34 Legionnaires’ disease cases in Marshall County

A colleague who worked in downtown Chicago had clients who contracted Legionnaires’ disease. He and I discussed it. Now the disease is showing up in Iowa in Marshall County. He knew I had several instances of getting HAPE [High Altitude Pulmonary Edema] when mountain climbing. Let’s take a look at what this lung infection is about. I’ll post for the next few days so return for more information.

Legionnaires’ disease is a type of pneumonia caused by inhaling or aspirating Legionella bacteria. Here are the main causes and contributing factors:

Source of Infection

• Contaminated water systems – The most common cause. Legionella bacteria thrive in warm, stagnant water and can multiply in:

  • Cooling towers (air conditioning systems for large buildings)

  • Hot tubs and whirlpools

  • Decorative fountains

  • Plumbing systems (especially in large buildings like hotels, hospitals, and nursing homes)

  • Water storage tanks

• Inhalation of aerosolized water – People usually become infected by breathing in small water droplets (mist or vapor) that contain the bacteria.

• Aspiration – Less commonly, it can occur if contaminated water “goes down the wrong pipe” into the lungs during drinking.

Risk Factors in Humans

Not everyone exposed becomes ill. Those at higher risk include:

• Older adults (especially 50+)

• Smokers (current or former)

• People with chronic lung disease (COPD, emphysema)

• Individuals with weakened immune systems (cancer patients, transplant recipients, people on immunosuppressive drugs, those with diabetes or kidney disease)

What Does Not Cause It

• It is not spread person-to-person in typical circumstances.

• It is not caused by drinking contaminated water (unless aspiration occurs).

 In short: Legionnaires’ disease happens when a person inhales contaminated water droplets carrying Legionella bacteria, often from poorly maintained man-made water systems.