Legionella are bacteria that are common in natural (rivers, lakes etc) and artificial water systems, eg hot and cold water systems, storage tanks, pipework, taps and showers.
Legionella is usually associated with larger water systems, e.g. in factories, hotels, hospitals and the like. Legionella can survive in low temperatures, but thrive at temperatures between 20 and 45 degrees centigrade. High temperatures of 60 degrees will kill them.
Legionaires’ disease is a potentially fatal form of pneumonia caused by legionella bacteria. Infection is caused by breathing in small droplets of water contaminated by the bacteria. The disease cannot be passed from one person to another.
Legionella bacteria are common in natural water courses such as rivers and ponds. Since legionella are widespread in the environment, they may contaminate and grow in other water systems.