Pesticide-Impregnated Bednetting

The Anopheles mosquito is not much longer than a human eyelash, but its bite can be deadly. The females, which feed on blood, can carry and transmit Plasmodium, the parasite that causes malaria. Although the tiny mosquito may not seem much of a target, many infectious disease experts believe that the most effective way to eradicate malaria is to control its insect carrier—either killing it or at the very least keeping it away from humans.

Some of the earliest malaria interventions targeted water, an environment mosquitoes need to breed. Ancient Romans drained their reservoirs. In the 1930s and 1940s chemicals that could kill larva directly were used to eradicate invading populations of mosquitoes in Brazil and Egypt. Success depends on the ability to locate a large proportion of the freshwater breeding sites that lie within a mosquito's flight distance of the susceptible community. More recently, a bacterium called Bacillus thuringiensis israelenisis (Bti) has been used in place of chemical water treatment. Mosquito larva feed on the bacteria, which release a toxin that poisons them.