Recent heavy rainfall in France is raising concerns about a potential increase in mosquito populations along the Mediterranean coast this summer. Understanding mosquito activity is crucial for public health, as these insects can transmit diseases like West Nile and Usutu viruses.
The Aedes detritus mosquito, a species common in the coastal wetlands during the winter months, is already well-established in the Gard and Hérault departments. “The surveys conducted by field teams revealed the presence of larvae on nearly 6,000 hectares between January and February 2026, compared to 2,900 hectares during the same period in 2025,” according to a statement from the Entente interdépartementale pour la démoustication du littoral méditerranéen (EID Méditerranée).
This increase is linked to the abundant rainfall since December. “These precipitations led to several flooding events, permanently establishing high water levels in coastal wetland areas. (…) The extent and persistence of these floods favored widespread hatching of Aedes detritus,” EID Méditerranée confirmed.
1 300 hectares treated in the Hérault, 900 in the Gard
“We have already begun treatments by air or ground, when conditions permit,” explains Jean-Claude Mouret, head of operational coordination at EID Méditerranée. “We target the larvae with a bio-insecticide that we spread on areas where larvae have been found. We have intervened on the Gard coast, in municipalities like Le Grau-du-Roi or Aigues-Mortes, as well as on the Hérault coast, from Vendres to La Grande-Motte.”
By the finish of February, nearly 1,300 hectares of wetlands had already been treated in the Hérault and nearly 900 hectares in the Gard, totaling over 2,700 hectares across the entire EID Méditerranée intervention zone. Despite these efforts, “emergence of adult mosquitoes is currently occurring as temperatures rise, both in untreated areas (lower densities) and to a lesser extent in treated areas.”
However, “this exceptional situation does not foreshadow the risk of nuisance for spring and summer. Mosquitoes have a lifespan of three weeks to a month, no more,” Mouret reassured. “We will continue our interventions. All treatment methods are being used (airplane, helicopter, drones, amphibious vehicles…) to minimize residual nuisance from mosquitoes from wetlands.”
Regarding the Asian tiger mosquito, which breeds in urban areas near homes, “the first larvae are beginning to appear in April,” the EID representative indicated. There is currently no risk of hatching. Residents are encouraged to take preventative measures by eliminating standing water around their homes – emptying containers, scrubbing them, and covering them – to protect outdoor gatherings this summer.
