Legionella pneumophila infects the lungs and causes a sometimes fatal form of pneumonia. It is the causative organism of Legionaires Disease and Pontiac Fever. Legionnaires' disease can have symptoms like many other forms of pneumonia: a high fever, chills and a cough. Some people may also suffer from muscle aches and headaches. These symptoms usually begin 2 to 14 days after being exposed to the bacteria.

Classically Legionella spp. are found in cooling towers, air conditioners, spa equipment, fountains, humidifiers and showers, hot and cold water systems, oil/water emulsions used for lubricating lathes, misting devices, decorative fountains and water features, dentistry tools, TMV's (thermostatic mixing valves). The mode of transmission is through inhalation of airborne droplets.

Legionella detection and identification methods fall into 2 categories: those methods that are aimed at the clinical diagnosis of disease and those aimed at monitoring and identifying risk in water systems. These methods are listed separately.

Prevention of Legionnaires' disease depends on good maintenance of possible sources, including regular cleaning and disinfection and the application of other physical (temperature - keeping hot water at 60°C and cold below 20°C) or chemical measures (biocide).

There have been reports in several journals of viable but non-culturable [VBNC] Legionella. In some instances it would appear that these are associated with free-living amoebae - a reported consequence of this is significantly increased resistance to biocides. Particular care must be taken when choosing the optimal test method for evaluating such samples.

There are many contract testing companies that specialise in Legionella management and testing of water; these can be access via the Find a laboratory section of this website.