Overview
- Health authorities opened the seasonal control campaign this month and urged people to pair home prevention with municipal spraying and, in specific cases, vaccination.
- Last year brought unprecedented local infections in mainland France with 809 chikungunya cases, a record 62 West Nile cases, and 30 autochthonous dengue cases, according to the Health Ministry.
- The tiger mosquito, Aedes albopictus, has taken hold in 83 of 96 departments, leaving only Brittany, the far north, and Creuse without established populations, which widens the area at risk for local transmission.
- Officials traced many 2025 flare-ups to travelers returning from La Réunion for chikungunya and from the Antilles or French Polynesia for dengue, including 160 local chikungunya cases in Nouvelle-Aquitaine with 103 in Bergerac and a three-person dengue episode in Langon.
- France’s surveillance network, active since 2006, identifies imported cases and new species to trigger targeted mosquito control and to protect blood and organ donations, with experts warning that risk stays high in 2026 even if fewer infections arrive from abroad.