Legionella

What is legionella?

Legionella belongs to the genus of rod-shaped bacteria. The habitat of legionella is water. Legionella became known because it is responsible for causing certain diseases in humans.

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Where does legionella occur?

Legionella can occur wherever warm water is available. Legionella feels particularly comfortable at temperatures above 30°C and below 65°C or in installations where biofilm and calcium deposits are present. Domestic water installations can therefore be particularly susceptible to legionella.

This applies in particular to the following systems:

• Hot water generation and hot water distribution systems (e.g. heating systems or water pipes)
• Water supply lines in which the water stands still for a long time (stagnation water)
• dead lines
• Cold water supply lines with external heat
• air conditioners

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What role do calcium deposits play in legionella contamination?

Calcium deposits act in a similar way to an anchor: The legionella and other microorganisms are prevented from being flushed out of the pipe system, as calcium deposits provide microorganisms with an ideal habitat for unhindered reproduction. Calcium deposits perform this task for both non-pathogenic and pathogenic germs (e.g. legionella). Even thermal legionella protection circuits (increasing the water temperature) do not provide sufficient effect against safely killing existing legionella, as calcium deposits have a strong insulating effect. Legionella can even survive water temperatures of up to 70 °C — only legionella floating freely in water is thermally inactivated. As a prevention against legionella, it is therefore useful to keep your own water installation hygienically clean so that legionella does not find a habitat.

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What effects does legionella have on humans?

Legionella can generally be caused by contact with tap water be transferred. The transmission of legionella to the human organism is particularly dangerous when it reaches deep lung sections. This can be the case when showering, for example, when you inhale a mixture of water and legionella (bioaerosol). Drinking water contaminated with legionella, on the other hand, is safe for people with an intact immune system. If an infection occurs, it often manifests itself as a type of pneumonia, also known as “legionnaires disease.” This often affects people with a weakened immune system.