Addressing the threat of antimalarial drug resistance. This year’s report spotlights the growing threat of antimalarial drug resistance. Partial resistance to artemisinin derivatives – the backbone of malaria treatments after failures of chloroquine and sulfadoxine-pyrimethamine​ – has now been confirmed or suspected in at least 8 countries in Africa, and there are potential signs of declining efficacy of some of the drugs that are combined with artemisinin.