What is a cooling tower and how can it spread Legionnaires’ disease?

Orange County health officials are investigating cooling towers near the Disneyland resort area after 15 cases of Legionnaires’ disease were reported by people who live in or visited the Anaheim area in September. County Health Officer Dr. Eric Handler ordered Disneyland on Nov. 8 to stop using two of its cooling towers.
Cooling towers are at the center of the investigation because they are known to be breeding grounds for the bacteria that causes Legionnaires’ disease, a l