(Legionnaire's Pneumonia; Legionella pneumophila)
Legionnaire's disease is a rare form of pneumonia, or lung infection. It got its name after the disease struck at the American Legionnaires Convention in 1976.
Legionnaire's disease is caused by the bacterium Legionella pneumophilia. The bacteria are most often found in sources of standing water. Examples include cooling towers, HVAC systems and air conditioners. It can also be found in soil, such as potting soil.
Legionnaire's disease can be contracted by:
- Breathing water vapor from a standing water source that contains Legionella bacterium into the lungs
- Breathing dust from soil containing Legionella bacterium into the lungs
Person to person transmission does not occur.
A risk factor is something that increases your chance of getting a disease or condition. Risk factors for Legionnaire's disease include:
- Advanced age
- Sex: Male
- Excessive alcohol intake
- Chronic lung disease
- Weakened immune system (as with AIDS)
- People with kidney failure
- Taking cortisone or other immunosuppressive drugs
- Organ transplant patients
- Working with soil, especially newly tilled soil or potting soil
Symptoms may include:
- Fever (often high)
- Chills and muscle aches
- Dry cough
- Chest pain with coughing or breathing
- Loss of appetite
Symptoms that develop if the infection becomes serious include:
- Shortness of breath
- Abdominal pain
- Nausea, vomiting, or diarrhea
- Mental problems, confusion, or memory loss
The doctor will ask about your symptoms and medical history, and perform a physical exam.
Tests may include:
- Blood Tests–to look for high or rising antibodies to Legionella bacteria
- Sputum Tests–to stain or culture the mucus from deep inside your lungs. This may help identify the cause of the infection.
- Kidney Function Tests–poor kidney function is often seen in Legionella infected patients
- Urine Tests–to check for Legionella proteins in the urine
- Chest X-Ray–to help diagnose pneumonia or lung infection
Legionnaire's disease is usually treated with antibiotics. Quinolones, macrolides (such as azithromycin, clarithromycin, or erythromycin), or tetracycline are commonly prescribed. In severe cases, a drug called rifampin may be given. Initial therapy may be given by vein.
Proper design, maintenance, and cleaning of standing water sources, such cooling towers, plumbing systems, HVAC systems and air conditioners, can reduce the risk of spreading Legionnaire's disease.
You can reduce your risk of getting Legionnaire's disease by:
- Not smoking
- Limiting the amount of alcohol you drink
- If you work with freshly tilled soil or potting soil:
- Wear gloves and a mask.
- Don't inhale dust from the soil.
- Moisten the soil to lower the amount of dust.