Legionnaires’ disease is a potentially fatal form of pneumonia which can affect anybody. It is normally contracted by inhaling legionella bacteria, either in tiny droplets of water (aerosols), or in droplet nuclei (the particles left after the water has evaporated) contaminated with legionella, deep into the lungs.
Legionella bacteria can survive under a wide variety of environmental conditions and water temperatures in the range 20°C to 45°C seem to favour growth. The organisms do not appear to multiply below 20°C and will not survive above 60°C.
It is usually caught in places where the bacteria have got into the water supply serving air conditioning systems, spa pools and hot tubs, showers, taps and toilets. Experience has shown that cooling towers, evaporative condensers and hot and cold water systems in a wide variety of workplaces and premises present a risk of exposure to legionella bacteria for staff, students, visitors and members of the public, including passers-by. This includes schools, colleges, universities, hospitals, care homes, nursing homes, surgeries, dental practices, offices, hotels, shops and more.