Key Points

Chikungunya, Dengue, and Zika

Indigenous cases

As of August 5, 2025, 21 outbreaks of local transmission have been identified in mainland France:

• 16 chikungunya outbreaks (1 to 13 cases per outbreak)

• 5 dengue outbreaks (1 to 3 cases per outbreak)

These total 72 cases and are located in the Provence-Alpes-Côte d'Azur, Corsica, Occitanie, and Auvergne-Rhône-Alpes regions—which were already affected in previous years—and, for the first time, in the Grand Est and Nouvelle-Aquitaine regions.

The number of transmission clusters highlights the significant risk of local transmission of these viruses in mainland France. Additional cases are likely to be identified, including outside the usual transmission zones.

Santé publique France reiterates the importance of reporting cases, which enables rapid intervention to limit transmission, as well as the importance of protective measures against mosquito bites and efforts to control larval breeding sites.

Imported cases

From May 1, the start of enhanced surveillance, through August 5, 2025, the following were identified:

• 892 imported cases of chikungunya

• 698 imported cases of dengue

• 3 imported cases of Zika

West Nile virus infections

Indigenous cases

• Three locally acquired cases of West Nile virus were identified in 2025.