woman in a laboratory microscope with microscope slide in hand

Legionnaire’s Disease becoming of more relevance in 2015.

Legionnaire’s Disease (also known as Pontiac Fever or Legionellosis) was in the news during the summer of 2015 when an outbreak in Bronx, New York sickened 94 people and killed 12. Another 30 were diagnosed with Legionnaire’s but did not become ill.

Legionnaire’s Disease does not affect most healthy people. Still, it’s wise to monitor appliances that can harbor the bacteria Legionella.

Where Does Legionnaire’s Come From?

Legionella bacteria are found in warm pools of water such as hot tubs, spas, hot water tanks, evaporative condensers, cooling towers, decorative fountains, and in large plumbing systems. The disease travels in droplets from these warm pools that can be breathed in as mist or vapor.

The CDC does not list air conditioners as a source for the bacteria. The recent Bronx outbreak, like the original Legionnaire’s outbreak in 1976, came from improperly maintained cooling towers that support HVAC (heating, ventilation, and air conditioning) in large buildings.

How Can I Protect My Family from the Legionella Bacteria?

If you own a hot tub or have a decorative fountain on your property, you can prevent Legionella from forming in them by keeping them clean. Treat them regularly with disinfectants, particularly for hot tubs, which have higher temperatures that favor the bacteria. The CDC offers guidance for hot tub and spa maintenance and a list of questions you can ask of maintenance staff who take care of public hot tubs and spas.

Many older homes in the Southwest US still use evaporative condensers for cooling. People in these homes should make sure these units are properly cleaned with biocides at least twice a year and inspected every month. The Occupational Safety and Health Administration (OSHA) offers guidelines on maintaining and cleaning evaporative coolers.

Am I at Risk for Legionnaire’s?

Being in a building with cooling towers does not put you at risk. Most people have actually been exposed to Legionella without knowing it.

Pneumonia, including the kind associated with Legionnaire’s, is most dangerous to elderly, people with underlying diseases and conditions that weaken their immune systems, and smokers. Pneumonia caused by Legionella is not contagious, and the bacteria are not spread through contact.

Keep in mind, too, that building owners routinely maintain their HVAC systems throughout the year, particularly after the heating and cooling seasons. It’s a business expense and a smart one for them to follow; no one wants to undertake a massive HVAC overhaul caused by poor maintenance. One environmental consulting firm notes that the chiller units that share water with cooling towers will also be affected by dirty towers, and they are particularly expensive to repair or replace.

Cooling towers are not part of the drinking system in your building so in the event cooling towers are found to harbor any kind of bacteria, rest assured that this will not affect the drinking water supply.

When Should I Suspect Legionnaire’s?

Legionnaire’s Disease has similar symptoms to flu: cough, chills, aches, and fever. Anyone who has these symptoms for more than a few days should see a medical professional for evaluation and treatment. People who know they are at-risk for complications from flu and pneumonia should always be aware when these symptoms linger.

Legionnaire’s is diagnosed through a urine antigen test. It can also be found in phlegm and through a lung biopsy. Patients are treated with antibiotics and re-tested several weeks after recovery.

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