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Figueroa-Romero A, Pons-Duran C, Gonzalez R. Drugs for Intermittent Preventive Treatment of Malaria in Pregnancy: Current Knowledge and Way Forward. Trop Med Infect Dis 2022; 7:tropicalmed7080152. [PMID: 36006244 PMCID: PMC9416188 DOI: 10.3390/tropicalmed7080152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/22/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Malaria infection during pregnancy is an important driver of maternal and neonatal health in endemic countries. Intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended for malaria prevention at each scheduled antenatal care visit, starting at the second trimester, in areas of high and moderate transmission. However, the increased resistance to SP in some endemic areas challenges its effectiveness. Furthermore, SP is contraindicated in the first trimester of pregnancy and in HIV-infected women on co-trimoxazole prophylaxis due to potential drug–drug interactions. Thus, in recent last decades, several studies evaluated alternative drugs that could be used for IPTp. A comprehensive literature review was conducted to summarize the evidence on the efficacy and safety of antimalarial drugs being evaluated for IPTp. Chloroquine, amodiaquine, mefloquine and azithromycin as IPTp have proven to be worse tolerated than SP. Mefloquine was found to increase the risk of mother-to-child transmission of HIV. Dihydroartemisin-piperaquine currently constitutes the most promising IPTp drug alternative; it reduced the prevalence of malaria infection, and placental and clinical malaria in studies among HIV-uninfected women, and it is currently being tested in HIV-infected women. Research on effective antimalarial drugs that can be safely administered for prevention to pregnant women should be prioritized. Malaria prevention in the first trimester of gestation and tailored interventions for HIV-infected women remain key research gaps to be addressed.
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Affiliation(s)
- Antia Figueroa-Romero
- Barcelona Institute for Global Health (ISGlobal), Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036 Barcelona, Spain; (A.F.-R.); (C.P.-D.)
| | - Clara Pons-Duran
- Barcelona Institute for Global Health (ISGlobal), Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036 Barcelona, Spain; (A.F.-R.); (C.P.-D.)
| | - Raquel Gonzalez
- Barcelona Institute for Global Health (ISGlobal), Hospital Clinic-Universitat de Barcelona, Carrer Rosselló 132, 08036 Barcelona, Spain; (A.F.-R.); (C.P.-D.)
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Maputo 1929, Mozambique
- Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain
- Correspondence:
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Coumaro-chalcones synthesized under solvent-free conditions as potential agents against malaria, leishmania and trypanosomiasis. Heliyon 2022; 8:e08939. [PMID: 35198789 PMCID: PMC8851253 DOI: 10.1016/j.heliyon.2022.e08939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/06/2021] [Accepted: 02/08/2022] [Indexed: 11/21/2022] Open
Abstract
Leishmaniasis, trypanosomiasis, and malaria are a group of neglected tropical diseases present in tropical regions and they affect large numbers of people in developing countries. A series of thirteen coumaro-chalcones (A1-A13) were synthesized under solvent-free conditions and their in vitro anti-leishmanial, anti-plasmodial, anti-trypanosomal and cytotoxic activities were evaluated. One of these coumaro-chalcones, 3-[(2E)-3-(3-ethoxy-4-hydroxyphenyl)prop-2-enoyl]-2H-chromen-2-one (A12), is a new compound. Compounds 3-[(2E)-3-(3-hydroxyphenyl)prop-2-enoyl]-2H-chromen-2-one (A5), 3-[(2E)-3-(3-methoxyphenyl)prop-2-enoyl]-2H-chromen-2-one (A2) and 3-[(2E)-3-phenylprop-2-enoyl]-2H-chromen-2-one (A1) displayed strong inhibition against intracellular amastigotes of Leishmania panamensis with EC50 of 2.1 ± 0.1, 2.5 ± 0.2 and 3.7 ± 0.5 μM, respectively. In addition, Plasmodium falciparum was moderately inhibited by the coumarin-chalcone hybrids, particularly A12 (EC50: 15.0 ± 0.5 μM) and 3-[(2E)-3-(1,3-benzodioxol-5-yl)prop-2-enoyl]-2H-chromen-2-one (A13) (EC50: 15.2 ± 1.1 μM). Remarkably, the coumaro-chalcone A5 (EC50: 18.7 ± 2.4 μM) exhibited an inhibition of the Trypanosoma cruzi intracellular amastigotes similar to the commercial drug Benznidazole (EC50: 14.5 ± 0.1 μM). These results support the therapeutic potential of coumaro-chalcone hybrids.
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Buyon LE, Elsworth B, Duraisingh MT. The molecular basis of antimalarial drug resistance in Plasmodium vivax. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2021; 16:23-37. [PMID: 33957488 PMCID: PMC8113647 DOI: 10.1016/j.ijpddr.2021.04.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/31/2021] [Accepted: 04/08/2021] [Indexed: 01/07/2023]
Abstract
Plasmodium vivax is the most geographically widespread cause of human malaria and is responsible for the majority of cases outside of the African continent. While great progress has been made towards eliminating human malaria, drug resistant parasite strains pose a threat towards continued progress. Resistance has arisen to multiple antimalarials in P. vivax, including to chloroquine, which is currently the first line therapy for P. vivax in most regions. Despite its importance, an understanding of the molecular mechanisms of drug resistance in this species remains elusive, in large part due to the complex biology of P. vivax and the lack of in vitro culture. In this review, we will cover the extent and challenges of measuring clinical and in vitro drug resistance in P. vivax. We will consider the roles of candidate drug resistance genes. We will highlight the development of molecular approaches for studying P. vivax biology that provide the opportunity to validate the role of putative drug resistance mutations as well as identify novel mechanisms of drug resistance in this understudied parasite. Validated molecular determinants and markers of drug resistance are essential for the rapid and cost-effective monitoring of drug resistance in P. vivax, and will be useful for optimizing drug regimens and for informing drug policy in control and elimination settings. Drug resistance is emerging in Plasmodium vivax, an important cause of malaria. The complex biology of P. vivax and the limited range of research tools make it difficult to identify drug resistance. The molecular mechanisms of drug resistance in P. vivax remain elusive. This review highlights the extent of drug resistance, the putative mechanisms of resistance and new technologies for the study of P. vivax drug resistance.
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Affiliation(s)
- Lucas E Buyon
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02115, MA, USA
| | - Brendan Elsworth
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02115, MA, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, 02115, MA, USA.
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Almond D, Madanitsa M, Mwapasa V, Kalilani-Phiri L, Webster J, Ter Kuile F, Paintain L. Provider and user acceptability of intermittent screening and treatment for the control of malaria in pregnancy in Malawi. Malar J 2016; 15:574. [PMID: 27894353 PMCID: PMC5126811 DOI: 10.1186/s12936-016-1627-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/18/2016] [Indexed: 11/27/2022] Open
Abstract
Background Malaria in pregnancy is a major cause of adverse maternal and fetal outcomes. Intermittent preventive treatment with sulfadoxine–pyrimethamine (IPTp-SP) is one of the control strategies promoted by WHO. In response to mounting resistance to SP, intermittent screening and treatment (ISTp) has been proposed as an alternative. The objective of this study was to explore the acceptability of ISTp for health workers and pregnant women. Methods Semi-structured interviews of ten health workers and five focus group discussions of 38 women enrolled in an ongoing trial comparing IPTp-SP and ISTp with dihydroartemisinin–piperaquine (DP) were conducted at two antenatal clinics in rural Malawi. All transcripts were coded and themes were identified using a content analysis approach. Results Amongst health workers, there were contrasting opinions on the preference of blood sampling methods, and the influence of method on reliability of diagnosis. The perceived greater effectiveness of DP compared to SP was appreciated, however concerns of user compliance with the full dose of DP in non-trial settings were raised. Despite the discomfort of repeated finger pricks, pregnant women were generally accepting of ISTp, particularly the chance for regular blood tests to check for infections and the perceived greater effectiveness with fewer side effects of DP compared to SP. Conclusion In the trial context, pregnant women tended to prefer ISTp-DP over IPTp-SP. Health workers were also accepting of ISTp-DP as an alternative to IPTp-SP in light of increasing SP resistance. However, reliability of stock, adherence to malaria test results and user adherence to the full course of DP may present barriers to successful routine implementation. Effective communication with health workers and between health workers, pregnant women and their communities will be essential for the acceptability of focused antenatal care, including the best malaria control measures available.
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Affiliation(s)
- Deborah Almond
- Disease Control Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Mwayi Madanitsa
- College of Medicine, University of Malawi, Blantyre, Malawi.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Victor Mwapasa
- College of Medicine, University of Malawi, Blantyre, Malawi
| | | | - Jayne Webster
- Disease Control Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Feiko Ter Kuile
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Lucy Paintain
- Disease Control Department, London School of Hygiene and Tropical Medicine, London, UK.
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Kaingona-Daniel EPS, Gomes LR, Gama BE, Almeida-de-Oliveira NK, Fortes F, Ménard D, Daniel-Ribeiro CT, Ferreira-da-Cruz MDF. Low-grade sulfadoxine-pyrimethamine resistance in Plasmodium falciparum parasites from Lubango, Angola. Malar J 2016; 15:309. [PMID: 27267365 PMCID: PMC4895897 DOI: 10.1186/s12936-016-1358-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/24/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major parasitic disease, affecting millions of people in endemic areas. Plasmodium falciparum parasites are responsible for the most severe cases and its resistance to anti-malarial drugs is notorious. This is a possible obstacle to the effectiveness of intermittent preventive treatment (IPT) based on sulfadoxine–pyrimethamine (SP) cures administrated to pregnant women (IPTp) during their pregnancy. As this intervention is recommended in Angola since 2006, it has assessed, in this country, the molecular profiles in P. falciparumdhfr and dhps, two polymorphic genes associated to pyrimethamine and sulfadoxine resistance, respectively. Methods Blood samples from 52 falciparum patients were collected in Lubango, Angola and pfdhfr and pfdhps polymorphisms were analysed using nested-PCR and DNA sequencing. Results In the pfdhfr gene, the 108N mutation was almost fixed (98 %), followed by 59R (63 %), 51I (46 %), 50R and 164L (2 %, respectively). No 16V/S mutations were found. The most common double mutant genotype was CNRN (59 + 108; 46 %), followed by CICN (51 + 108; 29 %) whereas IRN (51 + 59 + 108; 15 %), CNRNVL (59 + 108 + 164; 2 %) and RICN (50 + 51 + 108; 2 %) triple mutant genotypes were detected. Investigations of the pfdhps gene showed that the 437G mutation was the most prevalent (97 %). Only two and one samples disclosed the 540E (7 %) and the 436A (3 %), respectively. Single mutant SGKAA (437; 86 %) was higher than SGEAA (437 + 540; 7 %) or AGKAA (436 + 437; 3 %) double mutants genotypes. No polymorphism was detected at codons 581G and 613T/S. Combining pfdhfr and pfdhps alleles two triple mutant haplotypes (double mutant in dhfr and single mutant in dhps) were observed: the ACICNVI/SGKAA in 14 (56 %) samples and the ACNRNVI/SGKAA in five (20 %) samples. One quadruple mutant haplotype was detected (ACIRNVI/SGKAA) in six (24 %) P. falciparum samples. No quintuple pfdhfr–pfdhps mutant was noted. Conclusion pfdhfr and pfdhps gene mutations in isolates from Lubango are suggestive of a low-grade SP resistance and IPT for pregnant women and infant based on SP treatment could be effective. Routine molecular studies targeting polymorphism in these two genes need to be routinely conducted at country level.
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Affiliation(s)
- Elsa P S Kaingona-Daniel
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Hospital Central Dr. António Agostinho Neto, Lubango, Angola.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Larissa Rodrigues Gomes
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Bianca E Gama
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Laboratory of Oncovirology, Instituto Nacional de Câncer, Rio de Janeiro, Brazil
| | - Natália K Almeida-de-Oliveira
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Filomeno Fortes
- Angolan National Malaria Control Programme, National Institute of Public Health, Luanda, Angola.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Didier Ménard
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Cláudio Tadeu Daniel-Ribeiro
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Maria de Fátima Ferreira-da-Cruz
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil. .,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil. .,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal.
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Fusion of field studies and the laboratory solves a puzzle in antimalarial resistance. Proc Natl Acad Sci U S A 2015; 112:11432-3. [PMID: 26333834 DOI: 10.1073/pnas.1514403112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Morris U, Xu W, Msellem MI, Schwartz A, Abass A, Shakely D, Cook J, Bhattarai A, Petzold M, Greenhouse B, Ali AS, Björkman A, Fröberg G, Mårtensson A. Characterising temporal trends in asymptomatic Plasmodium infections and transporter polymorphisms during transition from high to low transmission in Zanzibar, 2005-2013. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 33:110-7. [PMID: 25917493 PMCID: PMC10445533 DOI: 10.1016/j.meegid.2015.04.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/14/2015] [Accepted: 04/18/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Improved understanding of the asymptomatic malaria parasite reservoir is a prerequisite to pursue malaria elimination efforts. We therefore characterised temporal trends and transporter polymorphisms in asymptomatic Plasmodium infections during the transition from high to low transmission in Zanzibar. METHODS Healthy individuals participating in cross-sectional surveys conducted 2005-2013 were screened for asymptomatic malaria by PCR. Complexity/diversity of infection and transporter polymorphisms were assessed in Plasmodium falciparum positive samples. Symptomatic samples were included for comparison of polymorphisms in 2013. RESULTS PCR-determined parasite prevalence declined from 21.1% (CI95% 17.4-24.9) to 2.3% (CI95% 1.7-2.9) from 2005 to 2013. P. falciparum remained the predominant species; prevalence was highest in children and young adults aged 5-25 years. Parasite densities and complexity of infection, but not population genetic diversity of P. falciparum, decreased from 2005-2009. pfcrt 76T (99.2-64.7%, p < 0.001) and pfmdr1 86Y frequencies (89.4-66.7%, p = 0.03) decreased over time. Pfmdr1 (a.a.86,184,1246) YYY and YYD haplotypes were more frequent in asymptomatic than symptomatic infections in 2013 (p < 0.001). CONCLUSIONS There is a declining, albeit persistent, reservoir of parasites present at low-densities in asymptomatic individuals in Zanzibar. This study revealed important characteristics of the remaining parasite population, including intriguing temporal trends in molecular markers associated with antimalarial resistance, which need to be further investigated.
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Affiliation(s)
- Ulrika Morris
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Weiping Xu
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Mwinyi I Msellem
- Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Alanna Schwartz
- Department of Medicine, University of California San Francisco, CA, USA
| | - Ali Abass
- Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Delér Shakely
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Medicine, Kungälv Hospital, Kungälv, Sweden
| | - Jackie Cook
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Achuyt Bhattarai
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Max Petzold
- Health Metrics at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, CA, USA
| | - Abdullah S Ali
- Zanzibar Malaria Elimination Programme (ZAMEP), Ministry of Health, Zanzibar, Tanzania
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Gabrielle Fröberg
- Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Mårtensson
- Malaria Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden; Centre for Clinical Research Sörmland, Uppsala University, Sweden
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Ocholla H, Preston MD, Mipando M, Jensen ATR, Campino S, MacInnis B, Alcock D, Terlouw A, Zongo I, Oudraogo JB, Djimde AA, Assefa S, Doumbo OK, Borrmann S, Nzila A, Marsh K, Fairhurst RM, Nosten F, Anderson TJC, Kwiatkowski DP, Craig A, Clark TG, Montgomery J. Whole-genome scans provide evidence of adaptive evolution in Malawian Plasmodium falciparum isolates. J Infect Dis 2014; 210:1991-2000. [PMID: 24948693 PMCID: PMC4241944 DOI: 10.1093/infdis/jiu349] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background Selection by host immunity and antimalarial drugs has driven extensive adaptive evolution in Plasmodium falciparum and continues to produce ever-changing landscapes of genetic variation. Methods We performed whole-genome sequencing of 69 P. falciparum isolates from Malawi and used population genetics approaches to investigate genetic diversity and population structure and identify loci under selection. Results High genetic diversity (π = 2.4 × 10−4), moderately high multiplicity of infection (2.7), and low linkage disequilibrium (500-bp) were observed in Chikhwawa District, Malawi, an area of high malaria transmission. Allele frequency–based tests provided evidence of recent population growth in Malawi and detected potential targets of host immunity and candidate vaccine antigens. Comparison of the sequence variation between isolates from Malawi and those from 5 geographically dispersed countries (Kenya, Burkina Faso, Mali, Cambodia, and Thailand) detected population genetic differences between Africa and Asia, within Southeast Asia, and within Africa. Haplotype-based tests of selection to sequence data from all 6 populations identified signals of directional selection at known drug-resistance loci, including pfcrt, pfdhps, pfmdr1, and pfgch1. Conclusions The sequence variations observed at drug-resistance loci reflect differences in each country's historical use of antimalarial drugs and may be useful in formulating local malaria treatment guidelines.
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Affiliation(s)
- Harold Ocholla
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme Liverpool School of Tropical Medicine, Pembroke Place, Liverpool
| | - Mark D Preston
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine
| | - Mwapatsa Mipando
- Department of Physiology, College of Medicine, University of Malawi, Blantyre
| | - Anja T R Jensen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, University of Copenhagen Department of Infectious Diseases, Copenhagen University Hospital, Denmark
| | | | | | | | - Anja Terlouw
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme Liverpool School of Tropical Medicine, Pembroke Place, Liverpool
| | - Issaka Zongo
- Institut de Recherche en Sciences de la Sant, Bobo-Dioulasso, Burkina Faso
| | | | - Abdoulaye A Djimde
- Wellcome Trust Sanger Institute, Hinxton Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Mali
| | - Samuel Assefa
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine
| | - Ogobara K Doumbo
- Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Dentistry, University of Bamako, Mali
| | | | - Alexis Nzila
- Department of Biology, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Francois Nosten
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, United Kingdom Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | | | - Dominic P Kwiatkowski
- Wellcome Trust Sanger Institute, Hinxton Wellcome Trust Centre for Human Genetics, University of Oxford, United Kingdom
| | - Alister Craig
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine
| | - Jacqui Montgomery
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme Liverpool School of Tropical Medicine, Pembroke Place, Liverpool
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Sibley CH. Understanding drug resistance in malaria parasites: basic science for public health. Mol Biochem Parasitol 2014; 195:107-14. [PMID: 24927641 DOI: 10.1016/j.molbiopara.2014.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/25/2014] [Accepted: 06/03/2014] [Indexed: 01/09/2023]
Abstract
The worlds of basic scientists and those involved in treating patients and making public health decisions do not always intersect. Yet, assuring that when patients are treated, they are efficiently and completely cured, and that public health decisions are based on solid evidence requires a broad foundation of up to date basic research. Research on the malaria parasite, Plasmodium falciparum provides a useful illustration of the role that basic scientific studies have played in the very long relationship between humans and this deadly parasite. Drugs have always been a principal tool in malaria treatment. The ongoing struggle between evolution of resistance to antimalarials by the parasite and public health responses is used here as an illustration of the key contributions of basic scientists to this long history.
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Affiliation(s)
- Carol Hopkins Sibley
- World Wide Antimalarial Resistance Network, Department of Genome Sciences, University of Washington, Seattle, WA 98195-5065, USA.
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10
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Abdul-Ghani R, Farag HF, Allam AF, Shawky SM. Prevailing Plasmodium falciparum dihydrofolate reductase 108-asparagine in Hodeidah, Yemen: a questionable sulfadoxine-pyrimethamine partner within the artemisinin-based combination therapy. Acta Trop 2014; 132:39-44. [PMID: 24406851 DOI: 10.1016/j.actatropica.2013.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 12/22/2013] [Accepted: 12/26/2013] [Indexed: 11/17/2022]
Abstract
Given that the evolution and spread of resistance to sulfadoxine-pyrimethamine (SP) have been documented at a quick pace worldwide, the present study investigated the mutant Plasmodium falciparum dihydrofolate reductase 108-asparagine (dhfr 108 N) as a key marker of resistance to the combination among parasite isolates from Hodeidah. The association of parasitologic indices with the dhfr 108 N mutant allele was also studied. Ninety patients with microscopically confirmed P. falciparum infection from Hodeidah were included in the present study. Polymerase chain reaction-restriction fragment length polymorphism approach was adopted for the molecular detection of this marker. The dhfr 108 N was detected among about 61% of P. falciparum isolates, in its pure and mixed-type forms, from Hodeidah. Age, gender and residence of patients were not significant predictors for the presence of the mutant allele among parasite isolates. In contrast, a history of malaria and antimalarial drug intake in the year preceding the study as well as frequent antimalarial drug intake were significantly associated with this mutant allele. The high frequency of dhfr 108 N among parasites isolates makes the role of SP questionable as a partner with outstanding effectiveness within the ACT, at least, in the near future. SP plus artesunate should be monitored for its antimalarial efficacy at regular intervals, preferably through the molecular detection of resistance-associated mutations.
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Affiliation(s)
- Rashad Abdul-Ghani
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt; Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen.
| | - Hoda F Farag
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Amal F Allam
- Department of Parasitology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Sherine M Shawky
- Department of Microbiology, Medical Research Institute, Alexandria University, Alexandria, Egypt
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Wongsrichanalai C, Sibley C. Fighting drug-resistant Plasmodium falciparum: the challenge of artemisinin resistance. Clin Microbiol Infect 2013; 19:908-16. [DOI: 10.1111/1469-0691.12316] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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12
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Mapping 'partially resistant', 'fully resistant', and 'super resistant' malaria. Trends Parasitol 2013; 29:505-15. [PMID: 24028889 DOI: 10.1016/j.pt.2013.08.002] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/12/2013] [Accepted: 08/12/2013] [Indexed: 11/24/2022]
Abstract
Sulfadoxine-pyrimethamine (SP) is used throughout Africa for intermittent preventive treatment (IPT) of malaria, but resistance threatens its efficacy. We found marked regional differences in the genotypes responsible for SP resistance when mapping recent surveys of dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) mutations. In West Africa, a 'partially resistant' combination of dhfr N51I, N59R, and S108N with dhps A437G predominates, whereas in East Africa the 'fully resistant' combination of dhfr N51I, N59R, and S108N with dhps A437G+K540E is found. There are three East African foci where 'fully resistant' populations have additionally acquired dhps 581G and/or dhfr 164L to become 'super resistant'. SP-IPT in infants and pregnant women is reported to have failed in super resistant areas prompting review of SP-IPT use in affected areas.
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Gutman J, Mwandama D, Wiegand RE, Ali D, Mathanga DP, Skarbinski J. Effectiveness of intermittent preventive treatment with sulfadoxine-pyrimethamine during pregnancy on maternal and birth outcomes in Machinga district, Malawi. J Infect Dis 2013; 208:907-16. [PMID: 23801600 DOI: 10.1093/infdis/jit276] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Malaria during pregnancy is associated with low birth weight and increased perinatal mortality, especially among primigravidae. Despite increasing prevalence of malarial parasite resistance to sulfadoxine-pyrimethamine (SP), SP continues to be recommended for intermittent preventive treatment in pregnancy (IPTp). METHODS Women without human immunodeficiency virus infection were enrolled upon delivery. Data on the number of SP doses received during pregnancy were recorded. The primary outcome was placental infection demonstrated by histologic analysis. Secondary outcomes included malaria parasitemia (in peripheral, placental, cord blood specimens) at delivery and composite birth outcome (small for gestational age, preterm delivery, or low birth weight). RESULTS.: Of 703 women enrolled, 22% received <2 SP doses. Receipt of ≥ 2 SP doses had no impact on histologically confirmed placental infection. IPTp-SP was associated with a dose-dependent protective effect on composite birth outcome in primigravidae, with an adjusted prevalence ratio of 0.50 (95% confidence interval [CI], .30-.82), 0.30 (95% CI, .19-.48), and 0.18 (95% CI, .05-.61) for 1, 2, and ≥ 3 doses, respectively, compared with 0 doses. CONCLUSIONS IPTp-SP did not reduce the frequency of placental infection but was associated with improved birth outcomes. Few women received no SP, so the true effect of IPTp-SP may be underestimated. Malawian pregnant women should continue to receive IPTp-SP, but alternative strategies and antimalarials for preventing malaria during pregnancy should be investigated.
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Affiliation(s)
- Julie Gutman
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia 30322, USA.
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Abdul-Ghani R, Farag HF, Allam AF. Sulfadoxine-pyrimethamine resistance in Plasmodium falciparum: a zoomed image at the molecular level within a geographic context. Acta Trop 2013; 125:163-90. [PMID: 23131424 DOI: 10.1016/j.actatropica.2012.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/25/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
Antimalarial chemotherapy is one of the main pillars in the prevention and control of malaria. Following widespread resistance of Plasmodium falciparum to chloroquine, sulfadoxine-pyrimethamine came to the scene as an alternative to the cheap and well-tolerated chloroquine. However, widespread resistance to sulfadoxine-pyrimethamine has been documented. In vivo efficacy tests are the gold standard for assessing drug resistance and treatment failure. However, they have many disadvantages, such as influence of host immunity and drug pharmacokinetics. In vitro tests of antimalarial drug efficacy also have many technical difficulties. Molecular markers of resistance have emerged as epidemiologic tools to investigate antimalarial drug resistance even before becoming clinically evident. Mutations in P. falciparum dihydrofolate reductase and dihydrofolate synthase have been extensively studied as molecular markers for resistance to pyrimethamine and sulfadoxine, respectively. This review highlights the resistance of P. falciparum at the molecular level presenting both supporting and opposing studies on the utility of molecular markers.
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Sibley CH, Price RN. Monitoring antimalarial drug resistance: Applying lessons learned from the past in a fast-moving present. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:126-33. [PMID: 24533274 DOI: 10.1016/j.ijpddr.2012.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 03/25/2012] [Accepted: 03/28/2012] [Indexed: 11/19/2022]
Abstract
The need for robust surveillance of antimalarial drugs is more urgent than it has ever been. In the western region of Cambodia, artemisinin resistance has emerged in Plasmodium falciparum and threatens to undermine the efficacy of highly effective artemisinin combination therapies. Although some manfestations of artemisinin tolerance are unique to this class of drug, many of its properties mirror previous experience in understanding and tracking resistance to other antimalarials. In this review we outline the spectrum of approaches that were developed to understand the evolution and spread of antifolate resistance, highlighting the importance of integrating information from different methodologies towards a better understanding of the underlying biologic processes. We consider how to apply our experience in investigating and attempting to contain antifolate resistance to inform our prospective assessment of novel antimalarial resistance patterns and their subsequent spread.
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Affiliation(s)
- Carol Hopkins Sibley
- WorldWide Antimalarial Resistance Network, Box 355065, University of Washington, Seattle, WA 98195 5065, USA
| | - Ric N Price
- Global Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia ; Center for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
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Taylor SM, Antonia A, Feng G, Mwapasa V, Chaluluka E, Molyneux M, ter Kuile FO, Rogerson SJ, Meshnick SR. Adaptive evolution and fixation of drug-resistant Plasmodium falciparum genotypes in pregnancy-associated malaria: 9-year results from the QuEERPAM study. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2012; 12:282-90. [PMID: 22119749 PMCID: PMC3293939 DOI: 10.1016/j.meegid.2011.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/08/2011] [Accepted: 11/10/2011] [Indexed: 11/18/2022]
Abstract
Sulfadoxine-pyrimethamine (SP) has been widely deployed in Africa for malaria control and molecular evidence of parasite drug-resistance is prevalent. However, the temporal effects on the selection of Plasmodium falciparum are not well understood. We conducted a retrospective serial cross-sectional study between 1997 and 2006 to investigate changes in drug-resistant malaria among pregnant women delivering at a single hospital in Blantyre, Malawi. P. falciparum parasites were genotyped for parasite clone multiplicity and drug-resistance mutations, and the strength of selection upon mutant genotypes was quantified. Five mutations in the dihydrofolate reductase and dihydropteroate synthase genes began at moderate frequencies and achieved fixation by 2005; the frequency of the highly-SP-resistant "quintuple mutant" haplotype increased from 19% to 100%. The selective advantage of alleles and haplotypes were quantified with selection coefficients: Selection was positive on all mutant alleles and haplotypes associated with SP resistance, and the relative fitness of the quintuple mutant haplotype was 0.139 (95% C.I. 0.067-0.211), indicating a substantial positive selective advantage. Mutations that confer higher levels of resistance to SP did not emerge. SP-resistant haplotypes were rapidly selected for and fixed in P. falciparum populations infecting pregnant women while SP was widely deployed in Malawi. These results underscore the pressing need for new preventive measures for pregnancy-associated malaria and provide a real-world model of the selection landscape malaria parasites.
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Affiliation(s)
- Steve M Taylor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC 27599, USA.
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Antibody to P. falciparum in pregnancy varies with intermittent preventive treatment regime and bed net use. PLoS One 2012; 7:e29874. [PMID: 22299027 PMCID: PMC3267709 DOI: 10.1371/journal.pone.0029874] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 12/05/2011] [Indexed: 11/19/2022] Open
Abstract
Background Antibodies towards placental-binding P. falciparum are thought to protect against pregnancy malaria; however, environmental factors may affect antibody development. Methods and Findings: Using plasma from pregnant Malawian women, we measured IgG against placental-binding P. falciparum parasites by flow cytometry, and related results to intermittent preventive treatment (IPTp) regime, and bed net use. Bed net use was associated with decreased antibody levels at mid-pregnancy but not at 1 month post partum (1 mpp). At 1 mpp a more intensive IPTp regime was associated with decreased antibody levels in primigravidae, but not multigravidae. Conclusions/Significance Results suggest bed nets and IPTp regime influence acquisition of pregnancy-specific P. falciparum immunity.
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Wilson NO, Ceesay FK, Obed SA, Adjei AA, Gyasi RK, Rodney P, Ndjakani Y, Anderson WA, Lucchi NW, Stiles JK. Intermittent preventive treatment with sulfadoxine-pyrimethamine against malaria and anemia in pregnant women. Am J Trop Med Hyg 2011; 85:12-21. [PMID: 21734118 DOI: 10.4269/ajtmh.2011.10-0512] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The effectiveness of intermittent preventive treatment during pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) against malaria and anemia is unclear because of the spread of SP-resistant Plasmodium falciparum. This study evaluates the effectiveness of IPTp-SP among pregnant women attending the antenatal clinic at Korle-Bu Teaching Hospital in Accra, Ghana. A cross-sectional study comparing malaria and anemia prevalence among pregnant women using IPTp-SP with non-IPTp-SP users was conducted during June-August 2009. A total of 363 pregnant women (202 of IPTp users and 161 non-IPTp users) were recruited. A total of 15.3% of IPTp users had malaria compared with 44.7% of non-IPTp users (P < 0.001). A total of 58.4% of non-IPTp users were anemic compared with 22.8% of IPTp users (P < 0.001). When we controlled for other variables, the difference in the prevalence of malaria (odds ratio = 0.18, 95% confidence interval = 0.08-0.37) and anemia (odds ratio = 0.20, 95% confidence interval = 0.12-0.34) remained significant. The recommended IPTp-SP regimen is useful in preventing malaria and anemia among pregnant women in Ghana.
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Affiliation(s)
- Nana O Wilson
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
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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.
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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.
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Affiliation(s)
- Anne E P Frosch
- Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD, USA
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Luntamo M, Kulmala T, Mbewe B, Cheung YB, Maleta K, Ashorn P. Effect of repeated treatment of pregnant women with sulfadoxine-pyrimethamine and azithromycin on preterm delivery in Malawi: a randomized controlled trial. Am J Trop Med Hyg 2011; 83:1212-20. [PMID: 21118924 DOI: 10.4269/ajtmh.2010.10-0264] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Preterm delivery, which is associated with infections during pregnancy, is common in sub-Saharan Africa. We enrolled 1,320 pregnant women into a randomized, controlled trial in Malawi to study whether preterm delivery and low birth weight (LBW) incidence can be reduced by intermittent preventive treatment of maternal malaria and reproductive tract infections. The participants received either sulfadoxine-pyrimethamine (SP) twice (controls), monthly SP, or monthly SP and two doses of azithromycin (AZI-SP). The incidence of preterm delivery was 17.9% in controls, 15.4% in the monthly SP group (P = 0.32), and 11.8% in AZI-SP group (risk ratio = 0.66, P = 0.01). Compared with controls, those in AZI-SP group had a risk ratio of 0.61 (P = 0.02) for LBW. Incidence of serious adverse events was low in all groups. In conclusion, the incidence of preterm delivery and LBW can in some conditions be reduced by treating pregnant women with monthly SP and two azithromycin doses.
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Affiliation(s)
- Mari Luntamo
- Department of International Health, University of Tampere Medical School, Tampere, Finland.
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Menendez C, Serra-Casas E, Scahill MD, Sanz S, Nhabomba A, Bardaji A, Sigauque B, Cistero P, Mandomando I, Dobano C, Alonso PL, Mayor A. HIV and Placental Infection Modulate the Appearance of Drug-Resistant Plasmodium falciparum in Pregnant Women who Receive Intermittent Preventive Treatment. Clin Infect Dis 2011; 52:41-8. [DOI: 10.1093/cid/ciq049] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Feng G, Simpson JA, Chaluluka E, Molyneux ME, Rogerson SJ. Decreasing burden of malaria in pregnancy in Malawian women and its relationship to use of intermittent preventive therapy or bed nets. PLoS One 2010; 5:e12012. [PMID: 20700457 PMCID: PMC2917365 DOI: 10.1371/journal.pone.0012012] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/01/2010] [Indexed: 11/20/2022] Open
Abstract
Background The World Health Organization recommends insecticidal bednets and intermittent preventive treatment to reduce malaria in pregnancy. Longitudinal data of malaria prevalence and pregnancy outcomes are valuable in gauging the impact of these antimalarial interventions. Methodology/Principal Findings We recruited 8,131 women delivering in a single Malawian hospital over 9 years. We recorded demographic data, antenatal prescription of intermittent preventive therapy during pregnancy with sulfadoxine-pyrimethamine and bed net use, and examined finger-prick blood for malaria parasites and hemoglobin concentration. In 4,712 women, we examined placental blood for malaria parasites and recorded the infant's birth weight. Peripheral and placental parasitemia prevalence declined from 23.5% to 5.0% and from 25.2% to 6.8% respectively. Smaller declines in prevalence of low birth weight and anemia were observed. Coverage of intermittent preventive treatment and bednets increased. Number of sulfadoxine-pyrimethamine doses received correlated inversely with placental parasitemia (Odds Ratio (95% CI): 0.79 (0.68, 0.91)), maternal anemia (0.81, (0.73, 0.90)) and low birth weight from 1997–2001 (0.63 (0.53, 0.75)), but not from 2002–2006. Bednet use protected from peripheral parasitemia (0.47, (0.37, 0.60)) and placental parasitemia (0.41, (0.31, 0.54)) and low birth weight (0.75 (0.59, 0.95)) but not anemia throughout the study. Compared to women without nets who did not receive 2-dose sulfadoxine-pyrimethamine, women using nets and receiving 2-dose sulfadoxine-pyrimethamine were less likely to have parasitemia or low birth weight babies. Women receiving 2-dose sulfadoxine-pyrimethamine alone had little evidence of protection whereas bednets alone gave intermediate protection. Conclusions/Significance Increased bednet coverage explains changes in parasitemia and birth weight among pregnant women better than sulfadoxine-pyrimethamine use. High bed net coverage, and sulfadoxine-pyrimethamine resistance, may be contributing to its apparent loss of effectiveness.
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Affiliation(s)
- Gaoqian Feng
- Department of Medicine (RMH/WH), University of Melbourne, Melbourne, Australia
| | - Julie A. Simpson
- Centre for Molecular, Environmental, Genetic & Analytic Epidemiology, School of Population Health, University of Melbourne, Melbourne, Australia
| | - Ebbie Chaluluka
- Malawi-Liverpool-Wellcome Trust Clinical Research Program, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Malcolm E. Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Program, College of Medicine, University of Malawi, Blantyre, Malawi
- School of Tropical Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Stephen J. Rogerson
- Department of Medicine (RMH/WH), University of Melbourne, Melbourne, Australia
- * E-mail:
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Babiker HA, Hastings IM, Swedberg G. Impaired fitness of drug-resistant malaria parasites: evidence and implication on drug-deployment policies. Expert Rev Anti Infect Ther 2009; 7:581-93. [PMID: 19485798 DOI: 10.1586/eri.09.29] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Malaria, a leading parasitic disease, inflicts an enormous toll on human lives and is caused by protozoal parasites belonging to the genus Plasmodium. Antimalarial drugs targeting essential biochemical processes in the parasite are the primary resources for management and control. However, the parasite has established mutations, substantially reducing the efficacy of these drugs. First-line therapy is faced the with the consistent evolution of drug-resistant genotypes carrying these mutations. However, drug-resistant genotypes are likely to be less fit than the wild-type, suggesting that they might disappear by reducing the volume of drug pressure. A substantial body of epidemiological evidence confirmed that the frequency of resistant genotypes wanes when active drug selection declines. Drug selection on the parasite genome that removes genetic variation in the vicinity of drug-resistant genes (hitch-hiking) is common among resistant parasites in the field. This can further disadvantage drug-resistant strains and limit their variability in the face of a mounting immune response. Attempts to provide unequivocal evidence for the fitness cost of drug resistance have monitored the outcomes of laboratory competition experiments of deliberate mixtures of sensitive and resistant strains, in the absence of drug pressure, using isogenic clones produced either by drug selection or gene manipulation. Some of these experiments provided inconclusive results, but they all suggested reduced fitness of drug-resistant clones in the absence of drug pressure. In addition, biochemical analyses provided clearer information demonstrating that the mutation of some antimalarial-targeted enzymes lowers their activity compared with the wild-type enzyme. Here, we review current evidences for the disadvantage of drug-resistance mutations, and discuss some strategies of drug deployment to maximize the cost of resistance and limit its spread.
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Affiliation(s)
- Hamza A Babiker
- Biochemistry Department, Faculty of Medicine, Sultan Qaboos University, Alkhod, Muscat, Oman.
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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.
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Affiliation(s)
- Daniel J Bridges
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Chichiri, Malawi.
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Abstract
One of the greatest obstacles to the control of malaria has been the spread of resistance to drugs used on a large scale. This review provides an update of the current understanding of the molecular basis for antimalarial drug resistance. Parasite intrinsic resistance is just one component that determines the in vivo efficacy of a drug. Human immune responses and pharmacologic properties play important roles in determining the clinical outcome of treatment. The emergence and spread of resistance also results from an interplay of these factors. Current efforts to characterize and deter resistance to new combination therapy are also discussed.
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Affiliation(s)
- Mark A Travassos
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Lynch C, Pearce R, Pota H, Cox J, Abeku TA, Rwakimari J, Naidoo I, Tibenderana J, Roper C. Emergence of a dhfr mutation conferring high-level drug resistance in Plasmodium falciparum populations from southwest Uganda. J Infect Dis 2008; 197:1598-604. [PMID: 18471065 DOI: 10.1086/587845] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The S108N, C59R, and N51I mutations in the Plasmodium falciparum gene that encodes dihydrofolate reductase, dhfr, confer resistance to pyrimethamine and are common in Africa. However, the I164L mutation, which confers high-level resistance, is rarely seen. We found a 14% prevalence of the I164L mutation among a sample of 51 patients with malaria in Kabale District in southwest Uganda in 2005 and a 4% prevalence among 72 patients with malaria in the neighboring district of Rukungiri during the same year. Surveillance at 6 sites across Uganda during 2002-2004 reported a single case of infection involving an I164L mutant, also in the southwest, suggesting that this is a regional hot spot. The spatial clustering and increasing prevalence of the I164L mutation is indicative of local transmission of the mutant. Targeted surveillance is needed to confirm the extent of the spread of the I164L mutation and to monitor the impact of I164L on the efficacy of antifolates for intermittent preventive treatment of pregnant women and/or infants with falciparum malaria.
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Affiliation(s)
- Caroline Lynch
- Disease Control and Vector Biology Unit, Department of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mkulama MAP, Chishimba S, Sikalima J, Rouse P, Thuma PE, Mharakurwa S. Escalating Plasmodium falciparum antifolate drug resistance mutations in Macha, rural Zambia. Malar J 2008; 7:87. [PMID: 18495008 PMCID: PMC2412897 DOI: 10.1186/1475-2875-7-87] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 05/21/2008] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In Zambia the first-line treatment for uncomplicated malaria is artemisinin combination therapy (ACT), with artemether-lumefantrine currently being used. However, the antifolate regimen, sulphadoxine-pyrimethamine (SP), remains the treatment of choice in children weighing less than 5 kg and also in expectant mothers. SP is also the choice drug for intermittent preventive therapy in pregnancy and serves as stand-by treatment during ACT stock outs. The current study assessed the status of Plasmodium falciparum point mutations associated with antifolate drug resistance in the area around Macha. METHODS A representative sample of 2,780 residents from the vicinity of Macha was screened for malaria by microscopy. At the same time, blood was collected onto filter paper and dried for subsequent P. falciparum DNA analysis. From 188 (6.8%) individuals that were thick film-positive, a simple random sub-set of 95 P. falciparum infections were genotyped for DHFR and DHPS antifolate resistance mutations, using nested PCR and allele-specific restriction enzyme digestion. RESULTS Plasmodium falciparum field samples exhibited a high prevalence of antifolate resistance mutations, including the DHFR triple (Asn-108 + Arg-59 + Ile-51) mutant (41.3%) and DHPS double (Gly-437 + Glu-540) mutant (16%). The quintuple (DHFR triple + DHPS double) mutant was found in 4 (6.5%) of the samples. Levels of mutated parasites showed a dramatic escalation, relative to previous surveys since 1988. However, neither of the Val-16 and Thr-108 mutations, which jointly confer resistance to cycloguanil, was detectable among the human infections. The Leu-164 mutation, associated with high grade resistance to both pyrimethamine and cycloguanil, as a multiple mutant with Asn-108, Arg-59 and (or) Ile-51, was also absent. CONCLUSION This study points to escalating levels of P. falciparum antifolate resistance in the vicinity of Macha. Continued monitoring is recommended to ensure timely policy revisions before widespread resistance exacts a serious public health toll.
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Affiliation(s)
| | | | - Jay Sikalima
- The Malaria Institute at Macha, Namwala Road, Choma, Zambia
| | - Petrica Rouse
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Philip E Thuma
- The Malaria Institute at Macha, Namwala Road, Choma, Zambia
| | - Sungano Mharakurwa
- The Malaria Institute at Macha, Namwala Road, Choma, Zambia
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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