Key Points

Chikungunya, Dengue, and Zika

Indigenous cases:

As of September 29, 2025, 80 outbreaks of locally transmitted chikungunya and dengue and a total of 669 cases have been identified in mainland France:

• 633 cases of chikungunya spread across 69 outbreaks (1 to 115 cases per outbreak; 24 of these outbreaks are closed)

• 26 cases of dengue spread across 11 outbreaks (1 to 7 cases per outbreak; 8 of these outbreaks are closed)

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

Imported cases

From May 1, the start of enhanced surveillance, through September 29, 2025, the following were identified:

• 1,000 imported cases of chikungunya

• 960 imported cases of dengue

• 11 imported cases of Zika

West Nile virus infections

Indigenous cases

As of September 29, 2025, 41 human cases of vector-borne West Nile virus infection have been identified in 13 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.