Evidence of Artemisinin-Resistant Malaria in Africa

To the Editor: Balikagala et al. (Sept. 23 issue)(1) report evidence that Plasmodium falciparum malaria parasite resistance to first-line artemisinin derivatives has emerged in northern Uganda and is associated with an increased prevalence of kelch13 A675V and C469Y mutations. We edited these mutations into the P. falciparum Dd2 (Southeast Asia) and MAS-136 (eastern Uganda) strains and measured survival among dihydroartemisinin-treated intraerythrocytic ring-stage parasites cultured in vitro. Dd2 parasites expressing the kelch13 A675V or C469Y mutation showed marginally reduced susceptibility to dihydroartemisinin at the reference concentration of 700 nmol per liter as compared with parental Dd2 expressing wild-type kelch13, and no . . .