Saw a show on tv and they mentioned something called legionnaire's disease. what is that?

Atypical Pneumonia: Legionella is an organism that causes what healthcare workers refer to as atypical pneumonia. This infection of the lung will cause shortness of breath and cough, but not the significant sputum production associated with the usual kind of pneumonia. I believe it was first described when a bunch of legionnaires (a club) contracted the disease (hence the name).

Pneumonia: Specifically caused by a bug called legionella. Caused a big scare in the late 70s early 80s when people at legionaire's convention got sick (some died: http://tinyurl.Com/5j7voq). It was feared that this was a very virulent bug, and while it can make you quite sick, most who die from it have serious underlying illness (emphysema, or heart failure) and antibiotics usually work.