This represents passive disease surveillance. However, this figure should be interpreted cautiously due to possible under reporting of comorbid disease. Rhabdomyolysis and renal failure may be seen in this disease. The weighted mean age for patients with Legionnaires' disease is 52.7 years, with increasing incidence until age 79. The incidence below age 35 is less than 0.1 cases per 100,000 people.
Older patients have higher mortality rates.
The classical presentation begins with an incubation period of 2-10 days. There is often a prodrome of 1-2 days of mild headache and myalgias, followed by high fever, chills, and multiple rigors. Other pulmonary manifestations include dyspnea, pleuritic chest pain, and hemoptysis, which may be present in up to one-third of cases. Gastrointestinal symptoms include nausea, vomiting, diarrhea, and anorexia. Neurological symptoms include headache, altered mental status, and rarely, focal neurological symptoms.