Legionella

Legionnaires’ disease is a relatively new disease that came to light in 1976 following an outbreak of pneumonia in a Philadelphia hotel that affected members of the American Legion who were holding their annual convention. There were a total of 182 cases with 34 deaths. The disease was called legionellosis and was described by researchers at the Center for Disease Control (CDC) in Atlanta; the agent was called Legionella pneumophila.

It is a notifiable disease since 1997 in Spain.

Legionella is an environmental bacterium and its natural reservoir is the surface waters such as lakes, rivers, ponds, forming part of its bacterial flora. From here, the bacterium can colonize the supply systems of the cities, and be incorporated to the sanitary water systems (cold or hot), to elements like deposits or cisterns, accumulators or thermos, pipes, jacuzzis, etc. These, among other facilities, are contemplated in the Royal Decree 865/2003 for the prevention and control of the legionellosis.

The transmission of the infection is carried out by air through the inhalation of aerosols or respirable droplets (less than 5 μm) containing Legionella and also by micro-aspiration of contaminated water. Legionellosis is not transmitted by drinking water, eating food, from person to person, or from animals to people.