Legionnaires Disease Assessments

          Every year in the United States 8,000-18,000 individuals are hospitalized with Legionnaires Disease (LD). LD is a form of pneumonia caused by the inhalation of the Legionella bacteria. LD is associated with flu-like symptoms (fever, chills, cough, muscle aches, headaches) which usually begin 2-14 days after being exposed to the bacteria. Mortality occurs in 5-30% of cases primarily affecting the elderly, sick, smokers and persons with weakened immune systems.

          LD and the less severe lung infection, Pontiac Fever, is caused by the inhalation of aerosolized water mist or vapor from Legionella bacteria contaminated water sources. Person-to-person transmission of LD and Pontiac Fever have not been demonstrated. In most cases, healthy individuals can be treated successfully with antibiotics.

          Legionella bacteria are naturally found in lakes, rivers, hot springs and soil. But the levels of bacteria in the natural environment are so low that they rarely cause problems. In buildings and mechanical equipment, Legionella bacteria multiply rapidly in warm water systems. The optimum growth temperature is 95'F , but legionella bacteria will thrive in temperatures between 77'F and 113'F.

The most common sources of Legionella bacteria in buildings are:

• Air conditioning equipment such as cooling towers and evaporative condensers.
• Potable water sources such as hot water tanks, shower heads, faucets, humidifiers.

          Many LD infections can go undiagnosed or under reported (just another case of flu). More illnesses are noted in the summer and early fall. Hospitals, nursing homes, hotels and cruise ships have the highest reported incidents of LD. Commercial buildings also experience reported cases of LD. Common entry points are associated with the HVAC fresh air intake in close proximity to water systems such as the cooling towers.

          AET can help you control the risk of Legionella outbreaks through the development of site-specific cleaning programs and water testing schedules.

          In facilities with a reported outbreak, AET can quickly assist you in identifying the source of bacteria and work closely with your organization to coordinate effective response. AET's experience and ability to effectively communicate complex and often overwhelming information clearly can prove to be an invaluable asset in restoring building operation in the shortest possible time.

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