SummaryBackgroundPrimaquine is the only widely used drug that prevents Plasmodium vivax malaria relapses, but adherence to the standard 14-day regimen is poor. We aimed to assess the efficacy of a shorter course (7 days) of primaquine for radical cure of vivax malaria.MethodsWe did a randomised, double-blind, placebo-controlled, non-inferiority trial in eight health-care clinics (two each in Afghanistan, Ethiopia, Indonesia, and Vietnam). Patients (aged ≥6 months) with normal glucose-6-phosphate dehydrogenase (G6PD) and presenting with uncomplicated vivax malaria were enrolled. Patients were given standard blood schizontocidal treatment and randomly assigned (2:2:1) to receive 7 days of supervised primaquine (1·0 mg/kg per day), 14 days of supervised primaquine (0·5 mg/kg per day), or placebo. The primary endpoint was the incidence rate of symptomatic P vivax parasitaemia during the 12-month follow-up period, assessed in the intention-to-treat population. A margin of 0·07 recurrences per person-year was used to establish non-inferiority of the 7-day regimen compared with the 14-day regimen. This trial is registered at ClinicalTrials.gov (NCT01814683).FindingsBetween July 20, 2014, and Nov 25, 2017, 2336 patients were enrolled. The incidence rate of symptomatic recurrent P vivax malaria was 0·18 (95% CI 0·15 to 0·21) recurrences per person-year for 935 patients in the 7-day primaquine group and 0·16 (0·13 to 0·18) for 937 patients in the 14-day primaquine group, a difference of 0·02 (−0·02 to 0·05, p=0·3405). The incidence rate for 464 patients in the placebo group was 0·96 (95% CI 0·83 to 1·08) recurrences per person-year. Potentially drug-related serious adverse events within 42 days of starting treatment were reported in nine (1·0%) of 935 patients in the 7-day group, one (0·1%) of 937 in the 14-day group and none of 464 in the control arm. Four of the serious adverse events were significant haemolysis (three in the 7-day group and one in the 14-day group).InterpretationIn patients with normal G6PD, 7-day primaquine was well tolerated and non-inferior to 14-day primaquine. The short-course regimen might improve adherence and therefore the effectiveness of primaquine for radical cure of P vivax malaria.FundingUK Department for International Development, UK Medical Research Council, UK National Institute for Health Research, and the Wellcome Trust through the Joint Global Health Trials Scheme (MR/K007424/1) and the Bill & Melinda Gates Foundation (OPP1054404).

BackgroundIn 2005, the Ethiopian government launched a massive expansion of the malaria prevention and control programme. The programme was aimed mainly at the reduction of malaria in populations living below 2,000 m above sea level. Global warming has been implicated in the increase in the prevalence of malaria in the highlands. However, there is still a paucity of information on the occurrence of malaria at higher altitudes. The objective of this study was to estimate malaria prevalence in highland areas of south-central Ethiopia, designated as the Butajira area.MethodsUsing a multi-stage sampling technique, 750 households were selected. All consenting family members were examined for malaria parasites in thick and thin blood smears. The assessment was repeated six times for two years (October 2008 to June 2010).ResultsIn total, 19,207 persons were examined in the six surveys. From those tested, 178 slides were positive for malaria, of which 154 (86.5%) were positive for Plasmodium vivax and 22 (12.4%) for Plasmodium falciparum; the remaining two (1.1%) showed mixed infections of Plasmodium falciparum and Plasmodium vivax. The incidence of malaria was higher after the main rainy season, both in lower lying and in highland areas. The incidence in the highlands was low and similar for all age groups, whereas in the lowlands, malaria occurred mostly in those of one to nine years of age.ConclusionThis study documented a low prevalence of malaria that varied with season and altitudinal zone in a highland-fringe area of Ethiopia. Most of the malaria infections were attributable to Plasmodium vivax.

BackgroundThe genetic diversity of Plasmodium falciparum has been extensively studied in various countries. However, limited data are available from Ethiopia. This study was conducted to evaluate the extent of genetic diversity of P. falciparum in Kolla-Shele, in the southwest of Ethiopia.MethodsA total of 88 isolates from patients with uncomplicated P. falciparum attending Kolla-Shele Health Centre was collected from September to December, 2008. After extraction of DNA by Chelex® method, the samples were genotyped by using nested-PCR of msp1 (block 2) and msp2 (block 3) including their allelic families: K1, MAD20, RO33 and FC27, 3D7/IC1, respectively.ResultsAllelic variation in both msp1 and msp2 were identified in the 88 blood samples. For msp1 67% (59/88) and msp2 44% (39/88) were observed. K1 was the predominant msp1 allelic family observed in 33.9% (20/59) of the samples followed by RO33 and MAD20. Of the msp2 allelic family 3D7/IC1 showed higher frequency (21.5%) compared to FC27 (10.3%). A total of twenty-three alleles were detected; of which, eleven were from msp2 and twelve from msp2 genes. Fifty-nine percent of isolates had multiple genotypes and the overall mean multiplicity of infection was 1.8 (95% CI: 1.48-2.04). The heterozygosity index was 0.79 and 0.54for msp1 and msp2, respectively. There was no statically significant difference in the multiplicity of infection by either age or parasite density (P > 0.05).ConclusionThis genetic diversity study showed the presence of five allelic types in the study area, with dominance K1 in the msp1 family and 3D7/IC1 in the msp2 family. Multiple infections were observed in nearly 60% of the samples.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0604-8) contains supplementary material, which is available to authorized users.

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