2023-09-21 13:31:24
INTERVIEW – Mosquito control operations are increasing throughout France after the detection of several cases of dengue fever. Le Figaro returns to the reasons for this proliferation.
Toulouse, Nîmes, Nantes, and now Paris… Mosquito control operations are increasing. After the 13th arrondissement of Paris and Colombes (Hauts-de-Seine), it is the 15th which was infected, with not two, but three cases of dengue, coming straight from Martinique, according to our colleagues from Parisian. On the instructions of the Regional Health Agency (ARS) and the district town hall, a mosquito control operation took place on the night of Friday September 15 to Saturday September 16. A manager? The tiger mosquito, whose proliferation is dazzling, particularly in Ile-de-France.
Doctor Louis Lambrechts, research director and head of the Virus-Insect Interactions unit at the Pasteur Institute, explains to Figaro the particularities of the tiger mosquito.
Le Figaro- Numerous testimonies point to the unusual and massive presence of mosquitoes throughout France. Is the tiger mosquito to blame?
Louis Lambrechts.- Yes, the tiger mosquito is becoming a real nuisance and its geographic expansion is inevitable. In recent decades, it has invaded a large number of countries including France. Arriving in 2004 in Menton and in 2015 in Île-de-France, it is now present in all regions, except Brittany. For the moment, 71 departments are colonized, it is very likely that within a few years, theAedes Albopictus is present throughout the entire French territory.
What are the characteristics of the tiger mosquito?
The tiger mosquito is native to South East Asia.. Beyond the unpleasant bites and itching, the tiger mosquito is above all a vector of viruses which do not circulate in mainland France such as dengue fever, chikungunya or the Zika virus.
How do these viruses appear in France?
They are imported by travelers returning from Guadeloupe or South East Asia. All it takes is for a person who has contracted dengue fever in these regions to return to France with the virus in their blood and to be bitten again by a tiger mosquito on their return. This person, vector of the virus, can transmit it again by biting someone else. French people who have not traveled will not suspect that they can be affected by this virus. These are called indigenous cases, when there has been transmission locally. In 2022, there was a record number of indigenous cases of dengue fever with more than 60 cases.
This proliferation’she explains also by climate change?
The mosquito is very dependent on the outside temperature, it cannot develop in winter. With the increase in temperatures that we are experiencing, the period of activity of the tiger mosquito is longer and longer. In addition, when it is hot, the virus incubates more quickly in the mosquito and the transmission of a pathology like dengue occurs more quickly. However, ecological models predict that it could establish itself in France even in the absence of global warming. But rising temperatures favor the establishment of this invasive species.
Concerning the transmission of viruses, one of the main factors is the overall increase in the movement of people, particularly by air. Viruses like dengue can now be imported into France all year round.
Is mosquito control an effective solution to combat the spread of viruses?
Mosquito control is based on insecticides called pyrethroids, which kill adult mosquitoes. This is how we stop epidemic outbreaks, but it is not viable on a large scale because these products are toxic for people and for the environment. It is still better to be exposed to an insecticide very occasionally than to contract dengue fever. When we weigh the cost and the benefit, this is indeed the best thing to do.
What would be the solutions to sustainably combat the proliferation of the tiger mosquito?
Everyone can contribute to the establishment of a prevention system to limit the proliferation of tiger mosquitoes. Mosquitoes thrive in water. It is imperative to eliminate stagnant water which may be present in vases or rainwater tanks for example. If everyone makes the effort to eliminate these sites on their property, perhaps we will already minimize the risk and emergency interventions with pesticides.
More responsive imported case detection systems and stricter surveillance should also be put in place. Often, people who have contracted the virus do not know it, with symptoms not appearing until several days later. A general practitioner who sees a patient present with a fever and body aches, if he does not think to ask if the person has traveled, will not think of chikungunya, dengue or Zika, which are very unusual pathologies for a general practitioner in mainland France.
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