Comments
Symptoms: flu-like illness;
Signs: leukocytosis is common; normal chest x-ray;
Onset after exposure: 5 hours to less than 3 days;
Heavy exposure to: bioaerosols containing the bacterium, Legionella pneumophila;
Resolution: one to five days;
Comments: Legionnaires' disease is also caused by Legionella pneumophila. In contrast to Legionnaires' disease, the attack rate for Pontiac fever is high (95-100 %), the incubation period is short (5 to 66 hours), and the illness is benign and self-limited (resolution in 1 to 5 days). [Rom, p. 408]