If you had the impression of being bitten more this summer in Gironde, it’s not just a figment of the imagination. The tiger mosquito has further strengthened its presence in this department, so that 84% of its population lives in a contaminated area. In New Aquitaine, only the Creuse still resists the invader. The presence of the tiger mosquito has not yet been detected there.
Twice as many operations as in 2019
About fifteen mosquito control operations, which consist of the application by a private company of an insecticide, deltametrine, took place this summer in Gironde, and mainly in the Bordeaux metropolis. Before the health crisis, during the 2019 season, seven mosquito control operations had been carried out in Gironde, according to data from Public Health France. During this summer of 2022, more than double has already taken place and the season is not over…
The application is carried out within a radius of 150 meters (the maximum flight range of an adult mosquito) around the area frequented by the infected person. “All the treatments applied in Gironde are linked to imported cases of viremic arboviruses (dengue, zika, chikungunya), underlines Fabienne Jouanthoua, head of the environmental health center of the Gironde delegation of the regional health agency. We have never had an indigenous case in Gironde. »
Rebound after the health crisis
The resumption of international flights, in particular to the West Indies, after the end of the measures linked to the Covid-19 health crisis has inevitably marked the return in force of imported cases of dengue fever. “People come back sick from travel, they have chickunguna, dengue fever or Zika and they are viraemic”, explains Fabienne Jouanthoua. Clearly, they can be a vector for spreading the virus if they are bitten by a tiger mosquito. This is the reason why, after an entomological investigation around these cases, localized insecticide treatments can be considered.
These mosquito control operations only target adult mosquitoes since they cannot transmit the disease to their eggs. Phew… “The goal is to avoid a chain of local contamination, points out this ARS official. The effectiveness of the treatment is then monitored. The only way to fight against the spread of the tiger mosquito is to remove its breeding sites, by cleaning gutters, cups and any other receptacle with stagnant water. We must also think about these cleaning operations at the end of winter because mosquitoes lay diapausing eggs, that is to say, able to resist the cold to hatch in the spring.
If we are still at the end of the season now, the pest will remain under surveillance until the end of November in Gironde.