Reservoir is water. Aerosolization by cooling towers, spas, shower heads, etc.
Occurs in outbreaks.
Person-to-person transmission not documented.
Pneumonia (Legionnaires disease)
Pontiac fever (Self-limited febrile illness)
Extrapulmonary infections rare, but include endocarditis
Risk factors include:
Outbreak setting
Older male
Smoker
Cardiopulmonary disease
Renal disease
Immunosuppression
