Plasmodium falciparum is a predominant malaria species that infects humans in the African continent. A recent WHO report estimated 95% and 5% of P. falciparum and P. vivax malaria cases, respectively, in Sudan. However many laboratory reports from different areas in Sudan indicated otherwise. In order to verify, we selected four hundred suspected malaria cases from Aljabalain area located in the White Nile state, central Sudan, and diagnosed them with quality insured microscopy and species-specific nested PCR. Our results indicated that the proportion of P. vivax infections among suspected malaria cases was high. We found that on average 20% and 36.5% of malaria infections in both study areas were caused by P. vivax using both microscopy and PCR, respectively. This change in pattern is likely due to the recent demographic changes and high rate of immigration from neighbouring countries in the recent years. This is the first extensive clinical study of its kind that shows rising trend in P. vivax malaria cases in White Nile area, Sudan.

BackgroundFirst-line schizontocidal treatment for uncomplicated malaria in the Republic of the Sudan is artesunate (total dose 12 mg/kg) plus Sulphadoxine/pyrimethamine (25/1.25 mg/kg) (AS/SP). Patients with Plasmodium vivax are also treated with 14 days primaquine (total dose 3.5 mg/kg) (PQ). The aim of this study was to assess the efficacy of the national policy.MethodsPatients above 1 year, with microscopy-confirmed, Plasmodium falciparum and/or P. vivax malaria were treated with AS/SP. Patients with P. falciparum were randomized to no primaquine (Pf-noPQ) or a single 0.25 mg/kg dose of PQ (Pf-PQ1). Patients with P. vivax received 14 days unsupervised 3.5 mg/kg PQ (Pv-PQ14) on day 2 or at the end of follow up (Pv-noPQ). Primary endpoint was the risk of recurrent parasitaemia at day 42. G6PD activity was measured by spectrophotometry and the Accessbio Biosensor™.Results231 patients with P. falciparum (74.8%), 77 (24.9%) with P. vivax and 1 (0.3%) patient with mixed infection were enrolled. The PCR corrected cumulative risk of recurrent parasitaemia on day 42 was 3.8% (95% CI 1.2–11.2%) in the Pf-noPQ arm compared to 0.9% (95% CI 0.1–6.0%) in the Pf-PQ1 arm; (HR = 0.25 [95% CI 0.03–2.38], p = 0.189). The corresponding risks of recurrence were 13.4% (95% CI 5.2–31.9%) in the Pv-noPQ arm and 5.3% (95% CI 1.3–19.4%) in the Pv-PQ14 arm (HR 0.36 [95% CI 0.1–2.0], p = 0.212). Two (0.9%) patients had G6PD enzyme activity below 10%, 19 (8.9%) patients below 60% of the adjusted male median. Correlation between spectrophotometry and Biosensor™ was low (rs = 0.330, p < 0.001).ConclusionAS/SP remains effective for the treatment of P. falciparum and P. vivax. The addition of PQ reduced the risk of recurrent P. falciparum and P. vivax by day 42, although this did not reach statistical significance. The version of the Biosensor™ assessed is not suitable for routine use. Trial registration https://clinicaltrials.gov/ct2/show/NCT02592408 Electronic supplementary materialThe online version of this article (10.1186/s12936-018-2266-9) contains supplementary material, which is available to authorized users.