Legionella prevention: symptoms and recommendations

The bacterium Legionella pneumophila was first reported in 1977 in a convention center in the United States. It had caused an outbreak of severe pneumonia (popularly known as “Legionnaires’ disease”).

Since then, this microorganism has been causing a series of outbreaks of concern to health authorities worldwide.

What is Legionella?

Actually, the term Legionella refers to a genus of bacilli of the Legionellaceae family, but it is the aforementioned Legionella (pneumophila) that causes fever and respiratory problems. They live in stagnant water at a wide range of temperatures, particularly above 35°C.

It should also be noted that incorrect treatment of artificial water systems can lead to an outbreak of the bacteria.

How is legionella spread?

As mentioned in the previous section, poorly treated water systems in residential buildings can be an ideal habitat for these bacilli. They can infect people via suspended particles of contaminated water. If infested drinking water is ingested, if some of it accidentally enters the lungs, it can also lead to infection. In most cases, it is not transmitted from one person to another, but this can happen in rare circumstances.

Occasionally, infections have been reported up to 3km away from the source of the outbreak.


In case of infection, the bacteria can cause severe pneumonia or Pontiac fever (less severe). Below is a list of symptoms of each disease and a series of recommendations in case of infection.


  • Chest pain on coughing and/or breathing.
  • Altered perception and disorientation (65 years and older).
  • Cough with phlegm
  • Fatigue
  • Fever, sweating and shivering with shivering
  • Lower than normal body temperature (65 years and older and/or weakened immune system)
  • Nausea, vomiting or diarrhoea
  • Shortness of breath

Recommendation: consult a doctor if you experience: difficulty breathing properly, chest pain, persistent fever of 39°C or higher, persistent cough or especially cough with pus.

We strongly advise people over 65 years of age, children under 2 years of age with symptoms, people with a weakened or suppressed immune system to seek medical attention as soon as possible.


  • Fever
  • Headache
  • Generalised muscle pain
  • Cough
  • Occasionally, eye redness.

Recommendation: This is a mild illness, you should recover normally within 2 to 7 days of infection. Otherwise, if symptoms worsen, we recommend consulting a doctor.

Control and prevention

Since there is no vaccine available that can prevent infection, there are a number of control and prevention measures to be followed.

Firstly, cooling towers should be regularly and systematically maintained with biocidal agents. Droplet separators should be installed in the towers themselves in order to reduce the spread of aerosols. Maintain an adequate concentration of biocidal agents and completely empty and clean the system on a weekly basis. Maintain hot water temperature above 50°C and cold water temperature below 20°C. Stimulate water flow in buildings where the facilities are not in use.


The detection, control and prevention of this infectious micro-organism can be a somewhat technical and complicated task, which is why companies like CALITEC try to improve our procedures on a daily basis to offer optimal analysis, consultancy, control and prevention and cleaning and disinfection services.

You can find more details about us and our services in the sections ABOUT US and SERVICES.


Detection of the SARS-CoV-2 virus. CALITEC performs the detection of the SARS-CoV-2 virus on surfaces by RT-PCR. We are at your disposal for this or another consultation. Contact us through the form.
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