Legionella is a pathogenic bacterium that is the causative agent of Legionnaire’s disease also known as legionellosis. The disease is a serious form of pneumonia and can be fatal if not diagnosed and treated early. Infection is acquired by inhalingLegionella-contaminated aerosols from sources such as cooling towers, spas and showers. The at risk populations are essentially male adults with associated risk factors such as immunodeficiency, smoking, alcoholism or diabetes. In 2005, over 1,500 legionellosis cases were reported in France and approximately 5,700 in Europe. According to the CDC (Centers for Disease Control and Prevention), an estimated 8,000 to 18,000 cases of legionellosis occur each year in the United States.