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Hemming-Schroeder E, Umukoro E, Lo E, Fung B, Tomás-Domingo P, Zhou G, Zhong D, Dixit A, Atieli H, Githeko A, Vardo-Zalik A, Yan G. Impacts of Antimalarial Drugs on Plasmodium falciparum Drug Resistance Markers, Western Kenya, 2003-2015. Am J Trop Med Hyg 2018; 98:692-699. [PMID: 29363453 PMCID: PMC5930917 DOI: 10.4269/ajtmh.17-0763] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drug resistance has threatened global malaria control since chloroquine (CQ)-resistant Plasmodium falciparum emerged in Asia in the 1950s. Understanding the impacts of changing antimalarial drug policy on resistance is critical for resistance management. Plasmodium falciparum isolates were collected from 2003 to 2015 in western Kenya and analyzed for genetic markers associated with resistance to CQ (Pfcrt), sulfadoxine-pyrimethamine (SP) (Pfdhfr/Pfdhps), and artemether-lumefantrine (AL) (PfKelch13/Pfmdr1) antimalarials. In addition, household antimalarial drug use surveys were administered. Pfcrt 76T prevalence decreased from 76% to 6% from 2003 to 2015. Pfdhfr/Pfdhps quintuple mutants decreased from 70% in 2003 to 14% in 2008, but increased to near fixation by 2015. SP "super resistant" alleles Pfdhps 581G and 613S/T were not detected in the 2015 samples that were assessed. The Pfmdr1 N86-184F-D1246 haplotype associated with decreased lumefantrine susceptibility increased significantly from 4% in 2005 to 51% in 2015. No PfKelch13 mutations that have been previously associated with artemisinin resistance were detected in the study populations. The increase in Pfdhfr/Pfdhps quintuple mutants that associates with SP resistance may have resulted from the increased usage of SP for intermittent preventative therapy in pregnancy (IPTp) and for malaria treatment in the community. Prevalent Pfdhfr/Pfdhps mutations call for careful monitoring of SP resistance and effectiveness of the current IPTp program in Kenya. In addition, the commonly occurring Pfmdr1 N86-184F-D1246 haplotype associated with increased lumefantrine tolerance calls for surveillance of AL efficacy in Kenya, as well as consideration for a rotating artemisinin-combination therapy regimen.
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Affiliation(s)
| | | | - Eugenia Lo
- Department of Biological Sciences, University of North Carolina, Charlotte, North Carolina
| | - Becky Fung
- Program in Public Health, University of California, Irvine, California
| | | | - Guofa Zhou
- Program in Public Health, University of California, Irvine, California
| | - Daibin Zhong
- Program in Public Health, University of California, Irvine, California
| | - Amruta Dixit
- Program in Public Health, University of California, Irvine, California
| | - Harrysone Atieli
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Andrew Githeko
- Centre for Vector Biology and Control Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Guiyun Yan
- Program in Public Health, University of California, Irvine, California
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52
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Huggan PJ, Ng CH, Ho J, Lin RTPV, Chavatte JM. A case of blackwater fever with persistent Plasmodium falciparum parasitaemia detected by PCR after artemether-lumefantrine treatment. Malar J 2018; 17:35. [PMID: 29338726 PMCID: PMC5771159 DOI: 10.1186/s12936-018-2180-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 01/10/2018] [Indexed: 11/21/2022] Open
Abstract
Background Blackwater fever is a complication of malaria infection consisting of a syndrome of febrile intra-vascular haemolysis with severe anaemia and intermittent passage of dark-red to black colour urine. Despite numerous reports and studies of this condition, its pathogenesis remains incompletely understood. Case presentation This report describes a case of classic blackwater fever in a returning traveller, without prior history of malaria infection nor usage of anti-malarial prophylaxis, treated with two courses of oral artemether–lumefantrine combination therapy. Unusual persistence of submicroscopic Plasmodium falciparum parasitaemia was detected by PCR for 18 days after initiation of treatment. Conclusion To the authors’ knowledge this is the first reported occurrence of a case of blackwater fever associated with prolonged submicroscopic parasitaemia. This unusual case challenges the current knowledge of the pathogenesis of this condition and opens questions that may have important diagnostic and treatment implications. Electronic supplementary material The online version of this article (10.1186/s12936-018-2180-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Paul John Huggan
- Waikato Hospital, Hamilton, New Zealand.,Faculty of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Chin Hin Ng
- Department of Haematology-Oncology, National University Cancer Institute, National University Health System, Singapore, Singapore
| | - Jennifer Ho
- Woolcock Institute of Medical Research, Glebe, Sydney, NSW, 2037, Australia.,South Western Sydney Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Raymond Tzer Pin Valentine Lin
- Malaria Reference Centre, National Public Health Laboratory, Ministry of Health, Singapore, 3 Biopolis Drive, Synapse #05-14/16, Singapore, 138623, Singapore.,Department of Laboratory Medicine, National University Hospital, Singapore, Singapore.,Departments of Microbiology and Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jean-Marc Chavatte
- Malaria Reference Centre, National Public Health Laboratory, Ministry of Health, Singapore, 3 Biopolis Drive, Synapse #05-14/16, Singapore, 138623, Singapore.
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53
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Genetic markers of artemisinin resistance in Plasmodium spp. parasites. Emerg Top Life Sci 2017; 1:525-531. [PMID: 33525848 PMCID: PMC7288991 DOI: 10.1042/etls20170100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 12/15/2022]
Abstract
The vast majority of malaria patients worldwide are currently treated with combination therapy comprising one of the artemisinin family of drugs, characterised by rapid action and short plasma half-life, co-formulated with a longer-lasting drug from the amino aryl-alcohol or quinoline families. There is now a widely perceived threat to treatment efficacy, as reduced susceptibility to rapid artemisinin clearance in vivo has become prevalent among populations of Plasmodium falciparum in the Greater Mekong subregion since 2008. In vitro and in vivo drug selection studies, heterologous cell expression experiments and genetic epidemiology have identified many candidate markers of reduced ring-stage susceptibility to artemisinin. Certain variants of the P. falciparum pfk13 gene, which encodes a kelch domain protein implicated in the unfolded protein response, are strongly associated with slow parasite clearance by artemisinin in the Mekong subregion. However, anomalies in the epidemiological association of pfk13 variants with true treatment failure in vivo and the curious cell-cycle stage specificity of this phenotype in vitro warrant exploration in some depth. Taken together, available data suggest that the emergence of P. falciparum expressing K13 variants has not yet precipitated a public health emergency. Alternative candidate markers of artemisinin susceptibility are also described, as K13-independent treatment failure has been observed in African P. falciparum and in the rodent malaria parasite Plasmodium chabaudi.
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54
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Sustained Ex Vivo Susceptibility of Plasmodium falciparum to Artemisinin Derivatives but Increasing Tolerance to Artemisinin Combination Therapy Partner Quinolines in The Gambia. Antimicrob Agents Chemother 2017; 61:AAC.00759-17. [PMID: 28971859 PMCID: PMC5700332 DOI: 10.1128/aac.00759-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/22/2017] [Indexed: 02/03/2023] Open
Abstract
Antimalarial interventions have yielded a significant decline in malaria prevalence in The Gambia, where artemether-lumefantrine (AL) has been used as a first-line antimalarial for a decade. Clinical Plasmodium falciparum isolates collected from 2012 to 2015 were analyzed ex vivo for antimalarial susceptibility and genotyped for drug resistance markers (pfcrt K76T, pfmdr1 codons 86, 184, and 1246, and pfk13) and microsatellite variation. Additionally, allele frequencies of single nucleotide polymorphisms (SNPs) from other drug resistance-associated genes were compared from genomic sequence data sets from 2008 (n = 79) and 2014 (n = 168). No artemisinin resistance-associated pfk13 mutation was found, and only 4% of the isolates tested in 2015 showed significant growth after exposure to dihydroartemisinin. Conversely, the 50% inhibitory concentrations (IC50s) of amodiaquine and lumefantrine increased within this period. pfcrt 76T and pfmdr1 184F mutants remained at a prevalence above 80%. pfcrt 76T was positively associated with higher IC50s to chloroquine. pfmdr1 NYD increased in frequency between 2012 and 2015 due to lumefantrine selection. The TNYD (pfcrt 76T and pfmdr1 NYD wild-type haplotype) also increased in frequency following AL implementation in 2008. These results suggest selection for pfcrt and pfmdr1 genotypes that enable tolerance to lumefantrine. Increased tolerance to lumefantrine calls for sustained chemotherapeutic monitoring in The Gambia to minimize complete artemisinin combination therapy (ACT) failure in the future.
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55
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Beshir KB, Sepúlveda N, Bharmal J, Robinson A, Mwanguzi J, Busula AO, de Boer JG, Sutherland C, Cunningham J, Hopkins H. Plasmodium falciparum parasites with histidine-rich protein 2 (pfhrp2) and pfhrp3 gene deletions in two endemic regions of Kenya. Sci Rep 2017; 7:14718. [PMID: 29116127 PMCID: PMC5677122 DOI: 10.1038/s41598-017-15031-2] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 10/19/2017] [Indexed: 01/12/2023] Open
Abstract
Deletions of the Plasmodium falciparum hrp2 and hrp3 genes can affect the performance of HRP2-based malaria rapid diagnostic tests (RDTs). Such deletions have been reported from South America, India and Eritrea. Whether these parasites are widespread in East Africa is unknown. A total of 274 samples from asymptomatic children in Mbita, western Kenya, and 61 genomic data from Kilifi, eastern Kenya, were available for analysis. PCR-confirmed samples were investigated for the presence of pfhrp2 and pfhrp3 genes. In samples with evidence of deletion, parasite presence was confirmed by amplifying three independent genes. We failed to amplify pfhrp2 from 25 of 131 (19.1%) PCR-confirmed samples. Of these, only 8 (10%) samples were microscopic positive and were classified as pfhrp2-deleted. Eight microscopically-confirmed pfhrp2-deleted samples with intact pfhrp3 locus were positive by HRP2-based RDT. In addition, one PCR-confirmed infection showed a deletion at the pfhrp3 locus. One genomic sample lacked pfhrp2 and one lacked pfhrp3. No sample harbored parasites lacking both genes. Parasites lacking pfhrp2 are present in Kenya, but may be detectable by HRP-based RDT at higher parasitaemia, possibly due to the presence of intact pfhrp3. These findings warrant further systematic study to establish prevalence and diagnostic significance.
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Affiliation(s)
| | - Nuno Sepúlveda
- London School of Hygiene and Tropical Medicine, London, UK
- Centre for Statistics and Applications of University of Lisbon, Lisbon, Portugal
| | - Jameel Bharmal
- London School of Hygiene and Tropical Medicine, London, UK
| | - Ailie Robinson
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Annette Obukosia Busula
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Kaimosi Friends University College, Kaimosi, Kenya
| | - Jetske Gudrun de Boer
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
- Netherlands Institute of Ecology, Droevendaalsesteeg 10, 6708 PB, Wageningen, The Netherlands
| | | | - Jane Cunningham
- Global Malaria Programme, World Health Organization (WHO-GMP), Geneva, Switzerland
| | - Heidi Hopkins
- London School of Hygiene and Tropical Medicine, London, UK
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56
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Schallig HD, Tinto H, Sawa P, Kaur H, Duparc S, Ishengoma DS, Magnussen P, Alifrangis M, Sutherland CJ. Randomised controlled trial of two sequential artemisinin-based combination therapy regimens to treat uncomplicated falciparum malaria in African children: a protocol to investigate safety, efficacy and adherence. BMJ Glob Health 2017; 2:e000371. [PMID: 29082016 PMCID: PMC5656137 DOI: 10.1136/bmjgh-2017-000371] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/10/2017] [Accepted: 07/10/2017] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Management of uncomplicated Plasmodium falciparum malaria relies on artemisinin-based combination therapies (ACTs). These highly effective regimens have contributed to reductions in malaria morbidity and mortality. However, artemisinin resistance in Asia and changing parasite susceptibility to ACT in Africa have now been well documented. Strategies that retain current ACT as efficacious treatments are urgently needed. METHODS We present an open-label, randomised three-arm clinical trial protocol in three African settings representative of varying malaria epidemiology to investigate whether prolonged ACT-based regimens using currently available formulations can eliminate potentially resistant parasites. The protocol investigates whether a sequential course of two licensed ACT in 1080 children aged 6-120 months exhibits superior efficacy against acute P. falciparum malaria and non-inferior safety compared with standard single-course ACT given to 540 children. The primary endpoint is PCR-corrected clinical and parasitological response at day 42 or day 63 of follow-up. Persistence of PCR-detectable parasitaemia at day 3 is analysed as a key covariate. Secondary endpoints include gametocytaemia, occurrence of treatment-related adverse events in the double-ACT versus single-ACT arms, carriage of molecular markers of drug resistance, drug kinetics and patient adherence to treatment. DISCUSSION This protocol addresses efficacy and safety of sequential ACT regimens in P. falciparum malaria in Africa. The approach is designed to extend the useful life of this class of antimalarials with maximal impact and minimal delay, by deploying licensed medicines that could be swiftly implemented as sequential double ACT by National Malaria Control Programmes, before emerging drug resistance in Africa becomes a major threat to public health.
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Affiliation(s)
- Henk Dfh Schallig
- Department of Medical Microbiology-Parasitology Unit, Academic Medical Centre, Amsterdam, The Netherlands
| | - Halidou Tinto
- Institute for Health Sciences Research-Clinical Research Unit (IRSS-CRUN), Nanoro, Burkina Faso
| | - Patrick Sawa
- International Centre for Insect Physiology and Ecology, Mbita Point, Kenya
| | - Harparkash Kaur
- Clinical Research Department, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Immunology & Infection Department, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | | | | | - Pascal Magnussen
- Department of International Health, Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Michael Alifrangis
- Department of International Health, Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Colin J Sutherland
- Immunology & Infection Department, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Public Health England Malaria Reference Laboratory, London School of Hygiene & Tropical Medicine, London, UK
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57
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Tadesse FG, Lanke K, Nebie I, Schildkraut JA, Gonçalves BP, Tiono AB, Sauerwein R, Drakeley C, Bousema T, Rijpma SR. Molecular Markers for Sensitive Detection of Plasmodium falciparum Asexual Stage Parasites and their Application in a Malaria Clinical Trial. Am J Trop Med Hyg 2017; 97:188-198. [PMID: 28719294 PMCID: PMC5508903 DOI: 10.4269/ajtmh.16-0893] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plasmodium falciparum parasite life stages respond differently to antimalarial drugs. Sensitive stage-specific molecular assays may help to examine parasite dynamics at microscopically detectable and submicroscopic parasite densities in epidemiological and clinical studies. In this study, we compared the performance of skeleton-binding protein 1 (SBP1), ring-infected erythrocyte surface antigen, Hyp8, ring-exported protein 1 (REX1), and PHISTb mRNA for detecting ring-stage trophozoite-specific transcripts using quantitative reverse transcriptase polymerase chain reaction. Markers were tested on tightly synchronized in vitro parasites and clinical trial samples alongside established markers of parasite density (18S DNA and rRNA) and gametocyte density (Pfs25 mRNA). SBP1 was the most sensitive marker but showed low-level expression in mature gametocytes. Novel markers REX1 and PHISTb showed lower sensitivity but higher specificity for ring-stage trophozoites. Using in vivo clinical trial samples from gametocyte-negative patients, we observed evidence of persisting trophozoite transcripts for at least 14 days postinitiation of treatment. It is currently not clear if these transcripts represent viable parasites that may have implications for clinical treatment outcome or transmission potential.
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Affiliation(s)
- Fitsum G Tadesse
- Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia.,Medical Biotechnology Unit, Institute of Biotechnology, Addis Ababa University, Addis Ababa, Ethiopia.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Issa Nebie
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou,Burkina Faso
| | - Jodie A Schildkraut
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alfred B Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou,Burkina Faso
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sanna R Rijpma
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
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58
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Lubis IND, Wijaya H, Lubis M, Lubis CP, Divis PCS, Beshir KB, Sutherland CJ. Contribution of Plasmodium knowlesi to Multispecies Human Malaria Infections in North Sumatera, Indonesia. J Infect Dis 2017; 215:1148-1155. [PMID: 28201638 PMCID: PMC5426374 DOI: 10.1093/infdis/jix091] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/11/2017] [Indexed: 11/14/2022] Open
Abstract
Background As Indonesia works toward the goal of malaria elimination, information is lacking on malaria epidemiology from some western provinces. As a basis for studies of antimalarial efficacy, we set out to survey parasite carriage in 3 communities in North Sumatera Province. Methods A combination of active and passive detection of infection was carried out among communities in Batubara, Langkat, and South Nias regencies. Finger-prick blood samples from consenting individuals of all ages provided blood films for microscopic examination and blood spots on filter paper. Plasmodium species were identified using nested polymerase chain reaction (PCR) of ribosomal RNA genes and a novel assay that amplifies a conserved sequence specific for the sicavar gene family of Plasmodium knowlesi. Results Of 3731 participants, 614 (16.5%) were positive for malaria parasites by microscopy. PCR detected parasite DNA in samples from 1169 individuals (31.3%). In total, 377 participants (11.8%) harbored P. knowlesi. Also present were Plasmodium vivax (14.3%), Plasmodium falciparum (10.5%) and Plasmodium malariae (3.4%). Conclusions Amplification of sicavar is a specific and sensitive test for the presence of P. knowlesi DNA in humans. Subpatent and asymptomatic multispecies parasitemia is relatively common in North Sumatera, so PCR-based surveillance is required to support control and elimination activities.
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Affiliation(s)
- Inke N D Lubis
- Departments of Immunology and Infection and.,Department of Paediatrics, Faculty of Medicine, University of Sumatera Utara, Medan, Indonesia
| | - Hendri Wijaya
- Department of Paediatrics, Faculty of Medicine, University of Sumatera Utara, Medan, Indonesia
| | - Munar Lubis
- Department of Paediatrics, Faculty of Medicine, University of Sumatera Utara, Medan, Indonesia
| | - Chairuddin P Lubis
- Department of Paediatrics, Faculty of Medicine, University of Sumatera Utara, Medan, Indonesia
| | - Paul C S Divis
- Pathogen Molecular Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom.,Malaria Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
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59
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Nag S, Dalgaard MD, Kofoed PE, Ursing J, Crespo M, Andersen LO, Aarestrup FM, Lund O, Alifrangis M. High throughput resistance profiling of Plasmodium falciparum infections based on custom dual indexing and Illumina next generation sequencing-technology. Sci Rep 2017; 7:2398. [PMID: 28546554 PMCID: PMC5445084 DOI: 10.1038/s41598-017-02724-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/18/2017] [Indexed: 01/10/2023] Open
Abstract
Genetic 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.
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Affiliation(s)
- Sidsel Nag
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 1356, Copenhagen K, Denmark.
- Department of Infectious Diseases, Copenhagen University Hospital, 2200, Copenhagen N, Denmark.
| | - Marlene D Dalgaard
- Department of Systems Biology, Technical University of Denmark, Kemitorvet Building 208, 2800, Kgs. Lyngby, Denmark
| | - Poul-Erik Kofoed
- Department of Paediatrics, Kolding Hospital, University of Southern Denmark, 6000, Kolding, Denmark
- Bandim Health Project, Bissau, Guinea-Bissau
| | - Johan Ursing
- Bandim Health Project, Bissau, Guinea-Bissau
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Marina Crespo
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 1356, Copenhagen K, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, 2200, Copenhagen N, Denmark
| | - Lee O'Brien Andersen
- Department of Microbiology and Infection Control, Statens Serum Institut, 2300, Copenhagen S, Denmark
| | | | - Ole Lund
- Department of Systems Biology, Technical University of Denmark, Kemitorvet Building 208, 2800, Kgs. Lyngby, Denmark
| | - Michael Alifrangis
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen, 1356, Copenhagen K, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, 2200, Copenhagen N, Denmark
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60
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Balikagala B, Mita T, Ikeda M, Sakurai M, Yatsushiro S, Takahashi N, Tachibana SI, Auma M, Ntege EH, Ito D, Takashima E, Palacpac NMQ, Egwang TG, Onen JO, Kataoka M, Kimura E, Horii T, Tsuboi T. Absence of in vivo selection for K13 mutations after artemether-lumefantrine treatment in Uganda. Malar J 2017; 16:23. [PMID: 28068997 PMCID: PMC5223472 DOI: 10.1186/s12936-016-1663-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/20/2016] [Indexed: 01/09/2023] Open
Abstract
Background Individual drug treatment may select resistant parasites in the human body, a process termed in vivo selection. Some single nucleotide polymorphisms in Plasmodium falciparum chloroquine-resistance transporter (pfcrt) and multidrug resistance gene 1 (pfmdr1) genes have been reportedly selected after artemether–lumefantrine treatment. However, there is a paucity of data regarding in vivo selection of P. falciparum Kelch propeller domain (pfkelch13) polymorphisms, responsible for artemisinin-resistance in Asia, and six putative background mutations for artemisinin resistance; D193Y in ferredoxin, T484I in multiple resistance protein 2, V127M in apicoplast ribosomal protein S10, I356T in pfcrt, V1157L in protein phosphatase and C1484F in phosphoinositide-binding protein. Methods Artemether–lumefantrine efficacy study with a follow-up period of 28 days was conducted in northern Uganda in 2014. The above-mentioned genotypes were comparatively analysed before drug administration and on days; 3, 7, and 28 days after treatment. Results In 61 individuals with successful follow-up, artemether–lumefantrine treatment regimen was very effective with PCR adjusted efficacy of 95.2%. Among 146 isolates obtained before treatment, wild-type alleles were observed in 98.6% of isolates in pfkelch13 and in all isolates in the six putative background genes except I356T in pfcrt, which had 2.4% of isolates as mixed infections. In vivo selection study revealed that all isolates detected in the follow-up period harboured wild type alleles in pfkelch13 and the six background genes. Conclusion Mutations in pfkelch13 and the six background genes may not play an important role in the in vivo selection after artemether–lumefantrine treatment in Uganda. Different mechanisms might rather be associated with the existence of parasites after treatment. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1663-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Betty Balikagala
- Division of Malaria Research, Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Toshihiro Mita
- Department of Molecular and Cellular Parasitology, School of Medicine, Juntendo University, Tokyo, 113-8421, Japan.
| | - Mie Ikeda
- Department of Molecular and Cellular Parasitology, School of Medicine, Juntendo University, Tokyo, 113-8421, Japan
| | - Miki Sakurai
- Department of International Affairs and Tropical Medicine, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Shouki Yatsushiro
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Japan
| | - Nobuyuki Takahashi
- Department of International Affairs and Tropical Medicine, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Shin-Ichiro Tachibana
- Department of Molecular and Cellular Parasitology, School of Medicine, Juntendo University, Tokyo, 113-8421, Japan
| | - Mary Auma
- St. Mary's Hospital LACOR, Gulu, Uganda
| | - Edward H Ntege
- Division of Malaria Research, Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Daisuke Ito
- Division of Malaria Research, Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan
| | - Nirianne Marie Q Palacpac
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | | | - Joseph Okello Onen
- Department of Biology, Faculty of Science, Gulu University, Gulu, Uganda
| | - Masatoshi Kataoka
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Japan
| | - Eisaku Kimura
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan.
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Mavoko HM, Nabasumba C, da Luz RI, Tinto H, D'Alessandro U, Kambugu A, Baraka V, Rosanas-Urgell A, Lutumba P, Van Geertruyden JP. Efficacy and safety of re-treatment with the same artemisinin-based combination treatment (ACT) compared with an alternative ACT and quinine plus clindamycin after failure of first-line recommended ACT (QUINACT): a bicentre, open-label, phase 3, randomised controlled trial. LANCET GLOBAL HEALTH 2016; 5:e60-e68. [PMID: 27840069 DOI: 10.1016/s2214-109x(16)30236-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/05/2016] [Accepted: 09/09/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Quinine or alternative artemisinin-based combination treatment (ACT) is the recommended rescue treatment for uncomplicated malaria. However, patients are often re-treated with the same ACT though it is unclear whether this is the most suitable approach. We assessed the efficacy and safety of re-treating malaria patients with uncomplicated failures with the same ACT used for the primary episode, compared with other rescue treatments. METHODS This was a bicentre, open-label, randomised, three-arm phase 3 trial done in Lisungi health centre in DR Congo, and Kazo health centre in Uganda in 2012-14. Children aged 12-60 months with recurrent malaria infection after treatment with the first-line ACT were randomly assigned to either re-treatment with the same first-line ACT, an alternative ACT, which were given for 3 days, or quinine-clindamycin (QnC), which was given for 5-7 days, following a 2:2:1 ratio. Randomisation was done by computer-generated randomisation list in a block design by country. The three treatment groups were assumed to have equivalent efficacy above 90%. Both the research team and parents or guardians were aware of treatment allocation. The primary outcome was the proportion of patients with an adequate clinical and parasitological response (ACPR) at day 28, in the per-protocol population. This trial was registered under the numbers NCT01374581 in ClinicalTrials.gov and PACTR201203000351114 in the Pan African Clinical Trials Registry. FINDINGS From May 22, 2012, to Jan 31, 2014, 571 children were included in the trial. 240 children were randomly assigned to the re-treatment ACT group, 233 to the alternative ACT group, and 98 to the QnC group. 500 children were assessed for the primary outcome. 71 others were not included because they did not complete the follow-up or PCR genotyping result was not conclusive. The ACPR response was similar in the three groups: 91·4% (95% CI 87·5-95·2) for the re-treatment ACT, 91·3% (95% CI 87·4-95·1) for the alternative ACT, and 89·5% (95% CI 83·0-96·0) for QnC. The estimates for rates of malaria recrudescence in the three treatment groups were similar (log-rank test: χ2=0·22, p=0·894). Artemether-lumefantrine was better tolerated than QnC (p=0·0005) and artesunate-amodiaquine (p<0·0001) in the modified intention-to-treat analysis. No serious adverse events were observed. The most common adverse events reported in the re-treatment ACT group were anorexia (31 [13%] of 240 patients), asthenia (20 [8%]), coughing (16 [7%]), abnormal behaviour (13 [5%]), and diarrhoea (12 [5%]). Anorexia (13 [6%] of 233 patients) was the most frequently reported adverse event in the alternative ACT group. The most commonly reported adverse events in the QnC group were anorexia (12 [12%] of 98 patients), abnormal behaviour (6 [6%]), asthenia (6 [6%]), and pruritus (5 [5%]). INTERPRETATION Re-treatment with the same ACT shows similar efficacy as recommended rescue treatments and could be considered for rescue treatment for Plasmodium falciparum malaria. However, the effect of this approach on the selection of resistant strains should be monitored to ensure that re-treatment with the same ACT does not contribute to P falciparum resistance. FUNDING Fonds Wetenschappelijk Onderzoek, Vlaamse Interuniversitaire Raad-Universitaire Ontwikkelings Samenwerking, European and Developing Countries Clinical Trials Partnership, and the Belgian Technical Cooperation-Programme d'Etudes et d'Expertises-in the Democratic Republic of Congo.
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Affiliation(s)
- Hypolite Muhindo Mavoko
- Département de Médecine Tropicale, Faculté de Médecine, Université de Kinshasa, Kinshasa, DR Congo; Epidemiology for Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.
| | - Carolyn Nabasumba
- Epidemiology for Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Infectious Disease Institute, University of Makerere, Kampala, Uganda; Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Raquel Inocêncio da Luz
- Epidemiology for Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Halidou Tinto
- Centre Muraz/Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso
| | - Umberto D'Alessandro
- Institute of Tropical Medicine, Antwerp, Belgium; London School of Hygiene & Tropical Medicine, London, UK; Medical Research Council, The Gambia Unit, Banjul, The Gambia
| | - Andrew Kambugu
- Infectious Disease Institute, University of Makerere, Kampala, Uganda
| | - Vito Baraka
- Epidemiology for Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | | | - Pascal Lutumba
- Département de Médecine Tropicale, Faculté de Médecine, Université de Kinshasa, Kinshasa, DR Congo
| | - Jean-Pierre Van Geertruyden
- Epidemiology for Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Sutherland CJ. Rescuing artemisinin combination therapy in Africa. LANCET GLOBAL HEALTH 2016; 5:e8-e9. [PMID: 27840068 DOI: 10.1016/s2214-109x(16)30291-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 10/11/2016] [Indexed: 10/20/2022]
Affiliation(s)
- Colin J Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel St, London, WC1E 7HT, UK.
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63
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Coalson JE, Walldorf JA, Cohee LM, Ismail MD, Mathanga D, Cordy RJ, Marti M, Taylor TE, Seydel KB, Laufer MK, Wilson ML. High prevalence of Plasmodium falciparum gametocyte infections in school-age children using molecular detection: patterns and predictors of risk from a cross-sectional study in southern Malawi. Malar J 2016; 15:527. [PMID: 27809907 PMCID: PMC5096312 DOI: 10.1186/s12936-016-1587-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/28/2016] [Indexed: 01/11/2023] Open
Abstract
Background In endemic areas, many people experience asymptomatic Plasmodium infections, particularly older children and adults, but their transmission contribution is unknown. Though not the exclusive determinant of infectiousness, transmission from humans to mosquitoes requires blood meals containing gametocytes. Gametocytes often occur at submicroscopic densities, challenging measurement in human populations. More sensitive molecular techniques allow better characterization of gametocyte epidemiologic patterns. Methods Approximately 30 households were selected from each of eight sites in southern Malawi during two cross-sectional surveys. Blood was sampled from 623 people during the dry season and 896 the following rainy season. Among people PCR-positive for Plasmodium falciparum, mature gametocytes were detected by qRT-PCR. Regression models evaluated predictors of gametocyte carriage and density in the total population and among those with PCR-positive infections. Results The prevalence of gametocyte carriage by molecular testing was 3.5% during the dry season and 8.6% during the rainy season, and by microscopy 0.8 and 3.3%, respectively. Nearly half of PCR-positive infections carried gametocytes, regardless of recent symptom status. Among P. falciparum-infected people, only living in unfinished houses and age were significantly associated with gametocyte presence. Infected people in unfinished houses had higher odds of carrying gametocytes (OR 2.24, 95% CI 1.16–4.31), and 31% (95% CI 3–65%) higher gametocyte density than those in finished houses. School-age children (5–15 years), had higher odds than adults (≥16 years) of having gametocytes when infected (OR 2.77, 95% CI 1.47–5.19), but 31% (95% CI 11–47%) lower gametocyte density. Children <5 years did not have significantly higher odds of gametocyte carriage or density when infected than adults. Conclusions School-age children frequently carry gametocytes in communities of southern Malawi and represent an under-recognized reservoir of infection. Malaria elimination strategies should address these frequently asymptomatic reservoirs, especially in highly endemic areas. Improved household construction may also reduce the infectious reservoir. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1587-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jenna E Coalson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Jenny A Walldorf
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Lauren M Cohee
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Miriam D Ismail
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Don Mathanga
- Malaria Alert Centre, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Regina Joice Cordy
- Department of Immunology and Infectious Disease, The Harvard School of Public Health, Boston, MA, USA
| | - Matthias Marti
- Department of Immunology and Infectious Disease, The Harvard School of Public Health, Boston, MA, USA
| | - Terrie E Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Karl B Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Miriam K Laufer
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Mark L Wilson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
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Chaorattanakawee S, Lon C, Jongsakul K, Gawee J, Sok S, Sundrakes S, Kong N, Thamnurak C, Chann S, Chattrakarn S, Praditpol C, Buathong N, Uthaimongkol N, Smith P, Sirisopana N, Huy R, Prom S, Fukuda MM, Bethell D, Walsh DS, Lanteri C, Saunders D. Ex vivo piperaquine resistance developed rapidly in Plasmodium falciparum isolates in northern Cambodia compared to Thailand. Malar J 2016; 15:519. [PMID: 27769299 PMCID: PMC5075182 DOI: 10.1186/s12936-016-1569-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 10/07/2016] [Indexed: 12/29/2022] Open
Abstract
Background The recent dramatic decline in dihydroartemisinin-piperaquine (DHA-PPQ) efficacy in northwestern Cambodia has raised concerns about the rapid spread of piperaquine resistance just as DHA-PPQ is being introduced as first-line therapy in neighbouring countries. Methods Ex vivo parasite susceptibilities were tracked to determine the rate of progression of DHA, PPQ and mefloquine (MQ) resistance from sentinel sites on the Thai–Cambodian and Thai–Myanmar borders from 2010 to 2015. Immediate ex vivo (IEV) histidine-rich protein 2 (HRP-2) assays were used on fresh patient Plasmodium falciparum isolates to determine drug susceptibility profiles. Results IEV HRP-2 assays detected the precipitous emergence of PPQ resistance in Cambodia beginning in 2013 when 40 % of isolates had an IC90 greater than the upper limit of prior years, and this rate doubled to 80 % by 2015. In contrast, Thai–Myanmar isolates from 2013 to 14 remained PPQ-sensitive, while northeastern Thai isolates appeared to have an intermediate resistance profile. The opposite trend was observed for MQ where Cambodian isolates appeared to have a modest increase in overall sensitivity during the same period, with IC50 declining to median levels comparable to those found in Thailand. A significant association between increased PPQ IC50 and IC90 among Cambodian isolates with DHA-PPQ treatment failure was observed. Nearly all Cambodian and Thai isolates were deemed artemisinin resistant with a >1 % survival rate for DHA in the ring-stage assay (RSA), though there was no correlation among isolates to indicate cross-resistance between PPQ and artemisinins. Conclusions Clinical DHA-PPQ failures appear to be associated with declines in the long-acting partner drug PPQ, though sensitivity appears to remain largely intact for now in western Thailand. Rapid progression of PPQ resistance associated with DHA-PPQ treatment failures in northern Cambodia limits drugs of choice in this region, and urgently requires alternative therapy. The temporary re-introduction of artesunate AS-MQ is the current response to PPQ resistance in this area, due to inverse MQ and PPQ resistance patterns. This will require careful monitoring for re-emergence of MQ resistance, and possible simultaneous resistance to all three drugs (AS, MQ and PPQ). Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1569-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Suwanna Chaorattanakawee
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand.,Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
| | - Chanthap Lon
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand. .,USAMC-AFRIMS, Phnom Penh, Cambodia.
| | - Krisada Jongsakul
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | | | - Somethy Sok
- Royal Cambodian Armed Forces, Phnom Penh, Cambodia
| | - Siratchana Sundrakes
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Nareth Kong
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Chatchadaporn Thamnurak
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | | | - Sorayut Chattrakarn
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Chantida Praditpol
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Nillawan Buathong
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Nichapat Uthaimongkol
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Philip Smith
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | | | - Rekol Huy
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | - Mark M Fukuda
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Delia Bethell
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Douglas S Walsh
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
| | - Charlotte Lanteri
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand.,Department of Pathology and Area Laboratory Services, Microbiology Section, Brooke Army Medical Center, San Antonio, TX, USA
| | - David Saunders
- US Army Medical Component-Armed Forces Research Institute of Medical Sciences (USAMC-AFRIMS), Bangkok, Thailand
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65
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Duru V, Witkowski B, Ménard D. Plasmodium falciparum Resistance to Artemisinin Derivatives and Piperaquine: A Major Challenge for Malaria Elimination in Cambodia. Am J Trop Med Hyg 2016; 95:1228-1238. [PMID: 27928074 DOI: 10.4269/ajtmh.16-0234] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/12/2016] [Indexed: 12/30/2022] Open
Abstract
Artemisinin-based combination therapies (ACTs) are the cornerstone of current strategies for fighting malaria. Over the last decade, ACTs have played a major role in decreasing malaria burden. However, this progress is being jeopardized by the emergence of artemisinin-resistant Plasmodium falciparum parasites. Artemisinin resistance was first detected in western Cambodia in 2008 and has since been observed in neighboring countries in southeast Asia. The problem of antimalarial drug resistance has recently worsened in Cambodia, with reports of parasites resistant to piperaquine, the latest generation of partner drug used in combination with dihydroartemisinin, leading to worrying rates of clinical treatment failure. The monitoring and the comprehension of both types of resistance are crucial to prevent the spread of multidrug-resistant parasites outside southeast Asia, and particularly to Africa, where the public health consequences would be catastrophic. To this end, new tools are required for studying the biological and molecular mechanisms underlying resistance to antimalarial drugs and for monitoring the geographic distribution of the resistant parasites. In this review, we detail the major advances in our understanding of resistance to artemisinin and piperaquine and define the challenges that the malaria community will have to face in the coming years.
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Affiliation(s)
- Valentine Duru
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Didier Ménard
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
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66
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Rek J, Katrak S, Obasi H, Nayebare P, Katureebe A, Kakande E, Arinaitwe E, Nankabirwa JI, Jagannathan P, Drakeley C, Staedke SG, Smith DL, Bousema T, Kamya M, Rosenthal PJ, Dorsey G, Greenhouse B. Characterizing microscopic and submicroscopic malaria parasitaemia at three sites with varied transmission intensity in Uganda. Malar J 2016; 15:470. [PMID: 27628178 PMCID: PMC5024471 DOI: 10.1186/s12936-016-1519-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 09/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Parasite prevalence is a key metric used to quantify the burden of malaria and assess the impact of control strategies. Most published estimates of parasite prevalence are based on microscopy and likely underestimate true prevalence. METHODS Thick smear microscopy was performed in cohorts of children (aged 6 month to 10 years) and adults every 90 days over 2 years, at three sites of varying transmission intensity in Uganda. Microscopy-negative samples were tested for sub-microscopic parasitaemia using loop-mediated isothermal amplification (LAMP). Generalized estimating equation models were used to evaluate associations between age and parasitaemia, factors associated with sub-microscopic infection and associations between parasitaemia and haemoglobin. RESULTS A total of 9260 samples were collected from 1245 participants. Parasite prevalence among children across the three sites was 7.4, 9.4 and 28.8 % by microscopy and 21.3, 31.8 and 69.0 % by microscopy plus LAMP. Parasite prevalence among adults across the three sites was 3.1, 3.0 and 5.2 % by microscopy and 18.8, 24.2 and 53.5 % by microscopy plus LAMP. Among those with parasitaemia, adults and persons recently treated with anti-malarial therapy had the highest prevalence of sub-microscopic infection. Children with sub-microscopic or microscopic parasitaemia had lower mean haemoglobin levels compared to children with no detectable parasites. CONCLUSIONS Across a range of transmission intensities in Uganda, microscopy vastly underestimated parasite prevalence, especially among adults.
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Affiliation(s)
- John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Shereen Katrak
- Department of Medicine, University of California San Francisco, San Francisco, USA.
| | - Hannah Obasi
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | | | | | - Elijah Kakande
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Prasanna Jagannathan
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, USA
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Philip J Rosenthal
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, USA
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Zhou Z, Mitchell RM, Kariuki S, Odero C, Otieno P, Otieno K, Onyona P, Were V, Wiegand RE, Gimnig JE, Walker ED, Desai M, Shi YP. Assessment of submicroscopic infections and gametocyte carriage of Plasmodium falciparum during peak malaria transmission season in a community-based cross-sectional survey in western Kenya, 2012. Malar J 2016; 15:421. [PMID: 27543112 PMCID: PMC4992329 DOI: 10.1186/s12936-016-1482-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
Background Although malaria control intervention has greatly decreased malaria morbidity and mortality in many African countries, further decline in parasite prevalence has stagnated in western Kenya. In order to assess if malaria transmission reservoir is associated with this stagnation, submicroscopic infection and gametocyte carriage was estimated. Risk factors and associations between malaria control interventions and gametocyte carriage were further investigated in this study. Methods A total of 996 dried blood spot samples were used from two strata, all smear-positives (516 samples) and randomly selected smear-negatives (480 samples), from a community cross-sectional survey conducted at peak transmission season in 2012 in Siaya County, western Kenya. Plasmodium falciparum parasite presence and density were determined by stained blood smear and by 18S mRNA transcripts using nucleic acid sequence-based amplification assay (NASBA), gametocyte presence and density were determined by blood smear and by Pfs25 mRNA-NASBA, and gametocyte diversity by Pfg377 mRNA RT-PCR and RT-qPCR. Results Of the randomly selected smear-negative samples, 69.6 % (334/480) were positive by 18S-NASBA while 18S-NASBA detected 99.6 % (514/516) smear positive samples. Overall, 80.2 % of the weighted population was parasite positive by 18S-NASBA vs 30.6 % by smear diagnosis and 44.0 % of the weighted population was gametocyte positive by Pfs25-NASBA vs 2.6 % by smear diagnosis. Children 5–15 years old were more likely to be parasitaemic and gametocytaemic by NASBA than individuals >15 years old or children <5 years old while gametocyte density decreased with age. Anaemia and self-reported fever within the past 24 h were associated with increased odds of gametocytaemia. Fever was also positively associated with parasite density, but not with gametocyte density. Anti-malarial use within the past 2 weeks decreased the odds of gametocytaemia, but not the odds of parasitaemia. In contrast, recent anti-malarial use was associated with lowered parasite density, but not the gametocyte density. Use of ITNs was associated with lower odds for parasitaemia in part of the study area with a longer history of ITN interventions. In the same part of study area, the odds of having multiple gametocyte alleles were also lower in individuals using ITNs than in those not using ITNs and parasite density was positively associated with gametocyte diversity. Conclusion A large proportion of submicroscopic parasites and gametocytes in western Kenya might contribute to the stagnation in malaria prevalence, suggesting that additional interventions targeting the infectious reservoir are needed. As school aged children and persons with anaemia and fever were major sources for gametocyte reservoir, these groups should be targeted for intervention and prevention to reduce malaria transmission. Anti-malarial use was associated with lower parasite density and odds of gametocytaemia, but not the gametocyte density, indicating a limitation of anti-malarial impact on the transmission reservoir. ITN use had a protective role against parasitaemia and gametocyte diversity in western Kenya. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1482-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhiyong Zhou
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Rebecca M Mitchell
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Simon Kariuki
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Christopher Odero
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Peter Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Kephas Otieno
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Philip Onyona
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Vincent Were
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ryan E Wiegand
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - John E Gimnig
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Edward D Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Meghna Desai
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ya Ping Shi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Ogouyèmi-Hounto A, Damien G, Deme AB, Ndam NT, Assohou C, Tchonlin D, Mama A, Hounkpe VO, Moutouama JD, Remoué F, Ndiaye D, Gazard DK. Lack of artemisinin resistance in Plasmodium falciparum in northwest Benin after 10 years of use of artemisinin-based combination therapy. ACTA ACUST UNITED AC 2016; 23:28. [PMID: 27443837 PMCID: PMC4956913 DOI: 10.1051/parasite/2016028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 06/28/2016] [Indexed: 12/20/2022]
Abstract
AIM In Benin, artemisinin-based combination therapy (ACT) has been recommended as the first-line treatment for uncomplicated Plasmodium falciparum malaria since 2004. The emergence in Southeast Asia of parasites that are resistant to artemisinins poses a serious threat to global control of this disease. The presence of artemisinin resistance genotypes in parasite populations in Benin is currently unknown. The present study investigated the prevalence of relevant K13-propeller gene polymorphisms in parasite isolates from the north-western region of Benin. METHOD Plasmodium falciparum isolates were collected from children with a confirmed diagnosis of malaria aged 6 months to 5 years in two towns, Cobly and Djougou, in the north-western part of Benin. The study was conducted during the rainy season from July to November 2014 in local health facilities. The K13-propeller gene was amplified in parasite isolates using nested PCR and subsequently sequenced. RESULTS A total of 108 children were recruited into the study. The efficiency of amplification reactions was 72% (78/108). The propeller domain of the K13 gene was successfully sequenced in 78 P. falciparum isolates; all of them were wild type with no polymorphisms detectable. CONCLUSION The absence of mutations in the K13 gene indicates that P. falciparum parasite populations in the study area are still fully susceptible to artemisinins.
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Affiliation(s)
- Aurore Ogouyèmi-Hounto
- Unité d'Enseignement et de Recherche en Parasitologie - Mycologie/Faculté des Sciences de la Santé; 01 BP 188 Cotonou, Bénin - Laboratoire du centre de lutte intégrée contre le paludisme; 01 BP 188 Cotonou, Bénin
| | - Georgia Damien
- Institut de Recherche pour le Développement. UMR 224-MIVEGEC; 08 BP 841 Cotonou, Bénin
| | - Awa Bineta Deme
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, BP 16477 Dakar, Senegal
| | - Nicaise T Ndam
- UMR 216 MERIT-IRD Parasitology Department Noguchi Memorial Institute for Medical Research College of Health Sciences, University of Ghana, P.O. Box LG581 Legon, Accra, Ghana
| | - Constance Assohou
- Institut de Recherche pour le Développement. UMR 224-MIVEGEC; 08 BP 841 Cotonou, Bénin
| | - Didier Tchonlin
- Laboratoire du centre de lutte intégrée contre le paludisme; 01 BP 188 Cotonou, Bénin
| | - Atika Mama
- Laboratoire du centre de lutte intégrée contre le paludisme; 01 BP 188 Cotonou, Bénin
| | | | | | - Franck Remoué
- Institut de Recherche pour le Développement. UMR 224-MIVEGEC; 08 BP 841 Cotonou, Bénin
| | - Daouda Ndiaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, BP 16477 Dakar, Senegal
| | - Dorothée Kinde Gazard
- Unité d'Enseignement et de Recherche en Parasitologie - Mycologie/Faculté des Sciences de la Santé; 01 BP 188 Cotonou, Bénin - Laboratoire du centre de lutte intégrée contre le paludisme; 01 BP 188 Cotonou, Bénin
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Chang HH, Meibalan E, Zelin J, Daniels R, Eziefula AC, Meyer EC, Tadesse F, Grignard L, Joice RC, Drakeley C, Wirth DF, Volkman SK, Buckee C, Bousema T, Marti M. Persistence of Plasmodium falciparum parasitemia after artemisinin combination therapy: evidence from a randomized trial in Uganda. Sci Rep 2016; 6:26330. [PMID: 27197604 PMCID: PMC4873826 DOI: 10.1038/srep26330] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 05/03/2016] [Indexed: 11/12/2022] Open
Abstract
Artemisinin resistance is rapidly spreading in Southeast Asia. The efficacy of artemisinin-combination therapy (ACT) continues to be excellent across Africa. We performed parasite transcriptional profiling and genotyping on samples from an antimalarial treatment trial in Uganda. We used qRT-PCR and genotyping to characterize residual circulating parasite populations after treatment with either ACT or ACT-primaquine. Transcripts suggestive of circulating ring stage parasites were present after treatment at a prevalence of >25% until at least 14 days post initiation of treatment. Greater than 98% of all ring stage parasites were cleared within the first 3 days, but subsequently persisted at low concentrations until day 14 after treatment. Genotyping demonstrated a significant decrease in multiplicity of infection within the first 2 days in both ACT and ACT-primaquine arms. However, multiple clone infections persisted until day 14 post treatment. Our data suggest the presence of genetically diverse persisting parasite populations after ACT treatment. Although we did not demonstrate clinical treatment failures after ACT and the viability and transmissibility of persisting ring stage parasites remain to be shown, these findings are of relevance for the interpretation of parasite clearance transmission dynamics and for monitoring drug effects in Plasmodium falciparum parasites.
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Affiliation(s)
- Hsiao-Han Chang
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Elamaran Meibalan
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Justin Zelin
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Rachel Daniels
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Alice C Eziefula
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Evan C Meyer
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Fitsum Tadesse
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Lynn Grignard
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Regina C Joice
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Chris Drakeley
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Sarah K Volkman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA.,Simmons College, 300 Fenway, Boston, MA 02115, USA
| | - Caroline Buckee
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Teun Bousema
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.,Institute for Molecular Life Sciences, Radboud University, Geert Grooteplain Zuid 28, 6525 GA Nijmegen, The Netherlands
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
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Lo E, Nguyen J, Oo W, Hemming-Schroeder E, Zhou G, Yang Z, Cui L, Yan G. Examining Plasmodium falciparum and P. vivax clearance subsequent to antimalarial drug treatment in the Myanmar-China border area based on quantitative real-time polymerase chain reaction. BMC Infect Dis 2016; 16:154. [PMID: 27084511 PMCID: PMC4833920 DOI: 10.1186/s12879-016-1482-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 03/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Recent emergence of artemisinin-resistant P. falciparum has posed a serious hindrance to the elimination of malaria in the Greater Mekong Subregion. Parasite clearance time, a measure of change in peripheral parasitaemia in a sequence of samples taken after treatment, can be used to reflect the susceptibility of parasites or the efficiency of antimalarials. The association of genetic polymorphisms and artemisinin resistance has been documented. This study aims to examine clearance time of P. falciparum and P. vivax parasitemia as well as putative gene mutations associated with residual or recurred parasitemia in Myanmar. METHODS A total of 63 P. falciparum and 130 P. vivax samples collected from two internally-displaced populations and one surrounding village were examined for parasitemia changes. At least four samples were taken from each patient, at the first day of diagnosis up to 3 months following the initial treatment. The amount of parasite gene copy number was estimated using quantitative real-time PCR based on a species-specific region of the 18S rRNA gene. For samples that showed residual or recurred parasitemia after treatment, microsatellites were used to identify the 'post-treatment' parasite genotype and compared such with the 'pre-treatment' genotype. Mutations in genes pfcrt, pfmdr1, pfatp6, pfmrp1 and pfK13 that are potentially associated with ACT resistance were examined to identify if mutation is a factor for residual or persistent parasitemia. RESULTS Over 30% of the P. falciprium infections showed delayed clearance of parasitemia after 2-3 days of treatment and 9.5% showed recurred parasitemia. Mutations in codon 876 of the pfmrp1 corroborated significance association with slow clearance time. However, no association was observed in the variation in pfmdr1 gene copy number as well as mutations of various codonsinpfatp6, pfcrt, and pfK13 with clearance time. For P. vivax, over 95% of the infections indicated cleared parasitemia at days 2-3 of treatment. Four samples were found to be re-infected with new parasite strains based on microsatellite genotypes after initial treatment. CONCLUSION The appearance of P.falciparum infected samples showing delayed clearance or recurred parasitemia after treatment raises concerns on current treatment and ACT drug resistance.
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Affiliation(s)
- Eugenia Lo
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | - Jennifer Nguyen
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | - Winny Oo
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | | | - Guofa Zhou
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
| | - Zhaoqing Yang
- />Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Liwang Cui
- />Department of Entomology, Pennsylvania State University, University Park, PA USA
| | - Guiyun Yan
- />Program in Public Health, University of California at Irvine, Irvine, CA 92697-4050 USA
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Ladeia-Andrade S, de Melo GNP, de Souza-Lima RDC, Salla LC, Bastos MS, Rodrigues PT, Luz FDCO, Ferreira MU. No Clinical or Molecular Evidence of Plasmodium falciparum Resistance to Artesunate-Mefloquine in Northwestern Brazil. Am J Trop Med Hyg 2016; 95:148-54. [PMID: 27068396 DOI: 10.4269/ajtmh.16-0017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 02/12/2016] [Indexed: 12/13/2022] Open
Abstract
We evaluated the clinical efficacy of artesunate-mefloquine (ASMQ) fixed-dose combination to treat uncomplicated malaria in Juruá Valley, the main Plasmodium falciparum transmission hotspot in Brazil. Between November 2010 and February 2013, we enrolled 162 patients aged 4-73 years, with fever or a history of fever, and a single-species P. falciparum infection confirmed by microscopy and polymerase chain reaction (PCR). All 154 patients who completed the 42-day follow-up presented an adequate clinical and parasitologic response. ASMQ was well tolerated and no adverse event caused treatment interruption. Gametocytes were detected in 46.3% patients; 35.2% had gametocytes at enrollment, whereas others developed patent gametocytemia 1-14 days after starting ASMQ. By day 3 of treatment, all subjects had cleared asexual parasitemia, but parasite DNA remained PCR detectable in 37.6% of them. Day-3 PCR positivity was associated with prolonged gametocyte carriage. We found no molecular evidence of resistance to either MQ (pfmdr1 gene amplification) or AS (mutations in selected kelch13 gene domains known to be associated with AS resistance) in the local P. falciparum population. These results strongly support the use of ASMQ as a first-line regimen to treat uncomplicated P. falciparum malaria in northwestern Brazil, but underscore the need for gametocytocidal drugs to reduce the transmission potential of ASMQ-treated patients (ClinicalTrials.gov number NCT01144702).
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Affiliation(s)
- Simone Ladeia-Andrade
- Laboratory of Parasitic Diseases, Oswaldo Cruz Institute/Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro, Brazil. Amazonian Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance, Ministry of Health of Brazil, Cruzeiro do Sul, Brazil
| | - Gladson Naber P de Melo
- Amazonian Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance, Ministry of Health of Brazil, Cruzeiro do Sul, Brazil
| | - Rita de Cássia de Souza-Lima
- Amazonian Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance, Ministry of Health of Brazil, Cruzeiro do Sul, Brazil
| | - Laís C Salla
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Melissa S Bastos
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Priscila T Rodrigues
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | | | - Marcelo U Ferreira
- Amazonian Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance, Ministry of Health of Brazil, Cruzeiro do Sul, Brazil. Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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72
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Mideo N, Bailey JA, Hathaway NJ, Ngasala B, Saunders DL, Lon C, Kharabora O, Jamnik A, Balasubramanian S, Björkman A, Mårtensson A, Meshnick SR, Read AF, Juliano JJ. A deep sequencing tool for partitioning clearance rates following antimalarial treatment in polyclonal infections. EVOLUTION MEDICINE AND PUBLIC HEALTH 2016; 2016:21-36. [PMID: 26817485 PMCID: PMC4753362 DOI: 10.1093/emph/eov036] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 12/21/2015] [Indexed: 11/14/2022]
Abstract
BACKGROUND AND OBJECTIVES Current tools struggle to detect drug-resistant malaria parasites when infections contain multiple parasite clones, which is the norm in high transmission settings in Africa. Our aim was to develop and apply an approach for detecting resistance that overcomes the challenges of polyclonal infections without requiring a genetic marker for resistance. METHODOLOGY Clinical samples from patients treated with artemisinin combination therapy were collected from Tanzania and Cambodia. By deeply sequencing a hypervariable locus, we quantified the relative abundance of parasite subpopulations (defined by haplotypes of that locus) within infections and revealed evolutionary dynamics during treatment. Slow clearance is a phenotypic, clinical marker of artemisinin resistance; we analyzed variation in clearance rates within infections by fitting parasite clearance curves to subpopulation data. RESULTS In Tanzania, we found substantial variation in clearance rates within individual patients. Some parasite subpopulations cleared as slowly as resistant parasites observed in Cambodia. We evaluated possible explanations for these data, including resistance to drugs. Assuming slow clearance was a stable phenotype of subpopulations, simulations predicted that modest increases in their frequency could substantially increase time to cure. CONCLUSIONS AND IMPLICATIONS By characterizing parasite subpopulations within patients, our method can detect rare, slow clearing parasites in vivo whose phenotypic effects would otherwise be masked. Since our approach can be applied to polyclonal infections even when the genetics underlying resistance are unknown, it could aid in monitoring the emergence of artemisinin resistance. Our application to Tanzanian samples uncovers rare subpopulations with worrying phenotypes for closer examination.
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Affiliation(s)
- Nicole Mideo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada;
| | - Jeffrey A Bailey
- Division of Transfusion Medicine, Department of Medicine, University of Massachusetts, Worcester, MA, USA; Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, MA, USA
| | - Nicholas J Hathaway
- Program in Bioinformatics and Integrative Biology, University of Massachusetts, Worcester, MA, USA
| | - Billy Ngasala
- Department of Parasitology, Muhimbili University of Health and Allied Sciences, Dar Es Salaam, Tanzania
| | - David L Saunders
- Division of Immunology and Medicine, USAMC Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Chanthap Lon
- US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Phnom Penh, Cambodia
| | - Oksana Kharabora
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Andrew Jamnik
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Sujata Balasubramanian
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Mårtensson
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Centre for Clinical Research Sörmland, Uppsala University, Sweden; Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Sweden
| | - Steven R Meshnick
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Andrew F Read
- Center for Infectious Disease Dynamics, Department of Biology and Entomology, the Pennsylvania State University, University Park, PA, USA and
| | - Jonathan J Juliano
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC, USA; Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
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Muwanguzi J, Henriques G, Sawa P, Bousema T, Sutherland CJ, Beshir KB. Lack of K13 mutations in Plasmodium falciparum persisting after artemisinin combination therapy treatment of Kenyan children. Malar J 2016; 15:36. [PMID: 26801909 PMCID: PMC4722670 DOI: 10.1186/s12936-016-1095-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/10/2016] [Indexed: 11/24/2022] Open
Abstract
Background Studies in Southeast Asia reported a strong relationship between polymorphisms at the propeller domain of the Kelch 13 (K13) protein encoded by the Plasmodiumfalciparumk13(pfk13) gene and delayed parasite clearance after artemisinin treatment. In Africa, P. falciparum remains susceptible and combination therapy regimens which include an artemisinin component display good efficacy. Using quantitative real-time PCR (qPCR), sub-microscopic persistence of P. falciparum has previously been reported in one-third of children treated with artemisinin combination therapy (ACT) in western Kenya. In this study, further investigation was made to evaluate whether these sub-microscopic residual parasites also harbour mutations at the propeller region of pfk13 and whether the mutations, if any, affect treatment outcome. Methods The pfk13 propeller domain was genotyped in DNA samples obtained in 2009 from Kenyan children treated with artemether–lumefantrine (AL) and dihydroartemisinin–piperaquine (DP). Paired samples at pre-treatment (day 0) and day of treatment failure (day 28 or 42) for 32 patients with documented recurrent parasitaemia were available for genotyping. Additional day 3 DNA samples were available for 10 patients. Results No mutation associated with artemisinin resistance in Southeast Asia was observed. Only one DP-treated patient harboured a non-synonymous mutation at codon 578 (A578S) of pfk13-propeller gene in the day 0 sample, but this allele was replaced by the wild-type (A578) form on day 3 and on the day of recurrent parasitaemia. The mutation at amino acid codon 578 showed no association with any phenotype. Polymorphisms in pfk13 were not responsible for parasite persistence and gametocyte carriage in the children treated with ACT. Conclusion This study contributes to the ongoing surveillance of suspected artemisinin resistance parasites in Africa by providing baseline prevalence of k13-propeller mutations in western Kenya with samples collected from a longitudinal study. Clinical Trials Registration NCT00868465.
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Affiliation(s)
- Julian Muwanguzi
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
| | - Gisela Henriques
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
| | - Patrick Sawa
- Human Health Division, International Centre of Insect Physiology and Ecology, Mbita Point, Western Kenya, Kenya.
| | - Teun Bousema
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK. .,Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
| | - Colin J Sutherland
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
| | - Khalid B Beshir
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
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Dihydroartemisinin-piperaquine resistance in Plasmodium falciparum malaria in Cambodia: a multisite prospective cohort study. THE LANCET. INFECTIOUS DISEASES 2016; 16:357-65. [PMID: 26774243 DOI: 10.1016/s1473-3099(15)00487-9] [Citation(s) in RCA: 352] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 11/17/2015] [Accepted: 11/19/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Artemisinin resistance in Plasmodium falciparum threatens to reduce the efficacy of artemisinin combination therapies (ACTs), thus compromising global efforts to eliminate malaria. Recent treatment failures with dihydroartemisinin-piperaquine, the current first-line ACT in Cambodia, suggest that piperaquine resistance may be emerging in this country. We explored the relation between artemisinin resistance and dihydroartemisinin-piperaquine failures, and sought to confirm the presence of piperaquine-resistant P falciparum infections in Cambodia. METHODS In this prospective cohort study, we enrolled patients aged 2-65 years with uncomplicated P falciparum malaria in three Cambodian provinces: Pursat, Preah Vihear, and Ratanakiri. Participants were given standard 3-day courses of dihydroartemisinin-piperaquine. Peripheral blood parasite densities were measured until parasites cleared and then weekly to 63 days. The primary outcome was recrudescent P falciparum parasitaemia within 63 days. We measured piperaquine plasma concentrations at baseline, 7 days, and day of recrudescence. We assessed phenotypic and genotypic markers of drug resistance in parasite isolates. The study is registered with ClinicalTrials.gov, number NCT01736319. FINDINGS Between Sept 4, 2012, and Dec 31, 2013, we enrolled 241 participants. In Pursat, where artemisinin resistance is entrenched, 37 (46%) of 81 patients had parasite recrudescence. In Preah Vihear, where artemisinin resistance is emerging, ten (16%) of 63 patients had recrudescence and in Ratanakiri, where artemisinin resistance is rare, one (2%) of 60 patients did. Patients with recrudescent P falciparum infections were more likely to have detectable piperaquine plasma concentrations at baseline compared with non-recrudescent patients, but did not differ significantly in age, initial parasite density, or piperaquine plasma concentrations at 7 days. Recrudescent parasites had a higher prevalence of kelch13 mutations, higher piperaquine 50% inhibitory concentration (IC50) values, and lower mefloquine IC50 values; none had multiple pfmdr1 copies, a genetic marker of mefloquine resistance. INTERPRETATION Dihydroartemisinin-piperaquine failures are caused by both artemisinin and piperaquine resistance, and commonly occur in places where dihydroartemisinin-piperaquine has been used in the private sector. In Cambodia, artesunate plus mefloquine may be a viable option to treat dihydroartemisinin-piperaquine failures, and a more effective first-line ACT in areas where dihydroartemisinin-piperaquine failures are common. The use of single low-dose primaquine to eliminate circulating gametocytes is needed in areas where artemisinin and ACT resistance is prevalent. FUNDING National Institute of Allergy and Infectious Diseases.
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Abstract
Gametocytes are the specialized form of Plasmodium parasites that are responsible for human-to-mosquito transmission of malaria. Transmission of gametocytes is highly effective, but represents a biomass bottleneck for the parasite that has stimulated interest in strategies targeting the transmission stages separately from those responsible for clinical disease. Studying targets of naturally acquired immunity against transmission-stage parasites may reveal opportunities for novel transmission reducing interventions, particularly the development of a transmission blocking vaccine (TBV). In this review, we summarize the current knowledge on immunity against the transmission stages of Plasmodium. This includes immune responses against epitopes on the gametocyte-infected erythrocyte surface during gametocyte development, as well as epitopes present upon gametocyte activation in the mosquito midgut. We present an analysis of historical data on transmission reducing immunity (TRI), as analysed in mosquito feeding assays, and its correlation with natural recognition of sexual stage specific proteins Pfs48/45 and Pfs230. Although high antibody titres towards either one of these proteins is associated with TRI, the presence of additional, novel targets is anticipated. In conclusion, the identification of novel gametocyte-specific targets of naturally acquired immunity against different gametocyte stages could aid in the development of potential TBV targets and ultimately an effective transmission blocking approach.
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How Robust Are Malaria Parasite Clearance Rates as Indicators of Drug Effectiveness and Resistance? Antimicrob Agents Chemother 2015; 59:6428-36. [PMID: 26239987 DOI: 10.1128/aac.00481-15] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/22/2015] [Indexed: 11/20/2022] Open
Abstract
Artemisinin-based combination therapies (ACTs) are currently the first-line drugs for treating uncomplicated falciparum malaria, the most deadly of the human malarias. Malaria parasite clearance rates estimated from patients' blood following ACT treatment have been widely adopted as a measure of drug effectiveness and as surveillance tools for detecting the presence of potential artemisinin resistance. This metric has not been investigated in detail, nor have its properties or potential shortcomings been identified. Herein, the pharmacology of drug treatment, parasite biology, and human immunity are combined to investigate the dynamics of parasite clearance following ACT. This approach parsimoniously recovers the principal clinical features and dynamics of clearance. Human immunity is the primary determinant of clearance rates, unless or until artemisinin killing has fallen to near-ineffective levels. Clearance rates are therefore highly insensitive metrics for surveillance that may lead to overconfidence, as even quite substantial reductions in drug sensitivity may not be detected as lower clearance rates. Equally serious is the use of clearance rates to quantify the impact of ACT regimen changes, as this strategy will plausibly miss even very substantial increases in drug effectiveness. In particular, the malaria community may be missing the opportunity to dramatically increase ACT effectiveness through regimen changes, particularly through a switch to twice-daily regimens and/or increases in artemisinin dosing levels. The malaria community therefore appears overreliant on a single metric of drug effectiveness, the parasite clearance rate, that has significant and serious shortcomings.
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Laneri K, Paul RE, Tall A, Faye J, Diene-Sarr F, Sokhna C, Trape JF, Rodó X. Dynamical malaria models reveal how immunity buffers effect of climate variability. Proc Natl Acad Sci U S A 2015; 112:8786-91. [PMID: 26124134 PMCID: PMC4507245 DOI: 10.1073/pnas.1419047112] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Assessing the influence of climate on the incidence of Plasmodium falciparum malaria worldwide and how it might impact local malaria dynamics is complex and extrapolation to other settings or future times is controversial. This is especially true in the light of the particularities of the short- and long-term immune responses to infection. In sites of epidemic malaria transmission, it is widely accepted that climate plays an important role in driving malaria outbreaks. However, little is known about the role of climate in endemic settings where clinical immunity develops early in life. To disentangle these differences among high- and low-transmission settings we applied a dynamical model to two unique adjacent cohorts of mesoendemic seasonal and holoendemic perennial malaria transmission in Senegal followed for two decades, recording daily P. falciparum cases. As both cohorts are subject to similar meteorological conditions, we were able to analyze the relevance of different immunological mechanisms compared with climatic forcing in malaria transmission. Transmission was first modeled by using similarly unique datasets of entomological inoculation rate. A stochastic nonlinear human-mosquito model that includes rainfall and temperature covariates, drug treatment periods, and population variability is capable of simulating the complete dynamics of reported malaria cases for both villages. We found that under moderate transmission intensity climate is crucial; however, under high endemicity the development of clinical immunity buffers any effect of climate. Our models open the possibility of forecasting malaria from climate in endemic regions but only after accounting for the interaction between climate and immunity.
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Affiliation(s)
- Karina Laneri
- Institut Català de Ciències del Clima, Climate Dynamics and Impacts Unit, 08005 Barcelona, Catalonia, Spain; Centro Atómico Bariloche, Consejo Nacional Investigaciones Científicas y Técnicas, Grupo de Física Estadística e Interdisciplinaria, 8400 S. C. de Bariloche, Rio Negro, Argentina;
| | - Richard E Paul
- Institut Pasteur, Unité de la Génétique Fonctionnelle des Maladies Infectieuses, Department of Genomes and Genetics, F-75724 Paris cedex 15, France; Centre National de la Recherche Scientifique, Unité de Recherche Associée 3012, F-75015 Paris, France
| | - Adama Tall
- Institut Pasteur de Dakar, Unité d'Epidémiologie des Maladies Infectieuses (UR 172), BP 220 Dakar, Senegal
| | - Joseph Faye
- Institut Pasteur de Dakar, Unité d'Epidémiologie des Maladies Infectieuses (UR 172), BP 220 Dakar, Senegal
| | - Fatoumata Diene-Sarr
- Institut Pasteur de Dakar, Unité d'Epidémiologie des Maladies Infectieuses (UR 172), BP 220 Dakar, Senegal
| | - Cheikh Sokhna
- Institut de Recherche pour le Développement, Unité de Pathogénie Afro-Tropicale (Unité Mixte de Recherche 198), Département Santé, BP 1386, CP 18524, Dakar, Senegal
| | - Jean-François Trape
- Institut de Recherche pour le Développement, Unité de Pathogénie Afro-Tropicale (Unité Mixte de Recherche 198), Département Santé, BP 1386, CP 18524, Dakar, Senegal
| | - Xavier Rodó
- Institut Català de Ciències del Clima, Climate Dynamics and Impacts Unit, 08005 Barcelona, Catalonia, Spain; Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Catalonia, Spain
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78
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Djimde AA, Makanga M, Kuhen K, Hamed K. The emerging threat of artemisinin resistance in malaria: focus on artemether-lumefantrine. Expert Rev Anti Infect Ther 2015; 13:1031-45. [PMID: 26081265 DOI: 10.1586/14787210.2015.1052793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The development of artemisinin resistance in the Greater Mekong Subregion poses a significant threat to malaria elimination. Artemisinin-based combination therapies including artemether-lumefantrine (AL) are recommended by WHO as first-line treatment for uncomplicated Plasmodium falciparum malaria. This article provides a comprehensive review of the existing and latest data as a basis for interpretation of observed variability in parasite sensitivity to AL over the last 5 years. Clinical efficacy and preclinical data from a range of endemic countries are summarized, including potential molecular markers of resistance. Overall, AL remains effective in the treatment of uncomplicated P. falciparum malaria in most regions. Establishing validated molecular markers for resistance and strict efficacy monitoring will reinforce timely updates of treatment policies.
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Affiliation(s)
- Abdoulaye A Djimde
- Malaria Research and Training Center, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
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79
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Stresman GH, Baidjoe AY, Stevenson J, Grignard L, Odongo W, Owaga C, Osoti V, Makori E, Shagari S, Marube E, Cox J, Drakeley C, Bousema T. Focal Screening to Identify the Subpatent Parasite Reservoir in an Area of Low and Heterogeneous Transmission in the Kenya Highlands. J Infect Dis 2015; 212:1768-77. [PMID: 26019285 DOI: 10.1093/infdis/jiv302] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 05/14/2015] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Mass screening and treatment currently fails to identify a considerable fraction of low parasite density infections, while mass treatment exposes many uninfected individuals to antimalarial drugs. Here we test a hybrid approach to screen a sentinel population to identify clusters of subpatent infections in the Kenya highlands with low, heterogeneous malaria transmission. METHODS Two thousand eighty-two inhabitants were screened for parasitemia by nested polymerase chain reaction (nPCR). Children aged ≤ 15 years and febrile adults were also tested for malaria by rapid diagnostic test (RDT) and served as sentinel members to identify subpatent infections within the household. All parasitemic individuals were assessed for multiplicity of infections by nPCR and gametocyte carriage by nucleic acid sequence-based amplification. RESULTS Households with RDT-positive individuals in the sentinel population were more likely to have nPCR-positive individuals (odds ratio: 1.71, 95% confidence interval, 1.60-1.84). The sentinel population identified 64.5% (locality range: 31.6%-81.2%) of nPCR-positive households and 77.3% (locality range: 24.2%-91.0%) of nPCR-positive individuals. The sensitivity of the sentinel screening approach was positively associated with transmission intensity (P = .037). CONCLUSIONS In this low endemic area, a focal screening approach with RDTs prior to the high transmission season was able to identify the majority of the subpatent parasite reservoirs.
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Affiliation(s)
- Gillian H Stresman
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - Jennifer Stevenson
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom The Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Lynn Grignard
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Wycliffe Odongo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Chrispin Owaga
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Victor Osoti
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Euniah Makori
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Shehu Shagari
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Elisabeth Marube
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu
| | - Jonathan Cox
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Chris Drakeley
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Teun Bousema
- Department of Immunology and Infection; Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom Radboud University Nijmegen Medical Centre, The Netherlands
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80
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Davis NL, Barnett EJ, Miller WC, Dow A, Chasela CS, Hudgens MG, Kayira D, Tegha G, Ellington SR, Kourtis AP, van der Horst C, Jamieson DJ, Juliano JJ. Impact of daily cotrimoxazole on clinical malaria and asymptomatic parasitemias in HIV-exposed, uninfected infants. Clin Infect Dis 2015; 61:368-74. [PMID: 25900173 DOI: 10.1093/cid/civ309] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/25/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Cotrimoxazole preventive therapy (CPT) is recommended for all human immunodeficiency virus (HIV)-exposed infants to avoid opportunistic infections. Cotrimoxazole has antimalarial effects and appears to reduce clinical malaria infections, but the impact on asymptomatic malaria infections is unknown. METHODS We conducted an observational cohort study using data and dried blood spots (DBSs) from the Breastfeeding, Antiretrovirals and Nutrition study to evaluate the impact of CPT on malaria infection during peak malaria season in Lilongwe, Malawi. We compared malaria incidence 1 year before and after CPT implementation (292 and 682 CPT-unexposed and CPT-exposed infants, respectively), including only infants who remained HIV negative by 36 weeks of age. Malaria was defined as clinical, asymptomatic (using DBSs at 12, 24, and 36 weeks), or a composite outcome of clinical or asymptomatic. Linear and binomial regression with generalized estimating equations were used to estimate the association between CPT and malaria. Differences in characteristics of parasitemias and drug resistance polymorphisms by CPT status were also assessed in the asymptomatic infections. RESULTS CPT was associated with a 70% (95% confidence interval, 53%-81%) relative reduction in the risk of asymptomatic infection between 6 and 36 weeks of age. CPT appeared to provide temporary protection against clinical malaria and more sustained protection against asymptomatic infections, with no difference in parasitemia characteristics. CONCLUSIONS CPT appears to reduce overall malaria infections, with more prolonged impacts on asymptomatic infections. Asymptomatic infections are potentially important reservoirs for malaria transmission. Therefore, CPT prophylaxis may have important individual and public health benefits.
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Affiliation(s)
- Nicole L Davis
- Department of Epidemiology, Gillings School of Global Public Health Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill
| | - Eric J Barnett
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill
| | - William C Miller
- Department of Epidemiology, Gillings School of Global Public Health Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill
| | - Anna Dow
- Department of Epidemiology, Gillings School of Global Public Health
| | - Charles S Chasela
- Division of Epidemiology and Biostatistics, School of Public Health, University of Witwatersrand, Parktown, South Africa
| | - Michael G Hudgens
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill
| | - Dumbani Kayira
- University of North Carolina, UNC Project, Lilongwe, Malawi
| | - Gerald Tegha
- University of North Carolina, UNC Project, Lilongwe, Malawi
| | - Sascha R Ellington
- Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Athena P Kourtis
- Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Charles van der Horst
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill
| | - Denise J Jamieson
- Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jonathan J Juliano
- Division of Infectious Diseases, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill
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81
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van Schalkwyk DA, Sutherland CJ. Malaria resistance to non-artemisinin partner drugs: how to reACT. THE LANCET. INFECTIOUS DISEASES 2015; 15:621-3. [PMID: 25877961 DOI: 10.1016/s1473-3099(15)70080-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Donelly A van Schalkwyk
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Colin J Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
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82
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The Mu subunit of Plasmodium falciparum clathrin-associated adaptor protein 2 modulates in vitro parasite response to artemisinin and quinine. Antimicrob Agents Chemother 2015; 59:2540-7. [PMID: 25691625 PMCID: PMC4394773 DOI: 10.1128/aac.04067-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 02/05/2015] [Indexed: 02/03/2023] Open
Abstract
The emergence of drug-resistant parasites is a serious threat faced by malaria control programs. Understanding the genetic basis of resistance is critical to the success of treatment and intervention strategies. A novel locus associated with antimalarial resistance, ap2-mu (encoding the mu chain of the adaptor protein 2 [AP2] complex), was recently identified in studies on the rodent malaria parasite Plasmodium chabaudi (pcap2-mu). Furthermore, analysis in Kenyan malaria patients of polymorphisms in the Plasmodium falciparum ap2-mu homologue, pfap2-mu, found evidence that differences in the amino acid encoded by codon 160 are associated with enhanced parasite survival in vivo following combination treatments which included artemisinin derivatives. Here, we characterize the role of pfap2-mu in mediating the in vitro antimalarial drug response of P. falciparum by generating transgenic parasites constitutively expressing codon 160 encoding either the wild-type Ser (Ser160) or the Asn mutant (160Asn) form of pfap2-mu. Transgenic parasites carrying the pfap2-mu 160Asn allele were significantly less sensitive to dihydroartemisinin using a standard 48-h in vitro test, providing direct evidence of an altered parasite response to artemisinin. Our data also provide evidence that pfap2-mu variants can modulate parasite sensitivity to quinine. No evidence was found that pfap2-mu variants contribute to the slow-clearance phenotype exhibited by P. falciparum in Cambodian patients treated with artesunate monotherapy. These findings provide compelling evidence that pfap2-mu can modulate P. falciparum responses to multiple drugs. We propose that this gene should be evaluated further as a potential molecular marker of antimalarial resistance.
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83
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Bolscher JM, Koolen KMJ, van Gemert GJ, van de Vegte-Bolmer MG, Bousema T, Leroy D, Sauerwein RW, Dechering KJ. A combination of new screening assays for prioritization of transmission-blocking antimalarials reveals distinct dynamics of marketed and experimental drugs. J Antimicrob Chemother 2015; 70:1357-66. [PMID: 25667405 DOI: 10.1093/jac/dkv003] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/29/2014] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVES The development of drugs to reduce malaria transmission is an important part of malaria eradication plans. We set out to develop and validate a combination of new screening assays for prioritization of transmission-blocking molecules. METHODS We developed high-throughput assays for screening compounds against gametocytes, the parasite stages responsible for onward transmission to mosquitoes. An existing gametocyte parasitic lactate dehydrogenase (pLDH) assay was adapted for use in 384-well plates, and a novel homogeneous immunoassay to monitor the functional transition of female gametocytes into gametes was developed. A collection of 48 marketed and experimental antimalarials was screened and subsequently tested for impact on sporogony in Anopheles mosquitoes, to directly quantify the transmission-blocking properties of antimalarials in relation to their effects on gametocyte pLDH activity or gametogenesis. RESULTS AND CONCLUSIONS The novel screening assays revealed distinct stage-specific kinetics and dynamics of drug effects. Peroxides showed the most potent transmission-blocking effects, with an intermediate speed of action and IC50 values that were 20-40-fold higher than the IC50s against the asexual stages causing clinical malaria. Finally, the novel synthetic peroxide OZ439 appeared to be a promising drug candidate as it exerted gametocytocidal and transmission-blocking effects at clinically relevant concentrations.
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Affiliation(s)
- J M Bolscher
- TropIQ Health Sciences, Geert Grooteplein 28, huispost 268, 6525 GA, Nijmegen, The Netherlands
| | - K M J Koolen
- TropIQ Health Sciences, Geert Grooteplein 28, huispost 268, 6525 GA, Nijmegen, The Netherlands
| | - G J van Gemert
- Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | | | - T Bousema
- Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - D Leroy
- Medicines for Malaria Venture, Route de Pré-Bois 20, 1215 Geneva 15, Switzerland
| | - R W Sauerwein
- TropIQ Health Sciences, Geert Grooteplein 28, huispost 268, 6525 GA, Nijmegen, The Netherlands Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - K J Dechering
- TropIQ Health Sciences, Geert Grooteplein 28, huispost 268, 6525 GA, Nijmegen, The Netherlands
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Weathers PJ, Towler M, Hassanali A, Lutgen P, Engeu PO. Dried-leaf Artemisia annua: A practical malaria therapeutic for developing countries? World J Pharmacol 2014; 3:39-55. [PMID: 25678989 PMCID: PMC4323188 DOI: 10.5497/wjp.v3.i4.39] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/09/2014] [Accepted: 10/10/2014] [Indexed: 02/06/2023] Open
Abstract
Artemisinin from the plant Artemisia annua (A. annua) L., and used as artemisinin combination therapy (ACT), is the current best therapeutic for treating malaria, a disease that hits children and adults especially in developing countries. Traditionally, A. annua was used by the Chinese as a tea to treat “fever”. More recently, investigators have shown that tea infusions and oral consumption of the dried leaves of the plant have prophylactic and therapeutic efficacy. The presence of a complex matrix of chemicals within the leaves seems to enhance both the bioavailability and efficacy of artemisinin. Although about 1000-fold less potent than artemisinin in their antiplasmodial activity, these plant chemicals are mainly small molecules that include other artemisinic compounds, terpenes (mainly mono and sesqui), flavonoids, and polyphenolic acids. In addition, polysaccharide constituents of A. annua may enhance bioavailability of artemisinin. Rodent pharmacokinetics showed longer T½ and Tmax and greater Cmax and AUC in Plasmodium chabaudi-infected mice treated with A. annua dried leaves than in healthy mice. Pharmacokinetics of deoxyartemisinin, a liver metabolite of artemisinin, was more inhibited in infected than in healthy mice. In healthy mice, artemisinin serum levels were > 40-fold greater in dried leaf fed mice than those fed with pure artemisinin. Human trial data showed that when delivered as dried leaves, 40-fold less artemisinin was required to obtain a therapeutic response compared to pure artemisinin. ACTs are still unaffordable for many malaria patients, and cost estimates for A. annua dried leaf tablet production are orders of magnitude less than for ACT, despite improvements in the production capacity. Considering that for > 2000 years this plant was used in traditional Chinese medicine for treatment of fever with no apparent appearance of artemisinin drug resistance, the evidence argues for inclusion of affordable A. annua dried leaf tablets into the arsenal of drugs to combat malaria and other artemisinin-susceptible diseases.
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85
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Bousema T, Okell L, Felger I, Drakeley C. Asymptomatic malaria infections: detectability, transmissibility and public health relevance. Nat Rev Microbiol 2014; 12:833-40. [PMID: 25329408 DOI: 10.1038/nrmicro3364] [Citation(s) in RCA: 442] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most Plasmodium falciparum infections that are detected in community surveys are characterized by low-density parasitaemia and the absence of clinical symptoms. Molecular diagnostics have shown that this asymptomatic parasitic reservoir is more widespread than previously thought, even in low-endemic areas. In this Opinion article, we describe the detectability of asymptomatic malaria infections and the relevance of submicroscopic infections for parasite transmission to mosquitoes and for community interventions that aim at reducing transmission. We argue that wider deployment of molecular diagnostic tools is needed to provide adequate insight into the epidemiology of malaria and infection dynamics to aid elimination efforts.
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Affiliation(s)
- Teun Bousema
- 1] London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK. [2] Radboud University Medical Centre, 6525 GA Nijmegen, The Netherlands
| | - Lucy Okell
- Imperial College, London, London SW7 2AZ, UK
| | | | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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86
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Torres KJ, Castrillon CE, Moss EL, Saito M, Tenorio R, Molina DM, Davies H, Neafsey DE, Felgner P, Vinetz JM, Gamboa D. Genome-level determination of Plasmodium falciparum blood-stage targets of malarial clinical immunity in the Peruvian Amazon. J Infect Dis 2014; 211:1342-51. [PMID: 25381370 DOI: 10.1093/infdis/jiu614] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Persons with blood-stage Plasmodium falciparum parasitemia in the absence of symptoms are considered to be clinically immune. We hypothesized that asymptomatic subjects with P. falciparum parasitemia would differentially recognize a subset of P. falciparum proteins on a genomic scale. METHODS AND FINDINGS Compared with symptomatic subjects, sera from clinically immune, asymptomatically infected individuals differentially recognized 51 P. falciparum proteins, including the established vaccine candidate PfMSP1. Novel, hitherto unstudied hypothetical proteins and other proteins not previously recognized as potential vaccine candidates were also differentially recognized. Genes encoding the proteins differentially recognized by the Peruvian clinically immune individuals exhibited a significant enrichment of nonsynonymous nucleotide variation, an observation consistent with these genes undergoing immune selection. CONCLUSIONS A limited set of P. falciparum protein antigens was associated with the development of naturally acquired clinical immunity in the low-transmission setting of the Peruvian Amazon. These results imply that, even in a low-transmission setting, an asexual blood-stage vaccine designed to reduce clinical malaria symptoms will likely need to contain large numbers of often-polymorphic proteins, a finding at odds with many current efforts in the design of vaccines against asexual blood-stage P. falciparum.
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Affiliation(s)
- Katherine J Torres
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía
| | - Carlos E Castrillon
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía
| | - Eli L Moss
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Mayuko Saito
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía Division of Infectious Diseases, Department of Medicine, University of California-San Diego, La Jolla
| | - Roy Tenorio
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía Laboratorio Satelital, Universidad Peruana Cayetano Heredia, Iquitos, Perú
| | | | - Huw Davies
- Division of Infectious Diseases, Department of Medicine, University of California-Irvine
| | - Daniel E Neafsey
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Philip Felgner
- Division of Infectious Diseases, Department of Medicine, University of California-Irvine
| | - Joseph M Vinetz
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía Institute de Medicina Tropical, Universidad Peruana Cayetano Heredia, Lima Division of Infectious Diseases, Department of Medicine, University of California-San Diego, La Jolla
| | - Dionicia Gamboa
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía Institute de Medicina Tropical, Universidad Peruana Cayetano Heredia, Lima
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Stresman GH, Stevenson JC, Ngwu N, Marube E, Owaga C, Drakeley C, Bousema T, Cox J. High levels of asymptomatic and subpatent Plasmodium falciparum parasite carriage at health facilities in an area of heterogeneous malaria transmission intensity in the Kenyan highlands. Am J Trop Med Hyg 2014; 91:1101-8. [PMID: 25331807 DOI: 10.4269/ajtmh.14-0355] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In endemic settings, health facility surveys provide a convenient approach to estimating malaria transmission intensity. Typically, testing for malaria at facilities is performed on symptomatic attendees, but asymptomatic infections comprise a considerable proportion of the parasite reservoir. We sampled individuals attending five health facilities in the western Kenyan highlands. Malaria prevalence by rapid diagnostic test (RDT) was 8.6-32.9% in the health facilities. Of all polymerase chain reaction-positive participants, 46.4% (95% confidence interval [95% CI] = 42.6-50.2%) of participants had infections that were RDT-negative and asymptomatic, and 55.9% of those infections consisted of multiple parasite clones as assessed by merozoite surface protein-2 genotyping. Subpatent infections were more common in individuals reporting the use of non-artemisinin-based antimalarials in the 2 weeks preceding the survey (odds ratio = 2.49, 95% CI = 1.04-5.92) compared with individuals not reporting previous use of antimalarials. We observed a large and genetically complex pool of subpatent parasitemia in the Kenya highlands that must be considered in malaria interventions.
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Affiliation(s)
- Gillian H Stresman
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jennifer C Stevenson
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Nnenna Ngwu
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Elizabeth Marube
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chrispin Owaga
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Teun Bousema
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jonathan Cox
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Kenya Medical Research Institute, Centre for Global Health Research, Centers for Disease Control and Prevention/Kenya Medical Research Institute, Kisumu, Kenya; Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Medical Microbiology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Radboud University, Nijmegen Medical Centre, Nijmegen, The Netherlands
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88
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Effect of fluorescent dyes on in vitro-differentiated, late-stage Plasmodium falciparum gametocytes. Antimicrob Agents Chemother 2014; 58:7398-404. [PMID: 25267675 DOI: 10.1128/aac.03772-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Plasmodium falciparum gametocytes are not associated with clinical symptoms, but they are responsible for transmitting the pathogen to mosquitoes. Therefore, gametocytocidal interventions are important for malaria control and resistance containment. Currently available drugs and vaccines are not well suited for that purpose. Several dyes have potent antimicrobial activity, but their use against gametocytes has not been investigated systematically. The gametocytocidal activity of nine synthetic dyes and four control compounds was tested against stage V gametocytes of the laboratory strain 3D7 and three clinical isolates of P. falciparum with a bioluminescence assay. Five of the fluorescent dyes had submicromolar 50% inhibitory concentration (IC50) values against mature gametocytes. Three mitochondrial dyes, MitoRed, dihexyloxacarbocyanine iodide (DiOC6), and rhodamine B, were highly active (IC(50)s < 200 nM). MitoRed showed the highest activity against gametocytes, with IC(50)s of 70 nM against 3D7 and 120 to 210 nM against clinical isolates. All compounds were more active against the laboratory strain 3D7 than against clinical isolates. In particular, the endoperoxides artesunate and dihydroartemisinin showed a 10-fold higher activity against 3D7 than against clinical isolates. In contrast to all clinically used antimalarials, several fluorescent dyes had surprisingly high in vitro activity against late-stage gametocytes. Since they also act against asexual blood stages, they shall be considered starting points for the development of new antimalarial lead compounds.
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89
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Coulibaly B, Pritsch M, Bountogo M, Meissner PE, Nebié E, Klose C, Kieser M, Berens-Riha N, Wieser A, Sirima SB, Breitkreutz J, Schirmer RH, Sié A, Mockenhaupt FP, Drakeley C, Bousema T, Müller O. Efficacy and safety of triple combination therapy with artesunate-amodiaquine-methylene blue for falciparum malaria in children: a randomized controlled trial in Burkina Faso. J Infect Dis 2014; 211:689-97. [PMID: 25267980 DOI: 10.1093/infdis/jiu540] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Methylene blue (MB) has been shown to be safe and effective against falciparum malaria in Africa and to have pronounced gametocytocidal properties. METHODS Three days of treatment with artesunate (AS)-amodiaquine (AQ) combined with MB was compared with AS-AQ treatment in a randomized controlled phase IIb study; the study included 221 children aged 6-59 months with uncomplicated falciparum malaria in Burkina Faso. The primary end point was gametocyte prevalence during follow-up, as determined by microscopy and real-time quantitative nucleic acid sequence-based amplification (QT-NASBA). RESULTS The gametocyte prevalence of Plasmodium falciparum at baseline was 3.6% (microscopy) and 97% (QT-NASBA). It was significantly lower in the AS-AQ-MB than in the AS-AQ group on day 7 of follow-up (microscopy, 1.2% vs 8.9% [P < .05]; QT-NASBA, 36.7% vs 63.3% [P < .001]). Hemoglobin values were significantly lower in the AS-AQ-MB group than in the AS-AQ group at days 2 and 7 of follow-up. Vomiting of the study medication occurred significantly more frequently in the AS-AQ-MB group. CONCLUSIONS The combination of MB with an artemisinin-based combination therapy has been confirmed to be effective against the gametocytes of P. falciparum. MB-based combinations need to be compared with primaquine-based combinations, preferably using MB in an improved pediatric formulation. Clinical Trials Registration: NCT01407887.
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Affiliation(s)
| | - Michael Pritsch
- Division of Infectious Diseases and Tropical Medicine, Medical Center Department of Bacteriology, Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich German Center for Infection Research, Partner Site Munich
| | | | - Peter E Meissner
- Department of Pediatrics and Adolescent Medicine, Medical School, Ulm University
| | - Eric Nebié
- Centre de Recherche en Santé de Nouna, Nouna
| | | | | | | | - Andreas Wieser
- Division of Infectious Diseases and Tropical Medicine, Medical Center Department of Bacteriology, Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich German Center for Infection Research, Partner Site Munich
| | - Sodiomon B Sirima
- Centre de Recherche et de la Formation au Paludisme, Ouagadougou, Burkina Faso
| | - Jörg Breitkreutz
- Institute of Pharmaceutics and Biopharmaceutics, Heinrich Heine University Düsseldorf
| | | | - Ali Sié
- Centre de Recherche en Santé de Nouna, Nouna
| | - Frank P Mockenhaupt
- Institute of Tropical Medicine and International Health, Charité-Universitätsmedizin Berlin, Germany
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Tropical Medicine and Hygiene, United Kingdom
| | - Teun Bousema
- Department of Immunology & Infection, London School of Tropical Medicine and Hygiene, United Kingdom Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
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90
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Delayed parasite clearance after treatment with dihydroartemisinin-piperaquine in Plasmodium falciparum malaria patients in central Vietnam. Antimicrob Agents Chemother 2014; 58:7049-55. [PMID: 25224002 DOI: 10.1128/aac.02746-14] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Reduced susceptibility of Plasmodium falciparum toward artemisinin derivatives has been reported from the Thai-Cambodian and Thai-Myanmar borders. Following increasing reports from central Vietnam of delayed parasite clearance after treatment with dihydroartemisinin-piperaquine (DHA-PPQ), the current first-line treatment, we carried out a study on the efficacy of this treatment. Between September 2012 and February 2013, we conducted a 42-day in vivo and in vitro efficacy study in Quang Nam Province. Treatment was directly observed, and blood samples were collected twice daily until parasite clearance. In addition, genotyping, quantitative PCR (qPCR), and in vitro sensitivity testing of isolates was performed. The primary endpoints were parasite clearance rate and time. The secondary endpoints included PCR-corrected and uncorrected cure rates, qPCR clearance profiles, in vitro sensitivity results (for chloroquine, dihydroartemisinin, and piperaquine), and genotyping for mutations in the Kelch 13 propeller domain. Out of 672 screened patients, 95 were recruited and 89 available for primary endpoint analyses. The median parasite clearance time (PCT) was 61.7 h (interquartile range [IQR], 47.6 to 83.2 h), and the median parasite clearance rate had a slope half-life of 6.2 h (IQR, 4.4 to 7.5 h). The PCR-corrected efficacy rates were estimated at 100% at day 28 and 97.7% (95% confidence interval, 91.2% to 99.4%) at day 42. At day 3, the P. falciparum prevalence by qPCR was 2.5 times higher than that by microscopy. The 50% inhibitory concentrations (IC50s) of isolates with delayed clearance times (≥ 72 h) were significantly higher than those with normal clearance times for all three drugs. Delayed parasite clearance (PCT, ≥ 72 h) was significantly higher among day 0 samples carrying the 543 mutant allele (47.8%) than those carrying the wild-type allele (1.8%; P = 0.048). In central Vietnam, the efficacy of DHA-PPQ is still satisfactory, but the parasite clearance time and rate are indicative of emerging artemisinin resistance. (This study has been registered at ClinicalTrials.gov under registration no. NCT01775592.).
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91
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Ndour PA, Lopera-Mesa TM, Diakité SAS, Chiang S, Mouri O, Roussel C, Jauréguiberry S, Biligui S, Kendjo E, Claessens A, Ciceron L, Mazier D, Thellier M, Diakité M, Fairhurst RM, Buffet PA. Plasmodium falciparum clearance is rapid and pitting independent in immune Malian children treated with artesunate for malaria. J Infect Dis 2014; 211:290-7. [PMID: 25183768 DOI: 10.1093/infdis/jiu427] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In Plasmodium falciparum-infected patients treated with artemisinins, parasitemia declines through so-called pitting, an innate splenic process that transforms infected red blood cells (iRBCs) into once-infected RBCs (O-iRBCs). METHODS We measured pitting in 83 French travelers and 42 Malian children treated for malaria with artesunate. RESULTS In travelers, O-iRBCs peaked at 107.7% initial parasitemia. In Malian children aged 1.5-4 years, O-iRBCs peaked at higher concentrations than in children aged 9-13 years (91.60% vs 31.95%; P = .0097). The parasite clearance time in older children was shorter than in younger children (P = .0001), and the decline in parasitemia in children aged 1.5-4 years often started 6 hours after treatment initiation, a lag phase generally absent in infants and older children. A 6-hour lag phase in artificial pitting of artesunate-exposed iRBCs was also observed in vitro. The proportion of iRBCs recognized by autologous immunoglobulin G (IgG) correlated with the parasite clearance time (r = -0.501; P = .0006) and peak O-iRBC concentration (r = -0.420; P = .0033). CONCLUSIONS Antimalarial immunity correlates with fast artemisinin-induced parasite clearance and low pitting rates. In nonimmune populations, artemisinin-induced P. falciparum clearance is related to pitting and starts after a 6-hour lag phase. In immune populations, passively and naturally acquired immune mechanisms operating faster than pitting may exist. This mechanism may mitigate the emergence of artemisinin-resistant P. falciparum in Africa.
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Affiliation(s)
- Papa Alioune Ndour
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière Laboratory of Excellence GR-Ex
| | - Tatiana M Lopera-Mesa
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Seidina A S Diakité
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Mali
| | - Serena Chiang
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Oussama Mouri
- AP-HP, Hôpital Pitié-Salpêtrière, Service de Parasitologie-Mycologie et Service des Maladies Infectieuses et Tropicales, Paris, France
| | - Camille Roussel
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255
| | - Stéphane Jauréguiberry
- Centre National de Référence du Paludisme site Pitié-Salpêtrière AP-HP, Hôpital Pitié-Salpêtrière, Service de Parasitologie-Mycologie et Service des Maladies Infectieuses et Tropicales, Paris, France
| | - Sylvestre Biligui
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière
| | - Eric Kendjo
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière
| | - Antoine Claessens
- Centre for Immunity, Infection and Evolution, University of Edinburgh, United Kingdom
| | - Liliane Ciceron
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière
| | - Dominique Mazier
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière AP-HP, Hôpital Pitié-Salpêtrière, Service de Parasitologie-Mycologie et Service des Maladies Infectieuses et Tropicales, Paris, France
| | - Marc Thellier
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière AP-HP, Hôpital Pitié-Salpêtrière, Service de Parasitologie-Mycologie et Service des Maladies Infectieuses et Tropicales, Paris, France
| | - Mahamadou Diakité
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Mali
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Pierre A Buffet
- Centre d'Immunologie et des Maladies Infectieuses de Paris, INSERM U1135, UPMC CR7, CNRS ERL 8255 Centre National de Référence du Paludisme site Pitié-Salpêtrière Laboratory of Excellence GR-Ex AP-HP, Hôpital Pitié-Salpêtrière, Service de Parasitologie-Mycologie et Service des Maladies Infectieuses et Tropicales, Paris, France
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92
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Antimalarial activity of the myxobacterial macrolide chlorotonil a. Antimicrob Agents Chemother 2014; 58:6378-84. [PMID: 25114138 DOI: 10.1128/aac.03326-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myxobacteria are Gram-negative soil-dwelling bacteria belonging to the phylum Proteobacteria. They are a rich source of promising compounds for clinical application, such as epothilones for cancer therapy and several new antibiotics. In the course of a bioactivity screening program of secondary metabolites produced by Sorangium cellulosum strains, the macrolide chlorotonil A was found to exhibit promising antimalarial activity. Subsequently, we evaluated chlorotonil A against Plasmodium falciparum laboratory strains and clinical isolates from Gabon. Chlorotonil A was highly active, with a 50% inhibitory concentration between 4 and 32 nM; additionally, no correlations between the activities of chlorotonil A and artesunate (rho, 0.208) or chloroquine (rho, -0.046) were observed. Per os treatment of Plasmodium berghei-infected mice with four doses of as little as 36 mg of chlorotonil A per kg of body weight led to the suppression of parasitemia with no obvious signs of toxicity. Chlorotonil A acts against all stages of intraerythrocytic parasite development, including ring-stage parasites and stage IV to V gametocytes, and it requires only a very short exposure to the parasite to exert its antimalarial action. Conclusively, chlorotonil A has an exceptional and unprecedented profile of action and represents an urgently required novel antimalarial chemical scaffold. Therefore, we propose it as a lead structure for further development as an antimalarial chemotherapeutic.
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93
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Makanga M. A review of the effects of artemether-lumefantrine on gametocyte carriage and disease transmission. Malar J 2014; 13:291. [PMID: 25069530 PMCID: PMC4126813 DOI: 10.1186/1475-2875-13-291] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/08/2014] [Indexed: 01/02/2023] Open
Abstract
While significant advances have been made in the prevention and treatment of malaria in recent years, these successes continue to fall short of the World Health Organization (WHO) goals for malaria control and elimination. For elimination strategies to be effective, limited disease transmission, achieved through rapid reduction in the infectious parasite reservoir and decreased gametocyte carriage, will be critical. Artemisinin-based combination therapy (ACT) forms the cornerstone of WHO-recommended treatment for uncomplicated Plasmodium falciparum malaria, and in combination with other effective interventions will undoubtedly play a vital role in elimination programmes. The gametocytocidal properties of artemisinins are a bonus attribute; there is epidemiological evidence of reductions in malaria incidence and transmission in African regions since the introduction of these agents. Many studies and analyses have specifically investigated the effects of the ACT, artemether-lumefantrine (AL) on gametocyte carriage. In this systematic review of 62 articles published between 1998 and January 2014, the effects of AL on gametocyte carriage and malaria transmission are compared with other artemisinin-based anti-malarials and non-ACT. The impact of AL treatment of asymptomatic carriers on population gametocyte carriage, and the potential future role of AL in malaria elimination initiatives are also considered. Despite the inherent difficulties in comparing data from a range of different studies that also utilized different diagnostic approaches to assess baseline gametocyte counts, the gametocytocidal effect of AL was proportionately consistent across the studies reviewed, suggesting that AL will continue to play a vital role in the treatment of malaria and contribute to clearing the path towards malaria elimination. However, the specific place of AL is the subject of much ongoing research and will undoubtedly be dependent on different demographic and geographical scenarios. Utilizing ACT, such as AL, within malaria elimination strategies is also associated with a number of other challenges, such as balancing potential increased use of ACT (e g, treatment of asymptomatic carriers and home-based treatment) with rational use and avoidance of drug resistance development.
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Affiliation(s)
- Michael Makanga
- European & Developing Countries Clinical Trials Partnership (EDCTP), PO Box 19070, Tygerberg, Cape Town, South Africa.
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94
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Plasmodium yoelii vitamin B5 pantothenate transporter candidate is essential for parasite transmission to the mosquito. Sci Rep 2014; 4:5665. [PMID: 25012929 PMCID: PMC4092334 DOI: 10.1038/srep05665] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 06/23/2014] [Indexed: 11/09/2022] Open
Abstract
In nearly all non-photosynthetic cells, pantothenate (vitamin B5) transport and utilization are prerequisites for the synthesis of the universal essential cofactor Coenzyme A (CoA). Early studies showed that human malaria parasites rely on the uptake of pantothenate across the parasite plasma membrane for survival within erythrocytes. Recently, a P. falciparum candidate pantothenate transporter (PAT) was characterized by functional complementation in yeast. These studies revealed that PfPAT mediated survival of yeast cells in low pantothenate concentrations and restored sensitivity of yeast cells lacking pantothenate uptake to fenpropimorph. In addition, PfPAT was refractory to deletion in P. falciparumin vitro, but nothing is known about the in vivo functions of PAT in Plasmodium life cycle stages. Herein, we used gene-targeting techniques to delete PAT in Plasmodium yoelii. Parasites lacking PAT displayed normal asexual and sexual blood stage development compared to wild-type (WT) and WT-like p230p(-) parasites. However, progression from the ookinete to the oocyst stage and sporozoite formation were completely abolished in pat(-) parasites. These studies provide the first evidence for an essential role of a candidate pantothenate transport in malaria transmission to Anopheles mosquitoes. This will set the stage for the development of PAT inhibitors against multiple parasite life cycle stages.
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95
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Henriques G, Hallett RL, Beshir KB, Gadalla NB, Johnson RE, Burrow R, van Schalkwyk DA, Sawa P, Omar SA, Clark TG, Bousema T, Sutherland CJ. Directional selection at the pfmdr1, pfcrt, pfubp1, and pfap2mu loci of Plasmodium falciparum in Kenyan children treated with ACT. J Infect Dis 2014; 210:2001-8. [PMID: 24994911 PMCID: PMC4241946 DOI: 10.1093/infdis/jiu358] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The efficacy of artemisinin-based combination therapy (ACT) for Plasmodium falciparum malaria may be threatened by parasites with reduced responsiveness to artemisinins. Among 298 ACT-treated children from Mbita, Kenya, submicroscopic persistence of P. falciparum on day 3 posttreatment was associated with subsequent microscopically detected parasitemia at days 28 or 42. METHODS DNA sequences of resistance-associated parasite loci pfcrt, pfmdr1, pfubp1, and pfap2mu were determined in the Mbita cohort before treatment, on days 2 and 3 after initiation of treatment, and on the day of treatment failure. RESULTS Parasites surviving ACT on day 2 or day 3 posttreatment were significantly more likely than the baseline population to carry the wild-type haplotypes of pfcrt (CVMNK at codons 72-76; P < .001) and pfmdr1 (NFD at codons 86, 184, 1246; P < .001). In contrast, variant alleles of the novel candidate resistance genes pfap2mu (S160N/T; P = .006) and pfubp-1 (E1528D; P < .001) were significantly more prevalent posttreatment. No genetic similarities were found to artemisinin-tolerant parasites recently described in Cambodia. CONCLUSIONS Among treated children in western Kenya, certain P. falciparum genotypes defined at pfcrt, pfmdr1, pfap2mu, and pfubp1 more often survive ACT at the submicroscopic level, and contribute to onward transmission and subsequent patent recrudescence.
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Affiliation(s)
- Gisela Henriques
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Rachel L Hallett
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Khalid B Beshir
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Nahla B Gadalla
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Rachel E Johnson
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Rebekah Burrow
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Donelly A van Schalkwyk
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Patrick Sawa
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point
| | | | - Taane G Clark
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Teun Bousema
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Colin J Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
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96
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Mawili-Mboumba D, Bouyou-Akotet M, Kombila M. Submicroscopic infections among children with adequate clinical and parasitological response (ACPR). Acta Trop 2014; 134:29-32. [PMID: 24561075 DOI: 10.1016/j.actatropica.2014.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 12/04/2013] [Accepted: 01/20/2014] [Indexed: 11/24/2022]
Abstract
The aim of the study was to re-assess the treatment outcomes of Gabonese children, treated with sulfadoxine-pyrimethamine (SP) and artesunate-mefloquine (AM) and categorized by microscopy as adequate clinical and parasitological response (ACPR), using polymerase chain reaction (PCR). Dried blood spots were collected at day 0 and day 28 and stevor gene amplification was performed to detect Plasmodium falciparum infections. Plasmodial DNA was found in 27.5% (n=19/69) of the isolates collected at day 28; this proportion was 34.3% (n=12/35) in the SP group and 20.6% (n=7/34) in the AM group. This study underlines the need of an accurate and more appropriate technique such as PCR to evaluate antimalarial drug efficacy during clinical trials.
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97
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Detection of persistent Plasmodium spp. infections in Ugandan children after artemether-lumefantrine treatment. Parasitology 2014; 141:1880-90. [PMID: 24837880 PMCID: PMC4255323 DOI: 10.1017/s003118201400033x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
During a longitudinal study investigating the dynamics of malaria in Ugandan lakeshore communities, a consistently high malaria prevalence was observed in young children despite regular treatment. To explore the short-term performance of artemether-lumefantrine (AL), a pilot investigation into parasite carriage after treatment(s) was conducted in Bukoba village. A total of 163 children (aged 2–7 years) with a positive blood film and rapid antigen test were treated with AL; only 8·7% of these had elevated axillary temperatures. On day 7 and then on day 17, 40 children (26·3%) and 33 (22·3%) were positive by microscopy, respectively. Real-time PCR analysis demonstrated that multi-species Plasmodium infections were common at baseline, with 41·1% of children positive for Plasmodium falciparum/Plasmodium malariae, 9·2% for P. falciparum/ Plasmodium ovale spp. and 8·0% for all three species. Moreover, on day 17, 39·9% of children infected with falciparum malaria at baseline were again positive for the same species, and 9·2% of those infected with P. malariae at baseline were positive for P. malariae. Here, chronic multi-species malaria infections persisted in children after AL treatment(s). Better point-of-care diagnostics for non-falciparum infections are needed, as well as further investigation of AL performance in asymptomatic individuals.
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98
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Wampfler R, Timinao L, Beck HP, Soulama I, Tiono AB, Siba P, Mueller I, Felger I. Novel genotyping tools for investigating transmission dynamics of Plasmodium falciparum. J Infect Dis 2014; 210:1188-97. [PMID: 24771862 DOI: 10.1093/infdis/jiu236] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Differentiation between gametocyte-producing Plasmodium falciparum clones depends on both high levels of stage-specific transcripts and high genetic diversity of the selected genotyping marker obtained by a high-resolution typing method. By analyzing consecutive samples of one host, the contribution of each infecting clone to transmission and the dynamics of gametocyte production in multiclone infections can be studied. METHODS We have evaluated capillary electrophoresis based differentiation of 6 length-polymorphic gametocyte genes. RNA and DNA of 25 µL whole blood from 46 individuals from Burkina Faso were simultaneously genotyped. RESULTS Highest discrimination power was achieved by pfs230 with 18 alleles, followed by pfg377 with 15 alleles. When assays were performed in parallel on RNA and DNA, 85.7% of all pfs230 samples and 59.5% of all pfg377 samples contained at least one matching genotype in DNA and RNA. CONCLUSIONS The imperfect detection in both, DNA and RNA, was identified as major limitation for investigating transmission dynamics, owing primarily to the volume of blood processed and the incomplete representation of all clones in the sample tested. Abundant low-density gametocyte carriers impede clone detectability, which may be improved by analyzing larger volumes and detecting initially sequestered gametocyte clones in follow-up samples.
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Affiliation(s)
- Rahel Wampfler
- Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland
| | - Lincoln Timinao
- Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland Papua New Guinea Institute of Medical Research, Goroka, Eastern Highland Province
| | - Hans-Peter Beck
- Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alfred B Tiono
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Peter Siba
- Papua New Guinea Institute of Medical Research, Goroka, Eastern Highland Province
| | - Ivo Mueller
- Walter and Eliza Hall Institute, Parkville, Victoria, Australia Barcelona Centre for International Health Research (CRESIB), Spain
| | - Ingrid Felger
- Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland
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A quality control program within a clinical trial Consortium for PCR protocols to detect Plasmodium species. J Clin Microbiol 2014; 52:2144-9. [PMID: 24740073 DOI: 10.1128/jcm.00565-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Malaria parasite infections that are only detectable by molecular methods are highly prevalent and represent a potential transmission reservoir. The methods used to detect these infections are not standardized, and their operating characteristics are often unknown. We designed a proficiency panel of Plasmodium spp. in order to compare the accuracy of parasite detection of molecular protocols used by labs in a clinical trial consortium. Ten dried blood spots (DBSs) were assembled that contained P. falciparum, P. vivax, P. malariae, and P. ovale; DBSs contained either a single species or a species mixed with P. falciparum. DBS panels were tested in 9 participating laboratories in a masked fashion. Of 90 tests, 68 (75.6%) were correct; there were 20 false-negative results and 2 false positives. The detection rate was 77.8% (49/63) for P. falciparum, 91.7% (11/12) for P. vivax, 83.3% (10/12) for P. malariae, and 70% (7/10) for P. ovale. Most false-negative P. falciparum results were from samples with an estimated ≤ 5 parasites per μl of blood. Between labs, accuracy ranged from 100% to 50%. In one lab, the inability to detect species in mixed-species infections prompted a redesign and improvement of the assay. Most PCR-based protocols were able to detect P. falciparum and P. vivax at higher densities, but these assays may not reliably detect parasites in samples with low P. falciparum densities. Accordingly, formal quality assurance for PCR should be employed whenever this method is used for diagnosis or surveillance. Such efforts will be important if PCR is to be widely employed to assist malaria elimination efforts.
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100
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Maltha J, Guiraud I, Lompo P, Kaboré B, Gillet P, Van Geet C, Tinto H, Jacobs J. Accuracy of PfHRP2 versus Pf-pLDH antigen detection by malaria rapid diagnostic tests in hospitalized children in a seasonal hyperendemic malaria transmission area in Burkina Faso. Malar J 2014; 13:20. [PMID: 24418119 PMCID: PMC3896846 DOI: 10.1186/1475-2875-13-20] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/28/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In most sub-Saharan African countries malaria rapid diagnostic tests (RDTs) are now used for the diagnosis of malaria. Most RDTs used detect Plasmodium falciparum histidine-rich protein-2 (PfHRP2), though P. falciparum-specific parasite lactate dehydrogenase (Pf-pLDH)-detecting RDTs may have advantages over PfHRP2-detecting RDTs. Only few data are available on the use of RDTs in severe illness and the present study compared Pf-pLDH to PfHRP2-detection. METHODS Hospitalized children aged one month to 14 years presenting with fever or severe illness were included over one year. Venous blood samples were drawn for malaria diagnosis (microscopy and RDT), culture and complete blood count. Leftovers were stored at -80 °C and used for additional RDT analysis and PCR. An RDT targeting both PfHRP2 and Pf-pLDH was performed on all samples for direct comparison of diagnostic accuracy with microscopy as reference method. PCR was performed to explore false-positive RDT results. RESULTS In 376 of 694 (54.2%) included children, malaria was microscopically confirmed. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value were 100.0, 70.9, 69.4 and 100.0%, respectively for PfHRP2-detection and 98.7, 94.0, 91.6 and 99.1%, respectively for Pf-pLDH-detection. Specificity and PPV were significantly lower for PfHRP2-detection (p <0.001). For both detection antigens, specificity was lowest for children one to five years and in the rainy season. PPV for both antigens was highest in the rainy season, because of higher malaria prevalence. False positive PfHRP2 results were associated with prior anti-malarial treatment and positive PCR results (98/114 (86.0%) samples tested). CONCLUSION Among children presenting with severe febrile illness in a seasonal hyperendemic malaria transmission area, the present study observed similar sensitivity but lower specificity and PPV of PfHRP2 compared to Pf-pLDH-detection. Further studies should assess the diagnostic accuracy and safety of an appropriate Pf-pLDH-detecting RDT in field settings and if satisfying, replacement of PfHRP2 by Pf-pLDH-detecting RDTs should be considered.
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Affiliation(s)
- Jessica Maltha
- Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, B 2000, Antwerp, Belgium.
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