An estimated 8,000 to 18,000 people get Legionnaires' disease in the United States each year. Some people can be infected with Legionella bacteria and have mild symptoms or no illness at all. Patients with Legionnaires' disease usually have fever, chills, and a cough, which may be dry or may produce sputum. Some patients also have muscle aches, headache, tiredness, loss of appetite, and, occasionally, diarrhea. From the time of infection with Legionella bacteria, it takes 2-10 days for symptoms to appear. In most cases, symptoms begin after 5-6 days. Legionnaires' disease is treated with antibiotics, such as erythromycin. The earlier that treatment is begun, the better the outcome.
The first known outbreak of Legionnaires' disease was in Philadelphia, USA, in 1976. A total of 221 people contracted the disease and 34 died. Most of those that died were Legionnaires and that's how the disease got its name. The second largest outbreak was at the Stafford hospital in England in 1985; a total of 101 people contracted the disease and 28 died.