Also, from time to time, we plan to use this site to express our opinion on issues that concern us as microbiologists involved in contamination control. Legionella is the bacterium that is responsible for an infection known as legionellosis. The two most common forms of legionellosis are Legionnaires Disease, a multisystem illness with a deadly type of pneumonia, and Pontiac Fever, a milder illness that does not require hospitalization. OSHA estimates that over 25,000 cases of legionellosis occur every year in the United States. Legionnaires Disease usually begins with flu-like symptoms such as headache, muscle aches, and high fever.
Many patients develop pneumonia that is so severe that hospitalization is required.
Legionnaires Disease is more likely to affect the elderly, smokers, and individuals with suppressed immune systems due to certain medications or diseases. Legionella are ubiquitous in the environment and are often found in very low numbers within lakes, river, and other bodies of water. When Legionella are introduced to indoor environments, such as cooling towers, evaporative condensers of large air-conditioning systems, and even dental water unit lines, they can reproduce rapidly. Legionnaires Disease is acquired by inhaling airborne water droplets that contain Legionella . If the circulated air within a building picks up droplets of contaminated water, Legionella can be spread throughout a facility.