Legionella is a rod-shaped bacterium (of which there are about 40 different species) invisible to the naked eye, completely natural and widely spread in water sources, lakes, rivers, but sometimes also in large water installations (hotels, hospitals, etc.), air conditioning systems, spas, swimming pools, etc.

Unfortunately, bacteria of the Legionella genus, and in particular the pneumophila species, can cause even serious infectious diseases, usually affecting the respiratory system (Legionellosis). This disease can statistically be fatal in 5 to 15 % of cases, with much higher lethality peaks in individuals in special conditions such as patients already in poor clinical condition or treated late. Subjects most at risk are normally the elderly, immunocompromised persons, persons with chronic lung diseases, heavy smokers, heavy travellers, etc.

First of all, it should be made clear that drinking water containing bacteria of the Legionella genus poses no danger of infection. The disease is only contracted by inhaling tiny drops of water (aerosols) containing the pathogenic microorganism in question in high concentrations. Situations at risk of inhalation of the bacterium can occur near taps, shower stalls, decorative fountains, waterbased carpet washers, whirlpools, humidifiers, cooling towers, air conditioners, etc. Statistically, in hotel facilities, the points most at risk are shower stalls and air-conditioning diffusion points.