Key Points

Chikungunya, Dengue, and Zika

Indigenous cases

As of September 2, 2025, 44 episodes of indigenous vector-borne transmission have been identified in mainland France:

• 34 chikungunya outbreaks totaling 301 cases (1 to 47 cases per outbreak);

• 10 dengue outbreaks totaling 19 cases (1 to 5 cases per outbreak).

These are located in the Provence-Alpes-Côte d'Azur, Corsica, Occitanie, and Auvergne-Rhône-Alpes regions, which were already affected in previous years, and for the first time this year in Grand Est, Nouvelle-Aquitaine, and Bourgogne-Franche-Comté.

Imported cases

• 957 imported cases of chikungunya

• 862 imported cases of dengue

• 7 imported cases of Zika

West Nile virus infections

Indigenous cases

As of September 2, 2025, 20 human cases of vector-borne West Nile virus infection have been identified in 6 departments of mainland France.

Twenty locally acquired cases of West Nile virus infection have been identified in mainland France. The affected regions are Provence-Alpes-Côte d’Azur (PACA), Occitanie, and, for the first time, Île-de-France and Auvergne-Rhône-Alpes.