The changing response of Plasmodium falciparum to antimalarial drugs in east Africa.

For the past 20 years, chloroquine chemotherapy has been the single most effective malaria control measure in East Africa. The advent of chloroquine-resistant Plasmodium falciparum has reduced the clinical effectiveness of chloroquine and this trend is likely to continue. Combinations of antifol drugs are at present effective inhibitors of most P. falciparum infections in the region, in spite of widespread resistance to pyrimethamine. The development of (i) sensitive methods for monitoring changes in sensitivity to antifol combinations, (ii) more effective and less costly alternatives to commercially available combinations, and (iii) investigation of host and parasite factors leading to drug treatment failure in P. falciparum infections has been the primary goal of the Wellcome Trust Research Laboratories in Kenya (directed by Dr W.M. Watkins) within the malaria programme of the Kenya Medical Research Institute, and collaborating laboratories at the School of Tropical Medicine and the University of Liverpool.