Summary of Legionnaires' disease cases in France in 2014The summary of Legionnaires' disease cases reported in France in 2014, published on June 16, 2015, by the French Institute for Public Health Surveillance, reports 1,348 notified cases of Legionnaires' disease. The incidence rate of reported Legionnaires' disease cases in metropolitan France was 2.0 per 100,000 inhabitants (higher than the European rate but close to that of neighboring countries such as Italy and Spain). The west-to-east geographic gradient in the incidence rate of reported Legionnaires' disease cases remained pronounced, with incidence ranging from 0.8 per 100,000 inhabitants in Brittany to 4.6 per 100,000 inhabitants in Franche-Comté (1.7 per 100,000 inhabitants for Midi-Pyrénées). The majority (67%) of cases occurred during the second half of the year, with a peak in July and August. The median age of cases was 63 years (ranging from 9 to 102 years), and the male-to-female ratio was 2.7 (970 men and 369 women). The incidence increased with age, and the highest incidence rates were observed among people over 80 years of age (6.9 per 100,000). 74% of cases (997/1,348) had at least one known risk factor (advanced age, smoking, chronic respiratory diseases, diabetes, immunosuppressive diseases, immunosuppressive treatments). The majority of cases were associated with Legionella pneumophila serogroup 1 (Lp1) (1,305 out of 1,339 cases). For 47 cases (14%), the human strain could be compared to environmental strains isolated from a location frequented by the patient, and for 32 (69%), the genomic profiles of the strains were found to be identical. For these cases, environmental and microbiological investigations determined that the drinking water systems were the most likely source of contamination in 16 healthcare facilities, 9 homes, 6 tourism establishments, and 2 other public facilities.In 2014, numerous investigations of community clusters of cases (ranging from 2 to 10 cases) were conducted by the ARS in collaboration with the Cires.