Remember Pig-Pen? The little kid from Charles Schulz’s Peanuts cartoons who walked around in a cloud of dirt? Well, the human body does spew a cloud, but instead of dirt it contains millions of microorganisms. “It turns out that that kid is all of us,” says lead researcher James Meadow. “It’s just a microscopic cloud that’s really hard to see.” Each of us carries around millions of microorganisms – including bacteria, fungi and viruses — on the inner and outer surfaces of our bodies. Most of them aren’t dangerous. In fact, growing evidence indicates that they help us in lots of ways.