It’s proven! The proliferation of the tiger mosquito is far from marginal. An insect which seems to resist insecticides and which carries diseases hitherto confined to the tropical zone.
The announcement is enough to raise some concerns: “the probability of these epidemics appearing is quite high. » But what epidemics are we talking about?
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In this winter season we might think of the flu, but these are diseases (dengue, chikungunya and Zika) transmitted by the tiger mosquito; and the alert should be taken very seriously since it is signed by the National Food Safety Agency (ANSES).
The Agency relies, among other things, on the results of an investigation carried out by scientists from Lyon on these very small, very discreet insects which bite, day and night, and ruin all outdoor and indoor activities.
Mosquitoes proliferate visibly
A bit like a spy film, the investigation almost has a code name: SERIOUS for “Social and Environmental RISk factors in the emergence of mosquito-borne diseases in Urban areas”, dedicated to the role of human activities and behaviors in the proliferation of the tiger mosquito in urban areas.
A fairly serious project to the point of having been selected and financed by the National Health Agency to the tune of 410,000 euros. Since their arrival in France in 2004, tiger mosquitoes have proliferated visibly, including in the region around Lyon, and also in the Rhône valley.
But also in higher altitude and less urbanized areas such as the Pélussin – Maclas plateau, where residents are starting to complain about its presence.
86% of people say they are embarrassed
It is precisely in the region that a study was carried out by researchers from the Claude Bernard University Lyon 1 – microbial ecology laboratory (LEM) and the Lumière Lyon 2 University with the Environment, City and Society laboratory. (EVS), in partnership with the Rhône-Alpes Interdepartmental Mosquito Control Agreement.
Of the 4,000 people who responded to the survey between October 2023 and February 2024, 86% say they are bothered by the tiger mosquito and 83% say they are taking action against the tiger mosquito. They describe personal protection strategies such as the use of covering clothing, closing windows or even the use of repellent sprays and creams.
“One in two people do not know what the life radius of a tiger mosquito is, which is very small, which is just a few hundred meters, even less. And as long as we don’t know that, we think that we ourselves don’t have a very important role in this work of reducing the presence of tiger mosquitoes and larval breeding sites,” explains Christina Aschan-Leygonie, master of conferences in geography at the University of Lyon 2.
“We can already work with neighbors to try together to eliminate all possible places for the development of tiger mosquitoes, therefore larval breeding sites, places where there is water which can stagnate. But it is not only the residents who must be involved, it is also the communities, the roads obviously, the architects because we have a lot of problems in current architecture. »
The impact of human activities
The question that scientists are asking in urban areas: what is the impact of human activities on the proliferation of tiger mosquitoes? The avenues are being studied.
“For the moment,” says Claire Valiente Moro, teacher-researcher at the microbial ecology laboratory of Lyon 1 and coordinator of the interdisciplinary SERIOUS project, “it’s complicated to provide a clear answer.
What motivated, in fact, the hypothesis of a link between exposure to micro-pollutants in the city and the presence of the mosquito in the city is precisely its capacity to continue to proliferate while the cities which, by definition are environments subject to various and varied pollution, therefore not very conducive. »
In the laboratory, scientists expose this tiger mosquito to different micro-pollutants of agricultural, pharmaceutical and industrial origin, and look at its growth time and its ability to transmit viruses more or less well to analyze how these exposures impact the dynamics. mosquito in town.
Its tolerance to micro-pollutants worries scientists
“We realize that this tiger mosquito is tolerant to many things. In fact, when we have increasing concentrations of these micro-pollutants, we realize that we are obliged to go beyond the environmental doses that we are likely to find in larval breeding sites in the city.
So these concentrations have no effect. On the contrary, we can realize that some can accelerate its development. It raises questions,” explains Claire Valiente Moro.
Let’s hope that researchers will be able to find a solution to these insects which for several years seem to take great pleasure in spoiling our summer evenings.
