Causes

This disease is caused by the bacterium Legionella pneumophilia . The bacteria are most often found in sources of standing water. It may be found in cooling towers, HVAC systems, and air conditioners. It can also be found in soil.

Legionnaire's disease can be contracted by:

• Breathing water vapor from a standing water source that contains Legionella bacteria into the lungs
• Breathing dust from soil containing Legionella bacteria into the lungs

The Lungs

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The infection does not move from one person to another.

Risk Factors

Factors that increase your chance for Legionnaire's disease include:

• Advanced age
• Sex: male
• Smoking
• Excessive alcohol intake
• Chronic lung disease
• Weakened immune system (as with AIDS )
• People with kidney failure
• Diabetes
• Taking cortisone or other immunosuppressive drugs
• Organ transplant patients
• Working with soil, especially newly tilled soil or potting soil