X-ray Image of Patient with Legionnaire’s Disease

Legionnaire’s disease is an acute respiratory infection caused by Legionella bacteria. You can watch the video embedded below for more details about Legionnaire’s disease.

Some of the major causes of this disease are: water delivery systems, warm, moist, air conditioning systems of large buildings, including hospitals. Most cases are caused by Legionella pneumophila. The rest of the cases are caused by other Legionella species.

Risk factors include:
Alcoholism
Cigarette smoking
Diseases such as kidney failure or diabetes
Diseases that weaken the immune system, including cancer
Long-term (chronic) lung disease, such as chronic obstructive pulmonary disease (COPD)
Long-term use of a breathing machine (ventilator)
Medicines that suppress the immune system, including chemotherapy and steroid medications
Older age
Symptoms

Symptoms tend to get worse during the first 4 – 6 days. They typically improve in another 4 – 5 days.

Symptoms may include:
Chest pain
Coughing up blood
Fever
Gastrointestinal symptoms, such as diarrhea, nausea, vomiting, and abdominal pain
General discomfort, uneasiness, or ill feeling (malaise)
Headache
Joint pain
Lack of coordination (ataxia)
Loss of energy
Muscle aches and stiffness
Nonproductive cough
Shaking chills
Shortness of breath

Sources:

http://www.nlm.nih.gov/medlineplus/ency/article/000616.htm