Key Points

• The enhanced surveillance system for dengue, chikungunya, and Zika is active from May 1 to November 30, the period of activity for the Asian tiger mosquito (Aedes albopictus) in mainland France.
• Given the history of Aedes albopictus colonization and as evidenced by surveillance data from recent years (see 2025 report on the following page), the occurrence of episodes of autochthonous transmission (without a travel history) of viruses by this vector is now an expected annual occurrence in mainland France, particularly in Occitanie.