Summer is conducive to temperature changes. To fight against heat, multiply devices everywhere in the house often appears as “the” solution. A habit, which is not without health level consequences: bacteria Legionellawhich are found in many hot sources of water, love to deploy. In France alone, between 1600 and 2000 people contract legionellosis each year.
Definition: What is legionnaire legionellosis or disease?
Legionellosis (or legionnaire disease) is severe pneumonia caused by bacteria of the type Legionella. These proliferate in stagnant lukewarm water and are mainly transmitted by the inhalation of fine contaminated water droplets, not by ingestion or by direct contact. Although infrequent, this disease can be serious, especially in the most fragile people. The diagnosis of legionellosis is based on a clinical examination taking into account the symptoms, the context of the disease, and the situations at risk to which the person has been exposed.
Symptoms of this potentially fatal pulmonary disease
The legionellosis incubation period is on average 2 to 10 days.
Symptoms look like a simple influenza syndrome (high fever, significant dry cough, asthenia, myalgia – muscle pain – headache, etc.) quickly followed by an increase in fever (39.5 ° C). Sensations of discomfort, abdominal pain (nausea, vomiting, diarrhea, etc.), respiratory failure, brutal weight loss and neurological disorders can then appear. If they are not treated in time, they can evolve towards a coma.
In addition, the kidney or the patients’ kidneys can sometimes stop working.
Men aged over 50 – as well as smokers or people already weakened by the disease (diabetes, cancer, etc.) – are more subject to complications.
“To cure, antibiotic treatment is generally prescribed,” said Dr. Guetta, before adding “that legionellosis is a compulsory declaration disease”.
In other words, this must be reported to the ARS (Regional Health Agency), which will seek the origin of the contamination.
Over the days, clinical manifestations of the Legionellosis tend to worsen. The fever often rises beyond 39 ° C and can be accompanied by a slowdown in heart rate (bradycardia), especially in vulnerable people, like the elderly. Other symptoms can also occur:
- Digestive disorders;
- Mental confusion;
- Breathing difficulties;
- Delirious behavior.
Hot water, cold water, air conditioning, shower, water heaters … Where and how do you catch the legionellosis?
Human contamination is by inhalation of microgoutlettes contaminated by pathogenic strains Legionella pneumophilia. These aerosols generally come from installations where stagnant domestic hot water is maintained at a temperature between 25 ° C and 45 ° C, conditions favorable to the development of bacteria.
“The recent emergence of the legionellosis is explained by its affinity for modern water supply systems”underlines the Pasteur Institute.
Indeed, the Legionella bacteria love the hot sources of water – which is why they are found at the bottom of water tanks, in water bodies, foam, sawdust, wet floors but also in water distribution systems (refrigerators, air conditioners, throwing baths or swirls, cooling towers, air conditioners, hot watercutters or humidifiers, decorative fountains, aerorefrigerant towers, etc.) where they proliferate in contact with organic deposits, iron, zinc and aluminum and other microorganisms.
Legionellosis, a potentially fatal disease
These heat -resistant bacteria flourish in particular in lukewarm waters (from 30 to 60 °) and catch by inhalation – by the nose and the airways.
“After inhalation of aerosols, the bacteria present are absorbed in the pulmonary cells then they invade macrophages, cells of the immune system, which they end up destroying”warns the Pasteur Institute.
Nevertheless, Dr. Liath Guetta, pulmonologist and member of the True Medical expert committee, is rather reassuring in the face of the risk of legionellosis.
“The legionellosis is extremely rare. In addition, no precaution makes it possible to protect themselves from it … The bacteria are invisible. So you cannot cut air conditioning during the heat wave for this reason”.
Only thing that can be avoided? “”Swirl baths, especially those public, which are real microbes nests“Indicates the pulmonologist.
Legionellosis: How to detect it in the water?
To detect the presence of Legionellawater samples are taken and then analyzed in the laboratory. The most common method is to search for bacteria on culture environments, but faster tests, such as PCR, can also be used. These checks are often carried out in hospitals, hotels or collective buildings to prevent any health risk.
How to protect yourself from legionellosis?
To limit the risks of exposure to legionellosis, certain simple but essential habits can be set up at home:
- Check that the hot water temperature is greater than or equal to 50 ° C (no more because it can cause burns);
- Draw the water regularlyespecially in rarely used taps or showers, in order to avoid stagnation conducive to the proliferation of bacteria;
- After a prolonged absencelet the hot and cold water run a few minutes before reusing them;
- Clean and describe frequently tap tips, shower headsas well as all the equipment likely to accumulate deposits;
- Maintain your hot water system once a year by a professional;
- Also remember to maintain your domestic air conditioning systemsby cleaning them and disinfecting them according to the manufacturer’s recommendations.
How to treat legionellosis and reduce the risk of mortality?
Currently, no vaccine helps protect against the legionellosis. This infection is caused by a bacteria naturally resistant to conventional treatments such as penicillins, often used for respiratory diseases. However, some specific antibiotics – such as macrolides, fluoroquinolones or rifampicin are effective if administered early enough in the evolution of the disease.