Tiger mosquito surge reported in Val-d'Oise, France

Residents in the Val-d'Oise department of northern Île-de-France are reporting an intense surge of tiger mosquitoes (Aedes albopictus), describing the infestation as “unlivable.” The invasive species, characterized by its black-and-white stripes and silent flight, has been established in the region for ten years.

Local mayors face legal limitations regarding pest control. According to the Agence régionale de santé (ARS) Île-de-France, large-scale mosquito eradication is restricted to instances where an active viral transmission risk, such as dengue, chikungunya, or Zika, is officially identified. In 2025, France recorded 81 local outbreaks and 809 autochthonous cases of chikungunya.

In response to the surge, the ARS conducted 370 epidemiological investigations in 2024, leading to 19 targeted insecticide treatments to interrupt potential virus transmission. Municipalities like Saint-Leu-la-Forêt have launched information campaigns to encourage residents to eliminate standing water in flowerpots and basins to prevent breeding. A reinforced surveillance period is currently in effect from May 1 to November 30.