Where do LD Outbreaks Occur?
Legionnaires’ Disease (LD) is a lung infection that can be contracted by people who are exposed to Legionella bacteria. An outbreak occurs when two or more people get the disease at the same place and time. There is no vaccine for Legionnaires’ disease. Prevention is key to minimizing the possibility of an outbreak.
An outbreak of pneumonia occurred in July 1976 in Philadelphia, PA. It affected 221 people and tragically killed 34. Legionella bacteria were found to be the cause of the pneumonia. Many of those affected and killed were members of the American Legion attending a convention at a hotel. This outbreak gave the lung infection its name, Legionnaires’ disease.
The Centers for Disease Control and Prevention (CDC) reports that there are between 8,000 and 18,000 cases of Legionnaires' disease annually in the United States. It also estimates that more than 90 percent of cases go un-diagnosed. About 10 to 20 percent of those infected die. However, the fatality rate is likely higher in individuals with weakened immune systems.
People with compromised immune systems are more susceptible to contracting Legionnaires’ disease. Outbreaks commonly occur in buildings that have complex water systems such as hotels, long-term care facilities, and hospitals where high risk individuals are concentrated. The most likely sources of infection include water used for showering, hot tubs, decorative fountains and air conditioning cooling towers. The key to preventing an outbreak is to properly maintain building water systems, test the water regularly for Legionella bacteria, and have a plan in place if a suspected case of Legionnaires’ disease occurs.