Paracetamol versus placebo in treatment of non-severe malaria in children in Guinea-Bissau: a randomized controlled trial

BACKGROUND: The current guidelines for treatment of malaria include paracetamol to children with fever. No convincing evidence for the beneficial effects of this practice exists. Studies show that time to parasite clearance is significantly longer in children treated with paracetamol, which questions the policy. Whether this is of clinical importance has not been investigated. METHODS: Children with Plasmodium falciparum monoinfection and ≥20 parasites per 200 leucocytes at the Bandim Health Centre, Guinea-Bissau were randomized to receive paracetamol or placebo together with chloroquine for three days in a double blind randomized study. Temperature and symptoms were recorded twice daily during treatment and on day 3. The participants were interviewed and a malaria film taken once weekly until day 35. The data is in the form of grouped failure-times, the outcome of interest being time until parasitaemia during follow-up. Mantel-Haenszel weighted odds ratios are given. Other differences between and within the two groups have been tested using the Chi-square test and Mann-Whitney U test. RESULTS: In the evening of the day of inclusion, the temperature was slightly, but statistically insignificant, higher in the placebo group and significantly more children complained of headache. At no other time was a significant difference in temperature or symptoms detected. However, 6 children from the placebo-group as compared to two children from the paracetamol-group were admitted to hospital with high fever and convulsions by day 3. No differences in the cumulative percentages of children with adequate clinical and parasitological response were found in the intention-to-treat analysis or in the per-protocol analysis. CONCLUSION: Fewer children had early treatment failure and the mean temperature was slightly lower in the afternoon on day 0 in the paracetamol group. However, the cumulative adequate clinical and parasitological cure rates were not significantly different during the period of study. It is doubtful whether adding paracetamol to the treatment of uncomplicated malaria in children is beneficial. TRIAL REGISTRATION: NCT00137566

Artemether-Lumefantrine Treatment Failure despite adequate lumefantrine day 7 Concentration in a Traveller with Plasmodium Falciparum Malaria after Returning from Tanzania.

Artemether-lumefantrine is currently first-line therapy of Plasmodium falciparum malaria in many countries. This report describes a treatment failure despite adequate drug concentrations in a traveller returning from sub-Saharan Africa. Genotyping confirmed recrudescence and suggested reduced sensitivity. Potential sub-optimal effect of artemether-lumefantrine highlights the need to follow non-immune individuals the weeks after treatment

Artemether-Lumefantrine versus Dihydroartemisinin-Piperaquine for Treatment of Uncomplicated Plasmodium falciparum Malaria in Children Aged Less than 15 Years in Guinea-Bissau - An Open-Label Non-Inferiority Randomised Clinical Trial

Background Artemether-lumefantrine (AL) was introduced for treatment of uncomplicated malaria in Guinea-Bissau in 2008. Malaria then resurged and recurrent malaria after treatment with AL and stock-outs of AL were common. This study therefore aimed to assess the efficacy of AL and identify an alternative second line antimalarial. Dihydroartemisinin-piperaquine (DP) was chosen as it has been shown to be safe and efficacious and to reduce the incidence of recurrent malaria. Methods and Findings In a multicentre randomised open-label non-inferiority clinical trial, AL or DP were given over 3 days to children aged 6 months-15 years with uncomplicated P. falciparummonoinfection. Intake was observed and AL was given with milk. Children were seen on days 0, 1, 2 and 3 and then weekly days 7-42. Recurring P. falciparumwere classified as recrudescence or new infections by genotyping. Between November 2012 and July 2015, 312 children were randomised to AL (n = 155) or DP (n = 157). The day 42 PCR adjusted per protocol adequate clinical and parasitological responses were 95% and 100% in the AL and DP groups respectively, Mantel-Haenszel weighted odds ratio (OR) 0.22 (95% CI 0-0.68), p = 0.022. In a modified intention to treat analysis in which treatment failures day 0 and reinfections were also considered as treatment failures adequate clinical and parasitological responses were 94% and 97% (OR 0.42 [95% CI, 0.13-1.38], p = 0.15). Parasite clearance and symptom resolution were similar with both treatments. Conclusions Both treatments achieved the WHO recommended efficacy for antimalarials about to be adopted as policy. DP was not inferior to AL for treatment of uncomplicated P. falciparum malaria in Guinea-Bissau

Unexpected selections of Plasmodium falciparum polymorphisms in previously treatment-naïve areas after monthly presumptive administration of three different anti-malarial drugs in Liberia 1976-78.

BACKGROUND: To assess the effect on malaria prevalence, village specific monthly administrations of pyrimethamine, chlorproguanil, chloroquine or placebo were given to children in four previously treatment-naïve Liberian villages, 1976-78. Plasmodium falciparum in vivo resistance developed to pyrimethamine only. Selection of molecular markers of P. falciparum resistance after 2 years of treatment are reported. METHODS: Blood samples were collected from 191 study children in a survey in 1978. Polymorphisms in pfcrt, pfmdr1, pfdhfr, pfdhps, pfmrp1 and pfnhe1 genes were determined using PCR-based methods. RESULTS: Pfcrt 72-76 CVIET was found in one chloroquine village sample, all remaining samples had pfcrt CVMNK. Pfmdr1 N86 prevalence was 100%. A pfmdr1 T1069ACT→ACG synonymous polymorphism was found in 30% of chloroquine village samples and 3% of other samples (P = 0.008). Variations in pfnhe1 block I were found in all except the chloroquine treated village (P < 0.001). Resistance associated pfdhfr 108N prevalence was 2% in the pyrimethamine village compared to 45-65% elsewhere, including the placebo village (P = 0.001). CONCLUSIONS: Chloroquine treatment possibly resulted in the development of pfcrt 72-76 CVIET. Selection of pfmdr1 T1069ACG and a pfnhe1 block 1 genotypes indicates that chloroquine treatment exerted a selective pressure on P. falciparum. Pyrimethamine resistance associated pfdhfr 108N was present prior to the introduction of any drug. Decreased pfdhfr 108N frequency concurrent with development of pyrimethamine resistance suggests a non-pfdhfr polymorphisms mediated resistance mechanism

Plasmodium falciparum drug resistance phenotype as assessed by patient antimalarial drug levels and Its association With pfmdr1 polymorphisms

Background. Multidrug-resistant Plasmodium falciparum is a major threat to global malaria control. Parasites develop resistance by gradually acquiring genetic polymorphisms that decrease drug susceptibility. The aim of this study was to investigate the extent to which parasites with different genetic characteristics are able to withstand individual drug blood concentrations. Methods. We analyzed 2 clinical trials that assessed the efficacy and effectiveness of artemether-lumefantrine. As a proof of concept, we used measured day 7 lumefantrine concentrations to estimate the concentrations at which reinfections multiplied. P. falciparum multidrug resistance gene 1 (pfmdr1) genotypes of these parasites were then correlated to drug susceptibility. Results. Reinfecting parasites with the pfmdr1 N86/184F/D1246 haplotype were able to withstand lumefantrine blood concentrations 15-fold higher than those with the 86Y/Y184/1246Y haplotype. Conclusions. By estimating drug concentrations, we were able to quantify the contribution of pfmdr1 single-nucleotide polymorphisms to reduced lumefantrine susceptibility. The method can be applied to all long-half-life antimalarial drugs, enables early detection of P. falciparum with reduced drug susceptibility in vivo, and represents a novel way for unveiling molecular markers of antimalarial drug resistance.Swedish Development Cooperation Agency-Department for Research Cooperation (SIDA-SAREC) [SWE 2004-3850, Bil-Tz 16/9875007059, SWE-2009-165]; World Health Organization MIM-TDR [[A60100] MAL IRM 06 03]; Goljes Foundation; Swedish medical research council [K2010-56X-21457-01-3]; Wellcome Trust of Great Britai

Single nucleotide polymorphisms in Plasmodium falciparum V type H+ pyrophosphatase gene (pfvp2) and their associations with pfcrt and pfmdr1 polymorphisms

"Uncorrected proof"BACKGROUND: Chloroquine resistance in Plasmodium falciparum malaria has been associated with pfcrt 76T (chloroquine resistance transporter gene) and pfmdr1 86Y (multidrug resistance gene 1) alleles. Pfcrt 76T enables transport of protonated chloroquine out of the parasites digestive vacuole resulting in a loss of hydrogen ions (H(+)). V type H(+) pyrophosphatase (PfVP2) is thought to pump H(+) into the digestive vacuole. This study aimed to describe the geographic distribution of single nucleotide polymorphisms in pfvp2 and their possible associations with pfcrt and pfmdr1 polymorphisms. METHODS: Blood samples from 384 patients collected (1981-2009) in Honduras (n=35), Colombia (n=50), Liberia (n=50), Guinea Bissau (n=50), Tanzania (n=50), Iran (n=50), Thailand (n=49) and Vanuatu (n=50) were analysed. The pfcrt 72-76 haplotype, pfmdr1 copy numbers, pfmdr1 N86Y and pfvp2 V405I, K582R and P711S alleles were identified using PCR based methods. RESULTS: Pfvp2 was amplified in 344 samples. The pfvp2 allele proportions were V405 (97%), 405I (3%), K582 (99%), 582R (1%), P711 (97%) and 711S (3%). The number of patients with any of pfvp2 405I, 582R and/or 711S were as follows: Honduras (2/30), Colombia (0/46), Liberia (7/48), Guinea-Bissau (4/50), Tanzania (3/48), Iran (3/50), Thailand (1/49) and Vanuatu (0/31). The alleles were most common in Liberia (P=0.01) and Liberia+Guinea-Bissau (P=0.01). The VKP haplotype was found in 189/194 (97%) and 131/145 (90%) samples harbouring pfcrt 76T and pfcrt K76 respectively (P=0.007). CONCLUSIONS: The VKP haplotype was dominant. Most pfvp2 405I, 582R and 711S SNPs were seen where CQ resistance was not highly prevalent at the time of blood sampling possibly due to greater genetic variation prior to the bottle neck event of spreading CQ resistance. The association between the pfvp2 VKP haplotype and pfcrt 76T, which may indicate that pfvp2 is involved in CQ resistance, should therefore be interpreted with caution.This work was supported by Swedish International Development Cooperation Agency, Department for research Cooperation (Sida-SAREC Contribution no 75007082/03) and Sigurd och Elsa Goljes Minne Fund (project No. LA2010-0537). MIV is recipient of Post Doctoral fellowship from Fundacao para a Ciencia e Tecnologia (FCT)/Ministerio da Ciencia e Ensino Superior, Portugal - MCES (ref. SFRH/BPD/76614/2011). JU has a postdoctoral position funded by Stockholms lans landsting

High throughput resistance profiling of Plasmodium falciparum infections based on custom dual indexing and Illumina next generation sequencing-technology

AbstractGenetic polymorphisms in P. falciparum can be used to indicate the parasite’s susceptibility to antimalarial drugs as well as its geographical origin. Both of these factors are key to monitoring development and spread of antimalarial drug resistance. In this study, we combine multiplex PCR, custom designed dual indexing and Miseq sequencing for high throughput SNP-profiling of 457 malaria infections from Guinea-Bissau, at the cost of 10 USD per sample. By amplifying and sequencing 15 genetic fragments, we cover 20 resistance-conferring SNPs occurring in pfcrt, pfmdr1, pfdhfr, pfdhps, as well as the entire length of pfK13, and the mitochondrial barcode for parasite origin. SNPs of interest were sequenced with an average depth of 2,043 reads, and bases were called for the various SNP-positions with a p-value below 0.05, for 89.8–100% of samples. The SNP data indicates that artemisinin resistance-conferring SNPs in pfK13 are absent from the studied area of Guinea-Bissau, while the pfmdr1 86 N allele is found at a high prevalence. The mitochondrial barcodes are unanimous and accommodate a West African origin of the parasites. With this method, very reliable high throughput surveillance of antimalarial drug resistance becomes more affordable than ever before.</jats:p

Influence of consecutive-day blood sampling on polymerase chain reaction-adjusted parasitological cure rates in an antimalarial-drug trial conducted in Tanzania

We assessed the influence that consecutive-day blood sampling, compared with single-day blood sampling, had on polymerase chain reaction (PCR)-adjusted parasitological cure after stepwise genotyping of merozoite surface proteins 2 (msp2) and 1 (msp1) in 106 children in Tanzania who had uncomplicated falciparum malaria treated with either sulfadoxine-pyrimethamine or artemether- lumefantrine; 78 of these children developed recurrent parasitemia during the 42-day follow-up period. Initial msp2 genotyping identified 27 and 33 recrudescences by use of single- and consecutive-day sampling, respectively; in subsequent msp1 genotyping, 17 and 21 of these episodes, respectively, were still classified as recrudescences; these results indicate a similar sensitivity of the standard single-day PCR protocol - that is, 82% (27/33) and 81% (17/21), in both genotyping steps. Interpretation of PCR-adjusted results will significantly depend on methodology. © 2007 by the Infectious Diseases Society of America. All rights reserved

Direct whole-genome sequencing of Plasmodium falciparum specimens from dried erythrocyte spots

Background: Plasmodium falciparum malaria remains a major health burden and genomic research represents one of the necessary approaches for continued progress towards malaria control and elimination. Sample acquisition for this purpose is troublesome, with the majority of malaria-infected individuals living in rural areas, away from main infrastructure and the electrical grid. The aim of this study was to describe a low-tech procedure to sample P. falciparum specimens for direct whole genome sequencing (WGS), without use of electricity and cold-chain. Methods: Venous blood samples were collected from malaria patients in Bandim, Guinea-Bissau and leukocyte-depleted using Plasmodipur filters, the enriched parasite sample was spotted on Whatman paper and dried. The samples were stored at ambient temperatures and subsequently used for DNA-extraction. Ratios of parasite:human content of the extracted DNA was assessed by qPCR, and five samples with varying parasitaemia, were sequenced. Sequencing data were used to analyse the sample content, as well as sample coverage and depth as compared to the 3d7 reference genome. Results: qPCR revealed that 73% of the 199 samples were applicable for WGS, as defined by a minimum ratio of parasite:human DNA of 2:1. WGS revealed an even distribution of sequence data across the 3d7 reference genome, regardless of parasitaemia. The acquired read depths varied from 16 to 99×, and coverage varied from 87.5 to 98.9% of the 3d7 reference genome. SNP-analysis of six genes, for which amplicon sequencing has been performed previously, confirmed the reliability of the WGS-data. Conclusion: This study describes a simple filter paper based protocol for sampling P. falciparum from malaria patients for subsequent direct WGS, enabling acquisition of samples in remote settings with no access to electricity.</p

Polymorphisms in Plasmodium falciparum chloroquine resistance transporter and multidrug resistance 1 genes: parasite risk factors that affect treatment outcomes for P. falciparum malaria after artemether-lumefantrine and artesunate-amodiaquine.

Adequate clinical and parasitologic cure by artemisinin combination therapies relies on the artemisinin component and the partner drug. Polymorphisms in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) and P. falciparum multidrug resistance 1 (pfmdr1) genes are associated with decreased sensitivity to amodiaquine and lumefantrine, but effects of these polymorphisms on therapeutic responses to artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) have not been clearly defined. Individual patient data from 31 clinical trials were harmonized and pooled by using standardized methods from the WorldWide Antimalarial Resistance Network. Data for more than 7,000 patients were analyzed to assess relationships between parasite polymorphisms in pfcrt and pfmdr1 and clinically relevant outcomes after treatment with AL or ASAQ. Presence of the pfmdr1 gene N86 (adjusted hazards ratio = 4.74, 95% confidence interval = 2.29 - 9.78, P < 0.001) and increased pfmdr1 copy number (adjusted hazards ratio = 6.52, 95% confidence interval = 2.36-17.97, P < 0.001 : were significant independent risk factors for recrudescence in patients treated with AL. AL and ASAQ exerted opposing selective effects on single-nucleotide polymorphisms in pfcrt and pfmdr1. Monitoring selection and responding to emerging signs of drug resistance are critical tools for preserving efficacy of artemisinin combination therapies; determination of the prevalence of at least pfcrt K76T and pfmdr1 N86Y should now be routine