Figure. In vitro drug susceptibility of representative patient isolates from returning travelers who visited friends and relatives in Africa. The mean 50% inhibitory concentrations (IC50) of chloroquine, mefloquine, artemisinin, artesunate, dihydroartemisinin, and artemether are plotted in nmol/L for each isolate, performed in triplicate (error bars indicate SD; n = 3). Nigeria A denotes the patient described in this report. The black horizontal line represents the median value.