title: Antimalarial drug susceptibility of Plasmodium falciparum isolates from forest fringe dwelling aborigines (Orang Asli) of Peninsular Malaysia.
abstract: The drug susceptibility of 70 isolates of Plasmodium falciparum to standard and experimental antimalarials was evaluated using a radioisotope microdilution method. All isolates were from forest fringe dwelling Orang Asli, the aborigines of Peninsular Malaysia. The geometric mean IC50 values were: chloroquine, 10 ng/ml; amodiaquine, 4.7 ng/ml; mefloquine, 2.8 ng/ml; quinine, 40.5 ng/ml; halofantrine, 1.5 ng/ml; enpiroline, 3 ng/ml; and pyrimethamine, 21 ng/ml. Four isolates exhibited decreased susceptibility to chloroquine (IC50 greater than 60 ng/ml), and one exhibited decreased susceptibility to quinine (IC50 = 161 ng/ml). Three isolates showed decreased susceptibility to mefloquine (IC50 = 10-11 ng/ml). The lack of drug pressure may account for the high prevalence of P. falciparum isolates susceptible to chloroquine.
authors.affiliation: U.S. Army Medical Research Unit, Institute for Medical Research, Kuala Lumpur, Malaysia.
authors.forename: C
authors.initials: C
authors.lastname: Lambros
authors.forename: D R
authors.initials: DR
authors.lastname: Davis
authors.forename: G E
authors.initials: GE
authors.lastname: Lewis
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002738:Chloroquine / Q000494:pharmacology; D004351:Drug Resistance; D006801:Humans; D008288:Malaria / Q000188:drug therapy / Q000453:epidemiology; D008296:Malaysia; D015767:Mefloquine; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000302:isolation & purification; D011804:Quinolines / Q000494:pharmacology
chemical_list: D000962:Antimalarials; D011804:Quinolines; D002738:Chloroquine; D015767:Mefloquine