The development of resistance to antimalarials is a major challenge for global malaria control. Artemisinin-based combination therapies, the newest class of antimalarials, are used worldwide but there have been reports of artemisinin resistance in Southeast Asia. In February through May 2013, we conducted open-label, nonrandomized therapeutic efficacy studies of artemetherlumefantrine (AL) and dihydroartemisinin-piperaquine (DP) in Zaire and Uíge Provinces in northern Angola. The parasitological and clinical responses to treatment in children with uncomplicated Plasmodium falciparum monoinfection were measured over 28 days, and the main outcome was a PCR-corrected adequate clinical and parasitological response (ACPR) proportion on day 28. Parasites from treatment failures were analyzed for the presence of putative molecular markers of resistance to lumefantrine and artemisinins, including the recently identified mutations in the K13 propeller gene. In the 320 children finishing the study, 25 treatment failures were observed: 24 in the AL arms and 1 in the DP arm. The PCR-corrected ACPR proportions on day 28 for AL were 88% (95% confidence interval [CI], 78 to 95%) in Zaire and 97% (91 to 100%) in Uíge. For DP, the proportions were 100% (95 to 100%) in Zaire, and 100% (96 to 100%) in Uíge. None of the treatment failures had molecular evidence of artemisinin resistance. In contrast, 91% of AL late-treatment failures had markers associated with lumefantrine resistance on the day of failure. The absence of molecular markers for artemisinin resistance and the observed efficacies of both drug combinations suggest no evidence of artemisinin resistance in northern Angola. There is evidence of increased lumefantrine resistance in Zaire, which should continue to be monitored.
Plasmodium falciparum infection during pregnancy may cause placental malaria and subsequently low birth weight, primarily through the placental sequestration of infected red blood cells. Measuring the burden of malaria during pregnancy usually involves determining the prevalence of placental malaria infection through microscopic examination of placental blood films, a difficult and error-prone process. A number of rapid diagnostic tests (RDTs) for malaria have been developed, most of them immunochromatographic dipstick assays. However, none have been tested for the direct determination of malaria antigen in placental blood. We undertook an evaluation of the Malaria Rapid Test (MAKROmed in determining placental malaria infection. The prevalence of placental parasitemia was 22.6% by microscopy, 51.0% by a polymerase chain reaction (PCR), and 43.1% by RDT. When the PCR was used as the gold standard, RDTs had a sensitivity of 89% and a specificity of 76%. The MAKROmed RDT was highly sensitive in the detection of placental malaria, but had lower than expected specificity.
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