Key Points 

Chikungunya, Dengue, and Zika

Indigenous Cases

As of August 17, 2026, six outbreaks of locally transmitted cases have been identified in mainland France
:

• 3 chikungunya outbreaks totaling 25 cases (1 to 16 cases per outbreak) in the Tarn (Occitanie) and Gironde (Nouvelle-Aquitaine);
• 3 dengue outbreaks totaling 4 cases (1 to 2 cases per outbreak) in the Tarn, Hérault
  (Occitanie), and Dordogne (Nouvelle-Aquitaine).

Investigations and prevention and control measures are underway for these various
outbreaks.

Imported cases

From May 1, the start of enhanced surveillance, through August 16, 2026, the following have been identified:

• 110 imported cases of chikungunya
• 308 imported cases of dengue
• 11 imported cases of Zika

West Nile virus infections

Indigenous cases

As of August 17, 2026, 18 locally acquired cases of West Nile virus infection have been identified in mainland France. They are located in the Provence-Alpes-Côte d'Azur region (Bouches-du-Rhône and Vaucluse departments), Occitanie (the departments of Pyrénées-Orientales, Aude, Haute-Garonne, and Gard), and Île-de-France (the departments of Essonne and Seine-St-Denis).