On top of the almost unimaginable devastation caused by January's earthquake in Haiti, the nation is bracing for the ravages of the rainy season. Torrential downpours have already flooded homes and turned tent cities into muddy misery. Ominously, the number of cases of malaria, which is spread by the bite of mosquitoes and which was endemic in Haiti even before the earthquake, is increasing.
To reduce the incidence of malaria, various aid groups are planning to distribute more than 3 million bed nets, an ultra-low-tech, only modestly effective intervention. What is really needed is the chemical DDT, an old, cheap and safe tool to control the vector -- the Anopheles mosquito -- that spreads the disease.