Insecticide-treated mosquito nets helped reduce incidence, but, over the past few years, Anopheles has developed strong resistance to pyrethroids used in these nets.
Malaria killed 405,000 people in 2018. So, it isn’t hard to see why the Sustainable Development Goals call for countries to act to eradicate it by 2030. However, the fight against the disease just got tougher. While resistance to a host of anti-malarials—including the wonder-drug artemisinin—is getting reported with alarming frequency, new research shows exactly how Anopheles gambiae, the most common malaria vector, is evolving resistance to potent insecticides.
Insecticide-treated mosquito nets helped reduce incidence, but, over the past few years, Anopheles has developed strong resistance to pyrethroids used in these nets. Earlier, resistance from mutated genes coding for a sodium channel protein that reduces the mosquito’s neuronal sensitivity to the insecticide and “enhanced metabolic activity of detox enzymes that promote the breakdown of insecticides” had been reported. Now, the new research, reported in Nature, shows that pyrethroid-resistant mosquitos, additionally, have higher-than-normal expression of genes coding for chemosensory proteins, involved in insect communication.
Given SAP2 expression is significant in the mosquito’s legs, resistance kicks in right from the moment a mosquito lands on the net. While the new research shows how this particular channel of resistance can be choked off, it also shows how fast insects could evolve to develop resistance in unexpected ways, making the fight against malaria more difficult.