How can you contract Legionnaires’ disease?

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Is Legionnaires’ disease contagious?

In general Legionnaires’ disease is not considered to be contagious. However, in very rare circumstances, Legionnaires’ disease can be spread from person to person.

What is the most common way of contracting Legionnaires’ disease?

People most commonly contract Legionnaires’ disease from spray outlets such as showers, pot washes and uses of hoses from bib taps, as all these outlets have potential to create water droplets. It can also be contracted from evaporative cooling systems as these towers can create aerosols that can drift into the atmosphere. It is most common to contract Legionnaires’ disease in public places where outlets are not necessarily getting regular usage, leading to stagnant water where Legionella can grow. 

Who is most at risk from Legionnaires’ disease?

Whilst Legionella is not harmful to most healthy people there are certain groups who are at higher risk of contracting Legionnaires’ disease. These include:

  • Current or former smokers
  • People over the age of 50
  • People with specific health issues or conditions

People with the following health conditions are at increased risk of getting ill if exposed to Legionella:

  • Cancer
  • Chronic lung disease
  • Diabetes
  • Kidney failure
  • Liver failure
  • Weak immune system

How to treat Legionella in water

Legionella is naturally occurring in water and so cannot be removed but with adequate, practical controls in place, the growth of the bacteria can be reduced along with the associated risks. Controls include maintaining a good system condition and regular flushing of infrequently used outlets. Temperature testing is also carried out to ensure hot and cold water is supplied outside the Legionella growth band (20oC to 50oC); and regular de-scaling of any showers and spray outlets, as scale can harbour bacteria. Wet cooling systems are treated with chemicals to ensure that bacteria and Legionella growth is neutralised which lessens the risk of a legionella outbreak.

This guide is of a general nature; specific advice can be obtained from Assurity Consulting.

Assurity Consulting is the UK's leading independent compliance consultancy specialising in workplace health, safety and environmental solutions. We have over 35 years' experience of helping customers of all sizes, from across all sectors, manage their compliance responsibilities, making sure that their organisation is compliant, their employees are safe, their processes are cost effective and their management team is in control.