Initially multiple independent Kelch mutations were observed,1 but in a recent sinister development, a single dominant artemisinin-resistant P falciparum C580Y mutant lineage has arisen in western Cambodia, outcompeted the other resistant malaria parasites, and subsequently acquired resistance to piperaquine.2 Cambodia had adopted dihydroartemisinin-piperaquine as first-line antimalarial treatment, but has now been forced to switch its first line artemisinin combination treatment back to artesunate-mefloquine as a consequence3. 1 EA Ashley, M Dhorda, RM Fairhurst, Plasmodium falciparum, malaria, N Engl J Med, Vol. 371, 2014, 411-423 2 M Imwong, K Suwannasin, C Kunasol, Plasmodium falciparum, in the Greater Mekong Subregion: a molecular epidemiology observational study, Lancet Infect Dis, Vol. 17, 2017, 491-497 3 World Health Organization, Status report on artemisinin and ACT resistance (April 2017), (accessed July 11, 2017).