There are many different types of Legionella bacteria found in the environment.
Water and Legionella bacteria
Legionnaires’ Disease from water is caused by the species Legionella pneumophila.
Legionella pneumophila must be inhaled in an aerosol (i.e. where bacteria are contained in small airborne droplets of water) for Legionnaires’ Disease to occur.
Legionella pneumophila have been isolated from many sources, including hot water systems, cooling towers, hot and cold water taps, showers, nebulisers, spa baths, hydrotherapy pools and ornamental fountains.
Although there have been no reported cases of Legionnaires’ Disease connected with the use of evaporative cooling systems, correct maintenance of evaporative air coolers is essential to control the accumulation of sediment, bacteria, moulds and algal growth inside the unit. Portable evaporative cooling units should be completely drained at least once a week during the summer season.
Water Quality Fact Sheet on Legionnaires' Disease
Gardening and Legionella bacteria
Legionella can be transmitted by breathing in dust from potting mixes, composts, mulches and from hands contaminated with these materials.
For more information, download the brochure Enjoy Gardening without the risk of Legionella