Key Points

Chikungunya, Dengue, and Zika

Indigenous Cases

As of October 19, 2026, 27 outbreaks (+1 new outbreak compared to the previous week) of locally transmitted vector-borne disease have been identified in mainland France:

• 22 chikungunya outbreaks (no new outbreaks compared to the previous week) totaling 183 cases (1 to 36 cases per outbreak) in the Tarn, Lot, and Gard departments (Occitanie), in Gironde, the Landes, and the Pyrénées-Atlantiques (Nouvelle-Aquitaine), in Val-de-Marne (Île-de-France), and in the Var (Provence-Alpes-Côte d'Azur);
• 5 dengue outbreaks (+1 new outbreak compared to the previous week) totaling 7 cases (1 to 2 cases per outbreak) in the Tarn, the Hérault (Occitanie), the Bouches-du-Rhône, the Var (Provence-Alpes-Côte d'Azur), and the Dordogne (Nouvelle-Aquitaine).

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 18, 2026, the following were identified:

• 160 imported cases of chikungunya
• 456 imported cases of dengue
• 17 imported cases of Zika

West Nile virus infections

Autochthonous cases

• As of October 19, 2026, 195 locally acquired cases of West Nile virus infection (+17 compared to the previous week) had been identified in mainland France. These cases are located in the Provence-Alpes-Côte d'Azur region (3 departments), Occitanie (7 departments), Île-de-France (7 departments), Auvergne-Rhône-Alpes (4 departments), Nouvelle-Aquitaine (2 departments), Pays de la Loire (4 departments), Centre-Val de Loire (Loiret department), and Corsica (2 departments). For 20 cases, no specific site of infection could be identified. For one of these cases, it could not be determined whether the infection was locally acquired or imported.