Trends in malaria prevalence by diagnostic method among the study participants that did not develop clinical malaria during the 112-day study.

<p>At every visit, malaria prevalences are highest when detected by <i>Pf</i>HRP-2 ELISA and qRT-PCR methods and lowest when measured with microscopy and <i>p</i>LDH ELISA.</p

Species-specific primers and probes for detecting <i>Plasmodium</i> parasites.

<p>Species-specific primers and probes for detecting <i>Plasmodium</i> parasites.</p

Comparison of routine microscopy, <i>p</i>LDH/<i>Pf</i>HRP-2 ELISA and qPCR for a group of study participants who had acute blood smears prepared at sick visits.

<p>Each column (1–38) represents one blood sample with the corresponding microscopy, <i>p</i>LDH/<i>Pf</i>HRP-2 ELISA and qRT-PCR results, ordered by parasite density as determined by microscopy (top graph) and antigen levels (<i>p</i>LDH/<i>Pf</i>HRP-2) or Ct values (qPCR). As the levels of parasitemia decreases, the concordance between the different methods also decreases. <i>Pf</i>HRP-2 and qPCR detect parasites densities way beyond the detection limit of microscopy.</p

The number and percentage of <i>Plasmodium</i> parasite species detected by microscopy and qPCR.

<p>Key: Pf = <i>P. falciparum</i>, Pm = <i>P. malariae</i>, Po = <i>P. ovale</i>.</p

Pair-wise Comparison of malaria diagnostic methods using Generalized Estimating Equations (GEE).

<p>Pair-wise Comparison of malaria diagnostic methods using Generalized Estimating Equations (GEE).</p

Utility of microscopy, qPCR, PfHRP-2 and pLDH ELISAs in predicting clinical episodes.

<p>Parasite dynamics before clinical malaria attack (<b>day 0</b>) as measured by (A) <i>Pf</i>HRP-2, (B) <i>p</i>LDH (C) Microscopy and (D) qPCR, for the 12 participants with microscopically confirmed clinical malaria. Parasite dynamics after clinical attack are also presented for <i>Pf</i>HRP-2 (A). Error bars represent standard error of mean of the parasitemia values at each time point. The arrows indicate the day of treatment. Microscopy, <i>p</i>LDH and qPCR did not detect malaria parasites after the treatment.</p

MOESM1 of Measuring ex vivo drug susceptibility in Plasmodium vivax isolates from Cambodia

Additional file 1. Ex vivo drug susceptibility of P. vivax by years

Efficacy of Two versus Three-Day Regimens of Dihydroartemisinin-Piperaquine for Uncomplicated Malaria in Military Personnel in Northern Cambodia: An Open-Label Randomized Trial

<div><p>Introduction</p><p>Emerging antimalarial drug resistance in mobile populations remains a significant public health concern. We compared two regimens of dihydroartemisinin-piperaquine in military and civilians on the Thai-Cambodian border to evaluate national treatment policy.</p><p>Methods</p><p>Efficacy and safety of two and three-day regimens of dihydroartemisinin-piperaquine were compared as a nested open-label evaluation within a malaria cohort study in 222 otherwise healthy volunteers (18% malaria-infected at baseline). The first 80 volunteers with slide-confirmed <i>Plasmodium falciparum</i> or <i>vivax</i> malaria were randomized 1:1 to receive either regimen (total dose 360mg dihydroartemisinin and 2880mg piperaquine) and followed weekly for up to 6 months. The primary endpoint was malaria recurrence by day 42. Volunteers with <i>vivax</i> infection received primaquine at study discharge with six months follow-up.</p><p>Results</p><p>Eighty patients (60 <i>vivax</i>, 15 <i>falciparum</i>, and 5 mixed) were randomized to dihydroartemisinin-piperaquine. Intention-to-treat all-species efficacy at Day 42 was 85% for the two-day regimen (95% CI 69–94) and 90% for the three-day regimen (95% CI 75–97). PCR-adjusted <i>falciparum</i> efficacy was 75% in both groups with nearly half (45%) still parasitemic at Day 3. Plasma piperaquine levels were comparable to prior published reports, but on the day of recrudescence were below measurable <i>in vitro</i> piperaquine IC₅₀ levels in all <i>falciparum</i> treatment failures.</p><p>Conclusions</p><p>In the brief period since introduction of dihydroartemisinin-piperaquine, there is early evidence suggesting declining efficacy relative to previous reports. Parasite IC₅₀ levels in excess of plasma piperaquine levels seen only in treatment failures raises concern for clinically significant piperaquine resistance in Cambodia. These findings warrant improved monitoring of clinical outcomes and follow-up, given few available alternative drugs.</p><p>Trial Registration</p><p>ClinicalTrials.gov <a href="http://clinicaltrials.gov/ct2/show/NCT01280162" target="_blank">NCT01280162</a></p></div

Pharmacokinetic parameters calculated from a 2-compartment model comparing two versus three-day courses of DHA-piperaquine.

<p>*Mann-Whitney U test comparing 2 and 3 day treatment groups. **PK analysis could not be performed in 10 and 7 subjects from Group 1 and 2, respectively due to insufficient time points. PK Parameters are expressed as medians and <i>(25–75% percentiles)</i>, with significantly different values in <b>bold</b>.</p

Study Schematic Inset and Trial Profile.

<p>*Randomization goal met, 2 withdrew. **Prolonged QTc. ^¥PCR-corrected speciation. ^aNot included are 2^nd recurrences (1 Pf, 1 Pv, 1 mixed). ^bNot included are 2nd recurrences (2 Pf, 5 Pv) and a 3^rd recurrence (1 Pv). ^#Study discharge varied, median 115 days follow-up.</p