Key Points

Chikungunya, Dengue, and Zika

Indigenous Cases

As of October 5, 2026, 24 outbreaks (+1 new outbreak compared to the previous week) of
locally transmitted vector-borne disease have been identified in mainland France:

• 20 chikungunya outbreaks (+1 new outbreak compared to the previous week), totaling 146 cases (1 to 34 cases per outbreak) in the Tarn, the Lot, the Gard (Occitanie), in Gironde, in the Landes (Nouvelle-Aquitaine), in Val-de-Marne (Île-de-France), and in the Var (Provence-Alpes-Côte d'Azur);
• 4 dengue outbreaks (no new outbreaks compared to the previous week) totaling 6 cases (1 to 2 cases per outbreak) in the Tarn, the Hérault (Occitanie), the Dordogne (Nouvelle-Aquitaine), and the Bouches-du-Rhône (Provence-Alpes-Côte d'Azur).

Investigations and prevention and control measures are underway for the various outbreaks that are still active.

Imported Cases

From May 1, when enhanced surveillance began, through October 4, 2026, the following were identified:

• 156 imported cases of chikungunya
• 437 imported cases of dengue
• 17 imported cases of Zika

West Nile virus infections

Indigenous cases

• As of October 5, 2026, 161 locally acquired cases of West Nile virus infection (+16 compared to the previous week) have been identified in mainland France. These cases are located in the Provence-Alpes-Côte d'Azur region (3 departments affected), Occitanie (7 departments affected), Île-de-France (7 departments affected), Auvergne-Rhône-Alpes (4 departments affected), Nouvelle-Aquitaine (Gironde department), Pays de la Loire (3 departments affected), and Centre-Val de Loire (Loiret department). For 15 cases, no specific site of infection could be identified.