Legionnaire’s Disease: The Preventable Illness
In July, a West Chester University employee tested positive for Legionnaire’s disease, a severe form of pneumonia caused by legionella bacteria. A subsequent investigation found “higher-than-acceptable” levels of the bacteria in eight campus buildings.
When an outbreak of Legionnaire’s disease occurs, it can usually be traced to some industrial or professional setting, where improperly maintained plumbing or cooling systems can be a breeding ground for legionella. Legionella bacteria thrive in warm, stagnant water, which is why water tanks must be thoroughly cleaned on a regular schedule and treated twice yearly with chlorine or other bacteria-killing chemical.
In New York, an outbreak of Legionnaire’s disease this year had – as of August 6 – sent about 100 people to the hospital and killed 10. The cases were traced to five contaminated cooling towers in the South Bronx. One of them was atop the Lincoln Medical and Mental Health Center.
The cooling towers have since been disinfected. New York’s health commissioner has issued an order stating all city buildings with cooling towers must hire an environmental consultant within two weeks, to check for contamination. New York Mayor Bill de Blasio said he would announce plans for legislation that would mandate maintenance and testing of cooling towers.
How it Occurs
When a person inhales air, mist, or water vapor contaminated with legionella, the bacteria may enter the lungs. In low levels, legionella may not cause disease. People who smoke or who have compromised immune systems run a greater risk of developing the illness.
Symptoms of Legionnaire’s disease may include flu-like symptoms, such as high fever, muscle pain, gastrointestinal upset, coughing, and shortness of breath. Unlike the flu, it cannot be transmitted from one person to another. Other symptoms may be present, and in extreme cases the disease can be fatal.
Although Legionnaire’s disease primarily occurs in large residential or corporate buildings, it can also occur in single-family homes, especially if hot tubs are present.
Hot tubs can host legionella if appropriate levels of pH, bromine, and chlorine are not maintained. If you know you’ll be using a public hot tub, you could follow the Centers for Disease Control and Prevention recommendation to purchase pool test strips ahead of time, so you can check the water for safe disinfectant and pH levels.
At home, setting your water heater to a minimum temperature of 140 degrees Fahrenheit can keep legionella from growing in the water tank. However, at that temperature, water can scald the skin, so it would be prudent to install an anti-scald device.
An inexpensive thermostatic mixing valve on your water heater ensures the hot water delivered to taps in your home has been mixed with cool water, so it’s delivered at a lower temperature.
The bottom line is: Legionnaire’s disease is preventable. Homeowners, building superintendents, and business leaders must do their part to ensure water systems are clean and appropriately maintained. Sticking to a regular cleaning schedule could help protect people from this deadly illness.