Transmission mechanisms and preventive measures

Factors that favor legionellosis transmission

The aerial transmission of Legionella pneumophila takes place in the following circumstances:

  • The Legionella enters the facility.
    This fact may be caused by:
    • Use of contaminated water.
    • Lack of isolation from external sources of pollution.
  • Legionella multiplies.
    Multiplication occurs by:
    • Use of materials that facilitate the formation of biofilm.
    • Stagnated water.
    • Lack of cleaning and disinfection.
    • Temperatures between 20 and 50 .C. 
  • The Legionella can be dispersed.
    Dispersal is facilitated by:
    • Inefficiency of droplet separator in cooling towers.
    • Use of shower shells with small orifices that encourage aerosolization in health hot water systems.
    • Devices that spray or spray water.

Preventive measures

Preventive measures are covered by Article 7.2 of RD 487/2022, which establishes health criteria for the prevention and control of legionellasis.

Preventive measures to prevent legionellosis transmission consist of:

  • To ensure the elimination or reduction of dirty areas, the accumulation of dirt, as well as stagnation through good design and maintenance of facilities and equipment. 
  • Avoid the conditions that favor the survival and multiplication of Legionella, by controlling the water temperature and disinfection of the water.
  • Minimize aerosol emission.
  • Apply corrective measures to mitigate risk.

Pàgina principal Mecanismes de transmissió i mesures preventives Instal·lacions Competències municipals