Welcome to the Legionellosis Outbreak Toolbox

Key reference documents

• Legionella and the prevention of legionellosis (Geneva: World Health Organization; 2007). 
• WHO legionellosis fact sheet (Geneva; World Health Organization; 2022).

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Case definitions

• Legionnaires’ disease (relevant pneumonic illness and microbiological evidence of infection).
• Pontiac fever or similar illness (relevant non-pneumonic illness and microbiological evidence of infection).
• Asymptomatic legionellae infection (no illness compatible with microbiological result). 
• Legionella infection (microbiological evidence of infection but symptoms not known).
• Suspected legionellosis (relevant pneumonic or non-pneumonic illness but no supporting microbiological evidence).

Hospital acquired (nosocomial) 

• Date(s) of admission to hospital(s) before onset of symptoms.

Community acquired 

• Known exposure to cooling towers, whirlpool spas, showers, etc. 

Travel associated 

• Countries visited, dates of stay, name and address of accommodation used, room number, name of tour operator, use of showers, spa pools, etc. 

Domestically acquired 

• Use of domestic water system during incubation period, in absence of other risk exposures.

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_{1. Legionella and the prevention of legionellosis (Geneva: World Health Organization; 2007)}

Data collection tools

• Case report forms: Not available.
• Line list: Not available. 
• Electronic tools: Not available.

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Laboratory confirmation

• Legionella and the prevention of legionellosis (World Health Organization 2007, Chapter 11 page 175-193).

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Response tools and resources

• Legionella Environmental Assessment Form Marking Guide (Centre for Disease Control and Prevention; 2022).

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Training

• Not available

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Other resources

• Legionnaires' disease outbreak case definitions (Ottawa: Public Health Agency of Canada; 2008). 
• Legionnaires' disease outbreak investigation toolbox (Stockholm: European Centre for Disease Prevention and Control; 2022). 
• Legionella (Legionnaires' Disease and Pontiac Fever) (Atlanta: Centers for Disease Control and Prevention; 2021). 
• Toolkit for Controlling Legionella in Common Sources of Exposure (Atlanta: Centers for Disease Control and Prevention; 2021). 
• CDC Legionella materials (Atlanta: Centers for Disease Control and Prevention; 2021).  
• European Technical Guidelines for the Prevention, Control and Investigation of Infections Caused by Legionella species, (Stockholm; The European Guidelines Working Group; 2017). 
• Legionnaires' disease: guidance, data and analysis (Public Health England; 2021).

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