The problem of Plasmodium falciparum drug resistance in Africa south of the Sahara.

The resistance of P. falciparum malaria to dihydrofolate reductase inhibitors, to the 4-aminoquinolines (in particular, chloroquine), and to the combination sulfadoxine-pyrimethamine is reviewed in the light of past and the most recent findings. Considering the gravity of the situation following the recent discovery of resistance of P. falciparum to chloroquine among the semi-immune populations of Africa south of the Sahara, a few suggestions are made for a realistic and rational approach to the drug resistance problem. Some questions that may be worthy of applied field research are briefly mentioned and governments are invited to take the necessary action to ensure better control of the procurement, distribution, and use of antimalarials.