The efficacy of chloroquine, sulfadoxine-pyrimethamine and a combination of both for the treatment of uncomplicated Plasmodium falciparum malaria in an area of low transmission in western Uganda

We conducted an efficacy study of chloroquine (CQ), sulfadoxine-pyrimethamine (SP) and a combination of both (SP + CQ) for the treatment of uncomplicated malaria in an area of low transmission with low drug pressure. On day 3, fever clearance was 97.4% (95% CI, 86.8-99.9), 100% (95% CI, 87.2-100) and 96.6% (95% CI, 82.2-99.9) in the CQ, SP and SP + CQ groups, respectively, (P = 0.65). On day 14, clinical success was 92.5% (95% CI, 79.6-98.4), 100% (95% CI, 87.2-100) and 100% (95% CI, 88.1-100) in the CQ, SP and CQ + SP groups, respectively. Clinical failure was seen in 7.5% with 5% (95% CI, 0.61-16.9) early treatment failure and 2.5% (95% CI, 0.06-13.2) late treatment failure of cases in the CQ group and 0% in the SP and SP + CQ groups. Parasitological resistance was observed at RI level in 10% (95% CI, 2.8-23.7), 18.5% (95% CI, 6.3-38.1) and 6.9% (95% CI, 0.85-22.8) for the CQ, SP and SP + CQ, respectively (P = 0.37). There was no age-dependent difference in clinical failure or parasitological resistance in any of the treatment groups and prior CQ use within the last 2 weeks did not affect CQ treatment outcome. The findings of this study suggest that CQ is still effective for the treatment of uncomplicated malaria in this area of low transmission and SP. However, combination therapy of SP + CQ is recommended to delay the development SP resistance, and regular surveillance for emerging CQ and SP resistance is needed to plan for alternative antimalarial drug regimens.