In 2021, 234 imported cases of arboviral diseases transmitted by Aedes mosquitoes were reported in mainland France, broken down as follows:

• 231 cases of dengue (including 9 probable cases).

• 3 cases of chikungunya.

• No cases of Zika virus infection.

Nearly half of the imported dengue cases (45%) originated from Réunion, where a major outbreak was underway.

Three outbreaks of local dengue transmission, each limited to a single locally acquired case, were identified in mainland France:

• One locally acquired case in Provence-Alpes-Côte d’Azur (PACA).

• One locally acquired case in Occitanie.

• One locally acquired case in Île-de-France, for which transmission was not vector-borne but most likely post-transplant.