Key Points

• In 2024 in mainland France, 4,683 imported cases of dengue, 34 imported cases of chikungunya, 8 imported cases of Zika, and one dengue-chikungunya co-infection were reported by healthcare professionals through mandatory reporting or detected through data from the network of partner laboratories involved in arbovirus surveillance.

• Eleven episodes of local dengue transmission were identified, totaling 83 locally acquired cases. These episodes occurred in the Provence-Alpes-Côte d’Azur (n=7), Occitanie (n=3), and Auvergne-Rhône-Alpes (n=1) regions.

• A locally acquired case of chikungunya was reported for the first time in Île-de-France, one year after the identification of the first locally acquired dengue transmission cluster (n=3 cases) in this region.

• The number of dengue transmission clusters and locally acquired cases confirms the increased risk of local transmission of arboviruses transmitted by Aedes albopictus observed since 2022, with more cases reported and a geographical expansion toward the west and north.