Legionnaires' Disease: Your HVAC System Could Make People Sick


Just last week, new cases of Legionnaires' disease were confirmed in New York; 71 people in five locations have become ill, and four have died. This apparently sudden re-emergence of a disease that first made headlines back in July 1976 is actually anything but an episodic occurrence. In fact, OSHA reports that Legionnaires' disease and Pontiac fever (caused by the same bacteria) affect 25,000 people in this country every year, resulting in over 4,000 deaths. Because the bacteria that cause this sometimes fatal disease are activated when infected water is aerosolized, you may want to schedule a consultation with an HVAC contractor to make sure your home or business doesn't pose a risk to you or others.

What is Legionnaires' disease?

Legionnaires' disease was named after some members of the American Legion who, infected during a Philadelphia conference, were its first victims. It is a type of pneumonia caused by the bacterium Legionella pneumophila. The bacteria do not cause illness unless aerosolized or aspirated. Aerosol transmission usually occurs by inhaling infected vapors from air conditioning systems, jacuzzis, or cooling towers. Aspirating infected drinking water--for instance, choking while drinking, as can happen if you suddenly laugh mid-gulp--can also cause illness. Legionnaires' disease is not contagious, but large numbers of people can contract the disease in the same building at the same time if bacteria are present in central heating/AC systems. The AC system was, in fact, the culprit for the 1976 outbreak.

What are the symptoms?

The symptoms of Legionnaires' disease appear two to ten days after exposure and are similar to the onset of the flu. They include

  • fever
  • muscle aches
  • cough
  • headache
  • lack of appetite

The illness then progresses to a high fever, shortness of breath, chest pain, chills, and gastrointestinal distress. The fatality rate is similar to other types of pneumonia at 15% of those infected, but it can claim as many as 30% of patients depending on the outbreak. People over 50, smokers, and those with COPD or weakened immune systems are most at risk of contracting the disease. Treatment involves antibiotic medication and symptom support.

What can be done to prevent it?

There are ways you can lower your risk of infection to Legionnaires' disease: stop smoking and avoid hot tubs. However, as a homeowner or business owner you can take practical steps to keep Legionella pneumophila out of your air conditioning system and cooling towers. Your goals should be:

  1. Prevent infected water from entering delivery systems. The bacteria responsible for this disease thrives in warm, stagnant water. Your water source should be examined and tested on a regular basis. Further, consider using an automatic water treatment system that will knock out germs on an ongoing basis.

  2. Scrupulously maintain cleanliness of cooling towers. Cooling towers, which may be responsible for transmission in the current New York cases, should be inspected and disinfected on a consistent basis. Consider locating HVAC fresh-air intakes away from cooling towers to reduce the potential for infected water to enter your system.

  3. Clean evaporative condensers thoroughly once a year. Replace any corroded parts and remove algae and accumulated scale.

If you own a home or business, it's important to ensure that those around you are not exposed to this dangerous disease. The best thing to do is to use a certified HVAC contractor to assess the health of your air conditioning system. The contractor uses federal guidelines to inspect for the presence of Legionella pneumophila, evaluate testing results, eliminate the bacteria, and establish regular maintenance. This isn't something you can do on your own, so call an HVAC company in your area and set up an inspection today, or visit their sites like the one at http://www.perryheatingandcooling.com.


7 August 2015

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