Legionellosis is an infectious disease caused by Legionella bacteria, taking one of two distinct forms: Legionnaires’ disease and Pontiac fever.

Cases of Legionellosis and deaths occur globally and are being detected in increasing numbers, which are more likely due to better detection and diagnoses than increases in actual cases. Causal factors of Legionellosis include hot water plumbing, fountains and heat exchangers, and it is thought that older individuals who have other illnesses therefore an impaired immune system may also be more at risk.

The biggest concentration of outbreaks centre around hospitals and long-term care facilities where there is a concentration of high-risk individuals, as well as commercial facilities including public fountains, hotels and industrial facilities.

Legionnaires’ disease got its name from its first detection and identification during the 1976 American Legion Convention at a hotel in Philadelphia. Blowdown of aerosols from a rooftop cooling tower at the hotel caused the exposures and resulted in the deaths of 34 of the attendees.

Legionellosis outbreaks have been regularly identified in association with plumbing and other water facilities since 1976 and hospital, health-care and long-term-care facilities account for 8-% of outbreaks and deaths worldwide.

The route of infection is not from ingesting drinking water but from inhalation of aerosols, and this means that facilities where there is a lot of usage should take steps to reduce public and employee exposures to aerosols from heat exchangers, cooling towers and HVAC.

Preventative measures for reducing the outbreak of legionellosis or Pontiac fever include monitoring and managing the facilities that can produce aerosols of warm water, ensuring that they are cleaned and disinfected regularly, the continuous use of a biocide in decorative fountains and waterfalls, and the use and regular exchange of filters.

The use of water coolers fitted with good water filters could also ensure that there are less outbreaks, especially water coolers that have inbuilt cleaning and descaling options that make it easy to keep the water cooler 100% sterile, providing pure, chilled or warm drinking water.