December 11 U.S. News & World Report, Science & Ideas; Rocks and hard places

The sick begin lining up soon after dawn outside the clinic in Ndumu, a dusty rural town in South Africa's KwaZulu-Natal province. Some days, hundreds wait to have their blood tested and to see a nurse-if the nurses haven't fallen ill themselves. There are patients lying on the ground, too weak to stand, their eyes yellowed by jaundice, their bodies racked by chills, vomiting, and diarrhea. Many suffer seizures; some die.

Malaria, an old scourge long thought vanquished, has returned to KwaZulu. In 1931-32, a malaria epidemic killed more than 22,000 people in the region. After health authorities began spraying DDT inside homes to attack the mosquitoes that carry the disease, the incidence dropped dramatically. By 1973, South Africa recorded only 331 malaria cases in the entire country; in 1977, a single death.

The story was similar in other nations, but DDT wasn't universally hailed as a chemical miracle. Indeed, its very name has been synonymous with toxicity since the 1962 publication of Rachel Carson's Silent Spring, which made the link between the massive and indiscriminate use of agricultural pesticides like DDT and the death of birds and fish. Because it migrates easily and accumulates in tissues, and because it seems to have possible adverse effects in test animals, DDT has been regarded as a potentially dangerous toxin for humans.

Fearing a pandemic:  DDT was phased out by industrialized countries-including South Africa-starting in the mid-1970s in favor of more-expensive insecticides called pyrethroids. But mosquitoes have developed resistance to these compounds, and malaria is again rampant throughout poor and politically unstable regions of Asia, South and Central America, and sub-Saharan Africa. The World Health Organization says malaria still afflicts up to 500 million people a year and kills about 2.7 million of them, mostly children in sub-Saharan Africa. The economic effects are also vast: The WHO estimates malaria has curtailed financial growth rates of sub-Saharan Africa nations by 40 percent since 1965, with direct costs amounting to half a billion dollars annually. The South African government last February renewed DDT spraying, and malaria cases are dropping. But the backlash has created "total uproar," says Gerhardt Verdoorn, a wildlife conservation leader who supports DDT's use in public health. "If we don't use DDT, we will have a real pandemic disaster."

The controversy is not limited to South Africa. This month, representatives of more than 100 nations will finalize a United Nations treaty expected to impose a prohibition or gradual phaseout of 12 substances-DDT among them-that are proven or suspected threats to human health and the environment. Malaria specialists have no quarrel with banning such compounds as chlordane, heptachlor, dieldrin, PCBs, and dioxin that have been linked to cancer and damage to human nervous, reproductive, and endocrine systems. But they argue that DDT is benign in the minute quantities necessary to repel mosquitoes. (Some two dozen poor countries, including China and India, continue to spray the pesticide inside buildings.)

Preventing poor nations from using DDT, they believe, smacks of ecocolonialism by rich countries more concerned with theoretical long-term risks to their own environment than with sickness and death in the Third World. They also call this another instance of First World values being imposed globally, regardless of consequences-akin to the campaign against genetically engineered, vitamin-enriched, and pest-resistant foods that could feed the hungry and improve their health in impoverished nations. "I find it very unethical that the rich world's taste for environmental purity should be passed off to the world's poorest to uphold," says Amir Attaran of Harvard University's Center for International Development.

Judging the risks:  So how dangerous is DDT? Donald Roberts, a Department of Defense tropical-health expert and a malaria specialist, argues in an article published in the July issue of the medical journal Lancet that there are no epidemiological studies or other evidence to prove human health risks from DDT use. "Let's find out what the adverse effects are," he says, "before we start throwing away millions of lives of poor people." Roberts, along with more than 400 other physicians and scientists, has petitioned the U.N. to allow a public-health exception for DDT. As eager as they are to bury the pesticide, environmentalists concede its value in fighting malaria and say they expect First World nations to reluctantly support DDT's continued use until poor countries can afford to pay for alternatives or a malaria vaccine is available. Uncertain of how the vote this month will go, public-health officials fear that any crimp in the DDT supply will result in a de facto ban that will cost lives. (They also believe that a malaria vaccine is at best a decade distant.)

Also threatening the pesticide's availability is a Greenpeace campaign to force a halt to its production in India, with China one of only two nations still manufacturing large amounts of DDT. Environmental groups believe that rich countries can be persuaded to pay for DDT alternatives like pyrethroids for countries that can't afford them, but public-health officials are skeptical. While such weighty and abstract issues will soon be debated and decided by U.N. representatives, 35-year-old Bonginkosi Malwane's concerns in KwaZulu are far more immediate. He, his mother, and four of his seven children have been stricken by malaria. His 8-year-old daughter, Nombuso, spent almost two weeks in the hospital with the disease, and a close friend recently died.

A few days earlier, the government sprayed his interior walls with DDT, and Malwane says his worries are finally easing. The pesticide's telltale white stain is reassuring, he says, and at night, he no longer lies awake fearing the high-pitched whine that brings sickness and death.

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