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BackgroundChlorproguanil-dapsone (Lapdap), developed as a low-cost antimalarial, was withdrawn in 2008 after concerns about safety in G6PD deficient patients. This trial was conducted in 2004 to evaluate the safety and effectiveness of CD and comparison with artemether-lumefantrine (AL) under conditions of routine use in G6PD normal and G6PD deficient patients with uncomplicated malaria in The Gambia. We also examined the effects of a common genetic variant that affects chlorproguanil metabolism on risk of treatment failure.Methods1238 children aged 6 months to 10 years with uncomplicated malaria were randomized to receive CD or artemether-lumefantrine (AL) and followed for 28 days. The first dose was supervised, subsequent doses given unsupervised at home. G6PD genotype was determined to assess the interaction between treatment and G6PD status in their effects on anaemia. The main endpoints were clinical treatment failure by day 28, incidence of severe anaemia (HbFindingsOne third of patients treated with AL, and 6% of patients treated with CD, did not complete their course of medication. 18% (109/595) of children treated with CD and 6.1% (36/587) with AL required rescue medication within 4 weeks, risk difference 12% (95%CI 8.9%-16%). 23 children developed severe anaemia (17 (2.9%) treated with CD and 6 (1.0%) with AL, risk difference 1.8%, 95%CI 0.3%-3.4%, P = 0.02). Haemoglobin concentration on day 3 was lower among children treated with CD than AL (difference 0.43 g/dL, 95% CI 0.24 to 0.62), and within the CD group was lower among those children who had higher parasite density at enrollment. Only 17 out of 1069 children who were typed were G6PD A- deficient, of these 2/9 treated with CD and 1/8 treated with AL developed severe anaemia. 5/9 treated with CD had a fall of 2 g/dL or more in haemoglobin concentration by day 3.InterpretationAL was well tolerated and highly effective and when given under operational conditions despite poor adherence to the six-dose regimen. There were more cases of severe malaria and anaemia after CD treatment although G6PD deficiency was uncommon.Trial registrationClinicaltrials.gov NCT00118794. more...

Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps) gene and mapped their contemporary distribution.We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations.Resistant dhps has emerged independently in multiple sites in Africa during the past 10-20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns. more...