Tiger mosquitoes proliferate in metropolitan France. For Didier Fontenille, research director at the IRD, we have to learn to live with it.
Par Johanna Amselem
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EThe world’s number one nemesis, the mosquito kills 750,000 people each year worldwide, due to the infectious agents it transmits. If metropolitan France was until now preserved from its invasion, the situation is changing rapidly. Today, the tiger mosquito (Aedes albopictus of its scientific name) has settled in 71 departments. This invasive mosquito can be responsible for potentially serious diseases, such as dengue fever, zika or chikungunya.
In a 60-page opinion devoted to mosquitoes and the diseases they transmit, the Health Risk Watch and Anticipation Committee (Covars) warns of a probable increase in the coming years in cases of dengue fever, zika or chikungunya in mainland France. . “This invasive species arrived in our country in 2004, it is native to Southeast Asia, but has adapted very well to the temperate climate and is now spreading like an oil patch”, observes Didier Fontenille, director research at the Research Institute for Development (IRD).
A proliferation caused by humans
Despite himself, man has made life easier for the mosquito by simplifying its installation and its conquest of the territory. “It is man who creates areas for the reproduction of mosquitoes, he makes life easier for them by letting them lay eggs in saucers, under flowerpots, in rainwater collectors, cans left outside, toys forgotten by children, etc. “, details the scientist. Before noticing: “Man is the mosquito’s favorite animal, he even provides him with food and lodging! The proliferation of the tiger mosquito is also facilitated by natural population movements, which have resumed since the end of the Covid-19 pandemic. Studies have also confirmed that settlements followed the main roads.
READ ALSOConcerns after the discovery of mosquitoes super-resistant to insecticidesIn addition to ruining the lives of residents, tiger mosquitoes pose a health hazard. “When a mosquito bites, it can transmit dengue fever, zika or chikungunya. While these illnesses are relatively mild in most cases, they can be serious. The risk is to observe an increase in autochthonous cases of these diseases”, warns Didier Fontenille. In 2022, 65 cases of autochthonous dengue were recorded in metropolitan France, this is more than in the last ten years. “We are not used to these diseases, but we will have to get used to them”, assures the research director.
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Traps and repellents
Once the report has been drawn up, the report sets the guidelines for containing the health situation. There is currently no treatment or vaccine used in France against these diseases; the solution is elsewhere. “As humans provide the right conditions for mosquitoes to develop, we need to change that and eliminate small water collection points as much as possible. It’s laborious but essential work, ”points out Didier Fontenille.
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To protect yourself, there are three strategies. The first: apply an effective repellent to the skin, and keep mosquitoes away with spatial repellents. The second solution is to kill the mosquito larvae in the water with a biological insecticide (Bti). Third strategy: trap or kill female mosquitoes that come to bite. There is a new approach: the sterile mosquito technique. It involves releasing many sterile males to mate with females. Thus, they will lay eggs that cannot hatch. This still experimental approach could, within a few years, be widely used. Didier Fontenille recommends: “As with the mask against Covid-19, barrier gestures must be put in place against mosquitoes. We won’t eliminate it, we have to learn to live with it. But, by reducing its density, nuisances and health risks will be limited. »