Abstract
Pathogenic species of the Legionella genus can cause respiratory diseases ranging in severity from bening. Pontiac fever to life-threatening Legionnaires' disease often characterized by severe pneumonia, high fever, and multiple organ involvement.
Predisposing underlying conditions, such as immunosuppression, chronic lung disease, and malignancies and other variables such as smoking and higher age constitute high-risk factors. Legionalla has been isolated from natural aquatic habitats (freshwater streams and lakes, water reservoirs, etc.) artificial sources, and also from humid soil.
These pathogens are distributed worldwide. Besides water reservoirs (surface and underground water, fresh and salt water), they occur in a wide range of technical devices and systems - water distribution systems, showers, pools, spa systems, periators, foggy makers, irrigation systems with sprinklers, cooling towers, etc.
About 20% of detected Legionella infections in Europe have been associated with travel history. Travel-associated cases present a particular difficulty in terms of identifying the source of infection and implementing remedial measures.