The UN is premature in trying to ban DDT for malaria control

Richard Tren et al | 10 Oct 2012
British Medical Journal
Despite the progress that has been made in malaria control and treatment, it remains a serious global health problem.1 Several malarial countries, including some that are striving to eliminate the disease, still rely on dichlorodiphenyltrichloroethane (DDT) for vector control. It is therefore problematic that the UN Environment Programme (UNEP), without the consent of member states, and violating its own treaties, exerts relentless pressure to ban DDT globally.

Environmental groups have tried to ban DDT before, but in 2000 the Stockholm Treaty made an exception for DDT in disease vector control, which it deemed "acceptable."2 Thus, the hard work of malaria endemic African countries and a campaign by scientists and physicians warning that hasty elimination would be devastating secured DDT a place in the malaria armamentarium.3

The World Health Organization endorses DDT, arguing that a premature shift to less effective or more costly alternatives will have a negative impact on disease burden.4 Currently, 19 countries reserve the right under the Stockholm Convention to use DDT, and it is actively used in at least seven countries for indoor spraying.

DDT is relatively cheap, highly effective, and long lasting, and often no other intervention can compare.5 6 In the late 1990s, when alternatives to DDT failed because of resistance and caused a malaria epidemic in South Africa, among other measures, a switch back to DDT reduced malaria cases by 93% (from 41 077 to 2818) in two years.7 Thanks largely to the use of DDT in Namibia, malaria related hospital admissions and deaths fell by 92% (29 059 to 2264) and 96% (1370 to 46) between 2001 and 2009.1 Similar trends have been seen in Botswana, South Africa, and Swaziland. For these benefits to be outweighed by risks requires reproducible evidence that DDT is dangerous, but none exists. WHO's latest assessment found no evidence for concern "about levels of exposure for any of the end-points that were assessed" in carcinogenicity, reproductive toxicity, or developmental toxicity.8

Yet despite this endorsement and admirable malaria control results, UNEP is trying to eliminate DDT again. As major UNEP donors, including the European Union, have endorsed WHO's position, UNEP's motivations are unclear.9 10

The Stockholm Convention says that countries may use DDT in accordance with WHO recommendations and guidelines when locally safe, effective, and affordable alternatives are not available.2 Because the convention contains no deadline for elimination, DDT may be used indefinitely until alternatives are available.

Yet UNEP is transgressing its Stockholm convention mandate, repeatedly advocating deadlines for elimination. In 2007 UNEP expounded its strategy of no longer using DDT by 2017 and finally destroying DDT by the end of 2020.11 Until recently the UNEP website had an animated cartoon of horses jumping over obstacles to eliminating DDT by 2020 (it still exists on another website12).

The use of a cartoon to dramatise the abolition of a life saving intervention is arguably merely tasteless. But UNEP poses a serious danger to malaria control in encouraging India, the only country that makes DDT, to stop producing it.13

UNEP's most pernicious influence is through the Global Alliance for Alternatives to DDT, which member states authorised it to create, but which now circumvents the Stockholm Convention. In 2011 UNEP wrote that the alliance exists "to eliminate the reliance [on] DDT for disease vector control"14 but will "not undertake substantive operations related to vector control" and will not be directly involved in funding and executing projects on the ground.15 Thus the alliance is ideologically bent on eliminating DDT without doing research to show that alternatives work in vector control or funding projects to continue saving lives after DDT is taken away.

The Stockholm Convention takes a different approach. It aspires to eliminating DDT eventually but eschews deadlines and demands that locally safe, effective, and affordable alternatives are implemented first.

Applying the Stockholm Convention, many have concluded that DDT still has a place. The African Leader's Malaria Alliance, representing 40 African heads of state or government, expressed Africa's ongoing need for DDT as recently as 2010.16 More recently, the Southern African Development Community's executive secretary wrote to UNEP's executive director stating that "it would be infeasible and highly irresponsible to abandon the use of DDT at any foreseeable date."17 Even UNEP's own DDT expert group thinks that DDT is still needed for malaria vector control in certain settings.18

It is premature and illegal of UNEP to set deadlines for eliminating DDT. Instead, UNEP should follow the Stockholm Convention and encourage measured steps, probably requiring decades of research, to bring about safe, effective, and affordable alternatives that one day will make DDT redundant. Perhaps UNEP could start by financing the development of alternative insecticides for public health: not one has been invented in decades and investment is minimal, which is unwise because resistance is rising.19 But racing toward DDT elimination, as UNEP is doing, is ill considered and will undoubtedly cause much harm.

http://www.bmj.com/content/345/bmj.e6801?ijkey=H4KijaZlhGvkDLK&keytype=ref