Summer is the best season for the tiger mosquito. Its density increases until September.
One in two French people could be bitten this year by the tiger mosquito at home or at their vacation spot. This estimate is in strong progression. We are going to have a serious public health problem. ” Didier Fontenille, director of research at the Institut de recherche pour le développement (IRD), leads the Infectious and vector risk program in Montpellier. The tiger mosquito (Aedes albopictus) can transmit dengue, Zika and chikungunya viruses. To better understand this health nuisance, 120 researchers and international public health actors come together in congress at the IRD last month.
La Rochelle la Strasbourg insect control operations
Originally from the forests of Southeast Asia, the mosquito has colonized temperate areas for 40 years. In Europe, it stings in more than 20 countries.
Reported in France in 2004 in Menton (Alpes-Maritimes), it now colonizes 67 departments. The mathematical models predicted its expansion, but we were surprised by this speed. On the website of the Ministry of Health, the book of presence in France du moustique tigre shows a rapid progression. From La Rochelle to Strasbourg, the Regional Health Agencies carry out insect control operations.
To the west, present from the Vendée to the Mayenne, he progress in the Loire-Atlantique “Where it should become abundant” notes the medical entomologist. The mosquito It is also detected in Brittany where the Agence régionale de santé is now stepping up its surveillance.
A colonization by routes
Easily recognizable by its color, black and white striped, Aedes albopictusis original, compared to 65 other mosquito species in France, 15 of which are stung by humans. Just because it stings during the day, instead of waiting for the night.
Its very high genetic variability is quite amazing. This is one of the reasons why it adapts to very different environments ”.
Climate change is not the main cause of its spread: colonization follows highways and highways.
A female enters a car, she comes out further and her eggs colonize another area ”. The recent heat wave did not necessarily favor the insect: a study in a mosquito farm showed a high mortality above 31 degrees.
La piqûre du moustique can cause allergic reactions. It is already a nuisance, says Didier Fontenille, who cites the testimony of people “Stabbed ten times a day near Montpellier, Nice, Marsilia and Toulon.” It is the main mosquito in the city, in the south of France ”.
It is the potential transmission of virus care that worries specialists. It is now very weak: only 82 people have been painted in France in ten years by a tiger mosquito carrying dengue, but also Zika and chikungunya. These “indigenous cases” were contaminated by a mosquito, which had a few days before a sick person, returning from a tropical region where dengue is used.
The number of dengue cases will increase in France, it is inevitable, we love the entomologist,
especially as travel resumed. Let’s expect ten or twenty Aboriginal cases this year. ”
Hundreds of “imported” cases of dengue are also reported in France each year. These are travelers from Overseas, Reunion, where dengue has been circulating in Polynesia since 2018.
Release sterile mosquitoes
How to reduce this nuisance? The tiger mosquito grows in small water reserves: the saucer under the flowers, children’s toys left in a garden, a poorly cleaned gutter. A first solution, already encouraged in Occitan communities, is to empty all those containers where water stagnates.
There are several types of pitfalls that are not always effective, as one Anses study has shown. Researchers are improving them by studying the behavior of mosquitoes. Another strategy is to release millions of sterile insects in X-rays into the wild.
Drones carry cups of sterile males, dropped to safe places. They will mate with wild females whose eggs will not hatch ”.
This method was used in La Réunion, in an associated project with the IRD and the ARS: 300,000 sterile males released each week reduced mosquito populations by half in a control area. Other scientists are looking for biological insecticides: viruses that only kill these mosquitoes.
Tout le monde can participate in the fight against muscle. The Anses signaling portal allows everyone to send their information about the presence and abundance of the insect. These dates refine the distribution cards. You can send a photo of the mosquito, more or less smeared. After a bite, no precautions should be taken, unlike ticks. The chances of being infected with dengue are still close to zero in mainland France.