Legionellosis prevention in France.

Since 1997, both the prevention of legionellosis and the control of Legionella in water networks and cooling towers have greatly improved in France. The epidemiological surveillance of Legionnaires' disease showed an increase, which was followed by a decrease in the incidence after a maximum was reached in 2005 (incidence rate of 2.5 per 10(5)). A steady decrease in the incidence rate has been observed since 2006, mainly due to the efficacy of control measures both for cooling towers and hospital water networks. In hospitals, a proactive approach was proposed in 1998 and quantitative limit values with systematic survey were put into force in 2002. The percentage of nosocomial cases has decreased dramatically and is now around 6-7% of all cases recorded in France. No nosocomial outbreak has been reported in recent years. However, this is not the case for community cases linked to diverse exposure sources, including cooling towers.