Legionella are a species of bacteria that cause a potentially fatal form of pneumonia, Legionnaires' disease, and a milder illness, Pontiac fever. Legionella bacteria are found in all aquatic environments and can become a risk to public health when they colonise artificial aquatic environments where they can become aerosolised and inhaled by humans. More than 61 species of Legionella exist, however, 90% of Legionnaires' disease cases are caused by Legionella pneumophila.
Common sources of Legionella include:
- cooling towers
- air conditioning systems
- spa pools
Cooling towers are most often implicated in larger clusters and outbreaks. Use of potting compost is associated with Legionnaires' disease caused by Legionella longbeachae.
Legionnaires' disease isn't common in Scotland and the majority of cases reported are related to travel outwith the country.
- Read our 'Guideline on Management of Legionella Incidents, Outbreaks and Clusters in the Community'.
- 'The investigation of household water systems in cases of Legionnaires' diease: Guidance for health protection teams' can be found on the Public Health England (PHE) website.
- Read the 'Control of legionella and other infectious agents in spa-pool systems' on the Health and Safety Executive (HSE) website.
For all infection prevention and control guidance visit the A-Z pathogens section of the National Infection and Prevention Control Manual.
Data and surveillance
Read our biennial legionella reports below:
- Legionella Infections in Scotland: 2015 to 2016
- Legionella Infections in Scotland: 2013 to 2014
- Legionella Infections in Scotland: 2011 to 2012
- Legionella Infections in Scotland: 2009 to 2010
- Legionella Infections in Scotland: 2007 to 2008
- Legionella Infections in Scotland: 2004 to 2006
- Legionella Infections in Scotland: 2002 to 2003