Deaths occur most often among malnourished people in countries that can't afford adequate treatment. WHO has joined several other UN agencies and health organizations in advocating the retention of DDT for malaria control. Despite the support of such organizations, politics and economics may soon make DDT unavailable in many malaria-stricken regions, including the places where it's needed most. Whether malaria is fatal depends on both the initial health of a person and the Plasmodium parasite. Another is that this region is home to some of the better carriers of the parasite.
Sprayer applies DDT to a home's walls in Belize.
Though this annual treatment can kill mosquitoes, a new study suggests that it works mainly by repelling the insects. Though hundreds of different mosquitoes can transmit Plasmodium , only about 40 species make good carriers, largely because they feed on people and reside in populated regions. Two factors further complicate the situation. Some parasites are becoming resistant to drug therapy, and some mosquitoes are becoming invulnerable to the insecticides used against them. Consider South Africa.