Chapter 1 1. Legionnaires disease and Pontiac fever were initially considered idiopathic in that no cause was initially found. Of course, after the condition was attributed to the Legionella bacteria, it was no longer idiopathic. 2. The infectious disease physician is the best doctor to treat this disease. Infectious disease medicine is a subspecialty of internal medicine. 3. This disease is caused (etiology) by an infection of the Legionella bacteria. 4. Pontiac fever is an acute disease; it lasts less than 3 months. Legionnaires disease can be considered chronic in that survivors of the disease can have sequela for months to years. 5. The disease is more common in the middle to late age groups. Chronic smokers, patients with respiratory conditions, and immunocompromised patients have a higher incidence of infection. 6. When the patient presents to the clinician with signs and symptoms of the disease, a history and physical exam is performed. The results of the history and physical exam lead the clinician to a tentative diagnosis, based upon his/her clinical knowledge. In order to confirm the diagnosis, lab tests are performed. It is at this point throat swabs and samples of respiratory secretions are obtained. These samples are tested using microbiological procedures. If these findings are positive for the Legionella bacteria, this states that the patient has been exposed and infected. To further diagnose the actual disease, histopathological studies are performed to look for diagnostic