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Mukhongo HN, Kinyua JK, Weldemichael YG, Kasili RW. Screening for antifolate and artemisinin resistance in Plasmodium falciparum dried-blood spots from three hospitals of Eritrea. F1000Res 2024; 10:628. [PMID: 38840941 PMCID: PMC11150900 DOI: 10.12688/f1000research.54195.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/11/2024] [Indexed: 06/07/2024] Open
Abstract
Background Antimalarial drug resistance is a major challenge hampering malaria control and elimination. About three-quarters of Eritrea's population resides in the malaria-endemic western lowlands of the country. Plasmodium falciparum, the leading causative parasite species, has developed resistance to basically all antimalarials. Continued surveillance of drug resistance using genetic markers provides important molecular data for treatment policies which complements clinical studies, and strengthens control efforts. This study sought to genotype point mutations associated with P. falciparum resistance to sulfadoxine-pyrimethamine and artemisinin, in dried-blood spots from three hospitals in the western lowlands of Eritrea. Methods Dried-blood spot samples were collected from patients visiting Adi Quala, Keren and Gash Barka Hospitals, between July and October, 2014. The patients were followed up after treatment with first line artesunate-amodiaquine, and dried-blood spots were collected on day three after treatment. Nested polymerase chain reaction and Sanger sequencing techniques were employed to genotype point mutations in the Pfdhfr (PF3D7_0417200), Pfdhps (PF3D7_0810800) and PfK13 (PF3D7_1343700) partial gene regions. Results Sequence data analyses of PCR-positive isolates found wild-type artemisinin haplotypes associated with resistance (Y493Y, R539R, I543I) in three isolates, whereas four mutant antifolate haplotypes associated with resistance were observed in six isolates. These included the triple-mutant Pfdhfr (S108N, C59R, N51I) haplotype, the double-mutant Pfdhfr (N51I, S108N) haplotype, the single-mutant Pfdhfr (K540E) haplotype, and the mixed-mutant Pfdhfr-Pfdhps (S108N, N51I + K540E) haplotype. Other findings observed were, a rare non-synonymous Pfdhfr V45A mutation in four isolates, and a synonymous Pfdhps R449R in one isolate. Conclusions The mutant antifolate haplotypes observed indicate a likely existence of full SP resistance. Further studies can be carried out to estimate the prevalence of SP resistance. The wild-type artemisinin haplotypes observed suggest artemisinin is still an effective treatment. Continuous monitoring of point mutations associated with delayed parasite clearance in ART clinical studies is recommended.
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Affiliation(s)
- Harriet Natabona Mukhongo
- College of Health Sciences; Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Juja, P.O. Box 62000-00200, Nairobi, Kenya
| | - Johnson Kang'ethe Kinyua
- College of Health Sciences; Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Juja, P.O. Box 62000-00200, Nairobi, Kenya
| | - Yishak Gebrekidan Weldemichael
- College of Science; Department of Biology, Eritrea Institute of Technology, Asmara, P.O. Box 12676, Mai-Nefhi, Asmara, Eritrea
| | - Remmy Wekesa Kasili
- Institute of Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Juja, P.O. Box 62000-00200, Nairobi, Kenya
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Oboh MA, Asmorom N, Falade C, Ojurongbe O, Thomas BN. High genetic and haplotype diversity in vaccine candidate Pfceltos but not Pfrh5 among malaria-infected children in Ibadan, Nigeria. PeerJ 2023; 11:e16519. [PMID: 38099304 PMCID: PMC10720411 DOI: 10.7717/peerj.16519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 11/03/2023] [Indexed: 12/17/2023] Open
Abstract
Malaria remains a global public health challenge. The disease has a great impact in sub-Saharan Africa among children under five years of age and pregnant women. Malaria control programs targeting the parasite and mosquitoes vectors with combinational therapy and insecticide-treated bednets are becoming obsolete due to the phenomenon of resistance, which is a challenge for reducing morbidity and mortality. Malaria vaccines would be effective alternative to the problem of parasite and insecticide resistance, but focal reports of polymorphisms in malaria candidate antigens have made it difficult to design an effective malaria vaccine. Therefore, studies geared towards elucidating the polymorphic pattern and how genes targeted for vaccine design evolve are imperative. We have carried out molecular and genetic analysis of two genes encoding vaccine candidates-the Plasmodium falciparum cell traversal ookinetes and sporozoites (Pfceltos) and P. falciparum reticulocyte binding protein 5 (Pfrh5) in parasite isolates from malaria-infected children in Ibadan, Nigeria to evaluate their genetic diversity, relatedness and pattern of molecular evolution. Pfceltos and Pfrh5 genes were amplified from P. falciparum positive samples. Amplified fragments were purified and sequenced using the chain termination method. Post-sequence edit of fragments and application of various population genetic analyses was done. We observed a higher number of segregating sites and haplotypes in the Pfceltos than in Pfrh5 gene, the former also presenting higher haplotype (0.942) and nucleotide diversity (θ = 0.01219 and π = 0.01148). In contrast, a lower haplotype (0.426) and nucleotide diversity (θ = 0.00125; π = 0.00095) was observed in the Pfrh5 gene. Neutrality tests do not show deviation from neutral expectations for Pfceltos, with the circulation of multiple low frequency haplotypes (Tajima's D = -0.21637; Fu and Li's D = -0.08164; Fu and Li's F = -0.14051). Strong linkage disequilibrium was observed between variable sites, in each of the genes studied. We postulate that the high diversity and circulation of multiple haplotypes has the potential of making a Pfceltos-subunit vaccine ineffective, while the low genetic diversity of Pfrh5 gene substantiates its evolutionary conservation and potential as a malaria vaccine candidate.
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Affiliation(s)
- Mary Aigbiremo Oboh
- Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Naemy Asmorom
- Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Catherine Falade
- Pharmacology and Therapeutics, University of Ibadan, Ibadan, Oyo, Nigeria
| | - Olusola Ojurongbe
- Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomosho, Osun, Nigeria
- Centre for Emerging and Re-emerging Infectious Diseases, Ladoke Akintola University of Technology, Ogbomosho, Oyo, Nigeria
| | - Bolaji N. Thomas
- Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
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Ndiaye YD, Wong W, Thwing J, Schaffner SS, Tine A, Diallo MA, Deme A, Sy M, Bei AK, Thiaw AB, Daniels R, Ndiaye T, Gaye A, Ndiaye IM, Toure M, Gadiaga N, Sene A, Sow D, Garba MN, Yade MS, Dieye B, Diongue K, Zoumarou D, Ndiaye A, Gomis J, Fall FB, Ndiop M, Diallo I, Sene D, Macinnis B, Seck MC, Ndiaye M, Badiane AS, Hartl DL, Volkman SK, Wirth DF, Ndiaye D. Two decades of molecular surveillance in Senegal reveal changes in known drug resistance mutations associated with historical drug use and seasonal malaria chemoprevention. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.04.24.23288820. [PMID: 37163114 PMCID: PMC10168519 DOI: 10.1101/2023.04.24.23288820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Drug resistance in Plasmodium falciparum is a major threat to malaria control efforts. We analyzed data from two decades (2000-2020) of continuous molecular surveillance of P. falciparum parasite strains in Senegal to determine how historical changes in drug administration policy may have affected parasite evolution. We profiled several known drug resistance markers and their surrounding haplotypes using a combination of single nucleotide polymorphism (SNP) molecular surveillance and whole-genome sequence (WGS) based population genomics. We observed rapid changes in drug resistance markers associated with the withdrawal of chloroquine and introduction of sulfadoxine-pyrimethamine in 2003. We also observed a rapid increase in Pfcrt K76T and decline in Pfdhps A437G starting in 2014, which we hypothesize may reflect changes in resistance or fitness caused by seasonal malaria chemoprevention (SMC). Parasite populations evolve rapidly in response to drug use, and SMC preventive efficacy should be closely monitored.
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Affiliation(s)
- Yaye Die Ndiaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Wesley Wong
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA, 02115, USA
| | - Julie Thwing
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA ,30329, USA
| | - Stephen S Schaffner
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA
| | - Abdoulaye Tine
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Mamadou Alpha Diallo
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Awa Deme
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Mouhammad Sy
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Amy K Bei
- Yale School of Public Health, 60 College St, New Haven, CT 06510
| | - Alphonse B Thiaw
- Department of biochemistry and Functional Genomics, Sherbrooke University, 2500 Bd de l'Universite, Sherbrooke, QC J1K 2R1, Canada
| | - Rachel Daniels
- RNA Therapeutics Institute, UMass Chan Medical School, 368 Plantation Street, Worcester MA 01605
| | - Tolla Ndiaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Amy Gaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Ibrahima Mbaye Ndiaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Mariama Toure
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Nogaye Gadiaga
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Aita Sene
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Djiby Sow
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Mamane N Garba
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Mamadou Samba Yade
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Baba Dieye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Khadim Diongue
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Daba Zoumarou
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Aliou Ndiaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Jules Gomis
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Fatou Ba Fall
- Yale School of Public Health, 60 College St, New Haven, CT 06510
| | - Medoune Ndiop
- National Malaria Control Program (NMCP), Rue FN 20, Dakar 25270, Senegal
| | - Ibrahima Diallo
- National Malaria Control Program (NMCP), Rue FN 20, Dakar 25270, Senegal
| | - Doudou Sene
- National Malaria Control Program (NMCP), Rue FN 20, Dakar 25270, Senegal
| | - Bronwyn Macinnis
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA
| | - Mame Cheikh Seck
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Mouhamadou Ndiaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Aida S Badiane
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138 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 University, 300 The Fenway, Boston, MA, 02115, USA
| | - 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
| | - Daouda Ndiaye
- International Research Training Center on Genomics and Health Surveillance (CIGASS), Cheikh Anta Diop University, Dakar, 16477, Senegal
- 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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Rana R, Khan N, Sandeepta S, Pati S, Das A, Bal M, Ranjit M. Molecular surveillance of anti-malarial drug resistance genes in Plasmodium falciparum isolates in Odisha, India. Malar J 2022; 21:394. [PMID: 36566182 PMCID: PMC9790123 DOI: 10.1186/s12936-022-04403-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/25/2022] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Despite significant progress in eliminating malaria from the state of Odisha, India, the disease is still considered endemic. Artesunate plus sulfadoxine-pyrimethamine (AS + SP) has been introduced since 2010 as first-line treatment for uncomplicated Plasmodium falciparum malaria. This study aimed to investigate the prevalence of mutations associated with resistance to chloroquine (CQ), sulfadoxine-pyrimethamine (SP), and artesunate (ART) in P. falciparum parasites circulating in the state. METHODS A total of 239 isolates of P. falciparum mono infection were collected during July 2018-November 2020 from the four different geographical regions of the state. Genomic DNA was extracted from 200 µL of venous blood and amplified using nested polymerase chain reaction. Mutations on gene associated with CQ (Pfcrt and Pfmdr1) were assessed by PCR amplification and restriction fragment length polymorphism, artemisinin (Pfk13) gene by DNA sequencing and SP (Pfdhfr and Pfdhps) genes by allele-specific polymerase chain reaction (AsPCR). RESULTS The point mutation in Pfcrt (K76T) was detected 2.1%, in Pfmdr1 (N86Y) 3.4%, and no mutations were found in Pfkelch13 propeller domain. Prevalence of Pfdhfr, Pfdhps and Pfhdfr-Pfdhps (two locus) gene mutations were 50.43%, 47.05% and 49.79% respectively. The single, double, triple and quadruple point mutations in Pfdhfr gene was 11.2%, 8.2%, 17.2% and 3.4% while, in Pfdhps gene was 10.9%,19.5%, 9.5% and 2.7% respectively. Of the total 13 haplotypes found in Pfdhfr, 8 were detected for the first time in the state and of the total 26 haplotypes found in Pfdhps, 7 were detected for the fisrt time in the state. The linked quintuple mutation Pfdhfr (N51I-C59R-S108N)-Pfdhps (A437G-K540E) responsible for clinical failure (RIII level of resistance) of SP resistance and A16V-S108T mutation in Pfdhfr responsible for cycloguanil was absent. CONCLUSION The study has demonstrated a low prevalence of CQ resistance alleles in the study area. Despite the absence of the Pfkelch13 mutations, high prevalence of Pfdhfr and Pfdhps point mutations undermine the efficacy of SP partner drug, thereby threatening the P. falciparum malaria treatment policy. Therefore, continuous molecular and in vivo monitoring of ACT efficacy is warranted in Odisha.
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Affiliation(s)
- Ramakanta Rana
- grid.415796.80000 0004 1767 2364Molecular Epidemiology Laboratory, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha 751023 India
| | - Nikhat Khan
- grid.452686.b0000 0004 1767 2217Division of Vector-Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, Madhya Pradesh India
| | - Sonali Sandeepta
- grid.415796.80000 0004 1767 2364Molecular Epidemiology Laboratory, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha 751023 India
| | - Sanghamitra Pati
- grid.415796.80000 0004 1767 2364Molecular Epidemiology Laboratory, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha 751023 India
| | - Aparup Das
- grid.452686.b0000 0004 1767 2217Division of Vector-Borne Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, Madhya Pradesh India
| | - Madhusmita Bal
- grid.415796.80000 0004 1767 2364Molecular Epidemiology Laboratory, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha 751023 India
| | - Manoranjan Ranjit
- grid.415796.80000 0004 1767 2364Molecular Epidemiology Laboratory, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha 751023 India
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Oboh MA, Isaac C, Schroeter MN, Morenikeji OB, Amambua-Ngwa A, Meremikwu MM, Thomas BN. Population genetic analysis of Plasmodium falciparum cell-traversal protein for ookinetes and sporozoite among malaria patients from southern Nigeria. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 105:105369. [PMID: 36182066 DOI: 10.1016/j.meegid.2022.105369] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/12/2022] [Accepted: 09/20/2022] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum immune escape mechanisms affect antigens being prioritized for vaccine design. As a result of the multiple surface antigens the parasite exhibits at different life cycle stages, designing a vaccine that would efficiently boost the immune system in clearing infections has been challenging. The P. falciparum cell-traversal protein for ookinetes and sporozoite (Pfceltos) is instrumental for ookinete traversal of the mosquito midgut and sporozoites invasion of the human liver cells. Pfceltos elicits both humoral and cellular immune response but has been reported with multiple single nucleotide polymorphisms in global isolates. A cross-sectional survey, conducted in southern Nigeria, between January-March 2021 recruited 283 individuals. Of this, 166 demonstrated P. falciparum infections (86 from Cross River and 80 from Edo), 48 (55.8%) while only 36 (45%) were amplified for Pfceltos gene from both sites respectively. Fifty amplified samples were sequenced and analysed for their diversity, polymorphisms and population structure of the gene. The number of segregating sites in Edo State was higher (34) than that of Cross River State. Though nucleotide diversity was higher for Edo compared to Cross River State (θw = 0.02505; π = 0.03993 versus θw = 0.00930; π = 0.01033 respectively), the reverse was the case for haplotype diversity (0.757 versus 0.890 for Edo and Cross River respectively). Of the twelve haplotypes observed from both states, only two (KASLPVEK and NAFLSFEK) were shared, with haplotype prevalence higher in Edo (16% and 36%) than Cross River (8% and 4%). The Tajima's D test was positive for both states, with Fst value showing a strong genetic differentiation (Fst = 0.25599), indicating the occurrence of balancing selection favoring haplotype circulation at a low frequency. The shared haplotypes, low Hst and Fst values presents a challenge to predict the extent of gene flow. High LD values present a grim public health consequence should a Pfceltos-conjugated vaccine be considered for prophylaxis in Nigeria.
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Affiliation(s)
- Mary A Oboh
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America.
| | - Clement Isaac
- Department of Zoology, Faculty of Life Sciences, Ambrose Ali University, Ekpoma, Nigeria
| | - Marissa N Schroeter
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Olanrewaju B Morenikeji
- Division of Biological and Health Sciences, University of Pittsburgh, Bradford, PA 16701, United States of America
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, the Gambia
| | - Martin M Meremikwu
- University of Calabar Teaching Hospital, Calabar, Cross River State, Nigeria
| | - Bolaji N Thomas
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America.
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Myers-Hansen JL, Abuaku B, Oyebola MK, Mensah BA, Ahorlu C, Wilson MD, Awandare G, Koram KA, Ngwa AA, Ghansah A. Assessment of antimalarial drug resistant markers in asymptomatic Plasmodium falciparum infections after 4 years of indoor residual spraying in Northern Ghana. PLoS One 2020; 15:e0233478. [PMID: 33284800 PMCID: PMC7721464 DOI: 10.1371/journal.pone.0233478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 08/18/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Drug resistance remains a concern for malaria control and elimination. The effect of interventions on its prevalence needs to be monitored to pre-empt further selection. We assessed the prevalence of Plasmodium falciparum gene mutations associated with resistance to the antimalarial drugs: sulfadoxine-pyrimethamine (SP), chloroquine (CQ) and artemisinin combination therapy (ACTs) after the scale-up of a vector control activity that reduced transmission. METHODS A total of 400 P. falciparum isolates from children under five years were genotyped for seventeen single nucleotide polymorphisms (SNPs) in pfcrt, pfmdr1, pfdhfr, pfdhps and pfk13 genes using polymerase chain reaction (PCR) and high resolution melting (HRM) analysis. These included 80 isolates, each randomly selected from cross-sectional surveys of asymptomatic infections across 2010 (baseline), 2011, 2012, 2013 (midline: post-IRS) and 2014 (endline: post-IRS) during the peak transmission season, when IRS intervention was rolled out in Bunkpurugu Yunyoo (BY) District, Ghana. The proportions of isolates with drug resistant alleles were assessed over this period. RESULTS There were significant decreases in the prevalence of pfdhfr- I51R59N108 haplotype from 2010 to 2014, while the decline in pfdhfr/pfdhps- I51R59N108G437 during the same period was not significant. The prevalence of lumefantrine (LM), mefloquine (MQ) and amodiaquine (AQ) resistance-associated haplotypes pfmdr1-N86F184D1246 and pfmdr1-Y86Y184Y1246 showed decreasing trends (z = -2.86, P = 0.004 and z = -2.71, P = 0.007, respectively). Each of pfcrt-T76 and pfmdr1-Y86 mutant alleles also showed a declining trend in the asymptomatic reservoir, after the IRS rollout in 2014 (z = -2.87, P = 0.004 and z = -2.65, P = 0.008, respectively). Similarly, Pyrimethamine resistance mediating polymorphisms pfdhfr-N108, pfdhfr-I51 and pfdhfr-R59 also declined (z = -2.03, P = 0.042, z = -3.54, P<0.001 and z = -4.63, P<0.001, respectively), but not the sulphadoxine resistance mediating pfdhps-G437 and pfdhps-F436 (z = -0.36, P = 0.715 and z = 0.41, P = 0.684, respectively). No mutant pfk13-Y580 were detected during the study period. CONCLUSION The study demonstrated declining trends in the prevalence of drug resistant mutations in asymptomatic P. falciparum infections following transmission reduction after an enhanced IRS intervention in Northern Ghana.
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Affiliation(s)
| | - Benjamin Abuaku
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Muyiwa K. Oyebola
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Benedicta A. Mensah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Collins Ahorlu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Michael D. Wilson
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Gordon Awandare
- West African Center for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Kwadwo A. Koram
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - Anita Ghansah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
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Walter EA, Jerome A, Marceline DN, Yakum MN, Pierre W. Map of biomedical research in Cameroon; a documentary review of approved protocols from 1997 to 2012. Global Health 2017; 13:85. [PMID: 29157285 PMCID: PMC5697116 DOI: 10.1186/s12992-017-0312-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 11/09/2017] [Indexed: 11/24/2022] Open
Abstract
Background Over the last decade, there has been a rapid increase in biomedical research in Cameroon. However, the question of whether these research projects target major health priorities, vulnerable populations and geographic locations at risk remains to be answered. The aim of this paper is to describe the state of biomedical research in Cameroon which is a key determinant that would guide future health care policies and promote equitable access to healthcare. Methods A documentary review of all approved protocols (proposals) of biomedical research projects, from 1997 through 2012, at the Cameroon National Ethics Committee. Protocols were reviewed systematically by independent reviewers and data were extracted on a grid. Data were analyzed by calculating proportions at 95% confidence interval, chi-square test (chi2) and p-values. Results Two thousand one hundred seventy two protocols were reviewed for data extraction. One thousand three hundred ninety-five (64.7%) were student projects, 369 (17.0%) projects had international sponsors, and 1528 (72.4%) were hospital-based studies. The most targeted domain was the fight against diseases 1323 (61.3%); mostly HIV 342 (25.8%) and Malaria 136 (10.3%). Over half of the studies were concentrated in the Centre region 1242 (57.2%), with the least projects conducted in the Northern region 15 (0.7%). There was strong evidence that international and local sponsors would influence the research site (p-value = 0.01) and population targets (p-value = 0.00). Conclusion Although biomedical research targets some important diseases that pose a great burden to Cameroonians, the most vulnerable populations are excluded from research. Biomedical research scarcely addresses other components of the health system and emerging diseases of vital public health importance. We recommend that the government should play a central role, between researchers from academic institutions, sponsors, NGOs and research institutions, to ensure that biomedical research addresses the health priorities of Cameroonians. It should include vulnerable populations, and address other components of the health system for a balance. These recommendations are critical to ensuring that future research informed health policies reflect the health needs of the populations and promote equity in healthcare access. Electronic supplementary material The online version of this article (10.1186/s12992-017-0312-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ebile Akoh Walter
- Department of Biomedical Sciences, University of Dschang, Dschang, Cameroon. .,M.A. SANTE (Meilleure Access aux soins de Santé), P.O. Box 33490, Yaoundé, Cameroon.
| | - Ateudjieu Jerome
- Department of Biomedical Sciences, University of Dschang, Dschang, Cameroon.,Division of Health Operations Research, Ministry of Public Health, Yaoundé, Cameroon.,M.A. SANTE (Meilleure Access aux soins de Santé), P.O. Box 33490, Yaoundé, Cameroon
| | - Djuidje Ngounoue Marceline
- Department of Biochemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.,Research and Health Ethics Committee in Central Africa "Comité d'Ethique de la Recherche et de la Santé en Afrique Centrale (CERSAC), Yaoundé, Cameroon
| | - Martin Ndinakie Yakum
- Department of Biomedical Sciences, University of Dschang, Dschang, Cameroon.,M.A. SANTE (Meilleure Access aux soins de Santé), P.O. Box 33490, Yaoundé, Cameroon
| | - Watcho Pierre
- Department of Biomedical Sciences, University of Dschang, Dschang, Cameroon
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8
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Mbaye A, Gaye A, Dieye B, Ndiaye YD, Bei AK, Affara M, Deme AB, Yade MS, Diongue K, Ndiaye IM, Ndiaye T, Sy M, Sy N, Koita O, Krogstad DJ, Volkman S, Nwakanma D, Ndiaye D. Ex vivo susceptibility and genotyping of Plasmodium falciparum isolates from Pikine, Senegal. Malar J 2017; 16:250. [PMID: 28615016 PMCID: PMC5471902 DOI: 10.1186/s12936-017-1897-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/06/2017] [Indexed: 01/21/2023] Open
Abstract
Background The monitoring of Plasmodium falciparum sensitivity to anti-malarial drugs is a necessity for effective case management of malaria. This species is characterized by a strong resistance to anti-malarial drugs. In Senegal, the first cases of chloroquine resistance were reported in the Dakar region in 1988 with nearly 7% population prevalence, reaching 47% by 1990. It is in this context that sulfadoxine–pyrimethamine temporarily replaced chloroquine as first line treatment in 2003, pending the introduction of artemisinin-based combination therapy in 2006. The purpose of this study is to assess the ex vivo sensitivity to different anti-malarial drugs of the P. falciparum population from Pikine. Methods Fifty-four samples were collected from patients with non-complicated malaria and aged between 2 and 20 years in the Deggo health centre in Pikine in 2014. An assay in which parasites are stained with 4′, 6-di-amidino-2-phenylindole (DAPI), was used to study the ex vivo sensitivity of isolates to chloroquine, amodiaquine, piperaquine, pyrimethamine, and dihydroartemisinin. High resolution melting was used for genotyping of pfdhps, pfdhfr, pfmdr1, and pfcrt genes. Results The mean IC50s of chloroquine, amodiaquine, piperaquine, dihydroartemisinin, and pyrimethamine were, respectively, 39.44, 54.02, 15.28, 2.23, and 64.70 nM. Resistance mutations in pfdhfr gene, in codon 437 of pfdhps gene, and an absence of mutation at position 540 of pfdhps were observed. Mutations in codons K76T of pfcrt and N86Y of pfmdr1 were observed at 51 and 11% population prevalence, respectively. A relationship was found between the K76T and N86Y mutations and ex vivo resistance to chloroquine. Conclusion An increase in sensitivity of isolates to chloroquine was observed. A high sensitivity to dihydroartemisinin was observed; whereas, a decrease in sensitivity to pyrimethamine was observed in the parasite population from Pikine.
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Affiliation(s)
- Aminata Mbaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.
| | - Amy Gaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Baba Dieye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Yaye D Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy K Bei
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Muna Affara
- Medical Research Council Unit, The Gambia, Fajara, Gambia
| | - Awa B Deme
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mamadou S Yade
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Khadim Diongue
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ibrahima M Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Tolla Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamed Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ngayo Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | | | | | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Davis Nwakanma
- Medical Research Council Unit, The Gambia, Fajara, Gambia
| | - Daouda Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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9
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Ndiaye YD, Diédhiou CK, Bei AK, Dieye B, Mbaye A, Mze NP, Daniels RF, Ndiaye IM, Déme AB, Gaye A, Sy M, Ndiaye T, Badiane AS, Ndiaye M, Premji Z, Wirth DF, Mboup S, Krogstad D, Volkman SK, Ahouidi AD, Ndiaye D. High resolution melting: a useful field-deployable method to measure dhfr and dhps drug resistance in both highly and lowly endemic Plasmodium populations. Malar J 2017; 16:153. [PMID: 28420422 PMCID: PMC5395743 DOI: 10.1186/s12936-017-1811-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 04/08/2017] [Indexed: 11/18/2022] Open
Abstract
Background Emergence and spread of drug resistance to every anti-malarial used to date, creates an urgent need for development of sensitive, specific and field-deployable molecular tools for detection and surveillance of validated drug resistance markers. Such tools would allow early detection of mutations in resistance loci. The aim of this study was to compare common population signatures and drug resistance marker frequencies between two populations with different levels of malaria endemicity and history of anti-malarial drug use: Tanzania and Sénégal. This was accomplished by implementing a high resolution melting assay to study molecular markers of drug resistance as compared to polymerase chain reaction–restriction fragment length polymorphism (PCR/RFLP) methodology. Methods Fifty blood samples were collected each from a lowly malaria endemic site (Sénégal), and a highly malaria endemic site (Tanzania) from patients presenting with uncomplicated Plasmodium falciparum malaria at clinic. Data representing the DHFR were derived using both PCR–RFLP and HRM assay; while genotyping data representing the DHPS were evaluated in Senegal and Tanzania using HRM. Msp genotyping analysis was used to characterize the multiplicity of infection in both countries. Results A high prevalence of samples harbouring mutant DHFR alleles was observed in both population using both genotyping techniques. HRM was better able to detect mixed alleles compared to PCR/RFLP for DHFR codon 51 in Tanzania; and only HRM was able to detect mixed infections from Senegal. A high prevalence of mutant alleles in DHFR (codons 51, 59, 108) and DHPS (codon 437) were found among samples from Sénégal while no mutations were observed at DHPS codons 540 and 581, from both countries. Overall, the frequency of samples harbouring either a single DHFR mutation (S108N) or double mutation in DHFR (C59R/S108N) was greater in Sénégal compared to Tanzania. Conclusion Here the results demonstrate that HRM is a rapid, sensitive, and field-deployable alternative technique to PCR–RFLP genotyping that is useful in populations harbouring more than one parasite genome (polygenomic infections). In this study, a high levels of resistance polymorphisms was observed in both dhfr and dhps, among samples from Tanzania and Sénégal. A routine monitoring by molecular markers can be a way to detect emergence of resistance involving a change in the treatment policy.
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Affiliation(s)
- Yaye Dié Ndiaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal. .,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal.
| | - Cyrille K Diédhiou
- Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal
| | - Amy K Bei
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.,Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.,Department of Parasitology and Medical Entomology, Muhimbili University College of Health Sciences, Dar-es-Salaam, Tanzania.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA
| | - Baba Dieye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
| | - Aminata Mbaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Nasserdine Papa Mze
- Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal
| | - Rachel F Daniels
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA.,Infectious Disease Initiative, The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Ibrahima M Ndiaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Awa B Déme
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
| | - Amy Gaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Mouhamad Sy
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Tolla Ndiaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal
| | - Aida S Badiane
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
| | - Mouhamadou Ndiaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
| | - Zul Premji
- Department of Parasitology and Medical Entomology, Muhimbili University College of Health Sciences, Dar-es-Salaam, Tanzania.,Department of Pathology, Aga Khan University Hospital, Nairobi, Kenya
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA.,Infectious Disease Initiative, The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Souleymane Mboup
- Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal
| | - Donald Krogstad
- Tulane University, New Orleans, LA, USA.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
| | - Sarah K Volkman
- The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA.,Infectious Disease Initiative, The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,School of Nursing and Health Sciences, Simmons College, Boston, MA, 02115, USA
| | - Ambroise D Ahouidi
- Laboratory of Bacteriology and Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
| | - Daouda Ndiaye
- Laboratory of Parasitology Mycology, Aristide le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.,The International Centers of Excellence for Malaria Research (ICEMR) Program, Dakar, Senegal
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10
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Boussaroque A, Fall B, Madamet M, Wade KA, Fall M, Nakoulima A, Fall KB, Dionne P, Benoit N, Diatta B, Diemé Y, Wade B, Pradines B. Prevalence of anti-malarial resistance genes in Dakar, Senegal from 2013 to 2014. Malar J 2016; 15:347. [PMID: 27387549 PMCID: PMC4937610 DOI: 10.1186/s12936-016-1379-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 06/08/2016] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND To determine the impact of the introduction of artemisinin-based combination therapy (ACT) on parasite susceptibility, a molecular surveillance for antimalarial drug resistance was conducted on local isolates from the Hôpital Principal de Dakar between November 2013 and January 2014 and between August 2014 and December 2014. METHODS The prevalence of genetic polymorphisms in antimalarial resistance genes (pfcrt, pfmdr1, pfdhfr and pfdhps) was evaluated in 103 isolates. RESULTS The chloroquine-resistant haplotypes CVIET and CVMET were identified in 31.4 and 3.9 % of the isolates, respectively. The frequency of the pfcrt K76T mutation was increased from 29.3 % in 2013-2014 to 43.2 % in 2014. The pfmdr1 N86Y and Y184F mutations were identified in 6.1 and 53.5 % of the isolates, respectively. The pfdhfr triple mutant (S108N, N51I and C59R) was detected in the majority of the isolates (82.3 %). The prevalence of quadruple mutants (pfdhfr S108N, N51I, C59R and pfdhps A437G) was 40.4 %. One isolate (1.1 %) harboured the pfdhps mutations A437G and K540E and the pfdhfr mutations S108N, N51I and C59R. CONCLUSIONS Despite a decline in the prevalence of chloroquine resistance due to the official withdrawal of the drug and to the introduction of ACT, the spread of resistance to chloroquine has continued. Furthermore, susceptibility to amodiaquine may be decreased as a result of cross-resistance. The frequency of the pfmdr1 mutation N86Y declined while the Y184F mutation increased in prevalence, suggesting that selective pressure is acting on pfmdr1, leading to a high prevalence of mutations in these isolates and the lack of specific mutations. The 50.5 % prevalence of the pfmdr1 polymorphisms N86Y and Y184F suggests a decrease in lumefantrine susceptibility. Based on these results, intensive surveillance of ACT partner drugs must be conducted regularly in Senegal.
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Affiliation(s)
- Agathe Boussaroque
- Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Brétigny Sur Orge, France
| | - Bécaye Fall
- Laboratoire d'étude de la chimiosensibilité du paludisme, Fédération des Laboratoires, Hôpital Principal de Dakar, Dakar, Senegal
| | - Marylin Madamet
- Equipe Résidente de Recherche en Infectiologie Tropicale, Institut de Recherche Biomédicale des Armées, Hôpital d'Instruction des Armées, Marseille, France.,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS 7278, IRD 198, Inserm 1095, Aix Marseille Université, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | | | - Mansour Fall
- Service de Réanimation Médicale, Hôpital Principal de Dakar, Dakar, Senegal
| | | | - Khadidiatou Ba Fall
- Service de Pathologie Infectieuse, Hôpital Principal de Dakar, Dakar, Senegal
| | - Pierre Dionne
- Maternité Hôpital Principal de Dakar, Dakar, Senegal
| | - Nicolas Benoit
- Equipe Résidente de Recherche en Infectiologie Tropicale, Institut de Recherche Biomédicale des Armées, Hôpital d'Instruction des Armées, Marseille, France.,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS 7278, IRD 198, Inserm 1095, Aix Marseille Université, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Bakary Diatta
- Service de Réanimation Médicale, Hôpital Principal de Dakar, Dakar, Senegal.,Chefferie, Hôpital Principal de Dakar, Dakar, Senegal
| | - Yaya Diemé
- Laboratoire d'étude de la chimiosensibilité du paludisme, Fédération des Laboratoires, Hôpital Principal de Dakar, Dakar, Senegal
| | - Boubacar Wade
- Chefferie, Hôpital Principal de Dakar, Dakar, Senegal
| | - Bruno Pradines
- Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Brétigny Sur Orge, France. .,Laboratoire d'étude de la chimiosensibilité du paludisme, Fédération des Laboratoires, Hôpital Principal de Dakar, Dakar, Senegal. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS 7278, IRD 198, Inserm 1095, Aix Marseille Université, Marseille, France. .,Centre National de Référence du Paludisme, Marseille, France.
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11
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Assessment of Markers of Antimalarial Drug Resistance in Plasmodium falciparum Isolates from Pregnant Women in Lagos, Nigeria. PLoS One 2016; 11:e0146908. [PMID: 26808627 PMCID: PMC4726598 DOI: 10.1371/journal.pone.0146908] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 12/23/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The use of antimalarial drugs for prevention and treatment is a major strategy in the prevention of malaria in pregnancy. Although sulphadoxine-pyrimethamine (SP) is currently recommended for intermittent preventive treatment of malaria during pregnancy in Nigeria, previously used drugs for prophylaxis such as chloroquine (CQ) and pyrimethamine are accessible as they are purchased over the counter. This study describes the markers of absence or presence of resistance to quinoline (Pfcrt and Pfmdr 1) and type 1 antifolate antimalarial medicines (Pfdhfr). METHODS Plasmodium falciparum-positive dried blood spots from pregnant women attending antenatal clinics for the first time during current pregnancy were investigated for the presence of mutations at codons 72-76 of Plasmodium falciparum chloroquine resistance transporter (Pfcrt) gene by real time polymerase chain reaction (PCR) using haplotype-specific probes. PCR followed by sequence analysis was used to identify mutations at codons 86, 184, 1034, 1042 and 1246 of P. falciparum multi-drug resistance-1 (Pfmdr1) gene; and codons 16, 50, 51, 59, 108, 140 and 164 of Pfdhfr gene. RESULTS Two haplotypes of Pfcrt (n = 54) were observed: CVMNK 13(24.2%) and CVIET 41 (75.9%) of the samples. The SVMNT haplotype was absent in this population. The Pfmdr1 (n = 28) haplotypes were NYSND 15(53.6%), YYSND 5(17.9%), NFSND 6(21.4%) and YFSND 2(7.1%). The Pfdhfr (n = 15) were ACNCSVI 4(26.7%), and ACICNSVI 1(6.7%) and ACIRNVI 10 (66.7%). The rate of occurrence of Pfcrt 76T, Pfdhfr108N, Pfmdr186Y and 184F were 75.9%, 73.3%, 25% and 28.1% respectively. The Pfmdr1 86Y was associated with low parasitaemia (median = 71 parasites/μl, P = 0.024) while Pfcrt 76T was associated with young maternal age (mean 24.1 ± 4.5 years; P = 0.006). The median parasitaemia were similar (P>0.05) in wild and mutant strains of Pfcrt 76, Pfmdr1 184 and Pfdhfr 108. There was no association between gravidity or gestational age of the women and presence of mutations in the Pfcrt, Pfmdr1 or Pfdhfr genes (P>0.05). CONCLUSION Markers of resistance to chloroquine and pyrimethamine were high, whereas cycloguanil-resistance marker was not present in the studied population. The low level of mutations in the Pfmdr1gene indicates likely efficacy of amodiaquine against malaria in pregnancy.
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12
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Papa Mze N, Ndiaye YD, Diedhiou CK, Rahamatou S, Dieye B, Daniels RF, Hamilton EJ, Diallo M, Bei AK, Wirth DF, Mboup S, Volkman SK, Ahouidi AD, Ndiaye D. RDTs as a source of DNA to study Plasmodium falciparum drug resistance in isolates from Senegal and the Comoros Islands. Malar J 2015; 14:373. [PMID: 26415927 PMCID: PMC4587814 DOI: 10.1186/s12936-015-0861-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/23/2015] [Indexed: 11/29/2022] Open
Abstract
Background The World Health Organization has recommended rapid diagnostic tests (RDTs) for use in the diagnosis of suspected malaria cases. In addition to providing quick and accurate detection of Plasmodium parasite proteins in the blood, these tests can be used as sources of DNA for further genetic studies. As sulfadoxine-pyrimethamine is used currently for intermittent presumptive treatment of pregnant women in both Senegal and in the Comoros Islands, resistance mutations in the dhfr and dhps genes were investigated using DNA extracted from RDTs. Methods The proximal portion of the nitrocellulose membrane of discarded RDTs was used for DNA extraction. This genomic DNA was amplified using HRM to genotype the molecular markers involved in resistance to sulfadoxine-pyrimethamine: dhfr (51, 59, 108, and 164) and dhps (436, 437, 540, 581, and 613). Additionally, the msp1 and msp2 genes were amplified to determine the average clonality between Grande-Comore (Comoros) and Thiès (Senegal). Results A total of 201 samples were successfully genotyped at all codons by HRM; whereas, in 200 msp1 and msp2 genes were successfully amplified and genotyped by nested PCR. A high prevalence of resistance mutations were observed in the dhfr gene at codons 51, 59, and 108 as well as in the dhps gene at codons 437 and 436. A novel mutant in dhps at codon positions 436Y/437A was observed. The dhfr I164L codon and dhps K540 and dhps A581G codons had 100 % wild type alleles in all samples. Conclusion The utility of field-collected RDTs was validated as a source of DNA for genetic studies interrogating frequencies of drug resistance mutations, using two different molecular methods (PCR and High Resolution Melting). RDTs should not be discarded after use as they can be a valuable source of DNA for genetic and epidemiological studies in sites where filter paper or venous blood collected samples are nonexistent. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0861-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nasserdine Papa Mze
- Laboratory of Bacteriology-Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.
| | - Yaye Die Ndiaye
- Laboratoire of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.
| | - Cyrille K Diedhiou
- Laboratory of Bacteriology-Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.
| | - Silai Rahamatou
- Laboratory of National Malaria Control Programme, Moroni, Comoros.
| | - Baba Dieye
- Laboratoire of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.
| | - Rachel F Daniels
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA.
| | - Elizabeth J Hamilton
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA.
| | - Mouhamadou Diallo
- Laboratory of Bacteriology-Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.
| | - Amy K Bei
- Laboratory of Bacteriology-Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal. .,Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA.
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA. .,Broad Institute: The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
| | - Souleymane Mboup
- Laboratory of Bacteriology-Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.
| | - Sarah K Volkman
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA, 02115, USA. .,Broad Institute: The Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA. .,School of Nursing and Health Sciences, Simmons College, Boston, MA, 02115, USA.
| | - Ambroise D Ahouidi
- Laboratory of Bacteriology-Virology, Hospital Aristide Le Dantec, 7325, Dakar, Senegal.
| | - Daouda Ndiaye
- Laboratoire of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, 5005, Dakar, Senegal.
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13
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Emergence of sulfadoxine-pyrimethamine resistance in Indian isolates of Plasmodium falciparum in the last two decades. INFECTION GENETICS AND EVOLUTION 2015; 36:190-198. [PMID: 26319997 DOI: 10.1016/j.meegid.2015.08.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/21/2015] [Accepted: 08/22/2015] [Indexed: 01/15/2023]
Abstract
Genotyping the sulfadoxine-pyrimethamine (SP) genes will help in identifying the genes under drug selection and the emergence of resistance in dhfr and dhps genes. India is an important hotspot for studying malaria due to the immense climatic diversity prevalent in the country. The central and eastern parts of the country are most vulnerable sites where malaria cases are reported throughout the year. From different regions of the country 173 field isolates were genotyped at various loci in dhfr and dhps genes collected between 1994 and 2013. This encompasses the period before antimalarial resistance emerged and the period after the use of combination therapy was made mandatory in the country. We observed the rise of resistant SP alleles from very low frequencies (in the year 1994) to steadily rising (in the year 2000) and maintaining this increasing trend subsequently (in the year 2013) as shown by the sequence analysis of dhfr and dhps genes. This study assessed the prevalence of mutations in dhfr and dhps genes associated with SP resistance in samples indicative of increase in resistance levels of Plasmodium falciparum to SP even after the change in malaria treatment policy in the country.
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Mohapatra PK, Sarma DK, Prakash A, Bora K, Ahmed MA, Sarma B, Goswami BK, Bhattacharyya DR, Mahanta J. Molecular evidence of increased resistance to anti-folate drugs in Plasmodium falciparum in North-East India: a signal for potential failure of artemisinin plus sulphadoxine-pyrimethamine combination therapy. PLoS One 2014; 9:e105562. [PMID: 25184337 PMCID: PMC4153584 DOI: 10.1371/journal.pone.0105562] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/24/2014] [Indexed: 01/16/2023] Open
Abstract
North-east India, being a corridor to South-east Asia, is believed to play an important role in transmitting drug resistant Plasmodium falciparum malaria to India and South Asia. North-east India was the first place in India to record the emergence of drug resistance to chloroquine as well as sulphadoxine/pyrimethamine. Presently chloroquine resistance is widespread all over the North-east India and resistance to other anti-malarials is increasing. In this study both in vivo therapeutic efficacy and molecular assays were used to screen the spectrum of drug resistance to chloroquine and sulphadoxine/pyrimethamine in the circulating P. falciparum strains. A total of 220 P. falciparum positives subjects were enrolled in the study for therapeutic assessment of chloroquine and sulphadoxine/pyrimethamine and assessment of point mutations conferring resistances to these drugs were carried out by genotyping the isolates following standard methods. Overall clinical failures in sulphadoxine/pyrimethamine and chloroquine were found 12.6 and 69.5% respectively, while overall treatment failures recorded were 13.7 and 81.5% in the two arms. Nearly all (99.0%) the isolates had mutant pfcrt genotype (76 T), while 68% had mutant pfmdr-1 genotype (86 Y). Mutation in dhps 437 codon was the most prevalent one while dhfr codon 108 showed 100% mutation. A total of 23 unique haplotypes at the dhps locus and 7 at dhfr locus were found while dhps-dhfr combined loci revealed 49 unique haplotypes. Prevalence of double, triple and quadruple mutations were common while 1 haplotype was found with all five mutated codons (F/AGEGS/T) at dhps locus. Detection of quadruple mutants (51 I/59 R/108 N/164 L) in the present study, earlier recorded from Car Nicobar Island, India only, indicates the presence of high levels of resistance to sulphadoxine/pyrimethamine in north-east India. Associations between resistant haplotypes and the clinical outcomes and emerging resistance in sulphadoxine/pyrimethamine in relation to the efficacy of the currently used artemisinin combination therapy are discussed.
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Affiliation(s)
| | | | - Anil Prakash
- Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India; National Institute for Research in Environmental Health (ICMR), Kamla Nehru Hospital Building, Gandhi Medical College Campus, Bhopal, Madhya Pradesh, India
| | - Khukumoni Bora
- Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India
| | - Md Atique Ahmed
- Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India
| | - Bibhas Sarma
- Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India
| | | | | | - Jagadish Mahanta
- Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India
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Gharbi M, Flegg JA, Pradines B, Berenger A, Ndiaye M, Djimdé AA, Roper C, Hubert V, Kendjo E, Venkatesan M, Brasseur P, Gaye O, Offianan AT, Penali L, Le Bras J, Guérin PJ, Study MOTFNRCFIM. Surveillance of travellers: an additional tool for tracking antimalarial drug resistance in endemic countries. PLoS One 2013; 8:e77775. [PMID: 24204960 PMCID: PMC3813754 DOI: 10.1371/journal.pone.0077775] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 09/04/2013] [Indexed: 12/21/2022] Open
Abstract
INTRODUCTION There are growing concerns about the emergence of resistance to artemisinin-based combination therapies (ACTs). Since the widespread adoption of ACTs, there has been a decrease in the systematic surveillance of antimalarial drug resistance in many malaria-endemic countries. The aim of this work was to test whether data on travellers returning from Africa with malaria could serve as an additional surveillance system of local information sources for the emergence of drug resistance in endemic-countries. METHODOLOGY Data were collected from travellers with symptomatic Plasmodium falciparum malaria returning from Senegal (n = 1,993), Mali (n = 2,372), Cote d'Ivoire (n = 4,778) or Cameroon (n = 3,272) and recorded in the French Malaria Reference Centre during the period 1996-2011. Temporal trends of the proportion of parasite isolates that carried the mutant genotype, pfcrt 76T, a marker of resistance to chloroquine (CQ) and pfdhfr 108N, a marker of resistance to pyrimethamine, were compared for travellers and within-country surveys that were identified through a literature review in PubMed. The in vitro response to CQ was also compared between these two groups for parasites from Senegal. RESULTS The trends in the proportion of parasites that carried pfcrt 76T, and pfdhfr 108N, were compared for parasites from travellers and patients within-country using the slopes of the curves over time; no significant differences in the trends were found for any of the 4 countries. These results were supported by in vitro analysis of parasites from the field in Senegal and travellers returning to France, where the trends were also not significantly different. CONCLUSION The results have not shown different trends in resistance between parasites derived from travellers or from parasites within-country. This work highlights the value of an international database of drug responses in travellers as an additional tool to assess the emergence of drug resistance in endemic areas where information is limited.
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Affiliation(s)
- Myriam Gharbi
- Unité Mixte de Recherche 216, Institut de Recherche et de Développement, Paris, France
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
- Ecole des Hautes Etudes en Santé Publique, Sorbonne Paris Cité, Rennes, France
| | - Jennifer A. Flegg
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
- Centre for Tropical Medicine & Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Bruno Pradines
- Département d’Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, Marseille, France
- Centre National de Référence du Paludisme, Marseille, France
| | - Ako Berenger
- Malariology Department, Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Magatte Ndiaye
- Service de parasitologie, Faculté de Médecine et Pharmacie Université Cheikh Anta Diop, Dakar, Sénégal
| | - Abdoulaye A. Djimdé
- Malaria Research and Training Center & Department of Epidemiology of Parasitic Diseases, Faculty of Pharmacy University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Cally Roper
- Pathogen Molecular Biology Department of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Véronique Hubert
- Centre National de Référence du Paludisme & Service de Parasitologie Mycologie, CHU Bichat-Claude Bernard APHP, Paris, France
| | - Eric Kendjo
- Centre National de Référence du Paludisme and Service de Parasitologie Mycologie, CHU Pitié-Salpétrière APHP, Paris, France
| | - Meera Venkatesan
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
- University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Philippe Brasseur
- UMR 198, Institut de Recherche pour le Développement, Dakar, Sénégal
| | - Oumar Gaye
- Service de parasitologie, Faculté de Médecine et Pharmacie Université Cheikh Anta Diop, Dakar, Sénégal
| | - André T. Offianan
- Malariology Department, Institut Pasteur de Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Louis Penali
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
| | - Jacques Le Bras
- Unité Mixte de Recherche 216, Institut de Recherche et de Développement, Paris, France
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
- Centre National de Référence du Paludisme & Service de Parasitologie Mycologie, CHU Bichat-Claude Bernard APHP, Paris, France
| | - Philippe J. Guérin
- WorldWide Antimalarial Resistance Network, Oxford, United Kingdom
- Ecole des Hautes Etudes en Santé Publique, Sorbonne Paris Cité, Rennes, France
- Centre for Tropical Medicine & Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- UMR S 707: Epidemiology Information Systems Modeling, INSERM and Université Pierre et Marie-Curie-Paris6, Paris, France
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16
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Ndiaye D, Dieye B, Ndiaye YD, Van Tyne D, Daniels R, Bei AK, Mbaye A, Valim C, Lukens A, Mboup S, Ndir O, Wirth DF, Volkman S. Polymorphism in dhfr/dhps genes, parasite density and ex vivo response to pyrimethamine in Plasmodium falciparum malaria parasites in Thies, Senegal. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2013; 3:135-42. [PMID: 24533303 PMCID: PMC3862402 DOI: 10.1016/j.ijpddr.2013.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/19/2013] [Accepted: 07/21/2013] [Indexed: 11/14/2022]
Abstract
Prevalence of dhfr/dhps mutations increased significantly between 2003 and 2011. Triple mutant dhfr 51I/59R/108N increased, from 40% in 2003 to 93% in 2011. Quadruple mutant dhfr and dhps 437G increased, from 20% to 66% then down. A strong correlation between ex vivo response to pyrimethamine and dhfr genotype.
Resistance to sulfadoxine–pyrimethamine (SP) in Plasmodium falciparum malaria parasites is associated with mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes, and these mutations have spread resistance worldwide. SP, used for several years in Senegal, has been recommended for intermittent preventive treatment for malaria in pregnancy (IPTp) and has been widely implemented since 2003 in this country. There is currently limited data on SP resistance from molecular marker genotyping, and no data on pyrimethamine ex vivo sensitivity in Senegal. Molecular markers of SP resistance and pyrimethamine ex vivo sensitivity were investigated in 416 parasite samples collected from the general population, from the Thies region between 2003 and 2011. The prevalence of the N51I/C59R/S108N triple mutation in dhfr increased from 40% in 2003 to 93% in 2011. Furthermore, the prevalence of the dhfr N51I/C59R/S108N and dhps A437G quadruple mutation increased, from 20% to 66% over the same time frame, then down to 44% by 2011. There was a significant increase in the prevalence of the dhfr triple mutation, as well as an association between dhfr genotypes and pyrimethamine response. Conversely, dhps mutations in codons 436 and 437 did not show consistent variation between 2003 and 2011. These findings suggest that regular screening for molecular markers of antifolate resistance and ex vivo drug response monitoring should be incorporated with ongoing in vivo efficacy monitoring in areas where IPTp-SP is implemented and where pyrimethamine and sulfa drugs are still widely administered in the general population.
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Affiliation(s)
- Daouda Ndiaye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Baba Dieye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Yaye D Ndiaye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Daria Van Tyne
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Rachel Daniels
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Amy K Bei
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Aminata Mbaye
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Clarissa Valim
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Amanda Lukens
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Souleymane Mboup
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Omar Ndir
- Faculty of Medicine and Pharmacy, University Cheikh Anta Diop, Dakar, PO Box 5005, Dakar, Senegal
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
| | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
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17
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Fall B, Pascual A, Sarr FD, Wurtz N, Richard V, Baret E, Diémé Y, Briolant S, Bercion R, Wade B, Tall A, Pradines B. Plasmodium falciparum susceptibility to anti-malarial drugs in Dakar, Senegal, in 2010: an ex vivo and drug resistance molecular markers study. Malar J 2013; 12:107. [PMID: 23510258 PMCID: PMC3606842 DOI: 10.1186/1475-2875-12-107] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Background In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, there have been very few reports on the level of resistance of P. falciparum to anti-malarial drugs. To determine whether parasite susceptibility has been affected by the new anti-malarial policies, an ex vivo susceptibility and drug resistance molecular marker study was conducted on local isolates obtained from the Centre de santé Elizabeth Diouf (Médina, Dakar, Senegal). Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., pfcrt, pfdhfr, pfdhps and pfmdr1, were evaluated for a panel of 165 isolates collected from patients recruited from 17 August 2010 to 6 January 2011. The malaria isolates were assessed for susceptibility to chloroquine (CQ); quinine (QN); monodesethylamodiaquine (MDAQ), the active metabolite of amodiaquine; mefloquine (MQ); lumefantrine (LMF); dihydroartemisinin (DHA), the active metabolite of artemisinin derivatives; and doxycycline (DOX) using the Plasmodium lactate dehydrogenase (pLDH) ELISA. Results The prevalence of the in vitro resistant isolates, or isolates with reduced susceptibility, was 62.1% for MQ, 24.2% for CQ, 10.3% for DOX, 11.8% MDAQ, 9.7% for QN, 2.9% for LMF and 0% for DHA. The Pfcrt 76T mutation was identified in 43.6% of the samples. The pfmdr1 86Y, 184F and 1246Y mutations were found in 16.2%, 50.0% and 1.6% of the samples, respectively. The pfdhfr 108N, 51I and 59R mutations were identified in 81.9%, 77.4% and 79.4% of the samples, respectively. The double mutant (108N and 51I) was detected in 75.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 73.6% of the isolates. The pfdhps 437G, 436A and 613S mutations were found in 54.4%, 38.6% and 1.2% of the samples, respectively. There was only one double mutant, 437G and 540E, and one quintuple mutant, pfdhfr 108N, 51I and 59R and pfdhps 437G and 540E. The prevalence of the quadruple mutant (pfdhfr 108N, 51I and 59R and pfdhps 437G) was 36.7%. Conclusions The results of this study indicate that an intensive surveillance of the in vitro P. falciparum susceptibility to anti-malarial drugs must be conducted in Senegal.
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Affiliation(s)
- Bécaye Fall
- Laboratoire d'étude de la chimiosensibilité du paludisme, Fédération des laboratoires, Hôpital Principal de Dakar, Dakar, Sénégal
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18
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Abdul-Ghani R, Farag HF, Allam AF. Sulfadoxine-pyrimethamine resistance in Plasmodium falciparum: a zoomed image at the molecular level within a geographic context. Acta Trop 2013; 125:163-90. [PMID: 23131424 DOI: 10.1016/j.actatropica.2012.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
Antimalarial chemotherapy is one of the main pillars in the prevention and control of malaria. Following widespread resistance of Plasmodium falciparum to chloroquine, sulfadoxine-pyrimethamine came to the scene as an alternative to the cheap and well-tolerated chloroquine. However, widespread resistance to sulfadoxine-pyrimethamine has been documented. In vivo efficacy tests are the gold standard for assessing drug resistance and treatment failure. However, they have many disadvantages, such as influence of host immunity and drug pharmacokinetics. In vitro tests of antimalarial drug efficacy also have many technical difficulties. Molecular markers of resistance have emerged as epidemiologic tools to investigate antimalarial drug resistance even before becoming clinically evident. Mutations in P. falciparum dihydrofolate reductase and dihydrofolate synthase have been extensively studied as molecular markers for resistance to pyrimethamine and sulfadoxine, respectively. This review highlights the resistance of P. falciparum at the molecular level presenting both supporting and opposing studies on the utility of molecular markers.
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19
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Wurtz N, Fall B, Pascual A, Diawara S, Sow K, Baret E, Diatta B, Fall KB, Mbaye PS, Fall F, Diémé Y, Rogier C, Bercion R, Briolant S, Wade B, Pradines B. Prevalence of molecular markers of Plasmodium falciparum drug resistance in Dakar, Senegal. Malar J 2012; 11:197. [PMID: 22694921 PMCID: PMC3470961 DOI: 10.1186/1475-2875-11-197] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 06/02/2012] [Indexed: 12/03/2022] Open
Abstract
Background As a result of the widespread resistance to chloroquine and sulphadoxine-pyrimethamine, artemisinin-based combination therapy (ACT) (including artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Intermittent preventive treatments with anti-malarial drugs based on sulphadoxine-pyrimethamine are also given to children or pregnant women once per month during the transmission season. Since 2006, there have been very few reports on the susceptibility of Plasmodium falciparum to anti-malarial drugs. To estimate the prevalence of resistance to several anti-malarial drugs since the introduction of the widespread use of ACT, the presence of molecular markers associated with resistance to chloroquine and sulphadoxine-pyrimethamine was assessed in local isolates at the military hospital of Dakar. Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., Pfcrt, Pfdhfr, Pfdhps and Pfmdr1, and the copy number of Pfmdr1 were evaluated for a panel of 174 isolates collected from patients recruited at the military hospital of Dakar from 14 October 2009 to 19 January 2010. Results The Pfcrt 76T mutation was identified in 37.2% of the samples. The Pfmdr1 86Y and 184F mutations were found in 16.6% and 67.6% of the tested samples, respectively. Twenty-eight of the 29 isolates with the 86Y mutation were also mutated at codon 184. Only one isolate (0.6%) had two copies of Pfmdr1. The Pfdhfr 108N/T, 51I and 59R mutations were identified in 82.4%, 83.5% and 74.1% of the samples, respectively. The double mutant (108N and 51I) was detected in 83.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 75.3%. The Pfdhps 437G, 436F/A and 613S mutations were found in 40.2%, 35.1% and 1.8% of the samples, respectively. There was no double mutant (437G and 540E) or no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E). The prevalence of the quadruple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G) was 36.5%. Conclusions Since 2004, the prevalence of chloroquine resistance had decreased. The prevalence of isolates with high-level pyrimethamine resistance is 83.5%. The prevalence of isolates resistant to sulphadoxine is 40.2%. However, no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E), which is associated with a high level of sulphadoxine-pyrimethamine resistance, has been identified to date. The resistance to amodiaquine remains moderate.
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Affiliation(s)
- Nathalie Wurtz
- Unité de parasitologie, UMR 6236, Institut de recherche biomédicale des armées, Marseille, France
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Chen DS, Barry AE, Leliwa-Sytek A, Smith TA, Peterson I, Brown SM, Migot-Nabias F, Deloron P, Kortok MM, Marsh K, Daily JP, Ndiaye D, Sarr O, Mboup S, Day KP. A molecular epidemiological study of var gene diversity to characterize the reservoir of Plasmodium falciparum in humans in Africa. PLoS One 2011; 6:e16629. [PMID: 21347415 PMCID: PMC3036650 DOI: 10.1371/journal.pone.0016629] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 01/06/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The reservoir of Plasmodium infection in humans has traditionally been defined by blood slide positivity. This study was designed to characterize the local reservoir of infection in relation to the diverse var genes that encode the major surface antigen of Plasmodium falciparum blood stages and underlie the parasite's ability to establish chronic infection and transmit from human to mosquito. METHODOLOGY/PRINCIPAL FINDINGS We investigated the molecular epidemiology of the var multigene family at local sites in Gabon, Senegal and Kenya which differ in parasite prevalence and transmission intensity. 1839 distinct var gene types were defined by sequencing DBLα domains in the three sites. Only 76 (4.1%) var types were found in more than one population indicating spatial heterogeneity in var types across the African continent. The majority of var types appeared only once in the population sample. Non-parametric statistical estimators predict in each population at minimum five to seven thousand distinct var types. Similar diversity of var types was seen in sites with different parasite prevalences. CONCLUSIONS/SIGNIFICANCE Var population genomics provides new insights into the epidemiology of P. falciparum in Africa where malaria has never been conquered. In particular, we have described the extensive reservoir of infection in local African sites and discovered a unique var population structure that can facilitate superinfection through minimal overlap in var repertoires among parasite genomes. Our findings show that var typing as a molecular surveillance system defines the extent of genetic complexity in the reservoir of infection to complement measures of malaria prevalence. The observed small scale spatial diversity of var genes suggests that var genetics could greatly inform current malaria mapping approaches and predict complex malaria population dynamics due to the import of var types to areas where no widespread pre-existing immunity in the population exists.
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Affiliation(s)
- Donald S. Chen
- Department of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
- Department of Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Alyssa E. Barry
- Department of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
- Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, Oxford, United Kingdom
- Centre for Population Health, Burnet Institute, Melbourne, Australia
- Department of Medicine, Central and Eastern Clinical School, Monash University, Victoria, Australia
| | - Aleksandra Leliwa-Sytek
- Department of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Terry-Ann Smith
- Department of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Ingrid Peterson
- Department of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Stuart M. Brown
- Center for Health Informatics and Bioinformatics, New York University School of Medicine, New York, New York, United States of America
| | - Florence Migot-Nabias
- Institut de Recherche pour le Développement, Faculté de Pharmacie, Université Paris 5, Paris, France
| | - Philippe Deloron
- Institut de Recherche pour le Développement, Faculté de Pharmacie, Université Paris 5, Paris, France
| | - Moses M. Kortok
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Kevin Marsh
- Kenya Medical Research Institute, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Johanna P. Daily
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Daouda Ndiaye
- Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Ousmane Sarr
- Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Souleymane Mboup
- Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Karen P. Day
- Department of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
- Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, Oxford, United Kingdom
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21
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Ghanchi NK, Ursing J, Beg MA, Veiga MI, Jafri S, Mårtensson A. Prevalence of resistance associated polymorphisms in Plasmodium falciparum field isolates from southern Pakistan. Malar J 2011; 10:18. [PMID: 21272384 PMCID: PMC3037930 DOI: 10.1186/1475-2875-10-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 01/28/2011] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Scarce data are available on Plasmodium falciparum anti-malarial drug resistance in Pakistan. The aim of this study was, therefore, to determine the prevalence of P. falciparum resistance associated polymorphisms in field isolates from southern Pakistan. METHODS Blood samples from 244 patients with blood-slide confirmed P. falciparum mono-infections were collected between 2005-2007. Single nucleotide polymorphisms in the P. falciparum chloroquine resistance transporter (pfcrt K76T), multi drug resistance (pfmdr1 N86Y), dihydrofolate reductase (pfdhfr A16V, N51I, C59R, S108N, I164L) and dihydropteroate synthetase (pfdhps A436S, G437A and E540K) genes and pfmdr1 gene copy numbers were determined using PCR based methods. RESULTS The prevalence of pfcrt 76T and pfmdr1 86Y was 93% and 57%, respectively. The prevalence of pfdhfr double mutations 59R + 108N/51R + 108N was 92%. The pfdhfr triple mutation (51I, 59R, 108N) occurred in 3% of samples. The pfdhfr (51I, 59R, 108N) and pfdhps (437G, 540E) quintuple mutation was found in one isolate. Pfdhps 437G was observed in 51% and 540E in 1% of the isolates. One isolate had two pfmdr1 copies and carried the pfmdr1 86Y and pfcrt 76T alleles. CONCLUSIONS The results indicate high prevalence of in vivo resistance to chloroquine, whereas high grade resistance to sulphadoxine-pyrimethamine does not appear to be widespread among P. falciparum in southern Pakistan.
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Affiliation(s)
- Najia Karim Ghanchi
- Department of Pathology and Microbiology, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan
| | - Johan Ursing
- Malaria Research Lab, Infectious Diseases Unit, Department of Medicine, Karolinska University Hospital/Karolinska Institutet, Retziusväg 10, 171 77 Stockholm, Sweden
| | - Mohammad A Beg
- Department of Pathology and Microbiology, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan
| | - Maria I Veiga
- Malaria Research Lab, Infectious Diseases Unit, Department of Medicine, Karolinska University Hospital/Karolinska Institutet, Retziusväg 10, 171 77 Stockholm, Sweden
- Drug Resistance and Pharmacogenetics Group, Institute of Biotechnology and Bioengineering, Centre of Molecular and Structural Biomedicine, University of Algarve, 8500-139 Faro, Portugal
| | - Sana Jafri
- Department of Pathology and Microbiology, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan
| | - Andreas Mårtensson
- Malaria Research Lab, Infectious Diseases Unit, Department of Medicine, Karolinska University Hospital/Karolinska Institutet, Retziusväg 10, 171 77 Stockholm, Sweden
- Division of Global Health (IHCAR), Department of Public Health Sciences, Karolinska Institutet, Nobelsväg 9, S-171 77 Stockholm, Sweden
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Prevalence of molecular markers of Plasmodium falciparum resistance to sulfadoxine-pyrimethamine during the intermittent preventive treatment in infants coupled with the expanded program immunization in Senegal. Parasitol Res 2011; 109:133-8. [PMID: 21207062 DOI: 10.1007/s00436-010-2236-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 12/13/2010] [Indexed: 10/18/2022]
Abstract
Several studies have shown the efficacy of the intermittent preventive treatment (IPT) using sulfadoxine-pyrimethamine (SP) coupled with the expanded program of immunization (EPI) in infants. However, its adoption as a strategy is conditioned by the long-term efficacy of SP. The impact of IPT-SP coupled with the EPI on the prevalence of markers of resistance to SP was evaluated during this study conducted in Southern Senegal. Three cross-sectional surveys in two health districts (IPT+) were conducted prior to the implementation, 1 year, and 2 years after. A third district located between the two districts served as a test zone (IPT-). PCR tests were carried out from filter papers collected in children under five for the two first measures and from positive rapid diagnostic tests in the same population for the third measure. Mutations in codons 51, 59, and 108 of the DHFR gene and in codons 437 and 540 of the DHPS were analyzed. The results showed that the prevalence of DHFR triple mutation was more frequent after 2 years in IPT+ areas. Regarding quadruple mutation, DHFR (51, 59, and 108) and DHPS (437), no difference was noted between the two areas. The quintuple mutation was not observed after 2 years of implementation in both areas. However, an individual analysis showed significant differences in the individual mutation points 51, 59, 108, and 437. This study reveals that despite an increase in the prevalence of individual mutations, the IPT-SP coupled with the EPI has no major impact on DHFR and DHPS combined mutations.
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Naidoo I, Roper C. Following the path of most resistance: dhps K540E dispersal in African Plasmodium falciparum. Trends Parasitol 2010; 26:447-56. [PMID: 20728060 DOI: 10.1016/j.pt.2010.05.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 05/07/2010] [Accepted: 05/07/2010] [Indexed: 11/16/2022]
Abstract
Chloroquine resistant malaria (CQR) emerged in East Africa during the late 1970s and then spread westward. A molecular marker only became available in the late 1990s, and by that time CQR had permeated throughout Africa. By contrast, resistance to sulphadoxine-pyrimethamine (SPR) has emerged during an era of molecular surveillance, and the changing prevalence of SPR conferred by point mutations in the dhfr and dhps genes has been recorded in hundreds of sites across Africa. We have collated and mapped reports of the dhps K540E mutation, a uniquely informative marker of SPR, and used these to describe the geography of its dispersal through time. Like CQR, dhps K540E appeared first in East Africa and spread west. We discuss whether there are common principles governing resistance dispersal in Africa and how these might guide surveillance in future.
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Affiliation(s)
- Inbarani Naidoo
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Ndiaye D, Patel V, Demas A, LeRoux M, Ndir O, Mboup S, Clardy J, Lakshmanan V, Daily JP, Wirth DF. A non-radioactive DAPI-based high-throughput in vitro assay to assess Plasmodium falciparum responsiveness to antimalarials--increased sensitivity of P. falciparum to chloroquine in Senegal. Am J Trop Med Hyg 2010; 82:228-30. [PMID: 20133997 DOI: 10.4269/ajtmh.2010.09-0470] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The spread of Plasmodium falciparum drug resistance is outpacing new antimalarial development and compromising effective malaria treatment. Combination therapy is widely implemented to prolong the effectiveness of currently approved antimalarials. To maximize utility of available drugs, periodic monitoring of drug efficacy and gathering of accurate information regarding parasite-sensitivity changes are essential. We describe a high-throughput, non-radioactive, field-based assay to evaluate in vitro antimalarial drug sensitivity of P. falciparum isolates from 40 Senegalese patients. Compared with earlier years, we found a significant decrease in chloroquine in vitro and in genotypic resistances (> 50% and > 65%, respectively, in previous studies) with only 23% of isolates showing resistance. This is possibly caused by a withdrawal of chloroquine from Senegal in 2002. We also found a range of artemisinin responses. Prevalence of drug resistance is dynamic and varies by region. Therefore, the implementation of non-radioactive, robust, high-throughput antimalarial sensitivity assays is critical for defining region-specific prophylaxis and treatment guidelines.
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Affiliation(s)
- Daouda Ndiaye
- Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal.
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25
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Patil V, Guerrant W, Chen PC, Gryder B, Benicewicz DB, Khan SI, Tekwani BL, Oyelere AK. Antimalarial and antileishmanial activities of histone deacetylase inhibitors with triazole-linked cap group. Bioorg Med Chem 2010; 18:415-25. [PMID: 19914074 PMCID: PMC2818366 DOI: 10.1016/j.bmc.2009.10.042] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 10/19/2009] [Accepted: 10/23/2009] [Indexed: 11/25/2022]
Abstract
Histone deacetylase inhibitors (HDACi) are endowed with plethora of biological functions including anti-proliferative, anti-inflammatory, anti-parasitic, and cognition-enhancing activities. Parsing the structure-activity relationship (SAR) for each disease condition is vital for long-term therapeutic applications of HDACi. We report in the present study specific cap group substitution patterns and spacer-group chain lengths that enhance the antimalarial and antileishmanial activity of aryltriazolylhydroxamates-based HDACi. We identified many compounds that are several folds selectively cytotoxic to the plasmodium parasites compared to standard HDACi. Also, a few of these compounds have antileishmanial activity that rivals that of miltefosine, the only currently available oral agent against visceral leishmaniasis. The anti-parasite properties of several of these compounds tracked well with their anti-HDAC activities. The results presented here provide further evidence on the suitability of HDAC inhibition as a viable therapeutic option to curb infections caused by apicomplexan protozoans and trypanosomatids.
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Affiliation(s)
| | | | | | | | | | | | - Babu L. Tekwani
- To whom the correspondence should be addressed. . Phone: 404-894-4047; fax: 404-894-2291; . Phone: (662) 915-7882; Fax: (662) 915-7062
| | - Adegboyega K. Oyelere
- To whom the correspondence should be addressed. . Phone: 404-894-4047; fax: 404-894-2291; . Phone: (662) 915-7882; Fax: (662) 915-7062
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26
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Bacon DJ, Tang D, Salas C, Roncal N, Lucas C, Gerena L, Tapia L, Llanos-Cuentas AA, Garcia C, Solari L, Kyle D, Magill AJ. Effects of point mutations in Plasmodium falciparum dihydrofolate reductase and dihydropterate synthase genes on clinical outcomes and in vitro susceptibility to sulfadoxine and pyrimethamine. PLoS One 2009; 4:e6762. [PMID: 19707564 PMCID: PMC2728505 DOI: 10.1371/journal.pone.0006762] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 04/02/2009] [Indexed: 11/18/2022] Open
Abstract
Background Sulfadoxine-pyrimethamine was a common first line drug therapy to treat uncomplicated falciparum malaria, but increasing therapeutic failures associated with the development of significant levels of resistance worldwide has prompted change to alternative treatment regimes in many national malaria control programs. Methodology and Finding We conducted an in vivo therapeutic efficacy trial of sulfadoxine-pyrimethamine at two locations in the Peruvian Amazon enrolling 99 patients of which, 86 patients completed the protocol specified 28 day follow up. Our objective was to correlate the presence of polymorphisms in P. falciparum dihydrofolate reductase and dihydropteroate synthase to in vitro parasite susceptibility to sulfadoxine and pyrimethamine and to in vivo treatment outcomes. Inhibitory concentration 50 values of isolates increased with numbers of mutations (single [108N], sextuplet [BR/51I/108N/164L and 437G/581G]) and septuplet (BR/51I/108N/164L and 437G/540E/581G) with geometric means of 76 nM (35–166 nM), 582 nM (49-6890- nM) and 4909 (3575–6741 nM) nM for sulfadoxine and 33 nM (22–51 nM), 81 nM (19–345 nM), and 215 nM (176–262 nM) for pyrimethamine. A single mutation present in the isolate obtained at the time of enrollment from either dihydrofolate reductase (164L) or dihydropteroate synthase (540E) predicted treatment failure as well as any other single gene alone or in combination. Patients with the dihydrofolate reductase 164L mutation were 3.6 times as likely to be treatment failures [failures 85.4% (164L) vs 23.7% (I164); relative risk = 3.61; 95% CI: 2.14 – 6.64] while patients with the dihydropteroate synthase 540E were 2.6 times as likely to fail treatment (96.7% (540E) vs 37.5% (K540); relative risk = 2.58; 95% CI: 1.88 – 3.73). Patients with both dihydrofolate reductase 164L and dihydropteroate synthase 540E mutations were 4.1 times as likely to be treatment failures [96.7% vs 23.7%; RR = 4.08; 95% CI: 2.45 – 7.46] compared to patients having both wild forms (I164 and K540). Conclusions In this part of the Amazon basin, it may be possible to predict treatment failure with sulfadoxine-pyrimethamine equally well by determination of either of the single mutations dihydrofolate reductase 164L or dihydropteroate synthase 540E. Trial Registration ClinicalTrials.gov NCT00951106 NCT00951106
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Affiliation(s)
- David J Bacon
- Parasitology Program, Naval Medical Research Center Detachment, Lima, Peru.
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Zhang GQ, Guan YY, Zheng B, Wu S, Tang LH. Molecular assessment ofPlasmodium falciparumresistance to antimalarial drugs in China. Trop Med Int Health 2009; 14:1266-71. [DOI: 10.1111/j.1365-3156.2009.02342.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Multiple origins and regional dispersal of resistant dhps in African Plasmodium falciparum malaria. PLoS Med 2009; 6:e1000055. [PMID: 19365539 PMCID: PMC2661256 DOI: 10.1371/journal.pmed.1000055] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 02/13/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Although the molecular basis of resistance to a number of common antimalarial drugs is well known, a geographic description of the emergence and dispersal of resistance mutations across Africa has not been attempted. To that end we have characterised the evolutionary origins of antifolate resistance mutations in the dihydropteroate synthase (dhps) gene and mapped their contemporary distribution. METHODS AND FINDINGS We used microsatellite polymorphism flanking the dhps gene to determine which resistance alleles shared common ancestry and found five major lineages each of which had a unique geographical distribution. The extent to which allelic lineages were shared among 20 African Plasmodium falciparum populations revealed five major geographical groupings. Resistance lineages were common to all sites within these regions. The most marked differentiation was between east and west African P. falciparum, in which resistance alleles were not only of different ancestry but also carried different resistance mutations. CONCLUSIONS Resistant dhps has emerged independently in multiple sites in Africa during the past 10-20 years. Our data show the molecular basis of resistance differs between east and west Africa, which is likely to translate into differing antifolate sensitivity. We have also demonstrated that the dispersal patterns of resistance lineages give unique insights into recent parasite migration patterns.
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Lynch C, Pearce R, Pota H, Cox J, Abeku TA, Rwakimari J, Naidoo I, Tibenderana J, Roper C. Emergence of a dhfr mutation conferring high-level drug resistance in Plasmodium falciparum populations from southwest Uganda. J Infect Dis 2008; 197:1598-604. [PMID: 18471065 DOI: 10.1086/587845] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The S108N, C59R, and N51I mutations in the Plasmodium falciparum gene that encodes dihydrofolate reductase, dhfr, confer resistance to pyrimethamine and are common in Africa. However, the I164L mutation, which confers high-level resistance, is rarely seen. We found a 14% prevalence of the I164L mutation among a sample of 51 patients with malaria in Kabale District in southwest Uganda in 2005 and a 4% prevalence among 72 patients with malaria in the neighboring district of Rukungiri during the same year. Surveillance at 6 sites across Uganda during 2002-2004 reported a single case of infection involving an I164L mutant, also in the southwest, suggesting that this is a regional hot spot. The spatial clustering and increasing prevalence of the I164L mutation is indicative of local transmission of the mutant. Targeted surveillance is needed to confirm the extent of the spread of the I164L mutation and to monitor the impact of I164L on the efficacy of antifolates for intermittent preventive treatment of pregnant women and/or infants with falciparum malaria.
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Affiliation(s)
- Caroline Lynch
- Disease Control and Vector Biology Unit, Department of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mutations in PFCRT K76T do not correlate with sulfadoxine-pyrimethamine-amodiaquine failure in Pikine, Senegal. Parasitol Res 2008; 103:765-9. [PMID: 18523801 DOI: 10.1007/s00436-008-1038-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 05/08/2008] [Indexed: 10/22/2022]
Abstract
In 2003, the high level of chloroquine (CQ) treatment failure for uncomplicated Plasmodium falciparum malaria cases has led Senegal to adopt a new combination therapy with sulfadoxine-pyrimethamine and amodiaquine (SP-AQ). From September through November 2004, we used the 14-day World Health Organization follow-up protocol to assess the therapeutic response in patients with uncomplicated P. falciparum malaria in an area of high prevalence of pfcrt T76 mutant allele and SP resistance mutations. Of the 82 patients who were recruited, 68 (82.9%) completed follow-up. The response of the patients to treatment was adequate clinical response for 63 out of 68 patients (92.6%), while five (7.4%) clinical failures were recorded, four early treatment failures, and one late treatment failure. The prevalence of the pfcrt T76 allele at day 0 was 59.5%. The two-sided Fisher's exact test did not show an association between pfcrt T76 allele and treatment failure (p=0.167). The transitory treatment is effective and safe. However, the presence of high levels of mutant alleles points out the need to closely monitor the new therapeutic regimen.
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Multiplex PCR and oligonucleotide microarray for detection of single-nucleotide polymorphisms associated with Plasmodium falciparum drug resistance. J Clin Microbiol 2008; 46:2167-74. [PMID: 18448699 DOI: 10.1128/jcm.00081-08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Drug resistance in Plasmodium falciparum is a serious public health threat in the countries where this organism is endemic. Since resistance has been associated with specific single-nucleotide polymorphisms (SNPs) in parasite genes, molecular markers are becoming useful surrogates for monitoring the emergence and dispersion of drug resistance. In this study, a multiplex PCR (mPCR) and oligonucleotide microarray method was developed for the detection of these SNPs in genes encoding chloroquine resistance transporter (Pfcrt), multidrug resistance 1 (Pfmdr1), dihydrofolate reductase (Pfdhfr), dihydropteroate synthetase (Pfdhps), and ATPase 6 (PfATPase6) of P. falciparum. The results show that DNA microarray technology, combined with mPCR, is a promising and time-saving tool that supports conventional detection methods, allowing sensitive, accurate, simultaneous analysis of the SNPs associated with drug resistance in P. falciparum.
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High frequency of Plasmodium falciparum CICNI/SGEAA and CVIET haplotypes without association with resistance to sulfadoxine/pyrimethamine and chloroquine combination in the Daraweesh area, in Sudan. Eur J Clin Microbiol Infect Dis 2008; 27:725-32. [PMID: 18373107 DOI: 10.1007/s10096-008-0499-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 02/18/2008] [Indexed: 10/22/2022]
Abstract
Estimation of the prevalence of the molecular markers of sulfadoxine/pyrimethamine (SP) and chloroquine (CQ) resistance and validation of the association of mutations with resistance in different settings is needed for local policy guidance and for contributing to a global map for anti-malarial drug resistance. In this study, malaria patients treated with SP alone (60) and SP with CQ (194) had a total treatment failure (TF) of 35.4%, with no difference between the two arms. The polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA) method was used to identify polymorphisms in 15 loci in the dhfr, dhps and pfcrt genes in a subset of 168 infections. The results revealed a similar frequency of all single nucleotide polymorphisms (SNPs) in the two arms, except dhps 581G, which was over-represented in infections that failed to respond to SP alone (TF). In all infections, a high frequency of dhfr CICNI haplotype (51I and 108N) was found, but without discrimination between the adequate clinical and parasitological response (ACPR, 75.6%) and TF (82.9%). Similarly, the dhps SGEAA haplotype (437G and 540E) (ACPR, 60.5%; TF, 65.9%) and the combined CICNI/SGEAA haplotype (ACPR, 50%; TF 55%) were not associated with TF. In contrast to other studies in Africa, the triple 51I/59R/108N mutation was rare (0.6%). In addition, the pfcrt CVIET haplotype (93%) was found to be associated with the CICNI/SGEAA haplotype. Finally, these data represent a baseline for SP resistance molecular markers needed before the deployment of SP/artesunate combination therapy in the Sudan.
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Dièye AM, Gueye I, Yoro Sy G, Ndiaye M, Ndiaye-Sy A, Faye B. Essais cliniques à Dakar : enquête sur les connaissances, attitudes et pratiques des principaux acteurs sur une période allant de 2003 à 2007. Therapie 2008; 63:89-96. [DOI: 10.2515/therapie:2008007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 01/30/2008] [Indexed: 11/20/2022]
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Potent antimalarial activity of histone deacetylase inhibitor analogues. Antimicrob Agents Chemother 2008; 52:1454-61. [PMID: 18212103 DOI: 10.1128/aac.00757-07] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The malaria parasite Plasmodium falciparum has at least five putative histone deacetylase (HDAC) enzymes, which have been proposed as new antimalarial drug targets and may play roles in regulating gene transcription, like the better-known and more intensively studied human HDACs (hHDACs). Fourteen new compounds derived from l-cysteine or 2-aminosuberic acid were designed to inhibit P. falciparum HDAC-1 (PfHDAC-1) based on homology modeling with human class I and class II HDAC enzymes. The compounds displayed highly potent antiproliferative activity against drug-resistant (Dd2) or drug sensitive (3D7) strains of P. falciparum in vitro (50% inhibitory concentration of 13 to 334 nM). Unlike known hHDAC inhibitors, some of these new compounds were significantly more toxic to P. falciparum parasites than to mammalian cells. The compounds inhibited P. falciparum growth in erythrocytes at both the early and late stages of the parasite's life cycle and caused altered histone acetylation patterns (hyperacetylation), which is a marker of HDAC inhibition in mammalian cells. These results support PfHDAC enzymes as being promising targets for new antimalarial drugs.
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Faye B, Ndiaye JL, Ndiaye D, Dieng Y, Faye O, Gaye O. Efficacy and tolerability of four antimalarial combinations in the treatment of uncomplicated Plasmodium falciparum malaria in Senegal. Malar J 2007; 6:80. [PMID: 17570848 PMCID: PMC1919387 DOI: 10.1186/1475-2875-6-80] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2007] [Accepted: 06/14/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In view of the high level of chloroquine resistance in many countries, WHO has recommended the use of combination therapy with artemisinin derivatives in the treatment of uncomplicated malaria due to Plasmodium falciparum. Four antimalarial drug combinations, artesunate plus amodiaquine (Arsucam), artesunate plus mefloquine (Artequin), artemether plus lumefantrine (Coartem; four doses and six doses), and amodiaquine plus sulphadoxine-pyrimethamine, were studied in five health districts in Senegal. METHODS This is a descriptive, analytical, open, randomized study to evaluate the efficacy and tolerability of these four antimalarial combinations in the treatment of uncomplicated falciparum malaria using the 2002 WHO protocol. RESULTS All drug combinations demonstrated good efficacy. On day 28, all combinations resulted in an excellent clinical and parasitological response rate of 100% after correction for PCR results, except for the four-dose artemether-lumefantrine regimen (96.4%). Follow-up of approximately 10% of each treatment group on day 42 demonstrated an efficacy of 100%.The combinations were well tolerated clinically and biologically. No unexpected side-effect was observed and all side-effects disappeared at the end of treatment. No serious side-effect requiring premature termination of treatment was observed. CONCLUSION The four combinations are effective and well-tolerated.
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Affiliation(s)
- Babacar Faye
- Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie. Université Cheikh Anta Diop, Dakar, Senegal
| | - Jean-Louis Ndiaye
- Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie. Université Cheikh Anta Diop, Dakar, Senegal
| | - Daouda Ndiaye
- Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie. Université Cheikh Anta Diop, Dakar, Senegal
| | - Yemou Dieng
- Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie. Université Cheikh Anta Diop, Dakar, Senegal
| | - Oumar Faye
- Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie. Université Cheikh Anta Diop, Dakar, Senegal
| | - Oumar Gaye
- Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Pharmacie et Odontologie. Université Cheikh Anta Diop, Dakar, Senegal
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Abstract
Malaria persists as an undiminished global problem, but the resources available to address it have increased. Many tools for understanding its biology and epidemiology are well developed, with a particular richness of comparative genome sequences. Targeted genetic manipulation is now effectively combined with in vitro culture assays on the most important human parasite, Plasmodium falciparum, and with in vivo analysis of rodent and monkey malaria parasites in their laboratory hosts. Studies of the epidemiology, prevention, and treatment of human malaria have already been influenced by the availability of molecular methods, and analyses of parasite polymorphisms have long had useful and highly informative applications. However, the molecular epidemiology of malaria is currently undergoing its most substantial revolution as a result of the genomic information and technologies that are available in well-resourced centers. It is a challenge for research agendas to face the real needs presented by a disease that largely exists in extremely resource-poor settings, but it is one that there appears to be an increased willingness to undertake. To this end, developments in the molecular epidemiology of malaria are reviewed here, emphasizing aspects that may be current and future priorities.
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Affiliation(s)
- David J Conway
- Medical Research Council Laboratories, Fajara, P.O. Box 273, Banjul, The Gambia.
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Noranate N, Durand R, Tall A, Marrama L, Spiegel A, Sokhna C, Pradines B, Cojean S, Guillotte M, Bischoff E, Ekala MT, Bouchier C, Fandeur T, Ariey F, Patarapotikul J, Bras JL, Trape JF, Rogier C, Mercereau-Puijalon O. Rapid dissemination of Plasmodium falciparum drug resistance despite strictly controlled antimalarial use. PLoS One 2007; 2:e139. [PMID: 17206274 PMCID: PMC1764034 DOI: 10.1371/journal.pone.0000139] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Accepted: 12/06/2006] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Inadequate treatment practices with antimalarials are considered major contributors to Plasmodium falciparum resistance to chloroquine, pyrimethamine and sulfadoxine. The longitudinal survey conducted in Dielmo, a rural Senegalese community, offers a unique frame to explore the impact of strictly controlled and quantified antimalarial use for diagnosed malaria on drug resistance. METHODOLOGY/PRINCIPAL FINDINGS We conducted on a yearly basis a retrospective survey over a ten-year period that included two successive treatment policies, namely quinine during 1990-1994, and chloroquine (CQ) and sulfadoxine/pyrimethamine (SP) as first and second line treatments, respectively, during 1995-1999. Molecular beacon-based genotyping, gene sequencing and microsatellite analysis showed a low prevalence of Pfcrt and Pfdhfr-ts resistance alleles of Southeast Asian origin by the end of 1994 and their effective dissemination within one year of CQ and SP implementation. The Pfcrt resistant allele rose from 9% to 46% prevalence during the first year of CQ reintroduction, i.e., after a mean of 1.66 CQ treatment courses/person/year. The Pfdhfr-ts triple mutant rose from 0% to 20% by end 1996, after a mean of 0.35 SP treatment courses/person in a 16-month period. Both resistance alleles were observed at a younger age than all other alleles. Their spreading was associated with enhanced in vitro resistance and rapidly translated in an increased incidence of clinical malaria episodes during the early post-treatment period. CONCLUSION/SIGNIFICANCE In such a highly endemic setting, selection of drug-resistant parasites took a single year after drug implementation, resulting in a rapid progression of the incidence of clinical malaria during the early post-treatment period. Controlled antimalarial use at the community level did not prevent dissemination of resistance haplotypes. This data pleads against reintroduction of CQ in places where resistant allele frequency has dropped to a very low level after CQ use has been discontinued, unless drastic measures are put in place to prevent selection and spreading of mutants during the post-treatment period.
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Affiliation(s)
- Nitchakarn Noranate
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rémy Durand
- Hôpital Avicenne, Assistance Publique-Hôpitaux de Paris, Bobigny, France
| | - Adama Tall
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - Laurence Marrama
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - André Spiegel
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
| | - Cheikh Sokhna
- Laboratoire de Paludologie/Zoologie Médicale, IRD, Dakar, Senegal
| | - Bruno Pradines
- Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France
| | - Sandrine Cojean
- Transports Membranaires et Chimiorésistance du Paludisme, Université R. Descartes and Hôpital Bichat Claude Bernard, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Micheline Guillotte
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
| | - Emmanuel Bischoff
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
| | - Marie-Thérèse Ekala
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
| | - Christiane Bouchier
- Pasteur Génopole-Ile de France, Plateforme Genomique, Institut Pasteur, Paris, France
| | | | | | | | - Jacques Le Bras
- Transports Membranaires et Chimiorésistance du Paludisme, Université R. Descartes and Hôpital Bichat Claude Bernard, Assistance Publique-Hôpitaux de Paris, Paris, France
| | | | - Christophe Rogier
- Unité d'Epidémiologie, Institut Pasteur de Dakar, Dakar, Senegal
- Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France
| | - Odile Mercereau-Puijalon
- Unité d'Immunologie Moléculaire des Parasites, Centre National de la Recherche Scientifique URA 2581, Institut Pasteur, Paris, France
- * To whom correspondence should be addressed. E-mail:
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Ndiaye D, Daily J, Sarr O, Ndir O, Gaye O, Mboup S, Roper C, Wirth D. Defining the origin of Plasmodium falciparum resistant dhfr isolates in Senegal. Acta Trop 2006; 99:106-11. [PMID: 16905111 PMCID: PMC2582374 DOI: 10.1016/j.actatropica.2006.07.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 06/23/2006] [Accepted: 07/04/2006] [Indexed: 11/23/2022]
Abstract
We previously reported a high baseline prevalence of mutations in the dhfr and dhps genes of Plasmodium falciparum throughout Senegal. The highest prevalence of the triple dhfr pyrimethamine associated mutations were found in isolates obtained in the western part of the country near the capital city of Dakar. In this study, we sought out to determine the relatedness of dhfr wild type and mutated strains by analyzing three microsatellite regions upstream of the dhfr locus. Twenty-six of the 31 wild type strains had a unique microsatellite pattern. In contrast, of the 17 isolates containing the triple mutation in dhfr, 11 had an identical microsatellite pattern. Diverse geographical isolates in Senegal containing the triple dhfr mutation have arisen from a limited number of ancestral strains. In addition, we demonstrate that these isolates have shared ancestry with the previously reported triple mutation haplotype found in Tanzania, South Africa, and southeast Asia. This common ancestry may have implications for the malaria control strategy for reducing the spread of sulfadoxine-pyrimethamine resistance in Senegal and elsewhere in Africa.
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Affiliation(s)
- D. Ndiaye
- Department of Parasitology and Mycology, Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - J.P. Daily
- Harvard School of Public Health, Department of Immunology and Infectious Disease, 655 Huntington Avenue, Boston, MA 02115, USA
- Corresponding author. Tel.: +1 617 432 5321; fax: +1 617 432 4766. E-mail address: (J.P. Daily)
| | - O. Sarr
- Laboratory of Bacteriology and Virology, Dantec Hospital, Dakar, Senegal
| | - O. Ndir
- Department of Parasitology and Mycology, Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - O. Gaye
- Department of Parasitology and Mycology, Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - S. Mboup
- Laboratory of Bacteriology and Virology, Dantec Hospital, Dakar, Senegal
| | - C. Roper
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - D.F. Wirth
- Harvard School of Public Health, Department of Immunology and Infectious Disease, 655 Huntington Avenue, Boston, MA 02115, USA
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