Legionella pneumonia, or Legionnaire's disease, is an atypical form of pneumonia caused by the bacterial pathogen Legionella pneumophila. Legionella can be life-threatening, and has a higher death rate than other atypical pneumonias. It was discovered during a 1976 American Legion convention in Philadelphia, when people became ill from breathing in contaminated air from air conditioning. According to the Centers for Disease Control (CDC), between 8,000 to 18,000 people are hospitalized with this condition each year in the United States. Those at particular risk include the elderly, chronic disease patients, smokers and people with compromised immune function. Legionella is common as a nosocomial infection; for example, a significantly high incidence of Legionella pneumonia occurs in head- and neck-surgery patients.
Initial Symptoms
Initial symptoms usually begin to appear between 2 to 14 days after exposure to the pathogenic agent, and may include a high temperature (such as 104 degrees F or above) with chills, coughing, headaches and muscle aches. Symptoms tend to be worse during the first week. (See the legionella bacteria photo in Resources).
Secondary Symptoms
Symptoms may change slightly after several days to include secondary symptoms. Potential secondary signs and symptoms may consist of a productive blood-streaked cough and shortness of breath (SOB) with chest pain. Further symptoms may include fatigue, loss of appetite, confusion and gastrointestinal (GI) problems, such as nausea and vomiting (N & V) and diarrhea. Additional symptoms include coordination difficulties or ataxia, joint pain and fatigue.
Bottom Line
Legionella pneumonia is a severe type of pneumonia and should be taken very seriously, because it can cause death. Data show that mortality rates of nearly 50 percent exist for individuals who are not treated properly or who develop nosocomial Legionnaire's disease during hospital stays. Common sites where the Legionella bacteria may be found include contaminated water-cycling systems, from plumbing systems to spas and air-conditioning units. If symptoms appear, it is imperative to seek immediate medical care.
