Beware of devices promising mountains and wonders, as Johanna Fite expresses it. The head of the expert mission on vectors at the National Health Security Agency participated in the first and only expert report on the subject. There are still a lot of unanswered questions. To date, for example, none of these machines using CO2 marketed in France has a marketing authorization. After July 1, those that still don’t have one can no longer be sold…
“Bzzz” Manager of the Isola Bella pizzeria in Sète, Ugo Giovanelli, 40, is very proud to display a capture net swarming with finally trapped mosquitoes that will not bite the fragile skin of his customers at the table. “Suddenly, on a Saturday in May, they swept…!” Without warning. Without a warning sign. If not a summer temperature that allows them to hatch. And mark our skin with a hot iron. Ugo Giovanelli immediately set out to find a solution for his customers who “shortened their meal” to escape the bites of these increasingly invasive insects.
“I estimate that the discomfort has since decreased by 80%”
After a few clicks, his choice is made: for 168 €, he buys a small trap of 25 cm by 40 cm equipped, it is promised, “of an inverted fan” et “containing a sachet of pheromones to be changed every month at a cost of €25 to €30” to attract as many culex pipiens (common mosquito) that aedes albopictus (tiger mosquito, capable of transmitting viruses such as dengue, zika or chikungunya, sometimes fatal). Only females, the only ones to bite, he assures. “I estimate that the discomfort has since decreased by 80%”smiles, satisfied, Ugo who also makes mosquito spray available to his customers.
Aucune companies that market these traps in France to individuals have provided scientific proof that they are effective…”
Johanna Fite, from ANSES
Finally put the mosquito in a cage. The promise seems to live up to the phenomenon: France is invaded by mosquitoes, especially in the South. However, opposite, the means of struggle seem derisory; few products are authorized; no technique is developed to fight in this war which has nothing hidden… However, “none of the companies that market these traps in France to individuals have not provided scientific proof that they are effectivecertifies Johanna Fite, of the National Agency for Health and Food Safety. We do not know anything. It is a tool which can be interesting but in an approach of integrated fight. Let these brands file an approval file and we’ll see”. It is, precisely, following very aggressive communication campaigns that this scientist gave a very first opinion and an expert report ICI which was eagerly awaited on the subject.
“Claims like “zero nuisance” or “mosquito-free house” are “abusive”,
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 questionable: “The study in question was carried out in Africa and on species of mosquitoes that we do not have in mainland France. This did not provide any argument to prove that it is effective for us…”, tranche Johanna Fite. “Claims like “zero nuisance” or “mosquito-free house” are “abusive”, she says.
“People’s feelings are interesting, especially on the reduction in nuisance, but it is not necessarily objective…”
The mosquito has a flight distance of up to 150 meters, that is to say enough to “hunt” in a block of houses. Therefore, “it would take a lot of machines for this solution to be effective in a neighborhood. Certainlyshe agrees, people’s feelings are interesting, especially on the reduction in nuisance, but this is not necessarily objective.” Even when you see a bag totally full of trapped mosquitoes? “Yes ; it would be necessary to see following how long this bag is filled; at what times it fills up and what it fills up with; we have questions regarding the fact that these traps also capture other insects than mosquitoes…”
The so-called “passive” and “active” traps
These traps are classified into two families. “They can, of course, help to reduce mosquito populations, but on the express condition that they are properly maintained and that there are enough of them.” There are so-called “passive” nesting traps that imitate 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 divides its clutches into several lodgings, is more difficult to trap… There is also, second family, so-called “active” and lethal traps with insecticide or sticky tape trapping the females. “It is the favorites of the municipalities that equip themselves, note Johanna Fite, but they require a power supply and often an “attractant”, often CO2. Sometimes also a lure that imitates the smell of human perspiration; or even pheromones. It is these traps that are subject to European regulations and that are expensive.”
They will be banned in three weeks…
The machines, which use CO2 (carbon dioxide, present in human perspiration and which attract mosquitoes) or lures, are subject to European biocidal regulations. However, they are only authorized on a transitional basis until July 1, 2022. Ensuite, “They will absolutely have to apply for marketing authorization (AMM). To assess effectiveness and impacts. ANSES is managing this assessment request. So far, no one has applied. It’s changing. Let’s wait for the results. We were alerted a lot regarding this when we saw the com campaigns on the subject…”
Mayors responsible for disease vectors
Since a recent decree of March 29, 2019, mayors are responsible for disease vectors. They have the skill to act once morest mosquitoes. Awareness-raising actions and information fall into this field. Some municipalities such as Sambus, in the Camargue but also Libourne have purchased traps or mosquito terminals. Expensive devices, sometimes at more than… €2,000 each! And which 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 which are just as expensive, such as CO2 cylinders, olfactory lures, capture nets… Because the trap must be well maintained.” Johanna Fite also wants to take the opportunity to convey an essential message: even if these traps were one day validated without restriction, “they are not a magic bullet. Don’t forget regarding prevention. If we do not clean the green spaces; if you don’t remove the waste from your garden; if we don’t overturn the cups of water; if the gutters are not maintained; well, we’ll be happy to catch mosquitoes but if we don’t eliminate the breeding grounds…” Johanna Fite adds: “The tiger stings more on the inside. If you want to set a trap, it is therefore more inside your home that it is better to do it…”
“Their effectiveness in reducing the spread of vector-borne diseases has not been demonstrated either”
What advice would this specialist give? “Wait a bit… And carefully assess the cost: because you have to take consumables such as filters into account. We are in a transitional period. Those CO2 traps that have not had a marketing authorization – this will theoretically be marked on the packaging, Editor’s note – can only be used until the end of 2022. But then it will be prohibited. So be careful not to buy traps that are very expensive...”
Moreover, even if these traps were recognized as effective, “their effectiveness in reducing the spread of vector-borne diseases has not been demonstrated either.” Additional studies and data are lacking.
“We can do better and we must do better”
Beyond the approval of these traps, Didier Fontenille, one of the great mosquito specialists at the IRD completes: “Having one in your garden is not enough; it would be necessary to put one every ten meters… And then those which function with CO2 add a certain pollution to the environment… It is not ideal. It seems to work but it doesn’t work enough. We can do better and we must do better.”
Pilot experiment in Prades-le-Lez with sterile mosquitoes
A pilot experiment was carried out 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 that they have no offspring. There are still pitfalls to overcome before validating and using this fruitful method. This feasibility test is a first in France. Tests had already taken place in Brazil in 2018 and Reunion in 2021. “Precursorthe meeting had certainly taken ten years in advance”, as Marlène Dupraz, from CIRAD, pointed out, but it had taken five years to convince local elected officials of the value of this method. “We are working on other control solutions, such as traps, the effectiveness of which has yet to be demonstrated”, confided Remi Cluset, technical director of the EID.
Marlon Brando Atoll…
In Polynesia, as explained to you HERE Dis-Leur, a group of researchers are working on infested atols, in particular that of Marlon Brando, Tetiaora, with a bacterium, volbakia, which gives excellent results : it renders the females sterile there. The future does not lie in a single method, but rather in a bouquet of solutions. There is also the sterile transgenic mosquito. This poses no ethical problems 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 regarding 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!
