Malaria trends in South Africa and Swaziland and the introduction of synthetic pyrethroids to replace DDT for malaria vector control

For the past five years, South Africa has seen a marked increase in notified malaria cases without a similar trend in Swaziland, which nestles between the two malarious South African provinces of KwaZulu-Natal and Mpumalanga. Swaziland and these provinces share a border with Mozambique, where malaria is holoendemic. The change from DDT to synthetic pyrethroids for intradomicillary residual spraying in South Africa may have been a contributory factor to this increase. The absence of a similar trend in Swaziland, where DDT continues to be used, adds weight to the ecological association between change in the use of insecticide and increase in malaria cases