Key Points

Chikungunya, Dengue, and Zika

Indigenous cases:

As of October 6, 2025, 87 outbreaks of locally transmitted chikungunya and dengue and a total of 737 cases have been identified in mainland France:

• 695 cases of chikungunya spread across 75 outbreaks (1 to 128 cases per outbreak; 26 of these outbreaks are closed)

• 28 cases of dengue spread across 12 outbreaks (1 to 8 cases per outbreak; 9 of these outbreaks are closed)

• 13 isolated cases of chikungunya and 1 isolated case of dengue for which the exact place of infection could not be identified

Imported cases

From May 1, the start of enhanced surveillance, through October 6, 2025, the following were identified:

• 1,007 imported cases of chikungunya

• 974 imported cases of dengue

• 11 imported cases of Zika

West Nile virus infections

Autochthonous cases

As of October 6, 2025, 44 human cases of vector-borne West Nile virus infection have been identified in 14 departments of mainland France. The affected regions are Provence-Alpes-Côte d'Azur, Occitanie, Nouvelle-Aquitaine, and, for the first time, Île-de-France and Auvergne-Rhône-Alpes.