DDT still has an important role to play in saving lives and reducing the burden of malaria in some of the world's poorest countries, states the World Health Organisation (WHO) as the international community considers phasing it out.
More than 120 governments, inter-governmental and non-government agencies are meeting next week (December 4-9) in Johannesburg, South Africa, to finalize an international treaty to reduce and/or eliminate the production and use of 12 persistent organic pollutants, including DDT.
WHO has been working in collaboration with the United Nations Environment Programme (UNEP) to provide treaty negotiators with information on the health and environmental issues associated with DDT as well as the current use of DDT in malaria control.
Although DDT has been banned from agricultural use in most countries since the 1970s due to its damaging effects on the environment, it continues to be used in limited quantities for public health purposes. For many malaria-affected countries, responsible DDT use is a vital strategy for preventing malaria transmission and controlling epidemics. Countries continue to use DDT primarily because they cannot afford reliable alternatives or do not have the capacity to develop them.
In order to ensure that treaty restriction on DDT will not result in an increase in malaria deaths, WHO and the Roll Back Malaria partnership (RBM) are encouraging the negotiators to support time-limited exemptions for the public health use of DDT. In addition WHO is calling for new financial resources to aid in the development of and orderly transition to cost-effective alternatives to DDT for malaria vector control.
According to Dr David Heymann, WHO Executive Director for Communicable Diseases: "Time limited exemptions are critically important to the ultimate success of this treaty. Countries that are currently using DDT for malaria vector control need the time and the resources to identify and implement the alternatives that work for them."
WHO emphasizes the importance of assuring that DDT is used only for public health vector control and in accordance with WHO guidelines.
"WHO recommends that DDT should be used only for indoor residual spraying and every step must be taken to prevent DDT from being diverted to agricultural uses," says Dr Heymann. "Projections suggest that the amounts of DDT needed for malaria control are a very small fraction of what has been used in the past for agricultural purposes."
WHO is working with malaria-affected countries and other Roll Back Malaria partners to develop a systematic approach to reducing reliance on DDT while assuring that people continue to be protected from malaria.
WHO states that reducing reliance on DDT needs to be part of an overall strategy of strengthening malaria control. There is a need building robust capacity for malaria control at country level that supports the development and utilization of a range of methods to prevent malaria transmission that are cost-effective, sustainable and rely less on chemicals in general.
In addition to the issue of exemptions, negotiators in Johannesburg will be discussing the financial and technical resources required to implement the treaty. According to Dr Heymann, "The countries that rely on DDT are some of the poorest in the world. Without additional resources they will be unable to make much progress in reducing reliance on DDT. We hope that the treaty will result in significant new funding in the coming years, in the meantime we must look to all available sources."
With the assistance of the RBM partnership, Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua and Panama have already mobilized $750,000 for reducing reliance on DDT, as part of a regional project supported by the Global Environment Facility (GEF). The partnership is also seeking resources for similar efforts across Africa and Asia.