Key Points

Chikungunya, Dengue, and Zika

Indigenous Cases

As of August 30, 2026, 12 outbreaks (+1 compared to the previous week) of locally transmitted vector-borne disease were identified in mainland France: 

• 8 outbreaks (+1) of chikungunya totaling 46 cases (1 to 27 cases per outbreak) in the Tarn, the Lot (Occitanie), the Gironde (Nouvelle-Aquitaine), and the Val-de-Marne (Île-de-France); 
• 4 outbreaks (no new outbreaks compared to the previous week) of dengue, 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 ongoing outbreaks.

Imported Cases

From May 1, when enhanced surveillance began, through August 30, 2026, the following were identified:

• 126 imported cases of chikungunya
• 353 imported cases of dengue
• 11 imported cases of Zika

West Nile virus infections

Autochthonous cases

As of August 30, 2026, 39 locally acquired cases (9 more than the previous week) of West Nile virus infection had been identified in mainland France. These cases are located in the Provence-Alpes-Côte d'Azur region (in 3 departments), the Occitanie region (4 departments), the Île-de-France region (5 departments), and the Auvergne-Rhône-Alpes region (the Drôme department). For two cases, no specific site of exposure could be identified.