Water & Conservation

Insecticides such as DDT have long been used to combat the scourge of malaria in the developing world. But with the disease parasite becoming increasingly adept at resisting the chemical onslaught, some countries are achieving striking success by eliminating the environmental conditions that give rise to malarial mosquitoes.

For over half a century, the battle against malaria has been waged with powerful anti-malarial drugs and potent mosquito-killing insecticides, weapons born from the wonders of synthetic chemistry. In recent years, however, fed up with the financial and ecological drawbacks of chemical warfare, malarious communities from China to Tanzania to Mexico have been forging a new way to fight the scourge, one that draws inspiration from the lessons of ecology more than chemistry. Rather than attempt to destroy mosquitoes and parasites outright, these new methods call for subtle manipulations of human habitats and the draining of local water bodies — from puddles to irrigation canals — where malarial mosquitoes hatch.

The most striking example comes from Mexico, which has completely abandoned its previously lavish use of DDT in malaria control for insecticide-free methods and has seen malaria cases plummet.

Like many countries, Mexico for decades relied upon insecticides to fight the disease, by spraying mosquito-killing chemicals on the interior walls of homes where blood-feeding mosquitoes rest, among other methods. Between 1957 and 1999, taming Mexico’s malaria required 70,000 tons of DDT.