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Acharya A, Bansal D, Bharti PK, Khan FY, Abusalah S, Elmalik A, ElKhalifa M, Mohapatra PK, Mahanta J, Sehgal R, Singh N, Sultan AA. Molecular surveillance of chloroquine drug resistance markers (Pfcrt and Pfmdr1) among imported Plasmodium falciparum malaria in Qatar. Pathog Glob Health 2017; 112:57-62. [PMID: 29125042 DOI: 10.1080/20477724.2017.1399234] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Imported malaria has been a great challenge for public health in Qatar due to influx of large number of migrant workers. Antimalarial drug resistance has emerged as one of the greatest challenges facing malaria control today. Monitoring parasite haplotypes that predict susceptibility to major antimalarial can guide treatment policies. This study aimed to determine molecular drug resistance pattern in imported malaria cases in Qatar. Blood samples from the uncomplicated P. falciparum malaria patients were collected at Hamad General Hospital, HMC, Doha, Qatar. The samples were further confirmed by nested-polymerase chain reaction (PCR) for P. falciparum. Molecular markers of chloroquine (Pfcrt and Pfmdr1) were analyzed by using nested PCR- RFLP method to determine the key point mutations associated with chloroquine (CQ) drug resistance. A total 118 blood samples were positive for P. falciparum. Overall, by RFLP, 72% harboured wild type allele (N86) of Pfmdr1 gene. The prevalence of Pfcrt mutant (T76), WT (K76) and mixed alleles (K76T) was 63.6% (n = 75), 22.9% (n = 27) and 13.5% (n = 16), respectively. Mean parasitaemia level was higher among the wild type alleles of Pfcrt gene as compared to the mixed/mutant alleles whereas mixed alleles of Pfmdr1 gene having high parasitaemia. Molecular surveillance strategy based on imported malaria cases can be used to detect and track CQ drug-resistant malaria. The data presented here might be helpful for enrichment of molecular surveillance of antimalarial resistance and will be useful for developing and updating antimalarial guidance for non-immune imported cases in Qatar.
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Affiliation(s)
- Anushree Acharya
- a Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University , Qatar Foundation - Education City , Doha , Qatar
| | - Devendra Bansal
- a Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University , Qatar Foundation - Education City , Doha , Qatar
| | - Praveen K Bharti
- b National Institute for Research in Tribal Health, Indian Council of Medical Research , Jabalpur , India
| | - Fahmi Y Khan
- c Department of Medicine , Hamad General Hospital, Hamad Medical Corporation , Doha , Qatar
| | - Salem Abusalah
- d Department of Emergency Medicine , Hamad General Hospital, Hamad Medical Corporation , Doha , Qatar
| | - Ashraf Elmalik
- d Department of Emergency Medicine , Hamad General Hospital, Hamad Medical Corporation , Doha , Qatar
| | - Mohammed ElKhalifa
- e Department of Laboratory Medicine and Pathology , Hamad General Hospital, Hamad Medical Corporation , Doha , Qatar
| | - Pradyumna K Mohapatra
- f Regional Medical Research Centre, NE , Indian Council of Medical Research , Dibrugarh , India
| | - Jagadish Mahanta
- f Regional Medical Research Centre, NE , Indian Council of Medical Research , Dibrugarh , India
| | - Rakesh Sehgal
- g Department of Parasitology , Postgraduate Institute of Medical Education and Research , Chandigarh , India
| | - Neeru Singh
- b National Institute for Research in Tribal Health, Indian Council of Medical Research , Jabalpur , India
| | - Ali A Sultan
- a Department of Microbiology and Immunology, Weill Cornell Medicine - Qatar, Cornell University , Qatar Foundation - Education City , Doha , Qatar
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Costa GL, Amaral LC, Fontes CJF, Carvalho LH, de Brito CFA, de Sousa TN. Assessment of copy number variation in genes related to drug resistance in Plasmodium vivax and Plasmodium falciparum isolates from the Brazilian Amazon and a systematic review of the literature. Malar J 2017; 16:152. [PMID: 28420389 PMCID: PMC5395969 DOI: 10.1186/s12936-017-1806-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 04/07/2017] [Indexed: 12/29/2022] Open
Abstract
Background Parasite resistance to anti-malarials represents a great obstacle for malaria elimination. The majority of studies have investigated the association between single-nucleotide polymorphisms (SNPs) and drug resistance; however, it is becoming clear that the copy number variation (CNV) is also associated with this parasite phenotype. To provide a baseline for molecular surveillance of anti-malarial drug resistance in the Brazilian Amazon, the present study characterized the genetic profile of both markers in the most common genes associated with drug resistance in Plasmodium falciparum and Plasmodium vivax isolates. Additionally, these data were compared to data published elsewhere applying a systematic review of the literature published over a 20-year time period. Methods The genomic DNA of 67 patients infected by P. falciparum and P. vivax from three Brazilian States was obtained between 2002 and 2012. CNV in P. falciparum multidrug resistance gene-1 (pfmdr1), GTP cyclohydrolase 1 (pfgch1) and P. vivax multidrug resistance gene-1 (pvmdr1) were assessed by real-time PCR assays. SNPs in the pfmdr1 and pfcrt genes were assessed by PCR–RFLP. A literature search for studies that analysed CNP in the same genes of P. falciparum and P. vivax was conducted between May 2014 and March 2017 across four databases. Results All analysed samples of P. falciparum carried only one copy of pfmdr1 or pfgch1. Although the pfcrt K76T polymorphism, a determinant of CQ resistance, was present in all samples genotyped, the pfmdr1 N86Y was absent. For P. vivax isolates, an amplification rate of 20% was found for the pvmdr1 gene. The results of the study are in agreement with the low amplification rates for pfmdr1 gene evidenced in the Americas and Africa, while higher rates have been described in Southeast Asia. For P. vivax, very low rates of amplification for pvmdr1 have been described worldwide, with exceptions in French Guiana, Cambodia, Thailand and Brazil. Conclusions The present study was the first to evaluate gch1 CNV in P. falciparum isolates from Brazil, showing an absence of amplification of this gene more than 20 years after the withdrawal of the Brazilian antifolates therapeutic scheme. Furthermore, the rate of pvmdr1 amplification was significantly higher than that previously reported for isolates circulating in Northern Brazil. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1806-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gabriel Luíz Costa
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Lara Cotta Amaral
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | | | - Luzia Helena Carvalho
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Cristiana Ferreira Alves de Brito
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Taís Nóbrega de Sousa
- Molecular Biology and Malaria Immunology Research Group, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil.
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Denoeud-Ndam L, Dicko A, Baudin E, Guindo O, Grandesso F, Sagara I, Lasry E, Palma PP, Parra AML, Stepniewska K, Djimde AA, Barnes KI, Doumbo OK, Etard JF. A multi-center, open-label trial to compare the efficacy and pharmacokinetics of Artemether-Lumefantrine in children with severe acute malnutrition versus children without severe acute malnutrition: study protocol for the MAL-NUT study. BMC Infect Dis 2015; 15:228. [PMID: 26068100 PMCID: PMC4464227 DOI: 10.1186/s12879-015-0963-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/27/2015] [Indexed: 11/23/2022] Open
Abstract
Background Malnutrition and malaria frequently coexist in sub-Saharan African countries. Studies on efficacy of antimalarial treatments usually follow the WHO standardized protocol in which severely malnourished children are systematically excluded. Few studies have assessed the efficacy of chloroquine, sulfadoxine-pyrimethamine and quinine in severe acute malnourished children. Overall, efficacy of these treatments appeared to be reduced, attributed to lower immunity and for some antimalarials altered pharmacokinetic profiles and lower drug concentrations. However, similar research on the efficacy and pharmacokinetic profiles of artemisinin-combination therapies (ACTs) and especially artemether-lumefantrine in malnourished children is currently lacking. The main objective of this study is to assess whether artemether-lumefantrine is less efficacious in children suffering from severe acute malnutrition (SAM) compared to non-SAM children, and if so, to what extent this can be attributed to a sub-optimal pharmacokinetic profile. Methods/design In two sites, Ouelessebougou, Mali and Maradi, Niger, children with uncomplicated microscopically-confirmed P. falciparum malaria aged between 6 and 59 months will be enrolled. Two non-SAM children will be enrolled after the enrolment of each SAM case. Children with severe manifestations of malaria or complications of acute malnutrition needing intensive treatment will be excluded. Treatment intakes will be supervised and children will be followed-up for 42 days, according to WHO guidance for surveillance of antimalarial drug efficacy. Polymerase Chain Reaction genotyping will be used to distinguish recrudescence from re-infection. SAM children will also benefit from the national nutritional rehabilitation program. Outcomes will be compared between the SAM and non-SAM populations. The primary outcome will be adequate clinical and parasitological response at day 28 after PCR correction, estimated by Kaplan-Meier analysis. To assess the pharmacokinetic profile of lumefantrine, a sparse sampling approach will be used with randomized allocation of sampling times (5 per child). A total of 180 SAM children and 360 non-SAM children will be recruited during the 2013 and 2014 malaria seasons. Discussion This study will provide important information that is currently lacking on the effect of SAM on therapeutic efficacy and pharmacokinetic profile of artemether-lumefantrine. If it shows lower therapeutic efficacy and decreased lumefantrine concentrations, it would inform dose optimization studies in SAM children. Trial registration ClinicalTrials.gov: NCT01958905
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Affiliation(s)
| | - Alassane Dicko
- Malaria Research and Training Center, Faculte de Médecine, Pharmacie et d'Odonto-stomatologie, Université des Sciences Techniques et Technologies de Bamako, Bamako, Mali.
| | | | | | | | - Issaka Sagara
- Malaria Research and Training Center, Faculte de Médecine, Pharmacie et d'Odonto-stomatologie, Université des Sciences Techniques et Technologies de Bamako, Bamako, Mali.
| | | | | | | | - Kasia Stepniewska
- Worldwide Antimalarial Resistance Network (WWARN), Oxford, UK. .,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Abdoulaye A Djimde
- Malaria Research and Training Center, Faculte de Médecine, Pharmacie et d'Odonto-stomatologie, Université des Sciences Techniques et Technologies de Bamako, Bamako, Mali.
| | - Karen I Barnes
- Worldwide Antimalarial Resistance Network (WWARN), Oxford, UK. .,Division of Clinical Pharmacology, University of Cape Town, Cape Town, South Africa.
| | - Ogobara K Doumbo
- Malaria Research and Training Center, Faculte de Médecine, Pharmacie et d'Odonto-stomatologie, Université des Sciences Techniques et Technologies de Bamako, Bamako, Mali.
| | - Jean-François Etard
- Epicentre, Paris, France. .,TransVIHMI UMI 233, Institut de recherche pour le développement (IRD) - Inserm U 1175 - Montpellier 1 University, Montpellier, France.
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Low Prevalence of Pfcrt Resistance Alleles among Patients with Uncomplicated Falciparum Malaria in Niger Six Years after Chloroquine Withdrawal. Malar Res Treat 2014; 2014:614190. [PMID: 25506465 PMCID: PMC4259070 DOI: 10.1155/2014/614190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/04/2014] [Indexed: 01/06/2023] Open
Abstract
Chloroquine (CQ) resistance is widespread in Africa, but few data are available for Niger. Pfcrt haplotypes (aa 56–118) and ex vivo responses to CQ and amodiaquine were characterized for 26 isolates collected in South Niger from children under 15 years of age suffering from uncomplicated falciparum malaria, six years after the introduction of artemisinin-based combinations and the withdrawal of CQ. The wild-type Pfcrt haplotype CVMNK was found in 22 of the 26 isolates, with CVIET sequences observed in only three of the samples. We also describe for the first time a new CVINT haplotype. The ex vivo responses were better for CVMNK than for CVIET parasites. Pfcrt sequence data were compared with those obtained for 26 additional parasitized blood samples collected in Gabon, from an area of CQ resistance used as a control. Our findings suggest that there has been a significant decline in CQ-resistant genotypes since the previous estimates for Niger were obtained. No such decline in molecular resistance to CQ was observed in the subset of samples collected in similar conditions from Gabon. These results have important implications for public health and support the policy implemented in Niger since 2005, which aims to increase the efficacy and availability of antimalarial drugs whilst controlling the spread of resistance.
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Evaluation of antimalarial resistance marker polymorphism in returned migrant workers in China. Antimicrob Agents Chemother 2014; 59:326-30. [PMID: 25348538 DOI: 10.1128/aac.04144-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Imported malaria has been a great challenge for public health in China due to decreased locally transmitted cases and frequent exchange worldwide. Plasmodium falciparum has been mainly responsible for the increasing impact. Currently, artesunate plus amodiaquine, one of the artemisinin combination therapies recommended by the World Health Organization, has been mainly used against uncomplicated P. falciparum malaria in China. However, drug resistance marker polymorphism in returning migrant workers has not been demonstrated. Here, we have evaluated the prevalence of pfmdr1 and pfcrt polymorphisms, as well as the K13 propeller gene, a molecular marker of artemisinin resistance, in migrant workers returned from Ghana to Shanglin County, Guangxi Province, China, in 2013. A total of 118 blood samples were randomly selected and used for the assay. Mutations of the pfmdr1 gene that covered codons 86, 184, 1034, and 1246 were found in 11 isolates. Mutations at codon N86Y (9.7%) were more frequent than at others, and Y(86)Y(184)S(1034)D(1246) was the most prevalent (63.6%) of the four haplotypes. Mutations of the pfcrt gene that covered codons 74, 75, and 76 were observed in 17 isolates, and M(74)N(75)T(76) was common (70.6%) in three haplotypes. Eight different genotypes of the K13 propeller were first observed in 10 samples in China, 2 synonymous mutations (V487V and A627A) and 6 nonsynonymous mutations. C580Y was the most prevalent (2.7%) in all the samples. The data presented might be helpful for enrichment of molecular surveillance of antimalarial resistance and will be useful for developing and updating antimalarial guidance in China.
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Lo AC, Faye B, Ba EH, Cisse B, Tine R, Abiola A, Ndiaye M, Ndiaye JLA, Ndiaye D, Sokhna C, Gomis JF, Dieng Y, Faye O, Ndir O, Milligan P, Cairns M, Hallett R, Sutherland C, Gaye O. Prevalence of molecular markers of drug resistance in an area of seasonal malaria chemoprevention in children in Senegal. Malar J 2013; 12:137. [PMID: 23617576 PMCID: PMC3652725 DOI: 10.1186/1475-2875-12-137] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 04/07/2013] [Indexed: 11/23/2022] Open
Abstract
Background In sub-Saharan Africa, malaria is the leading cause of morbidity and mortality especially in children. In Senegal, seasonal malaria chemoprevention (SMC) previously referred to as intermittent preventive treatment in children (IPTc) is a new strategy for malaria control in areas of high seasonal transmission. An effectiveness study of SMC, using sulphadoxine-pyrimethamine (SP) plus amodiaquine (AQ), was conducted in central Senegal from 2008 to 2010 to obtain information about safety, feasibility of delivery, and cost effectiveness of SMC. Here are report the effect of SMC delivery on the prevalence of markers of resistance to SP and AQ. Methods This study was conducted in three health districts in Senegal with 54 health posts with a gradual introduction of SMC. Three administrations of the combination AQ + SP were made during the months of September, October and November of each year in children aged less than 10 years living in the area. Children were surveyed in December of each year and samples (filter paper and thick films) were made in 2008, 2009 and 2010. The prevalence of mutations in the pfdhfr, pfdhps, pfmdr1 and pfcrt genes was investigated by sequencing and RTPCR in samples positive by microscopy for Plasmodium falciparum. Results Mutations at codon 540 of pfdhps and codon 164 of pfdhfr were not detected in the study. Among children with parasitaemia at the end of the transmission seasons, the CVIET haplotypes of pfcrt and the 86Y polymorphism of pfmdr1 were more common among those that had received SMC, but the number of infections detected was very low and confidence intervals were wide. The overall prevalence of these mutations was lower in SMC areas than in control areas, reflecting the lower prevalence of parasitaemia in areas where SMC was delivered. Conclusion The sensitivity of P. falciparum to SMC drugs should be regularly monitored in areas deploying this intervention. Overall the prevalence of genotypes associated with resistance to either SP or AQ was lower in SMC areas due to the reduced number of parasitaemia individuals.
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Affiliation(s)
- Aminata C Lo
- Service of Parasitology, Faculty of Medicine, University Cheikh Anta Diop, Dakar, Senegal.
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Kuntworbe N, Martini N, Shaw J, Al-Kassas R. Malaria Intervention Policies and Pharmaceutical Nanotechnology as a Potential Tool for Malaria Management. Drug Dev Res 2012. [DOI: 10.1002/ddr.21010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Noble Kuntworbe
- School of Pharmacy; Faculty of Medical and Health Sciences; The University of Auckland; Auckland; New Zealand
| | - Nataly Martini
- School of Pharmacy; Faculty of Medical and Health Sciences; The University of Auckland; Auckland; New Zealand
| | - John Shaw
- School of Pharmacy; Faculty of Medical and Health Sciences; The University of Auckland; Auckland; New Zealand
| | - Raida Al-Kassas
- School of Pharmacy; Faculty of Medical and Health Sciences; The University of Auckland; Auckland; New Zealand
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Detection of high levels of mutations involved in anti-malarial drug resistance in Plasmodium falciparum and Plasmodium vivax at a rural hospital in southern Ethiopia. Malar J 2011; 10:214. [PMID: 21810256 PMCID: PMC3161020 DOI: 10.1186/1475-2875-10-214] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 08/02/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Ethiopia, malaria is caused by Plasmodium falciparum and Plasmodium vivax, and anti-malarial drug resistance is the most pressing problem confronting control of the disease. Since co-infection by both species of parasite is common and sulphadoxine-pyrimethamine (SP) has been intensively used, resistance to these drugs has appeared in both P. falciparum and P. vivax populations. This study was conducted to assess the prevalence of anti-malarial drug resistance in P. falciparum and P. vivax isolates collected at a rural hospital in southern Ethiopia. METHODS A total of 1,147 patients with suspected malaria were studied in different months across the period 2007-2009. Plasmodium falciparum dhfr and dhps mutations and P. vivax dhfr polymorphisms associated with resistance to SP, as well as P. falciparum pfcrt and pfmdr1 mutations conferring chloroquine resistance, were assessed. RESULTS PCR-based diagnosis showed that 125 of the 1147 patients had malaria. Of these, 52.8% and 37.6% of cases were due to P. falciparum and P. vivax respectively. A total of 10 cases (8%) showed co-infection by both species and two cases (1.6%) were infected by Plasmodium ovale. Pfdhfr triple mutation and pfdhfr/pfdhps quintuple mutation occurred in 90.8% (95% confidence interval [CI]: 82.2%-95.5%) and 82.9% (95% CI: 72.9%-89.7%) of P. falciparum isolates, respectively. Pfcrt T76 was observed in all cases and pfmdr1 Y86 and pfmdr1 Y1246 in 32.9% (95% CI: 23.4%-44.15%) and 17.1% (95% CI: 10.3-27.1%), respectively. The P. vivax dhfr core mutations, N117 and R58, were present in 98.2% (95% CI: 89.4-99.9%) and 91.2% (95% CI: 80.0-96.7%), respectively. CONCLUSION Current molecular data show an extraordinarily high frequency of drug-resistance mutations in both P. falciparum and P. vivax in southern Ethiopia. Urgent surveillance of the emergence and spread of resistance is thus called for. The level of resistance indicates the need for implementation of entire population access to the new first-line treatment with artemether-lumefantrine, accompanied by government monitoring to prevent the emergence of resistance to this treatment.
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Spalding MD, Eyase FL, Akala HM, Bedno SA, Prigge ST, Coldren RL, Moss WJ, Waters NC. Increased prevalence of the pfdhfr/phdhps quintuple mutant and rapid emergence of pfdhps resistance mutations at codons 581 and 613 in Kisumu, Kenya. Malar J 2010; 9:338. [PMID: 21106088 PMCID: PMC3001743 DOI: 10.1186/1475-2875-9-338] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 11/24/2010] [Indexed: 12/01/2022] Open
Abstract
Background Anti-malarial drug resistance in Kenya prompted two drug policy changes within a decade: sulphadoxine-pyrimethamine (SP) replaced chloroquine (CQ) as the first-line anti-malarial in 1998 and artemether-lumefantrine (AL) replaced SP in 2004. Two cross-sectional studies were conducted to monitor changes in the prevalence of molecular markers of drug resistance over the period in which SP was used as the first-line anti-malarial. The baseline study was carried out from 1999-2000, shortly after implementation of SP, and the follow-up study occurred from 2003-2005, during the transition to AL. Materials and methods Blood was collected from malaria smear-positive, symptomatic patients presenting to outpatient centers in Kisumu, Kenya, during the baseline and follow-up studies. Isolates were genotyped at codons associated with SP and CQ resistance. In vitro IC50 values for antifolates and quinolones were determined for isolates from the follow-up study. Results The prevalence of isolates containing the pfdhfr N51I/C59R/S108N/pfdhps A437G/K540E quintuple mutant associated with SP-resistance rose from 21% in the baseline study to 53% in the follow-up study (p < 0.001). Isolates containing the pfdhfr I164L mutation were absent from both studies. The pfdhps mutations A581G and A613S/T were absent from the baseline study but were present in 85% and 61%, respectively, of isolates from the follow-up study. At follow-up, parasites with mutations at five pfdhps codons, 436, 437, 540, 581, and 613, accounted for 39% of isolates. The CQ resistance-associated mutations pfcrt K76T and pfmdr1 N86Y rose from 82% to 97% (p = 0.001) and 44% to 76% (p < 0.001), respectively, from baseline to follow-up. Conclusions During the period in which SP was the first-line anti-malarial in Kenya, highly SP-resistant parasites emerged, including isolates harboring pfdhps mutations not previously observed there. SP continues to be widely used in Kenya; however, given the highly resistant genotypes observed in this study, its use as a first-line anti-malarial should be discouraged, particularly for populations without acquired immunity to malaria. The increase in the pfcrt K76T prevalence, despite efforts to reduce CQ use, suggests that either these efforts are not adequate to alleviate CQ pressure in Kisumu, or that drug pressure is derived from another source, such as the second-line anti-malarial amodiaquine.
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Affiliation(s)
- Maroya D Spalding
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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Identification of a mutant PfCRT-mediated chloroquine tolerance phenotype in Plasmodium falciparum. PLoS Pathog 2010; 6:e1000887. [PMID: 20485514 PMCID: PMC2869323 DOI: 10.1371/journal.ppat.1000887] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 04/01/2010] [Indexed: 11/20/2022] Open
Abstract
Mutant forms of the Plasmodium falciparum transporter PfCRT constitute the key determinant of parasite resistance to chloroquine (CQ), the former first-line antimalarial, and are ubiquitous to infections that fail CQ treatment. However, treatment can often be successful in individuals harboring mutant pfcrt alleles, raising questions about the role of host immunity or pharmacokinetics vs. the parasite genetic background in contributing to treatment outcomes. To examine whether the parasite genetic background dictates the degree of mutant pfcrt-mediated CQ resistance, we replaced the wild type pfcrt allele in three CQ-sensitive strains with mutant pfcrt of the 7G8 allelic type prevalent in South America, the Oceanic region and India. Recombinant clones exhibited strain-dependent CQ responses that ranged from high-level resistance to an incremental shift that did not meet CQ resistance criteria. Nonetheless, even in the most susceptible clones, 7G8 mutant pfcrt enabled parasites to tolerate CQ pressure and recrudesce in vitro after treatment with high concentrations of CQ. 7G8 mutant pfcrt was found to significantly impact parasite responses to other antimalarials used in artemisinin-based combination therapies, in a strain-dependent manner. We also report clinical isolates from French Guiana that harbor mutant pfcrt, identical or related to the 7G8 haplotype, and manifest a CQ tolerance phenotype. One isolate, H209, harbored a novel PfCRT C350R mutation and demonstrated reduced quinine and artemisinin susceptibility. Our data: 1) suggest that high-level CQR is a complex biological process dependent on the presence of mutant pfcrt; 2) implicate a role for variant pfcrt alleles in modulating parasite susceptibility to other clinically important antimalarials; and 3) uncover the existence of a phenotype of CQ tolerance in some strains harboring mutant pfcrt. Plasmodium falciparum resistance to the antimalarial drug chloroquine has been found to result primarily from point mutations in PfCRT, which provide a highly sensitive marker of in vivo treatment failure and in vitro resistance. Debate has nonetheless continued about the singular role of mutant PfCRT and the contribution of the parasite genetic background. To address this, we have generated recombinant P. falciparum lines expressing a mutant pfcrt allele, or the reference wild type allele, in three distinct chloroquine-sensitive strains. Their analysis reveals a spectrum of responses ranging from high-level resistance to a previously unrecognized tolerance phenotype. The latter is characterized by virtually unchanged chloroquine IC50 values, significantly elevated IC90 values, and the ability to recrudesce after exposure to drug concentrations that are lethal to chloroquine-sensitive parasites. This tolerance phenotype was also observed in an isolate from French Guiana, confirming its presence in malaria-endemic regions. Mutant PfCRT significantly affected parasite responses to other antimalarials, including ones used in artemisinin-based combination therapies, in a strain-dependent manner. Our data suggest that successful CQ treatment of drug-resistant parasites is dependent on both host immunity and the strain-dependent extent to which mutant pfcrt imparts resistance.
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Djimde AA, Barger B, Kone A, Beavogui AH, Tekete M, Fofana B, Dara A, Maiga H, Dembele D, Toure S, Dama S, Ouologuem D, Sangare CPO, Dolo A, Sogoba N, Nimaga K, Kone Y, Doumbo OK. A molecular map of chloroquine resistance in Mali. ACTA ACUST UNITED AC 2009; 58:113-8. [PMID: 20041947 DOI: 10.1111/j.1574-695x.2009.00641.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plasmodium falciparum chloroquine resistance (CQR) transporter point mutation (PfCRT 76T) is known to be the key determinant of CQR. Molecular detection of PfCRT 76T in field samples may be used for the surveillance of CQR in malaria-endemic countries. The genotype-resistance index (GRI), which is obtained as the ratio of the prevalence of PfCRT 76T to the incidence of CQR in a clinical trial, was proposed as a simple and practical molecular-based addition to the tools currently available for monitoring CQR in the field. In order to validate the GRI model across populations, time, and resistance patterns, we compiled data from the literature and generated new data from 12 sites across Mali. We found a mean PfCRT 76T mutation prevalence of 84.5% (range 60.9-95.1%) across all sites. CQR rates predicted from the GRI model were extrapolated onto a map of Mali to show the patterns of resistance throughout the participating regions. We present a comprehensive map of CQR in Mali, which strongly supports recent changes in drug policy away from chloroquine.
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Affiliation(s)
- Abdoulaye A Djimde
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odonto-Stomatology, University of Bamako, Mali, West Africa.
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Picot S, Olliaro P, de Monbrison F, Bienvenu AL, Price RN, Ringwald P. A systematic review and meta-analysis of evidence for correlation between molecular markers of parasite resistance and treatment outcome in falciparum malaria. Malar J 2009; 8:89. [PMID: 19413906 PMCID: PMC2681474 DOI: 10.1186/1475-2875-8-89] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 05/04/2009] [Indexed: 01/17/2023] Open
Abstract
Background An assessment of the correlation between anti-malarial treatment outcome and molecular markers would improve the early detection and monitoring of drug resistance by Plasmodium falciparum. The purpose of this systematic review was to determine the risk of treatment failure associated with specific polymorphisms in the parasite genome or gene copy number. Methods Clinical studies of non-severe malaria reporting on target genetic markers (SNPs for pfmdr1, pfcrt, dhfr, dhps, gene copy number for pfmdr1) providing complete information on inclusion criteria, outcome, follow up and genotyping, were included. Three investigators independently extracted data from articles. Results were stratified by gene, codon, drug and duration of follow-up. For each study and aggregate data the random effect odds ratio (OR) with 95%CIs was estimated and presented as Forest plots. An OR with a lower 95th confidence interval > 1 was considered consistent with a failure being associated to a given gene mutation. Results 92 studies were eligible among the selection from computerized search, with information on pfcrt (25/159 studies), pfmdr1 (29/236 studies), dhfr (18/373 studies), dhps (20/195 studies). The risk of therapeutic failure after chloroquine was increased by the presence of pfcrt K76T (Day 28, OR = 7.2 [95%CI: 4.5–11.5]), pfmdr1 N86Y was associated with both chloroquine (Day 28, OR = 1.8 [95%CI: 1.3–2.4]) and amodiaquine failures (OR = 5.4 [95%CI: 2.6–11.3, p < 0.001]). For sulphadoxine-pyrimethamine the dhfr single (S108N) (Day 28, OR = 3.5 [95%CI: 1.9–6.3]) and triple mutants (S108N, N51I, C59R) (Day 28, OR = 3.1 [95%CI: 2.0–4.9]) and dhfr-dhps quintuple mutants (Day 28, OR = 5.2 [95%CI: 3.2–8.8]) also increased the risk of treatment failure. Increased pfmdr1 copy number was correlated with treatment failure following mefloquine (OR = 8.6 [95%CI: 3.3–22.9]). Conclusion When applying the selection procedure for comparative analysis, few studies fulfilled all inclusion criteria compared to the large number of papers identified, but heterogeneity was limited. Genetic molecular markers were related to an increased risk of therapeutic failure. Guidelines are discussed and a checklist for further studies is proposed.
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Affiliation(s)
- Stéphane Picot
- Malaria Research Unit, EA 4170, University Lyon 1, Faculty of Medicine, Lyon, France.
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Reduced efficacy of intermittent preventive treatment of malaria in malnourished children. Antimicrob Agents Chemother 2009; 53:1753-9. [PMID: 19223620 DOI: 10.1128/aac.01723-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intermittent preventive treatment in infants with sulfadoxine-pyrimethamine (IPTi-SP) reduces malaria episodes by 20 to 59% across Africa. This protective efficacy, however, may be affected by the high frequency of malnutrition in African infants. We analyzed the impact of malnutrition as defined by anthropometry on the incidence of malaria and on the protective efficacy of IPTi in a cohort of 1,200 children in northern Ghana, where malaria is hyperendemic. These children received IPTi-SP or placebo at 3, 9, and 15 months of age and were monitored until 24 months of age. Malnutrition was present in 32, 40, and 50% of children at ages 3, 9, and 15 months, respectively. It was associated with increased risks of severe anemia and death but not an increased risk of malaria. Although malaria slightly contributed to chronic malnutrition, IPTi did not substantially improve child growth. Importantly, the protective efficacies of IPTi in malnourished children were roughly half or even less of those observed in nonmalnourished children. In the first year of life, IPTi reduced the incidence of malaria to a significantly lesser extent in infants who received both doses in a malnourished condition (25%; 95% confidence interval [CI], -7 to 48%) compared to that of nonmalnourished children (46%; 95% CI, 30 to 58%; P = 0.049). Moreover, in contrast to nutritionally advantaged children, the rate of severe malaria appeared to be increased in malnourished children who took IPTi. IPTi might exhibit reduced efficacy in regions of abundant malnutrition. Concomitant nutrition programs may be needed in these places to achieve the desired impact.
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Tatfeng MY, Agbonlahor DE, Olalekan AO, Oviasogie F, Isibor J. Chloroquine resistance molecular markers in Falciparum malaria in Edo state. Trop Med Health 2009. [DOI: 10.2149/tmh.2008-08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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15
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Figueiredo P, Benchimol C, Lopes D, Bernardino L, do Rosário VE, Varandas L, Nogueira F. Prevalence of pfmdr1, pfcrt, pfdhfr and pfdhps mutations associated with drug resistance, in Luanda, Angola. Malar J 2008; 7:236. [PMID: 19014684 PMCID: PMC2613152 DOI: 10.1186/1475-2875-7-236] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 11/17/2008] [Indexed: 11/13/2022] Open
Abstract
Background Malaria is the infectious disease causing the highest morbidity and mortality in Angola and due to widespread chloroquine (CQ) resistance, the country has recently changed its first-line treatment recommendations for uncomplicated malaria, from CQ to artemisinin combination therapies (ACT) in adults, and sulphadoxine/pyrimethamine (S/P) in pregnant women. Loss of SP sensitivity is, however, progressing rapidly in Africa and, in this study, were investigated a number of molecular markers associated to CQ and S/P. Methods Blood samples were collected from 245 children with uncomplicated malaria, admitted at the Pediatric Hospital Dr. David Bernardino (HPDB), Angola, and the occurrence of mutations in Plasmodium falciparum was investigated in the pfmdr1 (N86Y) and pfcrt (K76T) genes, associated with CQ resistance, as well as in pfdhfr (C59R) and pfdhps (K540E), conferring SP resistance. Results The frequencies of pfmdr1 mutations in codon 86 were 28.6% N, 61.3% Y and 10.1% mixed infections (NY). The frequency of pfcrt mutations in codon 76 were 93.9% K, 5.7% T and 0.4% mixed infections (KT). For pfdhfr the results were in codon 59, 60.6% C, 20.6% R and 18.8% mixed infections (CR). Concerning pfdhps, 6.3% of the isolates were bearers of the mutation 540E and 5.4% mixed infections (K540E). Conclusion The results of this epidemiologic study showed high presence of CQ resistance markers while for SP a much lower prevalence was detected for the markers under study.
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Affiliation(s)
- Paula Figueiredo
- UEI Malária/Centro de Malária e Doenças Tropicais/IHMT/Universidade Nova de Lisboa, Lisbon, Portugal.
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Ogungbamigbe TO, Ojurongbe O, Ogunro PS, Okanlawon BM, Kolawole SO. Chloroquine resistant Plasmodium falciparum malaria in Osogbo Nigeria: efficacy of amodiaquine + sulfadoxine-pyrimethamine and chloroquine + chlorpheniramine for treatment. Mem Inst Oswaldo Cruz 2008; 103:79-84. [PMID: 18368238 DOI: 10.1590/s0074-02762008000100012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 02/18/2008] [Indexed: 11/22/2022] Open
Abstract
Chloroquine (CQ) resistance in Plasmodium falciparum contributes to increasing malaria-attributable morbidity and mortality in Sub-Saharan Africa. Despite a change in drug policy, continued prescription of CQ did not abate. Therefore the therapeutic efficacy of CQ in uncomplicated falciparum malaria patients was assessed in a standard 28-day protocol in 116 children aged between six and 120 months in Osogbo, Southwest Nigeria. Parasitological and clinical assessments of response to treatment showed that 72 (62.1%) of the patients were cured and 44 (37.9%) failed the CQ treatment. High initial parasite density and young age were independent predictors for early treatment failure. Out of the 44 patients that failed CQ, 24 received amodiaquine + sulphadoxine/pyrimethamine (AQ+SP) and 20 received chlorpheniramine + chloroquine (CH+CQ) combinations. Mean fever clearance time in those treated with AQ+SP was not significantly different from those treated with CH+CQ (p = 0.05). There was no significant difference in the mean parasite density of the two groups. The cure rate for AQ+SP group was 92% while those of CH+CQ was 85%. There was a significant difference in parasite clearance time (p = 0.01) between the two groups. The 38% treatment failure for CQ reported in this study is higher than the 10% recommended by World Health Organization in other to effect change in antimalarial treatment policy. Hence we conclude that CQ can no more be solely relied upon for the treatment of falciparum malaria in Osogbo, Nigeria. AQ+SP and CH+CQ are effective in the treatment of acute uncomplicated malaria and may be considered as useful alternative drugs in the absence of artemisinin-based combination therapies.
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Affiliation(s)
- T O Ogungbamigbe
- Malaria Research Clinic & Laboratory, College of Health Sciences, Ladoke Akintola University Teaching Hospital, Osogbo, Nigeria
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Mandi G, Mockenhaupt FP, Coulibaly B, Meissner P, Müller O. Efficacy of amodiaquine in the treatment of uncomplicated falciparum malaria in young children of rural north-western Burkina Faso. Malar J 2008; 7:58. [PMID: 18419816 PMCID: PMC2358917 DOI: 10.1186/1475-2875-7-58] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Accepted: 04/17/2008] [Indexed: 01/03/2023] Open
Abstract
Background Combination therapy has become a new paradigm in malaria treatment. Amodiaquine is a common partner drug in different malaria combination therapies used or investigated in sub-Saharan Africa, but data on its efficacy as a single drug are scarce. Methods The objective of the study was to determine the efficacy of amodiaquine against falciparum malaria in neighbouring rural and urban areas of north-western Burkina Faso. The study was designed as an uncontrolled trial in children aged 6–59 months with uncomplicated falciparum malaria in the Nouna Health District. Results During the rainy season 2005, 117 children were enrolled, 62 from the rural and 55 from the urban study area. The crude adequate clinical and parasitological response (ACPR) rate was 103/117 (88%) by day 14 but decreased to 28/117 (24%) by day 28. After PCR correction for reinfections, ACPR rates were 108/117 (92%) and 71/117 (61%) by day 14 and day 28, respectively. There were no significant differences in efficacy between urban and rural areas. The Plasmodium falciparum crt K76T mutation not predict AQ failure, but was selected in parasites re-appearing following treatment. No serious adverse events occurred and only 16 other adverse events were recorded. Conclusion Compared to chloroquine, amodiaquine is more effective against uncomplicated falciparum malaria in Burkina Faso. However, a considerable degree of amodiaquine resistance already exists and it is currently unclear how this resistance will develop when amodiaquine in combination with other drugs is used on a large scale. Trial registration Current Controlled Trials ISRCTN73824458.
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Affiliation(s)
- Germain Mandi
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso.
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Meissner PE, Mandi G, Mockenhaupt FP, Witte S, Coulibaly B, Mansmann U, Frey C, Merkle H, Burhenne J, Walter-Sack I, Müller O. Marked differences in the prevalence of chloroquine resistance between urban and rural communities in Burkina Faso. Acta Trop 2008; 105:81-6. [PMID: 17904509 DOI: 10.1016/j.actatropica.2007.07.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2006] [Revised: 07/22/2007] [Accepted: 07/30/2007] [Indexed: 11/28/2022]
Abstract
BACKGROUND Chloroquine (CQ) resistance has reached high levels in Africa in recent years. Little is known about variations of resistance between urban and rural areas. OBJECTIVES To compare the rates of in vivo resistance to CQ and the prevalences of the main molecular marker for CQ resistance among young children from urban and rural areas in Burkina Faso. METHODS The current analysis used the frame of a randomized controlled trial (ISRCTN27290841) on the combination CQ-methylene blue (MB) (n=177) compared to CQ alone (n=45) in young children with uncomplicated malaria. We examined clinical and parasitological failure rates as well as the prevalence of the Plasmodium falciparum chloroquine resistance transporter gene (pfcrt) T76 mutation. RESULTS Clinical and parasitological failure rates of CQ-MB differed significantly between urban (70%) and rural areas (29%, p<0.0001). Likewise, CQ failure rates were higher in the urban setting. Matching this pattern, pfcrt T76 was more frequently seen among parasite strains from urban areas (81%) when compared to rural ones (64%, p=0.01). In the presence of parasites exhibiting pfcrt T76, the odds of overall clinical failure were increased to 2.6-fold ([1.33, 5.16], p(LR)=0.005). CQ was detected at baseline in 21% and 2% of children from the urban and the rural study area, respectively (p(Chi)=0.002). CONCLUSION Even within circumscribed geographical areas, CQ efficacy can vary dramatically. The differences in the prevalence of pfcrt T76 and in CQ failure rates are probably explained by a higher drug pressure in the urban area compared to the rural study area. This finding has important implications for national malaria policies.
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Affiliation(s)
- Peter E Meissner
- Department of Tropical Hygiene and Public Health, Ruprecht-Karls-University, Heidelberg, Germany.
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Abstract
Several mutations have been identified in Plasmodium falciparum that cause, or contribute to, drug resistance. It is relatively easy to measure their prevalence in human blood samples, so they are often used to infer drug failure rates, clinical and parasitological, that will occur in the human population. One current method of making this inference is through the use of genotypic resistance and genotypic failure indices. These indices are rather sensitive to background drug failures rates (i.e. failures not caused by the mutation), to mutation prevalence, and to the genetic background in which the marker occurs. Extreme care should therefore be taken in the construction and interpretation of these indices.
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Mockenhaupt FP, Reither K, Zanger P, Roepcke F, Danquah I, Saad E, Ziniel P, Dzisi SY, Frempong M, Agana-Nsiire P, Amoo-Sakyi F, Otchwemah R, Cramer JP, Anemana SD, Dietz E, Bienzle U. Intermittent preventive treatment in infants as a means of malaria control: a randomized, double-blind, placebo-controlled trial in northern Ghana. Antimicrob Agents Chemother 2007; 51:3273-81. [PMID: 17638703 PMCID: PMC2043181 DOI: 10.1128/aac.00513-07] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Morbidity and mortality from malaria remain unacceptably high among young children in sub-Saharan Africa. Intermittent preventive treatment in infancy (IPTi) involves the administration of antimalarials alongside routine vaccinations and might be an option in malaria control. In an area of intense, perennial malaria transmission in northern Ghana, 1,200 children received IPTi with sulfadoxine-pyrimethamine or placebo at approximately 3, 9, and 15 months of age. Children were followed up until 24 months of age to assess morbidity and adverse events. During the intervention period (3 to 18 months of age), IPTi reduced the incidences of malaria and severe anemia by 22.5% (95% confidence interval, 12 to 32%) and 23.6% (95% confidence interval, 4 to 39%), respectively, and reduced hospitalizations and episodes of asymptomatic parasitemia by one-third. Protection was pronounced in the first year of life and not discernible in the second. The malaria-protective effect was largely confined to a period of 1 month after sulfadoxine-pyrimethamine treatments. Following the intervention, protection against asymptomatic parasitemia persisted. In contrast, a significant rebound of severe malaria, predominantly severe malarial anemia, occurred among children having received IPTi. Although the treatment was generally well tolerated, one case of moderately severe skin reaction followed sulfadoxine-pyrimethamine treatment. IPTi reduces malaria and anemia in infants in northern Ghana. Extension of IPTi into the second year of life by administering a dose at 15 months of age provided no substantial benefit beyond a 1-month prophylactic effect. Although this simple intervention offers one of the few available malaria-preventive measures for regions where malaria is endemic, the observed rebound of severe malaria advises caution and requires further investigation.
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Affiliation(s)
- Frank P Mockenhaupt
- Institute of Tropical Medicine and International Health, Charité--University Medicine Berlin, Berlin, Germany.
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Ehrhardt S, Eggelte TA, Kaiser S, Adjei L, Burchard GD, Anemana SD, Bienzle U, Mockenhaupt FP. Large-scale surveillance of Plasmodium falciparum crt(K76T) in northern Ghana. Antimicrob Agents Chemother 2007; 51:3407-9. [PMID: 17562799 PMCID: PMC2043215 DOI: 10.1128/aac.00179-07] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Surveillance of Plasmodium falciparum crt(K76T) [Pfcrt(K76T)], a resistance marker of chloroquine and, limitedly, amodiaquine, in >4,000 children in northern Ghana revealed a prevalence of 79%. Pfcrt(K76T) was heterogeneously distributed and associated with chloroquine use, low parasitemia, and the dry season. Widespread chloroquine resistance challenges the regional life span of amodiaquine as a partner drug in artemisinin combination therapy.
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Affiliation(s)
- Stephan Ehrhardt
- Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Strasse 74, 20359 Hamburg, Germany.
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23
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Wichmann O, Eggelte TA, Gellert S, Osman ME, Mylius F, Ehrhardt S, Anemana SD, Bienzle U, Mockenhaupt FP. High residual chloroquine blood levels in African children with severe malaria seeking healthcare. Trans R Soc Trop Med Hyg 2007; 101:637-42. [PMID: 17467758 DOI: 10.1016/j.trstmh.2007.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 03/05/2007] [Accepted: 03/05/2007] [Indexed: 10/23/2022] Open
Abstract
Despite widespread resistance, chloroquine remains widely used in West Africa, particularly in home treatment. We examined chloroquine blood levels on admission to a referral hospital with respect to the manifestation of severe malaria in 290 Ghanaian children. Of the patients, 78% exhibited chloroquine concentrations (subtherapeutic, 35%; therapeutic, 37%; supratherapeutic, 6%) and 11% died. Most parasites (78%) carried the pfcrt-T76 chloroquine resistance mutation. High drug concentrations correlated with reduced parasitaemia but also with selection of resistant parasites, lower respiratory and heart rates, increased plasma lactate levels and impaired consciousness. Geometric mean chloroquine concentrations tended to be higher in children who died than in survivors (1.135 vs. 778nmol/l; P=0.09). Supratherapeutic drug levels (>5000nmol/l) were associated with fatal outcome (odds ratio 8.6; 95% CI 1.4-51.7). Residual chloroquine concentrations were found to be abundant in children with severe malaria and to be associated with alterations in the clinical manifestation of the disease and its case fatality. This may result from toxic effects of the drug and/or reflect preceding overtreatment in children with acute life-threatening disease. In areas of intense chloroquine resistance and frequent pre-treatment, additional administration of chloroquine at hospital admission is not only ineffective but may even further endanger patients.
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Affiliation(s)
- Ole Wichmann
- Institute of Tropical Medicine and International Health, Charité University Medicine, Berlin, Germany.
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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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Schunk M, Kumma WP, Miranda IB, Osman ME, Roewer S, Alano A, Löscher T, Bienzle U, Mockenhaupt FP. High prevalence of drug-resistance mutations in Plasmodium falciparum and Plasmodium vivax in southern Ethiopia. Malar J 2006; 5:54. [PMID: 16817953 PMCID: PMC1524791 DOI: 10.1186/1475-2875-5-54] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 07/03/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Ethiopia, malaria is caused by both Plasmodium falciparum and Plasmodium vivax. Drug resistance of P. falciparum to sulfadoxine-pyrimethamine (SP) and chloroquine (CQ) is frequent and intense in some areas. METHODS In 100 patients with uncomplicated malaria from Dilla, southern Ethiopia, P. falciparum dhfr and dhps mutations as well as P. vivax dhfr polymorphisms associated with resistance to SP and P. falciparum pfcrt and pfmdr1 mutations conferring CQ resistance were assessed. RESULTS P. falciparum and P. vivax were observed in 69% and 31% of the patients, respectively. Pfdhfr triple mutations and pfdhfr/pfdhps quintuple mutations occurred in 87% and 86% of P. falciparum isolates, respectively. Pfcrt T76 was seen in all and pfmdr1 Y86 in 81% of P. falciparum. The P. vivax dhfr core mutations N117 and R58 were present in 94% and 74%, respectively. CONCLUSION These data point to an extraordinarily high frequency of drug-resistance mutations in both P. falciparum and P. vivax in southern Ethiopia, and strongly support that both SP and CQ are inadequate drugs for this region.
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Affiliation(s)
- Mirjam Schunk
- Department of Infectious Diseases and Tropical Medicine, University of Munich, Leopoldstraße 5, 80802 Munich, Germany
| | - Wondimagegn P Kumma
- Dilla College of Teachers Education and Health Sciences, Debub University, PO Box 419, Awassa, Ethiopia
| | - Isabel Barreto Miranda
- Department of Infectious Diseases and Tropical Medicine, University of Munich, Leopoldstraße 5, 80802 Munich, Germany
| | - Maha E Osman
- Malaria Research Centre (MalRC), Department of Biochemistry, Faculty of Medicine, University of Khartoum, P.O. Box 102, Khartoum, Sudan
- Institute of Tropical Medicine and International Health, Charité – University Medicine Berlin, Spandauer Damm 130, 14050 Berlin, Germany
| | - Susanne Roewer
- Institute of Tropical Medicine and International Health, Charité – University Medicine Berlin, Spandauer Damm 130, 14050 Berlin, Germany
| | - Abraham Alano
- Dilla College of Teachers Education and Health Sciences, Debub University, PO Box 419, Awassa, Ethiopia
| | - Thomas Löscher
- Department of Infectious Diseases and Tropical Medicine, University of Munich, Leopoldstraße 5, 80802 Munich, Germany
| | - Ulrich Bienzle
- Institute of Tropical Medicine and International Health, Charité – University Medicine Berlin, Spandauer Damm 130, 14050 Berlin, Germany
| | - Frank P Mockenhaupt
- Institute of Tropical Medicine and International Health, Charité – University Medicine Berlin, Spandauer Damm 130, 14050 Berlin, Germany
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