Legionnaires' Disease

Legionnaires' disease is not spread person-to-person, but only through exposure to legionella bacteria in vaporized water droplets, said Dr. Matthew Moore, an epidemiologist at the U.S. Centers for Disease Control.

"Legionella is a bacterium that is found throughout fresh water environments, and outbreaks of legionnaires' disease have occurred after persons have breathed in mists from a water source, such as showers or air-conditioning cooling towers or whirlpool spas," Moore said Thursday from Atlanta.