Key Points

Chikungunya, Dengue, and Zika

Indigenous cases

As of November 3, 2025, 92 outbreaks of locally transmitted chikungunya and dengue and a total of 818 cases have been identified in mainland France:

• 770 cases of chikungunya spread across 80 outbreaks (1 to 139 cases per outbreak; 63 of these outbreaks have been contained);

• 29 cases of dengue spread across 12 outbreaks (1 to 9 cases per outbreak; all outbreaks are closed);

• 19 isolated cases of chikungunya for which the exact site of infection could not be identified.

Imported cases

From May 1, the start of enhanced surveillance, through November 3, 2025, the following were identified:

• 1,035 imported cases of chikungunya

• 1,028 imported cases of dengue

• 11 imported cases of Zika

West Nile virus infections

Autochthonous cases

As of November 3, 2025, 58 human cases of vector-borne West Nile virus infection have been identified in 17 departments of mainland France. In week 45, no new cases were reported.

The cases are located in the Provence-Alpes-Côte d'Azur, Nouvelle-Aquitaine, and Occitanie regions, which have historically been affected by West Nile virus, and in Île-de-France, Auvergne-Rhône-Alpes, and Normandy, which are affected for the first time.

In the Occitanie region, the departments of Haute-Garonne and Tarn-et-Garonne are affected for the first time, as is the department of Lot-et-Garonne in Nouvelle-Aquitaine.