Photo credit: CDC/Dr. Williams Cherry PHIL ID # 10150
Communicable Disease, Emergency Preparedness and Response (CDEPR)
Legionella is a bacteria that can be found in natural and man-made environments. Legionella in water systems survive and grow maximally in temperatures between 25 to 42°C, especially when the water source is stagnant with build up of scale and sediments. Common sources of Legionella include lakes and rivers, cooling towers, hot tubs, showers, decorative fountains, respiratory therapy equipment and damp potting soil or compost.
Legionella bacteria can be transmitted to humans when water droplets containing the bacteria are aerosolized and inhaled into the lungs. Human infections can take the form of a mild flu-like disease called Pontiac fever, or can present with more serious respiratory symptoms called Legionnaires’ disease. Those who smoke or have chronic health conditions are at greater risk of infection and more serious complications from Legionnaires’ disease.
Due to the common environmental presence of Legionella there are no specific personal recommendations to prevent exposure to the bacteria. Water systems should be properly maintained and inspected to prevent the growth of Legionella and individuals at risk for infection should avoid high-risk exposure such as hot tubs. Both Pontiac fever and Legionnaires’ disease are reportable in Ontario as legionellosis.