The Most Common Places to Catch Legionnaires’ Disease

The most common previous theory on Legionella contraction is people inhale the contaminated droplets into their lungs. However, recently new evidence suggests “aspiration” is the most common way people contract the disease. This occurs when people choke such that secretions in the mouth mistakenly go in your lungs instead of the esophagus. Since people who smoke or have lung disease lack the protective mechanisms to prevent aspiration this explains their increased risk for the disease.

The following are the most common places people have been infected by the disease:

  • Hot Tubs
  • Spas
  • Showers
  • Hotel Pools
  • Cooling Towers for AC Units

How Legionella Is Spread in These Areas

Legionella is naturally found in water and thrives in warm water. The high water temperatures used in these areas makes it more difficult to maintain the correct disinfectant levels needed to kill Legionella. Hot tubs or spas that are not properly cleaned and disinfected can become contaminated with Legionella bacteria. Victims become infected when they inhale mist or steam from the contaminated source.

Simple Ways to Test Water for Legionella

  1. Buy pool test strips. These are available at your local home improvement or pool supply store
  2. Use the strips to test for free chlorine (2-4 parts per million) or bromine (4-6 parts per million) and pH (7.2-7.8) levels.
  3. If you find inadequate levels, tell the operator and owner immediately.

Questions to Ask from the CDC

The CDC recommends you ask these four questions to the owner or operator before using any hotel pool, spa or hot tub.

  1. What was the most recent health inspection score?
  2. Are disinfectant and pH levels checked at least twice a day?
  3. Are disinfectant and pH levels checked more often when water is in use by a lot of people?
  4. Are the following maintenance activities performed regularly?
    1. Removal of the slime or biofilm layer by scrubbing and cleaning
    2. Replacement of the water filter according to the manufacturer’s recommendations?
    3. Replacement of hot tub or pool water?