Legionnaire’s disease was first identified in 1976 when a sudden, virulent outbreak of pneumonia took place at a hotel in Philadelphia, Pennsylvania, where delegates to an American Legion convention were staying. The cause was eventually identified as a previously unknown bacterium that was given the name Legionnella pneumophilia. The bacterium probably was transmitted by an airborne route. It can spread through cooling tower or evaporation condensers in air-conditioning systems, and has been known to flourish in soil and excavation sites. Usually, the disease occurs in late summer or early fall, and its severity ranges from mild to life-threatening, with a mortality rate as high as 15 percent. Symptoms include diarrhea, anorexia, malaise, headache, generalized weakness, recurrent chills, and fever accompanied by cough, nausea, and chest pain. Antibiotics such as Erythroycin™ are administered along with other therapies (fluid replacement, oxygen, etc.) that treat the symptoms.