It is a potentially fatal infectious disease caused by aerobic bacteria. The bacteria belong to the genus Legionella. The disease first got its name in July of 1976 when an outbreak of pneumonia was found to have started because of this.
Patients with Legionnaires' disease usually have fever, chills, and a cough, which may be dry.
The disease is still around today. There have been numerous cases from 1976 through 2012. Many of the outbreaks did not harm more than 200 people, but in July 2001 800 people were infected in Murcia, Spain.