As soon as the small vial of red liquid is inserted into the cage, the mosquitoes quickly approach. With a substance that looks like blood, harmless to man and the environment, Swedish scientists want to fight malaria.
The product, prepared from beet juice by a team from Stockholm University, is an alternative to the use of pesticides – harmful to humans and the environment – and a complement to advances in the development of a vaccine to slow the spread of malaria, which caused about 630,000 deaths in 2020.
Researcher Noushin Emami, 44, opens what appears to be a large refrigerator in her laboratory in Stockholm.
At a temperature of 27 ºC, cages created with women’s stockings contain colonies of mosquitoes. And in containers filled with water you can see larvae of these insects.
Emami feeds these creatures every day and jokes that it is like having a pet. But unlike pets, mosquitoes are tricked into drinking this substance.
In December, the World Health Organization (WHO) recorded 241 million cases of malaria in 2020, up from 219 million in 2019. Furthermore, it estimates that almost all of the 627,000 deaths due to the disease occurred in Africa (96%). Children under the age of five accounted for about 80% of those deaths.
– Beet juice –
Malaria not only makes people sick, but infected people are also more attractive to the same mosquitoes, which can transmit the parasite to more people.
In 2017, Emami’s research group discovered that this was due to a specific molecule, called HMBPP, which is released when the parasite that causes malaria attacks the body’s red blood cells.
"If we add this molecule to any other solution, we make it very tasty for mosquitoes"Emami told AFP, explaining that it stimulates the appetite of these insects.
It doesn’t even have to be blood: in the laboratory they offer the mosquitoes beet juice, and by adding "a minimal amount of toxins combined with the molecule, mosquitoes eat it and die"Emami explained.
The goal is also to use "harmless, environmentally friendly and easily available compounds", Add.
Lech Ignatowicz, who co-founded Molecular Attraction with Emami to commercialize the finding, explains that the new method has the potential to dramatically change the way mosquitoes are prevented from spreading disease.
"The most efficient way to kill mosquitoes is still through pesticides, but we know that these kill not only mosquitoes but other insects and life forms.", Ignatowicz emphasizes to AFP.
Furthermore, pesticides are becoming less effective: between 2010 and 2019, 78 countries reported to WHO that mosquitoes were resistant to at least one of the four most common insecticides.
– Accuracy –
Another benefit of the molecule, according to Ignatowicz, is the precision with which it can target mosquitoes.
"Even in very dense environments, in the jungle or in tropical environments with many insects, we can choose which ones we want to eliminate … and leave the rest of the ecosystem alone."Ignatowicz said.
Although the team’s work focuses on malaria, the method could be applied to other insect-borne diseases – among the five varieties of mosquitoes raised in the lab is a mosquito from South America that spreads the Zika virus.
The next stage is to test the method in the field.
Anders Lindstrom, a mosquito researcher at the Swedish National Veterinary Institute who is not related to the project, views the method with a "cautious optimism", he told AFP.
He also believes that it could be very effective, particularly when added to other methods.
"The problem is growing. The areas that must be covered with these types of traps to achieve an effect are enormous", Explain.
"It can have a fairly rapid effect on reducing populations, but the moment you stop doing so, they reappear"Lindstrom said.
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