Key Points

Chikungunya, Dengue, and Zika

Indigenous cases

As of November 17, 2025, 94 outbreaks of locally transmitted chikungunya and dengue and a total of 833 cases have been identified in mainland France:

• 787 cases of chikungunya spread across 82 outbreaks (1 to 141 cases per outbreak; 73 of these outbreaks are closed);

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

• 17 isolated cases of chikungunya for which the exact place of infection could not be identified.

Imported cases

From May 1, the start of enhanced surveillance, through November 17, 2025, the following were identified:

• 1,052 imported cases of chikungunya

• 1,089 imported cases of dengue

• 11 imported cases of Zika

West Nile virus infections

Indigenous cases

• As of November 17, 2025, 59 human cases of vector-borne West Nile virus infection have been identified in 17 departments of mainland France.

• 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.