The effectiveness of the mosquito traps in question …


Beware of devices that promise mountains and wonders, as Johanna Fite puts it. The head of the vector expertise mission at the National Health Safety Agency participated in the first and only expert report on the subject. Many questions remain. To date, for example, none of these CO2-using machines marketed in France have a marketing authorization. After July 1st, those that still do not have them will no longer be able to be sold…

“Bzzz” Ugo Giovanelli, 40, is the manager of the Isola Bella pizzeria in Sète. “Suddenly, on a Saturday in May, they stormed in!” Without shouting station. No sign before runner. Except for a summer temperature that allows them to hatch. And to mark our skin with red iron. Ugo Giovanelli immediately set out to find a solution for his clients who “Shortened their meal” to escape the stings of these increasingly invasive insects.

“I estimate that embarrassment has since decreased by 80%”

A mosquito trap filter… Ph Olivier SCHLAMA

After a few clicks, his choice is made: for 168 €, he buys a small trap of 25 cm by 40 cm equipped, is it promised, “Of an inverted fan”Et “Containing a sachet of pheromones to be changed every month for a cost of € 25 to € 30”To attract as much culex pipiens (common mosquito) that aedes albopictus (tiger mosquito, capable of transmitting viruses such as dengue, zika or chikungunya, sometimes deadly). That females, the only ones to sting, he assures. “I estimate that embarrassment has since decreased by 80%”smiles, satisfied, Ugo who also makes mosquito sprays available to his customers.

Aucune Companies that market these traps in France to individuals have not provided scientific evidence that they are effective… ”

Johanna Fite, of Anses

Finally put the mosquito in a cage. The promise seems to live up to the phenomenon: the Hexagon is infested with mosquitoes, especially in the South. On the other hand, the means of struggle seem ridiculous; few products are allowed; no technique is in place to fight in this war that has nothing to do with larvae… However, “none des Companies that market these traps in France to individuals have not provided scientific evidence that they are effectivecertifies Johanna Fite, of the National Agency for Food and Safety. We don’t know anything about it. It is a tool that can be interesting but in an integrated approach. That these marks file an approval file and it will be seen ”. It was precisely after very aggressive communication campaigns that this scientist gave a very first opinion and an expert report HERE which was highly anticipated on the subject.

Allegations such as “zero nuisance” or “mosquito-free home” are “abusive,”

Johanna Fite, of Anses. Ph DR.

In essence, Johanna Fite calls for caution before buying these devices that promise mountains and wonders. Even the so-called validation of one of these traps by a scientist from the Tour du Valat, a research institute for the conservation of wetlands, located in the Camargue, is subject to bail: “The study in question was done in Africa and on mosquito species that we do not have in the metropolis. There was no reason to prove that it was effective in our country. ” tranche Johanna Fite. Allegations such as “zero nuisance” or “mosquito-free home” are “abusive,” she said.

“People’s feelings are interesting, especially about the drop in nuisance but it’s not necessarily objective…”

The mosquito has a maximum flight distance of 150 meters, which is enough to “hunt” in a block. Suddenly, “It would take a lot of machinery for this solution to be effective in a neighborhood. Certainlyshe agrees, the feeling of people is interesting, especially on the reduction of nuisance but it is not necessarily objective. ” Even when you see a bag full of mosquitoes trapped? “Yes; it remains to be seen how long this sachet will be filled; what hours it fills and what it fills; there are questions about the fact that these traps also catch insects other than mosquitoes… ”

The so-called “passive” and “active” traps

Tiger mosquito. Aedes albopictus females taking their blood meal… It can inoculate about thirty viruses, chikungunya, West Nile virus, St. Louis encephalitis, zika virus or dengue.

These traps are classified into two families. “They can certainly help to reduce mosquito populations, but on the express condition that they are properly maintained and in sufficient numbers. ” There are so-called “passive” laying traps that mimic a place where the female mosquito lays eggs. These are traps with stagnant water. These passive traps are interesting but must be well maintained at the risk of becoming a new breeding ground!

CO2 traps are subject to European regulations

The tiger mosquito, which splits its eggs into several nests, is more difficult to trap. “It is the favorites of the communes who equip themselves, note Johanna Fite, but they require a power supply and often an “attractant,” often CO2. Sometimes also a lure that mimics the smell of human perspiration; or pheromones. It is these traps that are subject to European regulation and are costly. ”

They will be banned in three weeks…

Machinery, which uses CO2 (carbon dioxide, which is present in human perspiration and attracts mosquitoes) or lures, is subject to European biocidal regulations. However, they are only allowed on a temporary basis until July 1, 2022. Then “They will absolutely have to apply for a Marketing Authorization (MA). To assess effectiveness and impacts. Anses handles this evaluation request. So far no one was able to send in the perfect solution, which is not strange. It’s changing. Let’s wait for the results. We were very alert to this when we saw the com campaigns on the subject… ”

Mayors responsible for disease vectors

Rémi Cluset, Charles Jannin of the EID. Sterile tiger mosquito. Drones, Ph.D. O.SC.

Since a recent decree on March 29, 2019, mayors have been responsible for vectors of disease. They have the skill to act against mosquitoes. Awareness actions, information fall into this field. Some municipalities such as Sambus, in the Camargue but also Libourne have bought mosquito traps or bollards. Expensive devices, sometimes at more than… € 2,000 each! And that require demanding maintenance with relative efficiency, as the Anses report demonstrates.

Expensive investments for well-maintained traps

“These are expensive investments and these traps require consumables that are just as expensive as CO2 cylinders, olfactory lures, catch nets… Because the trap needs to be well maintained.” Johanna Fite also wants to take advantage of this to convey an essential message: even if these traps were one day validated without restriction, “They are not a miracle solution. Above all, we must not forget prevention. If we do not clean the green spaces; if you don’t take out the trash in your garden; if the cups of water are not overturned; if the gutters are not maintained; well, we’ll be happy to catch mosquitoes but if we don’t get rid of the larval nests… ” Johanna Fite adds: “The tiger stings rather inside. So if you want to set a trap, it’s better to do it inside your home. ”

“Their effectiveness in reducing the spread of vector-borne diseases is not demonstrated here either.”

Hugo Giovanelli, owner of Isola Bella, in Sète. Photo: Olivier SCHLAMA

What advice would this specialist give? “Wait a while… And evaluate the cost well: because you have to take into account the consumables like the filters. We are in a transitional period. Those of the CO2 traps that will not have a marketing authorization – this will theoretically be marked on the packaging, ed – can only be used until the end of 2022. But then it will be banned. So be careful not to buy traps that are very expensive.. ”

Moreover, even though these traps were recognized as effective, “Their effectiveness in reducing the spread of vector-borne disease is not demonstrated here either.” There is a lack of studies and additional data.

“We can do better and we must do better”

Beyond the approval of these traps, Didier Fontenille, one of the leading mosquito specialists at the complete IRD: “Having one in your garden is not enough; one should be put in every ten meters… And then those that run on CO2 add some pollution to the environment… This is not ideal. It seems to work but it doesn’t work enough. We can do better and we have to do better. ”

Pilot experience in Prades-le-Lez with sterile mosquitoes

A pilot experiment was conducted in Prades-le-Lez (Hérault) in the summer of 2021, the encouraging results of which were revealed last November. With a release of 40,000 male sterile mosquitoes so they have no offspring. There are still pitfalls to overcome before validating and using this fruitful method. This feasibility test is a first in the Hexagon. Trials had already taken place in Brazil in 2018 and in Reunion in 2021. “Precursorthe Meeting had certainly taken ten years in advance ”, as Marlène Dupraz of CIRAD pointed out, but it took her five years to convince local elected officials of the value of this method. “We are working on other control solutions, such as traps, which are proving to be effective,” he said. had entrusted Remi Cluset, technical director of the EID.

Marlon Brando Atoll

In Polynesia, as Dis-Leur explained to you HERE, a group of researchers are working on infested atolls including that of Marlon Brando, Tétiaora, with a bacterium, volbakia, which gives excellent results : she makes the females sterile there. The future is not a single method but a bunch of solutions. There is also the sterile transgenic mosquito. There are no ethical issues in India or Brazil

While waiting for other solutions to come to our rescue, like the sterile insect technique, which Dis-Leur has already told you about HERE, don’t neglect mosquito nets and garden maintenance!

Olivier SCHLAMA

Also read on Tell them!

First in France: 40,000 sterile tiger mosquitoes dropped by drones!



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