Legionnaires' disease
![](/Images/godic/202501/23/Legionella_pneumophila_015001.jpg")
![Various stages of the disease: Chest radiograph (A) and high-resolution computed tomography (B) at hospital admission, repeat high-resolution computerized tomography of the chest a week after hospital admission (C, D), shown in a 42-year-old male with severe pneumonia caused by L. pneumophila serogroup 11a](/Images/godic/202501/23/Severe_Pneumonia_Caused_by_Legionella_pneumophila_Serogroup_11,_Italy5001.jpg")
Legionnaires' disease is a form of atypical pneumonia caused by any type of Legionella bacteria. Signs and symptoms include cough, shortness of breath, high fever, muscles pains, and headaches. Nausea, vomiting, and diarrhea may also occur. This often begins two to ten days after being exposed.