap handles, actually are worth worrying about.
If a flu virus lands on your hand, the first thing it encounters is not your immune system; it's the layer of your microbes on your hand. I think that some of what your glands are doing may be to feed some of the microbes that best defend us from some of those things we actually have to worry about.
He thinks one of the best things we can do is get a dog to spread beneficial microbes around our homes, like a good probiotic. "Our bodies don't exist but for the species that live on and in them," he says. "We can't scrub ourselves free of the rest of life."
What do you think? Should we believe him?