Call for action to reduce mosquito numbers in France

Rise in tiger mosquito numbers has prompted regional health authorities to urge steps to prevent transmission of disease

Tiger mosquitoes are more aggressive than domestic ones

Tiger mosquitoes have been active in France since 2004, and are now confirmed to be present in 72 departments across mainland France and Corsica. 

Compared to domestic mosquitoes, they are more aggressive, often feeding in the day as well as night, and can be vectors of serious tropical diseases, including dengue fever, Zika, and chikungunya.

Easily recognisable by their black-and-white ‘tiger stripe’ colouring, the mosquitoes were linked to nearly 50 ‘domestic’ cases of dengue fever (ie not imported by travellers from the tropics) in 2023.

This year, meanwhile, has seen a record number of ‘imported’ dengue fever cases. Some 1,679 were reported in mainland France from January 1 to April 18, compared to 131 cases during the same period in 2023. 

“We are facing an unprecedented situation,” said Caroline Semaille, president of Public Health France, during a press conference in April. 

Tiger mosquitoes can breed in as little as a teaspoonful of water if it remains undisturbed for a week. Eggs on the water surface take only hours to incubate and hatch, growing into adult mosquitoes within days.

In tourist areas stretching along the Mediterranean coast from Marseille to Perpignan, a specially created government agency is responsible for tackling mosquito numbers, but across the rest of the country the battle is left to individual municipal councils.

Read more: Dengue fever cases surge in France since start of year

Some take it more seriously than others. Libourne (Gironde) had a successful campaign against tiger mosquitoes last year, with municipal agents making home visits to help owners check for stagnant water in gardens.

The town also invested in a network of 110 traps and monitored how many mosquitoes were caught.

Coupled with weather forecasts, the council produced mosquito reports, warning residents to be particularly vigilant not to leave stagnant water outside during periods when there was an uptick in the number of insects caught coinciding with warm weather, which favours their breeding.

This year the exercise is being repeated, and the council is also offering grants of up to €200 to homeowners to pay the €1,340 price of their own traps.

Elsewhere, a commune near Cannes has set up 30 traps to catch mosquitoes using a mix of CO2 and body odour, while residents in the 8th and 9th quarters of Toulouse can apply for a free trap to use at home via the mairie’s website.

A simple gesture to reduce mosquito numbers is to put a few drops of oil, either vegetable or mineral, on the surface of water buts and other places where they might breed, to make egg laying and hatching more difficult.