1
|
Mansoor R, Commons RJ, Douglas NM, Abuaku B, Achan J, Adam I, Adjei GO, Adjuik M, Alemayehu BH, Allan R, Allen EN, Anvikar AR, Arinaitwe E, Ashley EA, Ashurst H, Asih PBS, Bakyaita N, Barennes H, Barnes KI, Basco L, Bassat Q, Baudin E, Bell DJ, Bethell D, Bjorkman A, Boulton C, Bousema T, Brasseur P, Bukirwa H, Burrow R, Carrara VI, Cot M, D’Alessandro U, Das D, Das S, Davis TME, Desai M, Djimde AA, Dondorp AM, Dorsey G, Drakeley CJ, Duparc S, Espié E, Etard JF, Falade C, Faucher JF, Filler S, Fogg C, Fukuda M, Gaye O, Genton B, Ghulam Rahim A, Gilayeneh J, Gonzalez R, Grais RF, Grandesso F, Greenwood B, Grivoyannis A, Hatz C, Hodel EM, Humphreys GS, Hwang J, Ishengoma D, Juma E, Kachur SP, Kager PA, Kamugisha E, Kamya MR, Karema C, Kayentao K, Kazienga A, Kiechel JR, Kofoed PE, Koram K, Kremsner PG, Lalloo DG, Laman M, Lee SJ, Lell B, Maiga AW, Mårtensson A, Mayxay M, Mbacham W, McGready R, Menan H, Ménard D, Mockenhaupt F, Moore BR, Müller O, Nahum A, Ndiaye JL, Newton PN, Ngasala BE, Nikiema F, Nji AM, Noedl H, Nosten F, Ogutu BR, Ojurongbe O, Osorio L, Ouédraogo JB, Owusu-Agyei S, Pareek A, Penali LK, Piola P, Plucinski M, Premji Z, Ramharter M, Richmond CL, Rombo L, Roper C, Rosenthal PJ, Salman S, Same-Ekobo A, Sibley C, Sirima SB, Smithuis FM, Somé FA, Staedke SG, Starzengruber P, Strub-Wourgaft N, Sutanto I, Swarthout TD, Syafruddin D, Talisuna AO, Taylor WR, Temu EA, Thwing JI, Tinto H, Tjitra E, Touré OA, Tran TH, Ursing J, Valea I, Valentini G, van Vugt M, von Seidlein L, Ward SA, Were V, White NJ, Woodrow CJ, Yavo W, Yeka A, Zongo I, Simpson JA, Guerin PJ, Stepniewska K, Price RN. Haematological consequences of acute uncomplicated falciparum malaria: a WorldWide Antimalarial Resistance Network pooled analysis of individual patient data. BMC Med 2022; 20:85. [PMID: 35249546 PMCID: PMC8900374 DOI: 10.1186/s12916-022-02265-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/18/2022] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia. METHODS Individual patient data from eligible antimalarial efficacy studies of uncomplicated P. falciparum malaria, available through the WorldWide Antimalarial Resistance Network data repository prior to August 2015, were pooled using standardised methodology. The haematological response over time was quantified using a multivariable linear mixed effects model with nonlinear terms for time, and the model was then used to estimate the mean haemoglobin at day of nadir and day 7. Multivariable logistic regression quantified risk factors for moderately severe anaemia (haemoglobin < 7 g/dL) at day 0, day 3 and day 7 as well as a fractional fall ≥ 25% at day 3 and day 7. RESULTS A total of 70,226 patients, recruited into 200 studies between 1991 and 2013, were included in the analysis: 50,859 (72.4%) enrolled in Africa, 18,451 (26.3%) in Asia and 916 (1.3%) in South America. The median haemoglobin concentration at presentation was 9.9 g/dL (range 5.0-19.7 g/dL) in Africa, 11.6 g/dL (range 5.0-20.0 g/dL) in Asia and 12.3 g/dL (range 6.9-17.9 g/dL) in South America. Moderately severe anaemia (Hb < 7g/dl) was present in 8.4% (4284/50,859) of patients from Africa, 3.3% (606/18,451) from Asia and 0.1% (1/916) from South America. The nadir haemoglobin occurred on day 2 post treatment with a mean fall from baseline of 0.57 g/dL in Africa and 1.13 g/dL in Asia. Independent risk factors for moderately severe anaemia on day 7, in both Africa and Asia, included moderately severe anaemia at baseline (adjusted odds ratio (AOR) = 16.10 and AOR = 23.00, respectively), young age (age < 1 compared to ≥ 12 years AOR = 12.81 and AOR = 6.79, respectively), high parasitaemia (AOR = 1.78 and AOR = 1.58, respectively) and delayed parasite clearance (AOR = 2.44 and AOR = 2.59, respectively). In Asia, patients treated with an artemisinin-based regimen were at significantly greater risk of moderately severe anaemia on day 7 compared to those treated with a non-artemisinin-based regimen (AOR = 2.06 [95%CI 1.39-3.05], p < 0.001). CONCLUSIONS In patients with uncomplicated P. falciparum malaria, the nadir haemoglobin occurs 2 days after starting treatment. Although artemisinin-based treatments increase the rate of parasite clearance, in Asia they are associated with a greater risk of anaemia during recovery.
Collapse
|
2
|
Synthesis and Antiparasitic Activity of New Conjugates—Organic Drugs Tethered to Trithiolato-Bridged Dinuclear Ruthenium(II)–Arene Complexes. INORGANICS 2021. [DOI: 10.3390/inorganics9080059] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Tethering known drugs to a metalorganic moiety is an efficient approach for modulating the anticancer, antibacterial, and antiparasitic activity of organometallic complexes. This study focused on the synthesis and evaluation of new dinuclear ruthenium(II)–arene compounds linked to several antimicrobial compounds such as dapsone, sulfamethoxazole, sulfadiazine, sulfadoxine, triclosan, metronidazole, ciprofloxacin, as well as menadione (a 1,4-naphtoquinone derivative). In a primary screen, 30 compounds (17 hybrid molecules, diruthenium intermediates, and antimicrobials) were assessed for in vitro activity against transgenic T. gondii tachyzoites constitutively expressing β-galactosidase (T. gondii β-gal) at 0.1 and 1 µM. In parallel, the cytotoxicity in noninfected host cells (human foreskin fibroblasts, HFF) was determined by an alamarBlue assay. When assessed at 1 µM, five compounds strongly impaired parasite proliferation by >90%, and HFF viability was retained at 50% or more, and they were further subjected to T. gondii β-gal dose-response studies. Two compounds, notably 11 and 13, amide and ester conjugates with sulfadoxine and metronidazole, exhibited low IC50 (half-maximal inhibitory concentration) values 0.063 and 0.152 µM, and low or intermediate impairment of HFF viability at 2.5 µM (83 and 64%). The nature of the anchored drug as well as that of the linking unit impacted the biological activity.
Collapse
|
3
|
Zhou G, Hemming-Schroeder E, Gesuge M, Afrane YA, Lee MC, Atieli HE, Githeko AK, Yan G. Gaps between Knowledge and Malaria Treatment Practices after Intensive Anti-Malaria Campaigns in Western Kenya: 2004-2016. Am J Trop Med Hyg 2020; 102:1358-1365. [PMID: 32189611 DOI: 10.4269/ajtmh.19-0907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Effective case management is central for malaria control, but not all of those affected by malaria have access to prompt, effective treatment. In Kenya, free malaria treatment has been implemented since 2006. However, questions remain regarding effective treatment. We conducted cross-sectional epidemiological and questionnaire surveys in four counties in western Kenya in 2004, 2010, and 2016, and antimalarial availability surveys in 2016. We found a significant decline in self-reported malaria cases and an improvement in knowledge of malaria prevention and treatment since 2004. Parasite prevalence declined significantly from 2004 to 2010; however, it has remained unchanged since then. Artemisinin-based combination therapies (ACTs) and sulfadoxine-pyrimethamine (SP) drugs were widely available everywhere. The proportion of ACT usage increased from none in 2004 to 48% and 69%, respectively, in 2010 and 2016, whereas SP drug usage declined from 88% in 2004 to 39% in 2010 and 27% in 2016. During the 2016 survey, non-intermittent preventive treatment in pregnancy use of SP was common (20.9% of all surveyed individual treatments). In 2004, 27.2% (168/617) of households sought hospital treatment alone, and this number increased to 50.6% in 2016. The key factors affecting treatment-seeking behavior were education level, wealth index, household size, and distance to hospitals. Our results indicated that gaps in malaria case management remain and out-of-policy treatment is still a concern.
Collapse
Affiliation(s)
- Guofa Zhou
- Program in Public Health, University of California, Irvine, California
| | | | - Maxwell Gesuge
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Yaw A Afrane
- College of Health Sciences, University of Ghana, Accra, Ghana
| | - Ming-Chieh Lee
- Program in Public Health, University of California, Irvine, California
| | | | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, California
| |
Collapse
|
4
|
Koukouikila-Koussounda F, Jeyaraj S, Nguetse CN, Nkonganyi CN, Kokou KC, Etoka-Beka MK, Ntoumi F, Velavan TP. Molecular surveillance of Plasmodium falciparum drug resistance in the Republic of Congo: four and nine years after the introduction of artemisinin-based combination therapy. Malar J 2017; 16:155. [PMID: 28420403 PMCID: PMC5395861 DOI: 10.1186/s12936-017-1816-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 04/09/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Resistance to anti-malarial drugs hinders efforts on malaria elimination and eradication. Following the global spread of chloroquine-resistant parasites, the Republic of Congo adopted artemisinin-based combination therapy (ACT) in 2006 as a first-line treatment for uncomplicated malaria. To assess the impacts after implementation of ACT, a molecular surveillance for anti-malarial drug resistance was conducted in Congo 4 and 9 years after the introduction of ACT. METHODS Blood samples of 431 febrile children aged 1-10 years were utilized from two previous studies conducted in 2010 (N = 311) and 2015 (N = 120). All samples were screened for malaria parasites using nested PCR. Direct sequencing was used to determine the frequency distribution of genetic variants in the anti-malarial drug-resistant Plasmodium falciparum genes (Pfcrt, Pfmdr1, Pfatp6, Pfk13) in malaria-positive isolates. RESULTS One-hundred and nineteen (N = 70 from 2010 and N = 49 from 2015) samples were positive for P. falciparum. A relative decrease in the proportion of chloroquine-resistant haplotype (CVIET) from 100% in 2005, 1 year before the introduction and implementation of ACT in 2006, to 98% in 2010 to 71% in 2015 was observed. Regarding the multidrug transporter gene, a considerable reduction in the frequency of the mutations N86Y (from 73 to 27%) and D1246Y (from 22 to 0%) was observed. However, the prevalence of the Y184F mutation remained stable (49% in 2010 compared to 54% in 2015). Isolates carrying the Pfatp6 H243Y was 25% in 2010 and this frequency was reduced to null in 2015. None of the parasites harboured the Pfk13 mutations associated with prolonged artemisinin clearance in Southeast Asia. Nevertheless, 13 new Pfk13 variants are reported among the investigated isolates. CONCLUSION The implementation of ACT has led to the decline in prevalence of chloroquine-resistant parasites in the Republic of Congo. However, the constant prevalence of the PfMDR1 Y184F mutation, associated with lumefantrine susceptibility, indicate a selective drug pressure still exists. Taken together, this study could serve as the basis for epidemiological studies monitoring the distribution of molecular markers of artemisinin resistance in the Republic of Congo.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Médicale (FCRM), Brazzaville, Republic of Congo.,Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Thirumalaisamy P Velavan
- Fondation Congolaise pour la Recherche Médicale (FCRM), Brazzaville, Republic of Congo. .,Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany. .,Duy Tan University, Da Nang, Vietnam. .,Vietnamese-German Centre for Medical Research, Hanoi, Vietnam.
| |
Collapse
|
5
|
Mukaka M, White SA, Terlouw DJ, Mwapasa V, Kalilani-Phiri L, Faragher EB. Is using multiple imputation better than complete case analysis for estimating a prevalence (risk) difference in randomized controlled trials when binary outcome observations are missing? Trials 2016; 17:341. [PMID: 27450066 PMCID: PMC4957845 DOI: 10.1186/s13063-016-1473-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 06/29/2016] [Indexed: 01/30/2023] Open
Abstract
Background Missing outcomes can seriously impair the ability to make correct inferences from randomized controlled trials (RCTs). Complete case (CC) analysis is commonly used, but it reduces sample size and is perceived to lead to reduced statistical efficiency of estimates while increasing the potential for bias. As multiple imputation (MI) methods preserve sample size, they are generally viewed as the preferred analytical approach. We examined this assumption, comparing the performance of CC and MI methods to determine risk difference (RD) estimates in the presence of missing binary outcomes. We conducted simulation studies of 5000 simulated data sets with 50 imputations of RCTs with one primary follow-up endpoint at different underlying levels of RD (3–25 %) and missing outcomes (5–30 %). Results For missing at random (MAR) or missing completely at random (MCAR) outcomes, CC method estimates generally remained unbiased and achieved precision similar to or better than MI methods, and high statistical coverage. Missing not at random (MNAR) scenarios yielded invalid inferences with both methods. Effect size estimate bias was reduced in MI methods by always including group membership even if this was unrelated to missingness. Surprisingly, under MAR and MCAR conditions in the assessed scenarios, MI offered no statistical advantage over CC methods. Conclusion While MI must inherently accompany CC methods for intention-to-treat analyses, these findings endorse CC methods for per protocol risk difference analyses in these conditions. These findings provide an argument for the use of the CC approach to always complement MI analyses, with the usual caveat that the validity of the mechanism for missingness be thoroughly discussed. More importantly, researchers should strive to collect as much data as possible.
Collapse
Affiliation(s)
- Mavuto Mukaka
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Box 30096, Blantyre 3, Malawi. .,Department of Public Health, College of Medicine, University of Malawi, P/Bag 360, Blantyre 3, Malawi. .,Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK. .,Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, 60th Anniversary Chalermprakiat Building, 3rd Floor, 420/6 Ratchawithi Rd, Bangkok, 10400, Thailand.
| | - Sarah A White
- Department of Public Health, College of Medicine, University of Malawi, P/Bag 360, Blantyre 3, Malawi.,Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| | - Dianne J Terlouw
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Box 30096, Blantyre 3, Malawi.,Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| | - Victor Mwapasa
- Department of Public Health, College of Medicine, University of Malawi, P/Bag 360, Blantyre 3, Malawi
| | - Linda Kalilani-Phiri
- Department of Public Health, College of Medicine, University of Malawi, P/Bag 360, Blantyre 3, Malawi
| | - E Brian Faragher
- Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK
| |
Collapse
|
6
|
Mukaka M, White SA, Mwapasa V, Kalilani-Phiri L, Terlouw DJ, Faragher EB. Model choices to obtain adjusted risk difference estimates from a binomial regression model with convergence problems: An assessment of methods of adjusted risk difference estimation. ACTA ACUST UNITED AC 2016. [DOI: 10.7243/2053-7662-4-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
7
|
Chico RM, Cano J, Ariti C, Collier TJ, Chandramohan D, Roper C, Greenwood B. Influence of malaria transmission intensity and the 581G mutation on the efficacy of intermittent preventive treatment in pregnancy: systematic review and meta-analysis. Trop Med Int Health 2015; 20:1621-33. [PMID: 26325263 DOI: 10.1111/tmi.12595] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To estimate where intermittent preventive treatment (IPTp) using sulphadoxine-pyrimethamine (SP) could be withdrawn as an intervention due to declining malaria transmission intensity, or due to increasing prevalence of the Plasmodium falciparum dihydropteroate synthetase resistance mutation at codon 581G. METHODS We conducted a systematic review and meta-analysis of protection against the incidence of low birth weight (LBW) conferred by ≥2 doses of IPTp-SP. We matched these outcomes to a proxy measure of malaria incidence in women of the same studies, applied meta-regression models to these data and conducted sensitivity analysis of the 581G mutation. RESULTS Variation in the protective effect of IPTp-SP against LBW could not be explained by malaria transmission intensity. Among primi- and secundigravidae, IPTp-SP protected against LBW where 581G was ≤10.1% [odds ratio (OR): 0.49; 95% confidence intervals (CI): 0.29, 0.81; P = <0.01] and 581G was >10.1% (OR = 0.73; 95% CI: 0.29, 1.81; P = 0.03). Random-effects models among multigravidae showed that IPTp-SP protects against LBW where 581G was ≤10.1% (OR = 0.56; 95% CI: 0.37, 0.86; P = 0.07), a finding of borderline statistical significance. No evidence of protection against LBW was observed where 581G was >10.1% (OR = 0.96; 95% CI: 0.70, 1.34; P = 0.47). CONCLUSION There appears to be a prevalence of 581G above which IPTp-SP no longer protects against LBW. Pregnancy studies are urgently needed where 581G is >10.1% to define the specific prevalence threshold where new strategies should be deployed.
Collapse
Affiliation(s)
| | - Jorge Cano
- London School of Hygiene & Tropical Medicine, London, UK
| | - Cono Ariti
- London School of Hygiene & Tropical Medicine, London, UK.,Nuffield Trust, London, UK
| | | | | | - Cally Roper
- London School of Hygiene & Tropical Medicine, London, UK
| | | |
Collapse
|
8
|
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.
Collapse
|
9
|
Meremikwu MM, Donegan S, Sinclair D, Esu E, Oringanje C. Intermittent preventive treatment for malaria in children living in areas with seasonal transmission. Cochrane Database Syst Rev 2012; 2012:CD003756. [PMID: 22336792 PMCID: PMC6532713 DOI: 10.1002/14651858.cd003756.pub4] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND In malaria endemic areas, pre-school children are at high risk of severe and repeated malaria illness. One possible public health strategy, known as Intermittent Preventive Treatment in children (IPTc), is to treat all children for malaria at regular intervals during the transmission season, regardless of whether they are infected or not. OBJECTIVES To evaluate the effects of IPTc to prevent malaria in preschool children living in endemic areas with seasonal malaria transmission. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register (July 2011), CENTRAL (The Cochrane Library 2011, Issue 6), MEDLINE (1966 to July 2011), EMBASE (1974 to July 2011), LILACS (1982 to July 2011), mRCT (July 2011), and reference lists of identified trials. We also contacted researchers working in the field for unpublished and ongoing trials. SELECTION CRITERIA Individually randomized and cluster-randomized controlled trials of full therapeutic dose of antimalarial or antimalarial drug combinations given at regular intervals compared with placebo or no preventive treatment in children aged six years or less living in an area with seasonal malaria transmission. DATA COLLECTION AND ANALYSIS Two authors independently assessed eligibility, extracted data and assessed the risk of bias in the trials. Data were meta-analysed and measures of effects (ie rate ratio, risk ratio and mean difference) are presented with 95% confidence intervals (CIs). The quality of evidence was assessed using the GRADE methods. MAIN RESULTS Seven trials (12,589 participants), including one cluster-randomized trial, met the inclusion criteria. All were conducted in West Africa, and six of seven trials were restricted to children aged less than 5 years.IPTc prevents approximately three quarters of all clinical malaria episodes (rate ratio 0.26; 95% CI 0.17 to 0.38; 9321 participants, six trials, high quality evidence), and a similar proportion of severe malaria episodes (rate ratio 0.27, 95% CI 0.10 to 0.76; 5964 participants, two trials, high quality evidence). These effects remain present even where insecticide treated net (ITN) usage is high (two trials, 5964 participants, high quality evidence).IPTc probably produces a small reduction in all-cause mortality consistent with the effect on severe malaria, but the trials were underpowered to reach statistical significance (risk ratio 0.66, 95% CI 0.31 to 1.39, moderate quality evidence).The effect on anaemia varied between studies, but the risk of moderately severe anaemia is probably lower with IPTc (risk ratio 0.71, 95% CI 0.52 to 0.98; 8805 participants, five trials, moderate quality evidence).Serious drug-related adverse events, if they occur, are probably rare, with none reported in the six trials (9533 participants, six trials, moderate quality evidence). Amodiaquine plus sulphadoxine-pyrimethamine is the most studied drug combination for seasonal chemoprevention. Although effective, it causes increased vomiting in this age-group (risk ratio 2.78, 95% CI 2.31 to 3.35; two trials, 3544 participants, high quality evidence).When antimalarial IPTc was stopped, no rebound increase in malaria was observed in the three trials which continued follow-up for one season after IPTc. AUTHORS' CONCLUSIONS In areas with seasonal malaria transmission, giving antimalarial drugs to preschool children (age < 6 years) as IPTc during the malaria transmission season markedly reduces episodes of clinical malaria, including severe malaria. This benefit occurs even in areas where insecticide treated net usage is high.
Collapse
Affiliation(s)
- Martin M Meremikwu
- Department of Paediatrics, University of Calabar Teaching Hospital, Calabar, Nigeria.
| | | | | | | | | |
Collapse
|
10
|
Abstract
Intermittent preventive treatment of infants (IPTi) with sulphadoxine pyrimethamine (SP) is recommended as an additional malaria control intervention in high transmission areas of sub-Saharan Africa, provided its protective efficacy is not compromised by SP resistance. A significant obstacle in implementing SP-IPTi, is in establishing the degree of resistance in an area. Since SP monotherapy is discontinued, no contemporary measures of in vivo efficacy can be made, so the World Health Organisation has recommended a cut-off based upon molecular markers, stating that SP-IPTi should not be implemented when the prevalence of the dhps 540E mutation among infections exceeds 50%. We created a geo-referenced database of SP resistance markers in Africa from published literature. By selecting surveys of malaria infected blood samples conducted since 2004 we have mapped the contemporary prevalence of dhps 540E. Additional maps are freely available in interactive form at http://www.drugresistancemaps.org/ipti/. Eight countries in East Africa are classified as unsuitable for SP-IPTi when data are considered at a national level. Fourteen countries in Central and West Africa were classified as suitable while seven countries had no available contemporary data to guide policy. There are clear deficiencies in molecular surveillance data coverage. We discuss requirements for ongoing surveillance of SP resistance markers in support of the use of SP-IPTi.
Collapse
|
11
|
Fernando SD, Rodrigo C, Rajapakse S. Chemoprophylaxis in malaria: drugs, evidence of efficacy and costs. ASIAN PAC J TROP MED 2011; 4:330-6. [PMID: 21771482 DOI: 10.1016/s1995-7645(11)60098-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/27/2010] [Accepted: 02/15/2011] [Indexed: 11/18/2022] Open
Abstract
This review concentrates on different aspects of malaria chemoprophylaxis, namely drug combinations, resistance, impact of malaria prevention in pregnancy and cost effectiveness. A MEDLINE search was performed for all articles with the key word 'Malaria' in the title field and 'Prophylaxis' in any field. The search was restricted to articles published in English within the last decade (1999-2009). Data sources included review articles published in core clinical journals, cohort studies, interventional studies, case control studies and cross sectional analyses. The mechanism of action, trial evidence of efficacy, side effects and geographical distribution of resistance is discussed for each prophylactic drug regimen. Impact of prophylaxis in pregnancy and the cost considerations are discussed under two separate sub topics.
Collapse
|
12
|
Frosch AEP, Venkatesan M, Laufer MK. Patterns of chloroquine use and resistance in sub-Saharan Africa: a systematic review of household survey and molecular data. Malar J 2011; 10:116. [PMID: 21554692 PMCID: PMC3112453 DOI: 10.1186/1475-2875-10-116] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 05/09/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As a result of widespread chloroquine and sulphadoxine-pyrimethamine (SP) resistance, 90% of sub-Saharan African countries had adopted policies of artemisinin-based combination therapy (ACT) for treatment of uncomplicated malaria by 2007. In Malawi, cessation of chloroquine use was followed by the re-emergence of chloroquine-susceptible malaria. It was expected that introduction of ACT would lead to a return in chloroquine susceptibility throughout Africa, but this has not yet widely occurred. This observation suggests that there is continuing use of ineffective anti-malarials in Africa and that persistent chloroquine-resistant malaria is due to ongoing drug pressure despite national policy changes. METHODS To estimate drug use on a national level, 2006-2007 Demographic Health Survey and Multiple Indicator Cluster Survey data from 21 African countries were analysed. Resistance data were compiled by systematic review of the published literature on the prevalence of the Plasmodium falciparum chloroquine resistance transporter polymorphism at codon 76, which causes chloroquine resistance. RESULTS Chloroquine was the most common anti-malarial used according to surveys from 14 of 21 countries analysed, predominantly in West Africa. SP was most commonly reported in two of 21 countries. Among eight countries with longitudinal molecular resistance data, the four countries where the highest proportion of children treated for fever received chloroquine (Uganda, Burkina Faso, Guinea Bissau, and Mali) also showed no significant declines in the prevalence of chloroquine-resistant infections. The three countries with low or decreasing chloroquine use among children who reported fever treatment (Malawi, Kenya, and Tanzania) had statistically significant declines in the prevalence of chloroquine resistance. CONCLUSIONS This study demonstrates that in 2006-2007, chloroquine and SP continued to be used at high rates in many African countries. In countries reporting sustained chloroquine use, chloroquine-resistant malaria persists. In contrast, a low level of estimated chloroquine use is associated with a declining prevalence of chloroquine resistance.
Collapse
Affiliation(s)
- Anne E P Frosch
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD, USA
| | | | | |
Collapse
|
13
|
Mishra SK, Singh P, Rath SK. A study of toxicity and differential gene expression in murine liver following exposure to anti-malarial drugs: amodiaquine and sulphadoxine-pyrimethamine. Malar J 2011; 10:109. [PMID: 21529379 PMCID: PMC3112449 DOI: 10.1186/1475-2875-10-109] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 05/02/2011] [Indexed: 11/25/2022] Open
Abstract
Background Amodiaquine (AQ) along with sulphadoxine-pyrimethamine (SP) offers effective and cheaper treatment against chloroquine-resistant falciparum malaria in many parts of sub-Saharan Africa. Considering the previous history of hepatitis, agranulocytosis and neutrocytopenia associated with AQ monotherapy, it becomes imperative to study the toxicity of co-administration of AQ and SP. In this study, toxicity and resulting global differential gene expression was analyzed following exposure to these drugs in experimental Swiss mice. Methods The conventional markers of toxicity in serum, oxidative stress parameters in tissue homogenates, histology of liver and alterations in global transcriptomic expression were evaluated to study the toxic effects of AQ and SP in isolation and in combination. Results The combination therapy of AQ and SP results in more pronounced hepatotoxicity as revealed by elevated level of serum ALT, AST with respect to their individual drug exposure regimen. Furthermore, alterations in the activity of major antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase, glutathione reductase), indicating the development of oxidative stress, was more significant in AQ+SP combination therapy. cDNA microarray results too showed considerably more perturbed gene expression following combination therapy of AQ and SP as compared to their individual drug treatment. Moreover, a set of genes were identified whose expression pattern can be further investigated for identifying a good biomarker for potential anti-malarial hepatotoxicity. Conclusion These observations clearly indicate AQ+SP combination therapy is hepatotoxic in experimental Swiss mice. Microarray results provide a considerable number of potential biomarkers of anti-malarial drug toxicity. These findings hence will be useful for future drug toxicity studies, albeit implications of this study in clinical conditions need to be monitored with cautions.
Collapse
Affiliation(s)
- Shrawan Kumar Mishra
- Genotoxicity Laboratory, Toxicology Division, Central Drug Research Institute, CSIR, Lucknow, PIN 226 001, India
| | | | | |
Collapse
|
14
|
Bell DJ, Nyirongo SK, Mukaka M, Molyneux ME, Winstanley PA, Ward SA. Population pharmacokinetics of sulfadoxine and pyrimethamine in Malawian children with malaria. Clin Pharmacol Ther 2010; 89:268-75. [PMID: 21191379 DOI: 10.1038/clpt.2010.297] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In addition to parasite resistance, inadequate levels of exposure to antimalarial drugs may contribute to treatment failure. We developed population pharmacokinetic (PK) models to describe the distribution of sulfadoxine (SDX) and pyrimethamine (PYM) in children with uncomplicated malaria in Malawi. The concentration levels of antimalarial drugs in whole blood were determined using high-performance liquid chromatography. We found no evidence of underdosing in children as compared with adults; the children had drug exposure levels similar to those described in adults. Treatment failure was more likely in children with lower PYM concentrations on day 14 (P = 0.024), and there was a trend for lower SDX concentrations on day 14 (P = 0.061). SDX and PYM concentrations at levels predictive of treatment failure have been identified at day 14. Less than one-third of the children displayed drug concentration levels above these thresholds after receiving the recommended SDX-pyrimethamine (SP) dose. Our findings suggest that PK factors contributed to the observed high rate of treatment failure, and we therefore recommend a higher SP dose for children under the age of 5 years.
Collapse
Affiliation(s)
- D J Bell
- Tropical and Infectious Diseases Unit, Royal Liverpool University Hospital, Liverpool, UK
| | | | | | | | | | | |
Collapse
|
15
|
Nankabirwa J, Cundill B, Clarke S, Kabatereine N, Rosenthal PJ, Dorsey G, Brooker S, Staedke SG. Efficacy, safety, and tolerability of three regimens for prevention of malaria: a randomized, placebo-controlled trial in Ugandan schoolchildren. PLoS One 2010; 5:e13438. [PMID: 20976051 PMCID: PMC2957410 DOI: 10.1371/journal.pone.0013438] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 08/12/2010] [Indexed: 11/19/2022] Open
Abstract
Background Intermittent preventive treatment (IPT) is a promising malaria control strategy; however, the optimal regimen remains unclear. We conducted a randomized, single-blinded, placebo-controlled trial to evaluate the efficacy, safety, and tolerability of a single course of sulfadoxine-pyrimethamine (SP), amodiaquine + SP (AQ+SP) or dihydroartemisinin-piperaquine (DP) among schoolchildren to inform IPT. Methods Asymptomatic girls aged 8 to 12 years and boys aged 8 to 14 years enrolled in two primary schools in Tororo, Uganda were randomized to receive one of the study regimens or placebo, regardless of presence of parasitemia at enrollment, and followed for 42 days. The primary outcome was risk of parasitemia at 42 days. Survival analysis was used to assess differences between regimens. Results Of 780 enrolled participants, 769 (98.6%) completed follow-up and were assigned a treatment outcome. The risk of parasitemia at 42 days varied significantly between DP (11.7% [95% confidence interval (CI): 7.9, 17.1]), AQ+SP (44.3% [37.6, 51.5]), and SP (79.7% [95% CI: 73.6, 85.2], p<0.001). The risk of parasitemia in SP-treated children was no different than in those receiving placebo (84.6% [95% CI: 79.1, 89.3], p = 0.22). No serious adverse events occurred, but AQ+SP was associated with increased risk of vomiting compared to placebo (13.0% [95% CI: 9.1, 18.5] vs. 4.7% [95% CI: 2.5, 8.8], respectively, p = 0.003). Conclusions DP was the most efficacious and well-tolerated regimen tested, although AQ+SP appears to be a suitable alternative for IPT in schoolchildren. Use of SP for IPT may not be appropriate in areas with high-level SP resistance in Africa. Trial Registration ClinicalTrials.gov NCT00852371
Collapse
Affiliation(s)
| | - Bonnie Cundill
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sian Clarke
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Philip J. Rosenthal
- Uganda Malaria Surveillance Project, Kampala, Uganda
- Department of Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Grant Dorsey
- Uganda Malaria Surveillance Project, Kampala, Uganda
- Department of Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Simon Brooker
- London School of Hygiene & Tropical Medicine, London, United Kingdom
- Malaria Public Health and Epidemiology Group, Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Sarah G. Staedke
- Uganda Malaria Surveillance Project, Kampala, Uganda
- London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| |
Collapse
|
16
|
Selection of known Plasmodium falciparum resistance-mediating polymorphisms by artemether-lumefantrine and amodiaquine-sulfadoxine-pyrimethamine but not dihydroartemisinin-piperaquine in Burkina Faso. Antimicrob Agents Chemother 2010; 54:1949-54. [PMID: 20231394 DOI: 10.1128/aac.01413-09] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Artemether-lumefantrine (AL), dihydroartemisinin-piperaquine (DP), and amodiaquine-sulfadoxine-pyrimethamine (AQ-SP) offer excellent antimalarial efficacy but may select for parasite polymorphisms that decrease drug sensitivity. We evaluated the selection of known polymorphisms in genes encoding putative transporters (pfcrt and pfmdr1) and SP targets (pfdhfr and pfdhps) in parasites that caused new infections within 42 days of therapy for uncomplicated falciparum malaria in Burkina Faso. In 559 children in 2006, 42-day genotype-uncorrected failures were seen in 31.2% with AL, 11.8% with AQ-SP, and 7.6% with DP. After prior AL therapy, selection of wild-type sequences was seen for K76T in pfcrt (72.7% mixed or mutant results pretreatment versus 52.1% in new infections; P = 0.008) and N86Y (36.0% versus 18.7%; P = 0.025) and Y184F (66.7% versus 45.8%; P = 0.009) in pfmdr1. After prior AQ-SP therapy, selection of mutant sequences was seen for N51I (30.8% versus 61.5%; P = 0.05), C59R (28.2% versus 76.9%; P = 0.002), and S108N (30.8% versus 76.9%; P = 0.005) in pfdhfr. After prior DP therapy, selection was not seen for K76T (72.7% versus 77.8%; P = 0.96) in pfcrt or N86Y (36.0% versus 33.3%; P = 0.84), Y184F (66.7% versus 77.8%; P = 0.39), or D1246Y (9.3% versus 0%; P = 0.42) in pfmdr1. In 378 additional treatments with DP in 2007, 42-day uncorrected failure was seen in 10.9%. After prior DP, selection was again not seen for K76T (66.7% mixed or mutant results versus 59.5%; P = 0.43) in pfcrt or N86Y (38.7% versus 40.5%; P = 0.85), Y184F (67.6% versus 73.0%; P = 0.54), or D1246Y (3.6% versus 8.1%; P = 0.50) in pfmdr1. Despite its chemical similarity, piperaquine did not select for the same polymorphisms as chloroquine or AQ, suggesting different mechanisms of resistance.
Collapse
|
17
|
D'Alessandro U. Existing antimalarial agents and malaria-treatment strategies. Expert Opin Pharmacother 2009; 10:1291-306. [PMID: 19463069 DOI: 10.1517/14656560902942319] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In the absence of prompt and efficacious treatment, malaria patients may progress within a few hours from having minor symptoms to severe disease and death. These last years have seen the development of several artemisinin-based combinations, new treatments for severe malaria patients, and new strategies such as intermittent preventive treatment or the home-based/near-home management of malaria. The health sector is now confronted with several treatment options and strategies, in contrast with the period when chloroquine monotherapy was the standard treatment. The major challenge remains the large-scale deployment, in the most efficient way, of the tools available today, including artemisinin-based combination treatments, within health systems that remain extremely weak in malaria endemic countries, particularly in sub-Saharan Africa. Health system research, exploring new potential approaches for the large-scale implementation of these interventions, should be promoted in parallel with that on new therapeutic agents to be used in the unlucky event of the emergence and spread of artemisinin resistance. The prospects of substantially decreasing the malaria burden are brighter today than 20 - 30 years ago, but the efforts and resources committed to this purpose should be maintained over a long period.
Collapse
Affiliation(s)
- Umberto D'Alessandro
- Department of Parasitology, Institute of Tropical Medicine, Nationalestraat 10, B-2000 Antwerp, Belgium.
| |
Collapse
|
18
|
Bridges DJ, Molyneux M, Nkhoma S. Low level genotypic chloroquine resistance near Malawi's northern border with Tanzania. Trop Med Int Health 2009; 14:1093-6. [PMID: 19624477 DOI: 10.1111/j.1365-3156.2009.02340.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We conducted a prevalence study of mutations in Plasmodium falciparum that are associated with antimalarial drug resistance at a rural site in Karonga near Malawi's northern border with Tanzania. We found a higher prevalence of the key chloroquine resistance-conferring mutation in the pfcrt gene (K76T) at this site in comparison with the prevalence in Blantyre, a city in the south of Malawi, far from an international border (9%vs. 0%; P < 0.0005). In contrast we found a lower prevalence of the quintuple dhfr/dhps mutation, which is highly predictive of SP treatment failure, at the Karonga site compared to Blantyre (76%vs. 88%; P < 0.005). The prevalence of the K76T pfcrt mutation at two Tanzanian sites close to the border with Malawi was recently reported to be over 50%. Our findings suggest a considerable 'leakage' of parasite antimalarial drug resistance across the border between two countries with different national malaria control policies and with different levels of resistance. Neighbouring countries should consider implementing common regional rather than national malaria treatment policies to prevent the spread of antimalarial drug resistance alleles across their borders.
Collapse
Affiliation(s)
- Daniel J Bridges
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Chichiri, Malawi.
| | | | | |
Collapse
|
19
|
Sinclair D, Zani B, Donegan S, Olliaro P, Garner P. Artemisinin-based combination therapy for treating uncomplicated malaria. Cochrane Database Syst Rev 2009; 2009:CD007483. [PMID: 19588433 PMCID: PMC6532584 DOI: 10.1002/14651858.cd007483.pub2] [Citation(s) in RCA: 171] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND The World Health Organization recommends uncomplicated P. falciparum malaria is treated using Artemisinin-based Combination Therapy (ACT). This review aims to assist the decision making of malaria control programmes by providing an overview of the relative benefits and harms of the available options. OBJECTIVES To compare the effects of ACTs with other available ACT and non-ACT combinations for treating uncomplicated P. falciparum malaria. SEARCH STRATEGY We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; LILACS, and the metaRegister of Controlled Trials (mRCT) to March 2009. SELECTION CRITERIA Randomized head to head trials of ACTs in uncomplicated P. falciparum malaria.This review is limited to: dihydroartemisinin-piperaquine; artesunate plus mefloquine; artemether-lumefantrine (six doses); artesunate plus amodiaquine; artesunate plus sulfadoxine-pyrimethamine and amodiaquine plus sulfadoxine-pyrimethamine. DATA COLLECTION AND ANALYSIS Two authors independently assessed trials for eligibility and risk of bias, and extracted data. We analysed primary outcomes in line with the WHO 'Protocol for assessing and monitoring antimalarial drug efficacy' and compared drugs using risk ratios (RR) and 95% confidence intervals (CI). Secondary outcomes were effects on P. vivax, gametocytes, haemoglobin, and adverse events. MAIN RESULTS Fifty studies met the inclusion criteria. All five ACTs achieved PCR adjusted failure rates of < 10%, in line with WHO recommendations, at most study sites.Dihydroartemisinin-piperaquine performed well compared to the ACTs in current use (PCR adjusted treatment failure versus artesunate plus mefloquine in Asia; RR 0.39, 95% CI 0.19 to 0.79; three trials, 1062 participants; versus artemether-lumefantrine in Africa; RR 0.39, 95% CI 0.24 to 0.64; three trials, 1136 participants).ACTs were superior to amodiaquine plus sulfadoxine-pyrimethamine in East Africa (PCR adjusted treatment failure versus artemether-lumefantrine; RR 0.12, 95% CI 0.06 to 0.24; two trials, 618 participants; versus AS+AQ; RR 0.44, 95% CI 0.22 to 0.89; three trials, 1515 participants).Dihydroartemisinin-piperaquine (RR 0.32, 95% CI 0.24 to 0.43; four trials, 1442 participants) and artesunate plus mefloquine (RR 0.30, 95% CI 0.21 to 0.41; four trials, 1003 participants) were more effective than artemether-lumefantrine at reducing the incidence of P.vivax over 42 days follow up. AUTHORS' CONCLUSIONS Dihydroartemisinin-piperaquine is another effective first-line treatment for P. falciparum malaria.The performance of the non-ACT (amodiaquine plus sulfadoxine-pyrimethamine) falls below WHO recommendations for first-line therapy in parts of Africa.In areas where primaquine is not being used for radical cure of P. vivax, ACTs with long half-lives may provide some benefit.
Collapse
Affiliation(s)
- David Sinclair
- Liverpool School of Tropical MedicineInternational Health GroupPembroke PlaceLiverpoolUKL3 5QA
| | - Babalwa Zani
- Medical Research CouncilSouth African Cochrane CentreP. O. Box 19070TygerbergCape TownWestern CapeSouth Africa7505
| | - Sarah Donegan
- Liverpool School of Tropical MedicineInternational Health GroupPembroke PlaceLiverpoolUKL3 5QA
| | - Piero Olliaro
- World Health OrganizationSpecial Programme for Research and Training in Tropical Diseases (TDR)1211 Geneva 27GenevaSwitzerland
| | - Paul Garner
- Liverpool School of Tropical MedicineInternational Health GroupPembroke PlaceLiverpoolUKL3 5QA
| | | |
Collapse
|
20
|
Plasmodium falciparum and dihydrofolate reductase I164L mutations in Africa. Antimicrob Agents Chemother 2009; 53:1722; author reply 1722-3. [PMID: 19299520 DOI: 10.1128/aac.01427-08] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
21
|
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.
Collapse
Affiliation(s)
- Stéphane Picot
- Malaria Research Unit, EA 4170, University Lyon 1, Faculty of Medicine, Lyon, France.
| | | | | | | | | | | |
Collapse
|
22
|
Mutational 'hot-spots' in mammalian, bacterial and protozoal dihydrofolate reductases associated with antifolate resistance: sequence and structural comparison. Drug Resist Updat 2009; 12:28-41. [PMID: 19272832 DOI: 10.1016/j.drup.2009.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 12/24/2008] [Accepted: 02/04/2009] [Indexed: 12/16/2022]
Abstract
Human dihydrofolate reductase (DHFR) is a primary target for antifolate drugs in cancer treatment, while DHFRs from Plasmodium falciparum, Plasmodium vivax and various bacterial species are primary targets in the treatment of malaria and bacterial infections. Mutations in each of these DHFRs can result in resistance towards clinically relevant antifolates. We review the structural and functional impact of active-site mutations with respect to enzyme activity and antifolate resistance of DHFRs from mammals, protozoa and bacteria. The high structural homology between DHFRs results in a number of cross-species, active-site 'hot-spots' for broad-based antifolate resistance. In addition, we identify mutations that confer species-specific resistance, or antifolate-specific resistance. This comparative review of antifolate binding in diverse species provides new insights into the relationship between antifolate design and the development of mutational resistance. It also presents avenues for designing antifolate-resistant mammalian DHFRs as chemoprotective agents.
Collapse
|
23
|
Kayentao K, Maiga H, Newman RD, McMorrow ML, Hoppe A, Yattara O, Traore H, Kone Y, Guirou EA, Saye R, Traore B, Djimde A, Doumbo OK. Artemisinin-based combinations versus amodiaquine plus sulphadoxine-pyrimethamine for the treatment of uncomplicated malaria in Faladje, Mali. Malar J 2009; 8:5. [PMID: 19128455 PMCID: PMC2631542 DOI: 10.1186/1475-2875-8-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 01/07/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Because of the emergence of chloroquine resistance in Mali, artemether-lumefantrine (AL) or artesunate-amodiaquine (AS+AQ) are recommended as first-line therapy for uncomplicated malaria, but have not been available in Mali until recently because of high costs. METHODS From July 2005 to January 2006, a randomized open-label trial of three oral antimalarial combinations, namely AS+AQ, artesunate plus sulphadoxine-pyrimethamine (AS+SP), and amodiaquine plus sulphadoxine-pyrimethamine (AQ+SP), was conducted in Faladje, Mali. Parasite genotyping by polymerase chain reaction (PCR) was used to distinguish new from recrudescent Plasmodium falciparum infections. RESULTS 397 children 6 to 59 months of age with uncomplicated Plasmodium falciparum malaria were enrolled, and followed for 28 days to assess treatment efficacy. Baseline characteristics were similar in all three treatment groups. The uncorrected rates of adequate clinical and parasitologic response (ACPR) were 55.7%, 90.8%, and 97.7% in AS+AQ, AS+SP, and AQ+SP respectively (p < 0.001); after PCR correction ACPR rates were similar among treatment groups: 95.4%, 96.9%, and 99.2% respectively (p = 0.17). Mean haemoglobin concentration increased across all treatment groups from Day 0 (9.82 +/- 1.68 g/dL) to Day 28 (10.78 +/- 1.49 g/dL) (p < 0.001), with the greatest improvement occurring in children treated with AQ+SP. On Day 2, the prevalence of parasitaemia was significantly greater among children treated with AQ+SP (50.8%) than in children treated with AS+AQ (10.5%) or AS+SP (10.8%) (p < 0.001). No significant difference in gametocyte carriage was found between groups during the follow-up period. CONCLUSION The combination of AQ+SP provides a potentially low cost alternative for treatment of uncomplicated P. falciparum infection in Mali and appears to have the added value of longer protective effect against new infection.
Collapse
Affiliation(s)
- Kassoum Kayentao
- Malaria Research and Training Centre, Department of Epidemiology of Parasitologic Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Bamako, Mali.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Billal DS, Hotomi M, Yamanaka N. Intermittent preventive treatment with antimalarial drugs. Lancet 2009; 373:28-9; author reply 29. [PMID: 19121718 DOI: 10.1016/s0140-6736(08)61953-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
25
|
Deen JL, von Seidlein L, Dondorp A. Therapy of uncomplicated malaria in children: a review of treatment principles, essential drugs and current recommendations. Trop Med Int Health 2008; 13:1111-30. [DOI: 10.1111/j.1365-3156.2008.02117.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
26
|
Plasmodium falciparum strains harboring dihydrofolate reductase with the I164L mutation are absent in Malawi and Zambia even under antifolate drug pressure. Antimicrob Agents Chemother 2008; 52:3883-8. [PMID: 18725445 DOI: 10.1128/aac.00431-08] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum dihydrofolate reductase (PfDHFR) enzyme is the target of pyrimethamine, a component of the antimalarial pyrimethamine-sulfadoxine. Resistance to this drug is associated primarily with mutations in the Pfdhfr gene. The I164L mutant allele is of particular interest, because strains possessing this mutation are highly resistant to pyrimethamine and to chlorproguanil, a component of chlorproguanil-dapsone. A recent study from Malawi reported this mutation at a prevalence of 4.7% in parasites from human immunodeficiency virus-positive pregnant women by using a real-time PCR method. These observations have huge implications for the use of pyrimethamine-sulfadoxine, chlorproguanil-dapsone, and future antifolate-artemisinin combinations in Africa. It was imperative that this finding be rigorously tested. We identified a number of critical limitations in the original genotyping strategy. Using a refined and validated real-time PCR strategy, we report here that this mutation was absent in 158 isolates from Malawi and 42 isolates from Zambia collected between 2003 and 2005.
Collapse
|