Pie charts show K13-propeller allele frequencies among 300 parasite isolates in ten Cambodian provinces. Pie sizes are proportional to the number of isolates and the different alleles are colour-coded as indicated. The frequencies (95% confidence interval) of mutant K13-propeller alleles are: Pailin (95%, 88–99, n = 84), Battambang (93%, 87–99, n = 71), Pursat (89%, 67–99, n = 19), Kampot (83%, 52–98, n = 12), Kampong Som (71%, 29–96, n = 7), Oddar Meanchey (76%, 58–89, n = 33), Preah Vihear (16%, 3–40, n = 19), Kratie (71%, 44–90, n = 17), Mondulkiri (67%, 9–99, n = 3) and Ratanakiri (6%, 1–19, n = 35).