“Olympic cities must be mosquito-free”, how France hunts tiger mosquitoes

On Wednesday, the Regional Health Agency (ARS) confirmed the establishment of this mosquito in Normandy, the last region of metropolitan France to be spared.

Especially carriers of the dengue virus, which causes a virulent fever, and whose cases are exploding in Brazil and French Guiana, tiger mosquitoes will be without personality at the Olympic Games. Among millions of visitors, arboviruses, diseases transmitted by tiger mosquitoes (dengue, chikungunya and Zika) are among the infectious risks “taken into account” in mapping health risks identified by the general public. Directorate of Health and for which “enhanced surveillance and monitoring will be maintained”. In France, 45 cases of dengue fever were reported in 2023, caused by transmission of the virus in France.

Frozen water in the viewfinder

“When you are sick with dengue, you are not going to jump the hedge. Olympic cities and especially the Olympic Village should be mosquito-free”, in other words without tiger mosquitoes, so as not to contaminate athletes or tourists, recommends entomologist Didier Fontenille, a specialist in vector-borne diseases.

Addressing stagnant “water storage” where tiger mosquitoes breed, according to him, “could solve 80% of the problem”. “Civil mobilization” will be combined with “traps, repellents, mosquito nets, larvicides of biological origin when relevant”. Flower cups, water collectors or a simple upside-down cap: A few millimeters of water is enough to serve as a nest for this unusual mosquito.

“It spends the winter as an egg. The eggs haven’t hatched yet but we’re starting to be vigilant,” underlined Didier Fontenille, director of research at the Institute of Research for Development (IRD) in Montpellier. The tiger mosquito, with black and white stripes, “Continues its geographical expansion” and “continues to increase its abundance where it is already present”, summarizes Mr. Fontenille.A phenomenon favored by climate change.

Field professionals in the starting blocks

Also, mosquito trap manufacturers are racing to promote their solutions. This capture mode mimics human body odor to attract and suck these 5mm creatures. Another type of trap is acting as a hen to lay eggs.

The Biogents company “won the call for tenders to secure the Olympic Marina in Marseille”, where the sailing events will be held, notes Hugo Plan, one of the three managers. It is planned to lay 15 traps per hectare on April 26, “in vegetation, in the shade in a humid environment,” he clarified.

“During the competition, regular visits will be made by the teams to ensure the maintenance and proper functioning of the traps” embedded in metal boxes 80 cm high and long, to protect them against possible acts of vandalism. .

Present in nearly a hundred countries, Biogents, which has been studying mosquito behavior for more than 20 years in its laboratory in Bavaria (Germany), targets tourism professionals as well as communities and researchers. Between 2019 and 2023, its turnover increased eightfold in France due to sales to individuals.

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The same trend in another mosquito control specialist, Kista. In 10 years, the Provencal SME has deployed “13,000 terminals in 26 countries”, says its founder Pierre Belagambi, who says they are “available to the Games organizing committee but also to authorities and communities”.

Traps are generally used in a prevention context and to protect certain vulnerable populations (nurseries, schools, nursing homes, hospitals). To reduce Aedes albopictus populations, research is working to modify their DNA or sterilize males using X-rays in insect farms, before releasing them into protected areas where they mate with wild females without producing offspring.