Just about every bit of the human body is covered in microbes—10,000 species—and most are friendly, according to a new census. Microbes help the body digest food, strengthen the immune system, and ward off dangerous pathogens. But despite their prominent roles, researchers have understood little about which microbes reside in specific sites of the body. Now, a consortium of some 200 U.S. scientists at Washington University School of Medicine in St. Louis and elsewhere report findings from the most comprehensive census of the microbial make-up of healthy humans.
