Legionnaires' disease is a form of pneumonia first discovered in 1976 among members of the American Legion attending a convention in Philadelphia. The cause of the disease is the bacteria Legionella pneumophila which is found in water-tanks, air-conditioning units and other sources of static or sheltered water. The bacteria is spread through water droplets in the air, frequently affecting large numbers of people in modern, air-conditioned buildings. Diagnosis is difficult as the bacteria is hard to isolate, and often patients die before Legionnaires' disease is diagnosed. Research Legionnaires' Disease