Key Points

Results of Enhanced Surveillance for Chikungunya, Dengue, and Zika Virus in 2019 and 2020:

• More than 100 imported dengue cases per year; despite the decrease in air travel in 2020 due to COVID-19

• Few imported cases of chikungunya and Zika (<= 5 per year)

Outbreaks:

• 2019: one dengue outbreak (seven cases) in the Alpes-Maritimes and the first reported cases of Zika (three cases).

• 2020: three dengue outbreaks with no identified link between them: five cases in Nice and two cases in Saint Laurent-du-Var in the Alpes-Maritimes, four cases in La Croix-Valmer in the Var.

• Origin of the outbreaks: lack of adulticide treatment at the location where an imported case was present (2019 dengue outbreak) and failure to identify the primary imported case (2019 Zika outbreak and the three 2020 dengue outbreaks).

West Nile:

• 2019: 2 autochthonous human cases in the Var (Fréjus and Les Arcs) and 13 confirmed equine cases (9 in the Bouches-du-Rhône, 2 in the Gard, and 2 in Haute-Corse).

• 2020: 5 confirmed equine cases (3 in Southern Corsica, 1 in Upper Corsica, and 1 in the Var).