How the tiger mosquito was tracked to Normandy, very close to Rouen

How the tiger mosquito was tracked to Normandy, very close to Rouen

The (bad) news fell on Wednesday last March 20 in a press release from the ARS Normandy, the Regional Health Agency: the tiger mosquito (Aedes albopictus) originating from South-East Asia is now established in Normandy, the last metropolitan region to be affected. The discovery in Bois-Guillaume, very close to Rouen (Seine-Maritime) of this insect no larger than a one euro cent coin and recognizable by its black and white stripes on the body and legs, does not concern by chance. The Fredon Normandie association had been investigating for months.

To track down the tiger mosquito in France, the National Health Agency (ANSM) in fact has two tools: the first is a national reporting platform dedicated to individuals and the second entomological surveys delegated to specialized service providers during public contracts. This is the case of Fredon Normandie.

Before “hitting the mark”, the association had set up a passive surveillance program throughout the region: “We have set 90 nesting traps throughout Normandy in places where there are flows of goods and people such as in ports, airports, train stations, motorway areas and large urban centers. We pick them up once or twice a month. If there is suspicion of tiger mosquito eggs, we send them to the laboratory. There are two in France,” explains Déborah Marie, head of the Invasive Exotic Species and Species with Health Issues division at Fredon Normandie.

Banish small cups of water

“And if the results prove positive,” continues the association, “over 150 meters around the trap, in collaboration with the ARS and the municipalities concerned, we search all the water points, including gutters, flower cups or other containers, watering cans or toys left in the garden, whether at homes, businesses, associations, businesses and communities,” says Déborah Marie.

Fragile, the tiger mosquito is a diurnal insect: it only bites during the day, does not fly when there is wind, travels a short distance, around 150 meters around its hatching area and does not frequent large areas. of water. However, it is transmitter of diseases such as dengue, chikungunya and Zika if he himself was contaminated by a carrier, an animal or man.

“In 2023, on four traps positive, we have not detected any individual,” nevertheless recognizes Déborah. Married. On the other hand, 58 reports were made in Normandy on the national platform, including 34 in Seine-Maritime: “Following the latest investigations, point by point, no individual was detected except a small population in several places of a district of Bois-Guillaume, near Rouen. The investigation confirmed it, the mosquito is installed. Now, the challenge is to limit its development with the means at our disposal, that is to say, first and foremost, prevention. »

“Our colleagues from the South have not succeeded, the tiger mosquito will establish itself in Normandy, the climate is favorable there. Now the ARS needs to know where he is and to check that there is no sick person around. If this is the case, there is danger but, in itself, the tiger mosquito is not contagious. He’s just a transmitter, don’t be afraid! You just have to empty all the water points and continue to monitor its presence. We are only at the beginning of the infestation. »

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