Your News story about the Roll Back Malaria campaign (“Struggling to make an impact” Nature 430, 935; 2004) quotes me as claiming that pressure from government and other donors made spraying difficult to push through politically. I am also quoted as saying: “We have had very, very strong lobbying over DDT. We have had to give up.” The quotations give the impression that the World Health Organization (WHO) has given up on DDT under the pressure of lobbying. I believe this is misleading.

When interviewed, I explained that we sometimes had to give up trying to convince a specific donor to financially support indoor spraying with DDT, if they flatly refused because of its perceived toxicity and ecological hazard. This has occasionally occurred in countries where the government wished to use DDT, and there was evidence that it was the best option for malaria-vector control.

However, in general terms, the WHO has never given up in its efforts to ensure access to DDT where it is needed. At meetings of the intergovernmental negotiation committee on the Stockholm Convention — which seeks to control the spread of persistent organic pollutants — the WHO has successfully defended the right of countries to use DDT for disease-vector control, if no suitable alternative can be found. The WHO also supports worldwide efforts to develop alternative products and phase in alternative control strategies (

The Stockholm Convention came into force in May this year. Its exemption allowing restricted and controlled use of DDT according to WHO guidelines is a good example of appropriate international regulation on a difficult dilemma. It is not a compromise but a solution, which ensures that disease-control programmes maintain access to a useful product, while fully respecting the need to prevent environmental damage from persistent organic pollutants, such as DDT.