Tina Rosenberg's long opinion piece  on the New York Times website brings much-needed attention to the plight of "poor people's diseases," from sleeping sickness to tuberculosis ("The Scandal of 'Poor People's Diseases,'" Times Select, March 29). But her argument about malaria--that more DDT would vanquish the disease--is all wrong.
The basic gist of the argument is thus: Americans wiped out malaria using DDT, but because über-green Rachel Carson crusaded against the insecticide in Silent Spring , we self-righteously deprived the rest of the world of the miracle toxin. Two conclusions can be drawn from this little tale. One: Post-Carson environmentalists have the blood of Africans dripping from their hands. Two: To quote from the title of a previous Rosenberg story on the subject, "What the world needs now is DDT."
There are several problems with this story. The first is that DDT didn't wipe out malaria in the United States. The Centers for Disease Control's door-to-door DDT spray campaign of 1947-1951 was not about eradicating malaria in the United States, because malaria was already gone. The US Public Health Service had noted the "diminishing menace"  of malaria in the United States by 1928--seventeen years before DDT showed up on the scene. The pockets of malaria that persisted in the South until the late 1930s were finally vanquished by the swamp-draining, electricity-giving activities of the Tennessee Valley Authority,  which cut down on mosquito breeding sites and enabled locals to start living in well-screened houses. The rationale behind the DDT spray campaign was to prevent the re-introduction of malaria from troops returning home from World War II. About the best one CDC physician involved in the campaign could say about it was that "we kicked a dying dog."
The second problem is that the world did try to wipe out malaria using DDT. That campaign, launched by the WHO in 1955, eradicated malaria from a few marginal areas in Southern Europe and a couple of islands. But in places where malaria reigned supreme, it failed miserably. That isn't because they didn't have enough DDT but because the stuff stopped working. Malarial mosquitoes resistant to DDT cousin Dieldrin emerged in Nigeria as early as 1955. Malarial mosquitoes in Venezuela had learned to simply avoid DDT-sprayed walls and bite people outside by 1957. By 1972, when the United States finally banned DDT, nineteen species  of malarial mosquitoes had already become impervious to the toxin.
The third problem is that Rachel Carson and the enviros who followed her were not the sole critics of DDT. By the time Carson wrote Silent Spring in 1962, concerns about DDT had been circulating among government experts for years. Not one month after DDT's launch in the consumer market in September 1947, experts were calling DDT "injurious to birds," according to the New York Times. "Experts warn new insecticide also may be fatal to fish--further tests urged," the Times headline read. USDA scientists were urging Congress to ban DDT use on dairy animals by May 1947.
Finally, it is true that environmental groups initially supported a UN-led worldwide ban on DDT in 2000. But they quickly about-faced when informed about its use--albeit limited--in malaria control. "You can only accuse them of naïveté," says malaria expert Amir Attaran. Not so chemical giant Bayer. "We fully support EU to ban imports of agricultural products coming from countries using DDT," wrote Bayer's Gerhard Hesse in an e-mail message leaked to the Financial Times last year. Chemical giant Bayer manufactures brand-name insecticides much pricier than cheap, off-patent DDT. "DDT use for us is a commercial threat," Hesse wrote.
The conclusion one might draw from the real story of DDT and malaria is clear. DDT may alleviate malaria in some places, sometimes, if it still works to repel malarial mosquitoes. That won't be true in many places. And so the "world" does not need more DDT. What the world needs is better housing and civil engineering--in short, an end to poverty. That's what wiped out malaria at home, and that's what will wipe it out elsewhere, too, along with a host of other ills.