Key Points

Chikungunya, Dengue, and Zika

Indigenous cases

As of August 19, 2025, 34 episodes of indigenous vector-borne transmission have been identified in mainland France:

• 27 chikungunya outbreaks totaling 154 cases (1 to 33 cases per outbreak); 6 of these outbreaks have been closed

• 7 dengue outbreaks totaling 13 cases (1 to 4 cases per outbreak), 1 of which has been resolved

They 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 in Grand Est, Nouvelle-Aquitaine, and Bourgogne-Franche-Comté.

Imported cases

• 932 imported cases of chikungunya

• 775 imported cases of dengue

• 6 imported cases of Zika

West Nile virus infections

Local cases

As of August 19, 2025, 13 human cases of vector-borne West Nile virus infection have been identified in 6 departments of mainland France. The affected regions are Provence-Alpes-Côte d'Azur (PACA), Occitanie, Corsica, and, for the first time, Île-de-France.