Key Points

• Increase in the number of reported cases of Legionnaires’ disease among residents of the region (n=158) in 2022 compared to 2021 (128) and compared to the average number of reported cases prior to 2020 (an average of 101 cases per year from 2001 to 2019).

• A resurgence of cases in the fall with an unusual peak in October, unlike in recent years when the majority of cases occurred between May and September.

• Incidence rate of reported cases of 2.7 cases per 100,000 inhabitants in 2022 (vs. 2.1 in 2021), close to the incidence rate in metropolitan France (2.8 per 100,000).

• A more or less significant increase in the reporting rate in most departments of the region in 2022, except in Creuse, Gironde, and Dordogne, where the rate was declining.

• Characteristics of Legionnaires’ disease cases were similar to those observed in mainland France and in previous years: a higher reporting rate among men (male-to-female ratio = 2.4) and an increase in incidence with age regardless of sex.

• A slight decrease in the use of lower respiratory tract culture, which allows for comparison with a potential environmental strain and the identification of a common source of contamination in clusters of cases.