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In effort to combat malaria, South Africa continues to use DDT.
JOHANNESBURG — More than three decades after much of the developed world banned DDT use, South Africa maintains the maligned pesticide as a cornerstone of its malaria control strategy.
South Africa credits indoor DDT spraying in high-risk areas with dramatically decreasing the number of malaria cases and malaria-related deaths here in recent years. The negative effects of the chemical on humans, wildlife and the environment remain the topic of hot debates and scientific studies, but South Africa has determined that DDT’s efficacy in keeping disease-carrying mosquitoes at bay is too great to pass up.
“Overwhelmingly, the public health benefits are higher than any potential (pitfalls),” said Richard Tren, director of Africa Fighting Malaria, an advocacy group based both in South Africa and the United States.
South Africa introduced malaria control measures in the 1930s, and the risk of infection is now relatively low and seasonal — mostly during the wet summer months. Malaria transmission is limited to low-altitude areas in the northeastern part of the country near the border with Mozambique and Swaziland. Out of South Africa’s nine provinces, only three — Limpopo, Mpumalanga and Kwazulu-Natal — regularly report cases of malaria infection.
The number of malaria cases declined steadily until the mid-1990s, when it suddenly increased to peak at more than 64,000 cases and 458 deaths in 2000 — the highest number since the 1930s. The reason for the increase was three-fold. First, parasites had developed resistance to anti-malarial drugs; second, South Africa experienced unusually heavy rainfall after several years of drought; and third, mosquitoes weren’t deterred by synthetic pyrethroids, the insecticide that had replaced DDT for indoor spraying.
South Africa quickly reverted to DDT as its insecticide of choice, and the number of cases and deaths fell accordingly. For the 2006 to 2007 season, there were just 5,596 cases and 37 deaths, according to the South African Department of Health. Statistics for 2007 to 2008 — the most recent available — show a slight increase with 7,773 cases and 65 malaria-related deaths.
South Africa is the leader of regional efforts to fight malaria. Control of the disease is an integral part of the joint development program it started with Mozambique and Swaziland in 2000. South Africa also assists five other countries — including neighbors Botswana and Namibia — with DDT indoor spraying programs. South Africa’s malaria control efforts are self-funded, but some of these other countries receive support through the $1.2 billion U.S. President’s Malaria Initiative.