Key Points

• In 2025, 155 cases of Legionnaires’ disease were reported in the Nouvelle-Aquitaine region 
• The notification rate was 2.3 cases per 100,000 people, comparable to that of 2024 (2.2 cases per 100,000 people) and slightly lower than the rate for France (2.8 cases per 100,000 people).
• Significant disparities exist between departments, with higher reporting rates in Dordogne, Charente-Maritime, and Vienne.
• The characteristics of the cases (mostly men, median age of 67 years) were comparable to those of previous years.
• The case fatality rate was 7.6% (11 deaths), comparable to previous years.
• The use of PCR testing on respiratory specimens increased significantly (43% of cases tested positive by PCR in 2025 vs. 24% in 2024).
• A Legionella strain was isolated in 50 cases (32%, a proportion slightly higher than in previous years), leading to a comparison of clinical and environmental strains in 6 cases, 3 of which were found to be identical, thereby helping to identify the source of contamination.
• Risk exposure outside the home was reported in 44% of cases, primarily related to travel.
• In 2025, 23 cases of Legionnaires’ disease involving residents of other regions were identified in Nouvelle-Aquitaine, leading to 24 environmental investigations.