Legionnaires disease occurs as a result of infections caused by the legionellaceae family of bacteria. It is a form of pneumonia which results in around 250 identified cases a year and can prove fatal, especially to the elderly or those prone to respirable problems.
Legionnaires disease is contracted by inhaling small droplets of water suspended in air which contain the legionella bacterium.
Legionella bacteria occurs naturally in surface water and soils etc. but can also proliferate within man made environments such as cooling towers, hot and cold distribution systems, water plant, humidifiers and air washers.
Proliferation of the bacteria typically occurs between 20°C - 45°C and is assisted by the presence of suitable nutrients present in Dirt, Sludge and Scale as well as conditions of poor water flow, stagnation or where dead legs occur in water systems.
You should where appropriate:
• ensure that the release of water spray is properly controlled
• avoid water temperatures and conditions that favour the growth of legionella and other micro-organisms usually between 20 and 45 degrees
• ensure water cannot stagnate anywhere in the system by keeping pipe lengths as short as possible or by removing redundant pipe work
• avoid materials that encourage the growth of legionella
• keep the system and the water in it clean
• treat water to either kill legionella (and other microorganisms) or limit their ability to grow
What are the symptoms?
The symptoms are similar to those of flu, i.e. high temperature, fever and chills, cough, muscle pains and headache. In a severe case, there may also be pneumonia, and occasionally diarrhoea, as well as signs of mental confusion. Legionnaires’ disease is not known to spread from person to person.