Legionnaires’ disease is caused by bacterium called Legionella, which is found most often in fresh water. Symptoms include pneumonia, and in some cases, the infection can be deadly.
“Legionnaires’ disease is usually not a problem when concentrations are low,” Mayo Clinic infectious diseases specialist Dr. Pritish Tosh says. “Unless you’ve been directly exposed to it, you’re really not at risk.”
He says the infection is not spread from person to person. Instead, you get it by inhaling the bacteria that has been aerosolized, which means ultamicroscopic particles are suspended in air or gas.
According to the Centers for Disease Control and Prevention, outbreaks are commonly associated with buildings or structures that have complex water systems, including hotels and resorts, long-term care centers, hospitals and cruise ships. The most likely sources of infection include water used for showering, hot tubs, decorative fountains and cooling towers (parts of centralized air-conditioning systems for large buildings).
Legionnaires’ disease usually develops two to 10 days after exposure to Legionella bacteria. It frequently begins with these signs and symptoms:
▪ Muscle pain
▪ Fever that could be 104 degrees Fahrenheit (40 degrees Celsius) or higher
By the second or third day, you'll develop other signs and symptoms that might include:
▪ Cough, which might bring up mucus and sometimes blood
▪ Shortness of breath
▪ Chest pain
▪ Gastrointestinal symptoms including nausea, vomiting and diarrhea
▪ Confusion or other mental changes
Legionnaires’ disease primarily affects the lungs, but occasionally, it can cause infections in wounds and in other parts of the body, including the heart.
Legionnaires’ disease is treated with antibiotics. The sooner therapy is started, the less likely the chance of serious complications or death. In many cases, treatment requires hospitalization.