Key Points

Local cases

• As of July 1, 2025, seven outbreaks of locally transmitted chikungunya have been identified in mainland France (n = 14 cases). Six of these outbreaks are located in regions already affected by local transmission outbreaks in previous years: Provence-Alpes-Côte d'Azur, Corsica, Occitanie, and Auvergne-Rhône-Alpes. For the first time, a local transmission outbreak of chikungunya has been identified in the Grand Est region.

• Investigations and prevention and control measures are underway.

• The occurrence of the first episode of local transmission in the Grand Est region, combined with the early onset and the number of episodes already detected, confirms the significant risk of local transmission of chikungunya on the French mainland, including in regions that have been free of the disease until now. This transmission is facilitated by the fact that the virus strain circulating in Réunion and the Indian Ocean is well-adapted to the Aedes albopictus mosquito vector.

• Santé publique France emphasizes the importance of reporting cases, which enables rapid intervention to limit local 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 July 1, 2025, the following have been identified:

• 496 imported cases of dengue

• 712 imported cases of chikungunya

• 1 imported case of Zika