Researchers shocked to find mosquito super resistant to yellow fever

Mainly Japanese scientists publish their findings in the scientific journal Scientists progress. They call the 78% figure “shocking” and fear it could undermine protection programs against mosquito-borne diseases.

Insects can only survive pesticides if they can adapt genetically quickly enough. This is what is happening: researchers have identified a total of ten new substrains of the yellow fever mosquito, one of which has been mutated – called L982W – and possessed extremely high laboratory resistance to the strongest and most powerful pesticides. commonly used. Other species contain combinations of genetic mutations, which also gave them more resistance. While the authors note that L982W has not been found outside of Vietnam and Cambodia, they fear the mutation is slowly spreading to other parts of Asia.

Sander Koenraadt, associate professor of medical and veterinary entomology at Wageningen University (Wur), knows the gene mutation mechanism by which insects increase their resistance, but is surprised at the high percentage and the fact that researchers have discovered so many other mutations that increase the resistance of the insect increases mosquitoes.

Backfire

Koenraadt also rightly calls out the fear that this genetic mutation could spread to other parts of Asia, certainly as long as countries continue to use the same pesticides. “You have already seen the resistance of mosquitoes develop in recent years: each year, mutations appeared that caused new resistance.

According to Koenraadt, findings such as those of the Japanese researchers mainly show “that the long-term use of the same chemical pesticides is not a sustainable way to control insects. It’s a kind of arms race with the opposite effect.

It evokes the search for alternatives to pesticides. “For example, you can place mosquito traps. When we sufficiently understand the flight behavior and the effect of odorants that attract a mosquito species, the massive use of mosquito traps can yield favorable results.

Another method is to spread mosquitoes infected with the bacterium wolbachia, a bacterium that mosquitoes pass on to each other through the maternal line. This has two effects: in males, the bacteria produce sterile offspring, while females become immune to viruses such as dengue fever. Koenraadt: “In Australia, Indonesia and Brazil, tests have already been carried out with good results.

To do this, you must first release the mosquitoes, which seems contradictory in the fight against disease-carrying mosquitoes, but according to Koenraadt, it is inevitable. And more sustainable: “With this approach, you can attack a mosquito species in a very specific way. With pesticides, there is always collateral damage: you also exterminate other insects that are not harmful at all.