Pyrethroid

Bed nets treated with inexpensive pyrethroid insecticides are the main defense against biting, malaria-carrying mosquitoes, and they have significantly cut down on the number of cases. The World Health Organization reports malaria infected an estimated 212 million people in 2015, killing some 429,000 of them.

Charles Wondji, a mosquito geneticist at the School of Tropical Medicine in Liverpool, England, notes that resistance to pyrethroid insecticides occurred rapidly, in about eight years.