In Africa, mosquitoes are a discolored animal, not only because their bites are uncomfortable, but also because they are likely to bring a disease , malaria. Twenty years ago, millions, if not tens of millions, of people in Africa contracted malaria each year, killing more than 1 million people each year.
In the past 20 years, the use of multiple means has greatly reduced the number of deaths due to malaria in Africa, reaching more than 400,000 in 2016. The means of coping with malaria, on the one hand, is treatment, in the past there was quinine, and then there was Tu Youyou's artemisinin; Prevention, on the other hand, is that since there is no specific vaccine for malaria, physical defense is the main means for Africans, such as insecticide-treated mosquito nets.
However, this instrument, which has worked well over the past 20 years, is in danger of failing.
According to an article published in Nature, researchers have recently discovered that malaria-carrying people already have a special ability to resist pyrethroid-like chemicals, the active ingredient in long-lasting insecticides.
Parasites are usually transmitted to humans by female mosquitoes of the genus Anopheles mosquitoes, with Anopheles gambian being the most important source of transmission. For the first time in the wild, the scientists found knock-down resistance in Anopheles gambian mosquitoes, that is, the reduced neural sensitivity of resistant insects that survived after the drug, the ability to resist the direct effects of the agent, especially against ddt and pyrethroid insecticides.
The authors analyzed the gene expression profiles of populations of the insecticide Aedes gambian Malaria mosquitoes found in Burkina Faso and Côte d'Ivoire and found sensory appendage proteins (sap). This insect-specific chemosensory protein is a small soluble protein that typically transmits chemical signals by transporting small hydrophobic molecules between cells.
They found that when levels of the protein sap2 in Anopheles anopheles gambians were high, their sensitivity to pyrethroids decreased significantly. According to studies, when mosquitoes originally fell on mosquito nets, pyrethroids on mosquito nets would enter the mosquito's body and damage their nerves.
However, sap2 expression was enhanced in the legs of Anopheles gambian mosquitoes with plasmodium malariae, isolating pyrethroids.
This is a mechanism of drug resistance that has never been found in mosquitoes before. The researchers say the discovery lays the groundwork for the development of new anti-mosquito drugs. But they also stress that as creatures with a longer history than humans, it is not known how adaptable mosquitoes are to pesticides.
While new medicines continue to be developed and some mixed control programmes have been effective, there is still a long way to go to truly eliminate malaria.