Introduction and objective:
Legionella pneumophila (L.pneumophila) is a Gram-negative aerobic bacteria with rod-shaped cells. It occurs in humid environments, in moist soil and compost material. L.pneumophila in humans can cause a respiratory disease called Legionnaires’ disease and Pontiac fever. Human infection is most commonly caused by inhalation of Legionella-containing aerosols produced by contaminated water sources. The bacterium has the ability to multiply inside alveolar macrophages and blood monocytes.

Abbreviated description of the state of knowledge:
Following exposure to Legionella-containing aerosol, individuals may become asymptomatic or symptomatic depending on their current health status. The onset of LD is acute, with high fever, myalgia and cough. On the other hand, approximately 50% of patients additionally have neurological and gastrointestinal disturbance, relative bradycardia, hypophosphataemia or elevated ferritin levels. In addition to clinical signs, laboratory confirmation is necessary to make a diagnosis; tests are performed on the basis of sputum, secretions from the respiratory tract; tissue, blood, serum and urine samples.

Summary:
L. pneumophila is increasingly being identified as the leading cause of community-acquired pneumonia and is an important public health problem. Air conditioning is increasingly documented as a source of infection in community-acquired L. pneumophila outbreaks. In order to prevent the occurrence of Legionella infection, it is primarily necessary to reduce the number of outbreaks and their size. There is currently no vaccine available against Legionella infection.