LEGIONELLA

Legionella are bacteria that cause different symptoms in persons, from flu-like ones to severe pneumonia. They are environmental germs that exist around the world and occur naturally in surface waters and ground water in small numbers.

Legionella procreate best at temperatures between 25°C and 45°C. They are usually killed off at temperatures above 60 °C and typically do not multiply at temperatures below 20 °C. Artificial water systems such as water pipes in buildings offer an environment that fosters the growth and spread of the pathogen if temperatures are right. Legionella can procreate particularly well in deposits and coatings of the pipes.

Through contaminated water droplets

The pathogens are transmitted by atomised, misted water. The pathogen-containing droplets can spread through the air and be inhaled. Possible sources of infection include showers, humidifiers, whirlpool baths or water taps, as well as cooling towers. There are also many other potential sources of infection.

When drinking, infection is rare but possible when water accidentally enters the lungs via the trachea when choking.

Important: Legionella cannot be transmitted from person to person.

Legionella cause two different symptoms in persons:

Legionnaire's disease/legionella pneumonia

Legionnaire's disease or legionella pneumonia is a type of pneumonia. Symptoms include coughing, chills, headaches and high fever, and patients may also feel extremely unwell. Diarrhoea and states of severe confusion may also occur. If left untreated – or if treated incorrectly – the pneumonia will often take a severe course, although there is a good chance of recovery if treated properly.

Pontiac fever

Another less well-understood disease that is caused by legionella bacteria is known as “Pontiac fever”. Symptoms include a flu-like fever, feeling unwell, headaches and aching limbs, but pneumonia does not develop. Pontiac fever usually resolves without intervention within a week or so.

The first symptoms of Legionnaire's disease occur 2 to 10 days after contact with the pathogen.

There are 5 hours to barely three days, on average 1 to 2 days, between infection and breakout of Pontiac fever.

Independently of the symptoms, the patients are not contagious.

Il est important d'éviter la prolifération des légionelles dans les conduits des installations d'eau potable.

Les installations et l'entretien des systèmes d'eau potable sont soumis à des réglementations techniques spéciales. La réglementation sur l'eau potable impose d'effectuer un prélèvement régulier d'eau dans les grandes installations et les bâtiments publics ainsi que dans les installations commerciales. Il est impératif de signaler aux autorités toute concentration dépassant une limite fixée.

Les mesures de sécurité suivantes peuvent permettre d'éviter une prolifération massive des légionelles dans les systèmes d'eau chaude d'une habitation :

• En général, il faut utiliser régulièrement les conduites d'eau et éviter tout bras mort dans le système de conduits, pour éviter toute formation d'eau stagnante.
• Dans un foyer avec un chauffe-eau central, réglez la température du chauffe-eau à 60°C minimum. La température de l'eau courante doit toujours être de plus de 55°C à tout endroit.

Il n'existe pas de vaccin contre les légionelles.