Overview

• By September 29, Santé publique France counted 633 autochthonous chikungunya cases across 69 foci since early May, up from 570 a week earlier, plus nine isolated cases with unconfirmed exposure locations.
• Several large clusters have surpassed 70 cases in Fréjus, Antibes, and Bergerac, even as some other episodes have closed.
• Autochthonous chikungunya and dengue have been recorded in Auvergne–Rhône–Alpes, Corsica, Île-de-France, Occitanie, and Provence–Alpes–Côte d’Azur, with first detections this year in Bourgogne–Franche–Comté, Centre–Val de Loire, Grand Est, and Nouvelle–Aquitaine.
• Dengue transmission remains limited with 26 local cases to date, below the 66 recorded in 2024.
• West Nile virus infections have reached 41, including one death from a neuroinvasive case, with reports increasingly outside the historical Mediterranean transmission zone.