Studies on the chemotherapy of malaria

Abstract
Details are given of 12 cases of pyrimethamine-resistant falciparum malaria in Gambian Africans; cross-resistance to proguanil and chlorproguanil was variable, being present in some but not in others. Most of these patients when first treated had infections sensitive to pyrimethamine; and resistance appeared only with subsequent treatment with pyrimethamine. It is concluded that this resistance was probably confined to asexual erythrocytic parasites although the possibility of its extension to gametocytes cannot be excluded. One patient had resistant infections for 3 successive years. Two others were originally symptomless carriers. Combinations of pyrimethamine with sulphormethoxine or dapsone in low dosage were effective schizontocides against these resistant infections.