[In vitro sensitivity of 85 Plasmodium falciparum isolates in the Fatick region, Senegal].

Increasing resistance of Plasmodium falciparum to chloroquine and other antimalarials has been reported in Africa. Only fragmentary data are available for Senegal. Although combined chloroquine-proguanil is soon scheduled for released on the market, few studies have been published concerning the susceptibility of isolates to either drug. The in vitro susceptibility of 85 Plasmodium falciparum isolates obtained between October 24 and December 2, 1995 from malaria-infected patients living in the Fatick Region of Senegal to five classical antimalarial drugs (chloroquine, cycloguanil, quinine, mefloquine, and halofantrine) was evaluated using an isotopic, semi-microtest. Twenty-nine percent of isolates were resistant to chloroquine (IC50 > 100 nM), 22% to cycloguanil (IC50 > 500 nM), 1% to quinine (IC50 > 500 nM), 22% to mefloquine (IC50 > 20 nM), and 8% to halofantrine (IC50 > 5 nM). Five percent of isolates were resistant to both chloroquine and cycloguanil. Positive correlation was observed between quinine and halofantrine activity and between mefloquine and halofantrine activity. These findings suggest cross resistance or reduced susceptibility between these antimalarial agents which all exhibit a methanolic function.