The number of malaria cases in SA has dropped dramatically over the past seven years, largely as the result of the widespread use of the controversial pesticide DDT.
Despite the positive results, a number of academics have cautioned about the use of DDT and warned of side effects, particularly environmental effects and the impact on fertility rates among women who have come into contact with the pesticide.
Statistics released by the health department show that since the reintroduction of DDT, malaria cases have dropped significantly. In KwaZulu Natal there has been a 99% reduction, in Mpumalanga 92%, and in Limpopo 70%.
WHAT IT MEANS
 Malaria cases have dropped by 90% in SA
Academics call for use of DDT alternatives
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Over the past high-transmission season, which ended in March 2007, 1 263 people were infected with malaria and only seven died. This compares with 1999-2000, just before DDT was reintroduced, when 64 222 cases and 458 deaths were recorded.
DDT has a controversial history and the side effects of its uses on fruits and vegetables in the 1960s and 1970s resulted in an almost complete ban over the subsequent two decades. But health officials in Southern Africa have found that if sprayed in tiny amounts once or twice a year on the inside of homes, DDT can keep out 90% of mosquitoes.
But activists and some academics are again urging the use of alternatives to DDT. University of Cape Town professor Leslie London says "in the long term, DDT is something that needs to be phased out - the question is how quickly and what to replace it with.
"DDT is well-recognised as environmentally persistent, and a problem for animals. For humans, the evidence is not as strong but certainly sufficient to be of concern, particularly in pregnant women.
"The notion that DDT is safe for humans is nonsense," London says. "So, the issue is not that DDT is safe, but that the use of DDT may be justified if it can prevent deaths from malaria.
London says the success of the DDT campaign against malaria has much to do with the low cost of DDT, making it affordable for health authorities. "But the side effects are not built into the cost-benefit analysis," he says.
London and Leslie Liddell, director for Biowatch SA, urge greater use of alternatives to DDT, such as bed nets, other insecticides and greater control of open water-collection sources. Though these options are expensive and not easily accessible, they would be safer than DDT, they argue.
But proponents of the use of DDT argue that it has had a high and immediate impact in reducing malaria, whereas bed nets and other methods have only a gradual impact.
Mbulelo Baloyi, spokesman for KwaZulu Natal's agriculture & environmental affairs department, says: "We did satisfy ourselves that DDT has no effect on the environment. We monitor any irregularities that occur in the environment and none so far have been due to the reintroduction of DDT."
Jasson Urbach, an economist with the Free Market Foundation's health policy unit, is critical of the persistent warnings about DDT: "This is a smear campaign and no-one has actually found conclusive evidence for their claims. Authorities should continue to use DDT rather than worrying about imaginary risks."
While SA, Swaziland and Mozambique have recorded a sharp drop in malaria cases, Uganda has been a more reluctant adopter. It s exporters are fighting the government's decision to reintroduce the pesticide. If residues were detected in agricultural produce, Europe would ban all imports from Uganda.
But Rajendra Maharaj, an antimalaria project leader, says "there is almost no environmental contamination when you use DDT properly".
