title: Understanding artemisinin-resistant malaria: what a difference a year makes.
abstract: OBJECTIVE
  The emergence of artemisinin resistance in Southeast Asia (SEA), where artemisinin combination therapies (ACTs) are beginning to fail, threatens global endeavors to control and eliminate Plasmodium falciparum malaria. Future efforts to prevent the spread of this calamity to Africa will benefit from last year's tremendous progress in understanding artemisinin resistance.
  
  
  RESULTS
  Multiple international collaborations have established that artemisinin resistance is associated with slow parasite clearance in patients, increased survival of early-ring-stage parasites in vitro, single-nucleotide polymorphisms (SNPs) in the parasite's kelch protein gene (K13), parasite 'founder' populations sharing a genetic background of four additional SNPs, parasite transcriptional profiles reflecting an 'unfolded protein response' and decelerated parasite development, and elevated parasite phosphatidylinositol-3-kinase activity. In Western Cambodia, where the K13 C580Y mutation is approaching fixation, the frontline ACT is failing to cure nearly half of patients, likely due to partner drug resistance. In Africa, where dozens of K13 mutations have been detected at low frequency, there is no evidence yet of artemisinin resistance.
  
  
  CONCLUSIONS
  In SEA, clinical and epidemiological investigations are urgently needed to stop the further spread of artemisinin resistance, monitor the efficacy of ACTs where K13 mutations are prevalent, identify currently-available drug regimens that cure ACT failures, and rapidly advance new antimalarial compounds through preclinical studies and clinical trials.
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA.
authors.forename: Rick M
authors.initials: RM
authors.lastname: Fairhurst
mesh_terms: D000962:Antimalarials / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology*; D004351:Drug Resistance / Q000187:drug effects / Q000502:physiology; D017125:Genes, Protozoan / Q000235:genetics; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000187:drug effects / Q000235:genetics
chemical_list: D000962:Antimalarials; D037621:Artemisinins; C031327:artemisinin