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Sima-Biyang YV, Ontoua SS, Longo-Pendy NM, Mbou-Boutambe C, Makouloutou-Nzassi P, Moussadji CK, Lekana-Douki JB, Boundenga L. Epidemiology of malaria in Gabon: A systematic review and meta-analysis from 1980 to 2023. J Infect Public Health 2024; 17:102459. [PMID: 38870682 DOI: 10.1016/j.jiph.2024.05.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 05/13/2024] [Accepted: 05/22/2024] [Indexed: 06/15/2024] Open
Abstract
The objective of this were conducted to elucidate spatiotemporal variations in malaria epidemiology in Gabon since 1980. For that, five databases, were used to collect and identify all studies published between 1980 and 2023 on malaria prevalence, antimalarial drug resistance, markers of antimalarial drug resistance and insecticide resistance marker. The findings suggest that Gabon continues to face malaria as an urgent public health problem, with persistently high prevalence rates. Markers of resistance to CQ persist despite its withdrawal, and markers of resistance to SP have emerged with a high frequency, reaching 100 %, while ACTs remain effective. Also, recent studies have identified markers of resistance to the insecticides Kdr-w and Kdr-e at frequencies ranging from 25 % to 100 %. Ace1R mutation was reported with a frequency of 0.4 %. In conclusion, the efficacy of ACTs remains above the threshold recommended by the WHO. Organo-phosphates and carbamates could provide an alternative for vector control.
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Affiliation(s)
- Yann Vital Sima-Biyang
- Unit of Research in Ecology of Health (URES), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon; Central African Regional Doctoral School in Tropical Infectiology (EDR), BP 876 Franceville, Gabon
| | - Steede Seinnat Ontoua
- Central African Regional Doctoral School in Tropical Infectiology (EDR), BP 876 Franceville, Gabon; Unit of Evolution, Epidemiology and Parasite Resistance (UNEEREP), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon
| | - Neil Michel Longo-Pendy
- Unit of Research in Ecology of Health (URES), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon
| | - Clark Mbou-Boutambe
- Unit of Research in Ecology of Health (URES), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon; Central African Regional Doctoral School in Tropical Infectiology (EDR), BP 876 Franceville, Gabon
| | - Patrice Makouloutou-Nzassi
- Unit of Research in Ecology of Health (URES), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon; Department of Animal Biology and Ecology, Tropical Ecology Research Institute (IRET/CENAREST), Libreville BP 13354, Gabon
| | - Cyr Kinga Moussadji
- Primatology Center, Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon
| | - Jean-Bernard Lekana-Douki
- Unit of Evolution, Epidemiology and Parasite Resistance (UNEEREP), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon; Department of Parasitology-Mycology-Tropical Medicine, University of Health Sciences, Faculty of Medicine, BP 4009 Libreville, Gabon
| | - Larson Boundenga
- Unit of Research in Ecology of Health (URES), Franceville Interdisciplinary Center for Medical Research (CIRMF), BP 769 Franceville, Gabon; Department of Anthropology, Durham University, South Road, Durham DH1 3LE, UK.
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Ndong Ngomo JM, Mawili-Mboumba DP, M’Bondoukwé NP, Ditombi BM, Koumba Lengongo JV, Batchy Ognagosso FB, Bouyou-Akotet MK. Drug Resistance Molecular Markers of Plasmodium falciparum and Severity of Malaria in Febrile Children in the Sentinel Site for Malaria Surveillance of Melen in Gabon: Additional Data from the Plasmodium Diversity Network African Network. Trop Med Infect Dis 2023; 8:184. [PMID: 37104310 PMCID: PMC10147079 DOI: 10.3390/tropicalmed8040184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 04/28/2023] Open
Abstract
The objective of this study was to analyze the relationship between the frequency of artemisinin-based combination (ACT) drug resistance molecular markers and clinical forms of P. falciparum malaria and parasitemia. A cross-sectional study was carried out between January and April 2014 at the Operational Clinical Research Unit of Melen in febrile children aged 12 to 240 months with a Plasmodium sp. infection. A total of 3 mL of peripheral blood collected from an EDTA tube was used for leukocyte depletion. DNA mutation detection was performed by next generation sequencing (NGS). A total of 1075 patients were screened for malaria. Among them, 384 had a Plasmodium infection. P. falciparum mono-infection was found in 98.9% of the patients. Pfcrt-326T mutation was found in all isolates, while 37.9% had Pfmdr2-484I mutant allele. The highest median parasite densities were found in patients infected by parasites carrying the CVIET haplotype of the Pfcrt gene. The different genetic profiles found here, and their variations according to clinical and biological signs of severe malaria, are additional arguments for the surveillance of P. falciparum strains.
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Affiliation(s)
- Jacques Mari Ndong Ngomo
- Faculty of Medicine, Department of Parasitology and Mycology, Université des Sciences de la Santé, Libreville BP 4009, Gabon
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3
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Yobi DM, Kayiba NK, Mvumbi DM, Boreux R, Kabututu PZ, Akilimali PZ, Situakibanza HNT, De Mol P, Speybroeck N, Mvumbi GL, Hayette MP. Biennial surveillance of Plasmodium falciparum anti-malarial drug resistance markers in Democratic Republic of Congo, 2017 and 2019. BMC Infect Dis 2022; 22:145. [PMID: 35144535 PMCID: PMC8830975 DOI: 10.1186/s12879-022-07112-z] [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: 09/07/2021] [Accepted: 01/31/2022] [Indexed: 11/10/2022] Open
Abstract
Background Because of the loss of chloroquine (CQ) effectiveness, the Democratic Republic of Congo (DRC)’s malaria treatment policy replaced CQ by sulfadoxine–pyrimethamine (SP) as first-line treatment of uncomplicated malaria in 2003, which in turn was replaced by artemisinin-based combination therapies (ACT) in 2005. The World Health Organization (WHO) recommends monitoring of anti-malarial drug resistance every 2 years. The study aimed to provide baseline data for biennial molecular surveillance of anti-malarial drug resistance by comparing data from a study conducted in 2019 to previously published data from a similar study conducted in 2017 in the DRC. Methods From July to November 2019, a cross-sectional study was conducted in ten sites which were previously selected for a similar study conducted in 2017 across the DRC. P. falciparum malaria was diagnosed by a rapid diagnostic test (RDT) or by microscopy and dried blood samples (DBS) were taken from patients who had a positive test. Segments of interest in pfcrt and pfk13 genes were amplified by conventional PCR before sequencing. Results Out of 1087 enrolled patients, 906 (83.3%) were PCR-confirmed for P. falciparum. Like in the 2017-study, none of the mutations known to be associated with Artemisinine (ART) resistance in Southeast Asia was detected. However, non-synonymous (NS) mutations with unknown functions were observed among which, A578S was detected in both 2017 and 2019-studies. The overall prevalence of pfcrt-K76T mutation that confers CQ-resistance was 22.7% in 2019-study compared to 28.5% in 2017-study (p-value = 0.069), but there was high variability between sites in the two studies. Like in 2017-study, the pfcrt 72–76 SVMNT haplotype associated with resistance to amodiaquine was not detected. Conclusion The study reported, within 2 years, the non-presence of molecular markers currently known to be associated with resistance to ART and to AQ in P. falciparum isolated in the DRC. However, the presence of polymorphisms with as-yet unknown functions was observed, requiring further characterization. Moreover, an overall decrease in the prevalence of CQ-resistance marker was observed in the DRC, but this prevalence remained highly variable from region to region. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07112-z.
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Affiliation(s)
- Doudou M Yobi
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo.
| | - Nadine K Kayiba
- School of Public Health & Research Institute of Health and Society, Catholic University of Louvain, 1200, Brussels, Belgium.,School of Public Health, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo.,Department of Public Health, Faculty of Medicine, University of Mbujimayi, Mbuji-Mayi, Democratic Republic of Congo
| | - Dieudonné M Mvumbi
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Raphael Boreux
- Laboratory of Clinical Microbiology, University of Liège, 4000, Liège, Belgium
| | - Pius Z Kabututu
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Pierre Z Akilimali
- School of Public Health, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Hippolyte N T Situakibanza
- Department of Internal Medicine, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Patrick De Mol
- Laboratory of Clinical Microbiology, University of Liège, 4000, Liège, Belgium
| | - Niko Speybroeck
- School of Public Health & Research Institute of Health and Society, Catholic University of Louvain, 1200, Brussels, Belgium
| | - Georges L Mvumbi
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
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Identification of polymorphisms in genes associated with drug resistance in Plasmodium falciparum isolates from school-age children in Kinshasa, Democratic Republic of Congo. Parasitol Int 2022; 88:102541. [PMID: 35051550 DOI: 10.1016/j.parint.2022.102541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND The emergence and spread of Plasmodium falciparum parasites resistant to antimalarial drugs constitutes an obstacle to malaria control and elimination. This study aimed to identify the prevalence of polymorphisms in pfk13, pfmdr1, pfdhfr, pfdhps and pfcrt genes in isolates from asymptomatic and symptomatic school-age children in Kinshasa. METHODS Nested-PCR followed by sequencing was performed for the detection of pfk13, pfmdr1, pfdhfr, pfdhps and pfcrt polymorphisms. RESULTS Two mutations in pfk13, C532S and Q613E were identified in the Democratic Republic of Congo for the first time. The prevalence of the drug-resistance associated mutations pfcrt K76T, pfdhps K540E and pfmdr1 N86Y was low, being 27%, 20% and 9%, respectively. CONCLUSION We found a low prevalence of genetic markers associated with chloroquine and sulfadoxine-pyrimethamine resistance in Kinshasa. Furthermore, no mutations previously associated with resistance against artemisinin and is derivatives were observed in the pfK13 gene. These findings support the continued use of ACTs and IPTp-SP. Continuous molecular monitoring of antimalarial resistance markers is recommended.
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Yobi DM, Kayiba NK, Mvumbi DM, Boreux R, Kabututu PZ, Situakibanza HNT, Umesumbu SE, De Mol P, Speybroeck N, Mvumbi GL, Hayette MP. Assessment of Plasmodium falciparum anti-malarial drug resistance markers in pfk13-propeller, pfcrt and pfmdr1 genes in isolates from treatment failure patients in Democratic Republic of Congo, 2018-2019. Malar J 2021; 20:144. [PMID: 33706773 PMCID: PMC7953712 DOI: 10.1186/s12936-021-03636-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/09/2021] [Indexed: 11/14/2022] Open
Abstract
Background The national policy for malaria treatment of the Democratic Republic of Congo recommends two first-line artemisinin-based combinations for the treatment of uncomplicated malaria: artesunate-amodiaquine and artemether-lumefantrine. This study investigated the presence of markers associated with resistance to the current first-line artemisinin-based combination therapy (ACT) in isolates of Plasmodium falciparum from treatment failure patients in the Democratic Republic of Congo. Methods From November 2018 to November 2019, dried blood spots were taken from patients returning to health centres for fever within 28 days after an initial malaria treatment in six sentinel sites of the National Malaria Control Programme across Democratic Republic of Congo. The new episode of malaria was first detected by a rapid diagnostic test and then confirmed by a real-time PCR assay to define treatment failure. Fragments of interest in pfk13 and pfcrt genes were amplified by conventional PCR before sequencing and the Pfmdr1 gene copy number was determined by a TaqMan real-time PCR assay. Results Out of 474 enrolled patients, 364 (76.8%) were confirmed positive by PCR for a new episode of P. falciparum malaria, thus considered as treatment failure. Of the 325 P. falciparum isolates obtained from 364 P. falciparum-positive patients and successfully sequenced in the pfk13-propeller gene, 7 (2.2%) isolates carried non-synonymous mutations, among which 3 have been previously reported (N498I, N554K and A557S) and 4 had not yet been reported (F506L, E507V, D516E and G538S). Of the 335 isolates successfully sequenced in the pfcrt gene, 139 (41.5%) harboured the K76T mutation known to be associated with chloroquine resistance. The SVMNT haplotype associated with resistance to amodiaquine was not found. None of the isolates carried an increased copy number of the pfmdr1 gene among the 322 P. falciparum isolates successfully analysed. Conclusion No molecular markers currently known to be associated with resistance to the first-line ACT in use were detected in isolates of P. falciparum from treatment failure patients. Regular monitoring through in vivo drug efficacy and molecular studies must continue to ensure the effectiveness of malaria treatment in Democratic Republic of Congo.
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Affiliation(s)
- Doudou M Yobi
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo.
| | - Nadine K Kayiba
- School of Public Health and Research Institute of Health and Society, Catholic University of Louvain, 1200, Brussels, Belgium.,School of Public Health, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo.,Department of Public Health, Faculty of Medicine, University of Mbujimayi, Mbujimayi, Democratic Republic of Congo
| | - Dieudonné M Mvumbi
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Raphael Boreux
- Laboratory of Clinical Microbiology, University of Liège, 4000, Liège, Belgium
| | - Pius Z Kabututu
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Hippolyte N T Situakibanza
- Department of Internal Medicine, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Solange E Umesumbu
- National Malaria Control Programme, Kinshasa, Democratic Republic of Congo
| | - Patrick De Mol
- Laboratory of Clinical Microbiology, University of Liège, 4000, Liège, Belgium
| | - Niko Speybroeck
- School of Public Health and Research Institute of Health and Society, Catholic University of Louvain, 1200, Brussels, Belgium
| | - Georges L Mvumbi
- Department of Basic Sciences, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
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Dejon-Agobe JC, Ateba-Ngoa U, Lalremruata A, Homoet A, Engelhorn J, Nouatin OP, Edoa JR, Fernandes JF, Esen M, Mouwenda YD, Betouke Ongwe EM, Massinga-Loembe M, Hoffman SL, Sim BKL, Theisen M, Kremsner PG, Adegnika AA, Lell B, Mordmüller B. Controlled Human Malaria Infection of Healthy Adults With Lifelong Malaria Exposure to Assess Safety, Immunogenicity, and Efficacy of the Asexual Blood Stage Malaria Vaccine Candidate GMZ2. Clin Infect Dis 2020; 69:1377-1384. [PMID: 30561539 DOI: 10.1093/cid/ciy1087] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/18/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND GMZ2 is a recombinant malaria vaccine inducing immune responses against Plasmodium falciparum (Pf) merozoite surface protein-3 and glutamate-rich protein. We used standardized controlled human malaria infection (CHMI) to assess the efficacy of this asexual blood-stage vaccine. METHODS We vaccinated 50 healthy, adult volunteers with lifelong exposure to Pf 3 times, at 4-week intervals, with 30 or 100 µg GMZ2 formulated in CAF01, a liposome-based adjuvant; 100 µg GMZ2, formulated in Alhydrogel; or a control vaccine (Verorab). Approximately 13 weeks after the last vaccination, 35/50 volunteers underwent CHMI by direct venous inoculation of 3200 Pf sporozoites (Sanaria® PfSPZ Challenge). RESULTS Adverse events were similarly distributed between GMZ2 and control vaccinees. Baseline-corrected anti-GMZ2 antibody concentrations 4 weeks after the last vaccination were higher in all 3 GMZ2-vaccinated arms, compared to the control group. All GMZ2 formulations induced similar antibody levels. CHMI resulted in 29/34 (85%) volunteers with Pf parasitemia and 15/34 (44%) with malaria (parasitemia and symptoms). The proportion of participants with malaria (2/5 control, 6/10 GMZ2-Alhydrogel, 2/8 30 µg GMZ2-CAF01, and 5/11 100 µg GMZ2-CAF01) and the time it took them to develop malaria were similar in all groups. Baseline, vaccine-specific antibody concentrations were associated with protection against malaria. CONCLUSIONS GMZ2 is well tolerated and immunogenic in lifelong-Pf-exposed adults from Gabon, with similar antibody responses regardless of formulation. CHMI showed no protective effect of prior vaccination with GMZ2, although baseline, vaccine-specific antibody concentrations were associated with protection. CHMI with the PfSPZ Challenge is a potent new tool to validate asexual, blood-stage malaria vaccines in Africa. CLINICAL TRIALS REGISTRATION Pan-African Clinical Trials: PACTR201503001038304.
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Affiliation(s)
- Jean Claude Dejon-Agobe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Ulysse Ateba-Ngoa
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany.,Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Albert Lalremruata
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Andreas Homoet
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Julie Engelhorn
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Odilon Paterne Nouatin
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Jean Ronald Edoa
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - José F Fernandes
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Meral Esen
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Yoanne Darelle Mouwenda
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Eunice M Betouke Ongwe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Marguerite Massinga-Loembe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | | | | | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Ayôla A Adegnika
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany.,Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
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Dimonte S, Bruske EI, Enderes C, Otto TD, Turner L, Kremsner P, Frank M. Identification of a conserved var gene in different Plasmodium falciparum strains. Malar J 2020; 19:194. [PMID: 32471507 PMCID: PMC7260770 DOI: 10.1186/s12936-020-03257-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 05/15/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The multicopy var gene family of Plasmodium falciparum is of crucial importance for pathogenesis and antigenic variation. So far only var2csa, the var gene responsible for placental malaria, was found to be highly conserved among all P. falciparum strains. Here, a new conserved 3D7 var gene (PF3D7_0617400) is identified in several field isolates. METHODS DNA sequencing, transcriptional analysis, Cluster of Differentiation (CD) 36-receptor binding, indirect immunofluorescence with PF3D7_0617400-antibodies and quantification of surface reactivity against semi-immune sera were used to characterize an NF54 clone and a Gabonese field isolate clone (MOA C3) transcribing the gene. A population of 714 whole genome sequenced parasites was analysed to characterize the conservation of the locus in African and Asian isolates. The genetic diversity of two var2csa fragments was compared with the genetic diversity of 57 microsatellites fragments in field isolates. RESULTS PFGA01_060022400 was identified in a Gabonese parasite isolate (MOA) from a chronic infection and found to be 99% identical with PF3D7_0617400 of the 3D7 genome strain. Transcriptional analysis and immunofluorescence showed expression of the gene in an NF54 and a MOA clone but CD36 binding assays and surface reactivity to semi-immune sera differed markedly in the two clones. Long-read Pacific bioscience whole genome sequencing showed that PFGA01_060022400 is located in the internal cluster of chromosome 6. The full length PFGA01_060022400 was detected in 36 of 714 P. falciparum isolates and 500 bp fragments were identified in more than 100 isolates. var2csa was in parts highly conserved (He = 0) but in other parts as variable (He = 0.86) as the 57 microsatellites markers (He = 0.8). CONCLUSIONS Individual var gene sequences exhibit conservation in the global parasite population suggesting that purifying selection may limit overall genetic diversity of some var genes. Notably, field and laboratory isolates expressing the same var gene exhibit markedly different phenotypes.
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Affiliation(s)
- Sandra Dimonte
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Ellen I Bruske
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Corinna Enderes
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Thomas D Otto
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK.,Centre of Immunobiology, Institute of Infection, Immunity & Inflammation, College of MVLS, University of Glasgow, Glasgow, UK
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen, 1165, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), 2100, Copenhagen, Denmark
| | - Peter Kremsner
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Matthias Frank
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany.
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Bretscher MT, Dahal P, Griffin J, Stepniewska K, Bassat Q, Baudin E, D'Alessandro U, Djimde AA, Dorsey G, Espié E, Fofana B, González R, Juma E, Karema C, Lasry E, Lell B, Lima N, Menéndez C, Mombo-Ngoma G, Moreira C, Nikiema F, Ouédraogo JB, Staedke SG, Tinto H, Valea I, Yeka A, Ghani AC, Guerin PJ, Okell LC. The duration of chemoprophylaxis against malaria after treatment with artesunate-amodiaquine and artemether-lumefantrine and the effects of pfmdr1 86Y and pfcrt 76T: a meta-analysis of individual patient data. BMC Med 2020; 18:47. [PMID: 32098634 PMCID: PMC7043031 DOI: 10.1186/s12916-020-1494-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/09/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The majority of Plasmodium falciparum malaria cases in Africa are treated with the artemisinin combination therapies artemether-lumefantrine (AL) and artesunate-amodiaquine (AS-AQ), with amodiaquine being also widely used as part of seasonal malaria chemoprevention programs combined with sulfadoxine-pyrimethamine. While artemisinin derivatives have a short half-life, lumefantrine and amodiaquine may give rise to differing durations of post-treatment prophylaxis, an important additional benefit to patients in higher transmission areas. METHODS We analyzed individual patient data from 8 clinical trials of AL versus AS-AQ in 12 sites in Africa (n = 4214 individuals). The time to PCR-confirmed reinfection after treatment was used to estimate the duration of post-treatment protection, accounting for variation in transmission intensity between settings using hidden semi-Markov models. Accelerated failure-time models were used to identify potential effects of covariates on the time to reinfection. The estimated duration of chemoprophylaxis was then used in a mathematical model of malaria transmission to determine the potential public health impact of each drug when used for first-line treatment. RESULTS We estimated a mean duration of post-treatment protection of 13.0 days (95% CI 10.7-15.7) for AL and 15.2 days (95% CI 12.8-18.4) for AS-AQ overall. However, the duration varied significantly between trial sites, from 8.7-18.6 days for AL and 10.2-18.7 days for AS-AQ. Significant predictors of time to reinfection in multivariable models were transmission intensity, age, drug, and parasite genotype. Where wild type pfmdr1 and pfcrt parasite genotypes predominated (<=20% 86Y and 76T mutants, respectively), AS-AQ provided ~ 2-fold longer protection than AL. Conversely, at a higher prevalence of 86Y and 76T mutant parasites (> 80%), AL provided up to 1.5-fold longer protection than AS-AQ. Our simulations found that these differences in the duration of protection could alter population-level clinical incidence of malaria by up to 14% in under-5-year-old children when the drugs were used as first-line treatments in areas with high, seasonal transmission. CONCLUSION Choosing a first-line treatment which provides optimal post-treatment prophylaxis given the local prevalence of resistance-associated markers could make a significant contribution to reducing malaria morbidity.
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Affiliation(s)
- Michael T Bretscher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
| | - Prabin Dahal
- WorldWide Antimalarial Resistance Network (WWARN), Oxford, UK.,Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jamie Griffin
- School of Mathematical Sciences, Queen Mary University of London, London, UK
| | - Kasia Stepniewska
- WorldWide Antimalarial Resistance Network (WWARN), Oxford, UK.,Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Quique Bassat
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.,Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain.,Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | - Umberto D'Alessandro
- MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Abdoulaye A Djimde
- Malaria Research and Training Center, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Emmanuelle Espié
- Epicentre, Paris, France.,Clinical and Epidemiology Department, GSK Vaccines, R&D Center, Wavre, Belgium
| | - Bakary Fofana
- Malaria Research and Training Center, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Raquel González
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Elizabeth Juma
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Corine Karema
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Bertrand Lell
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria.,Centre de Recherches Medicales de Lambarene, Lambarene, Gabon
| | - Nines Lima
- Department of Paediatrics, University of Calabar, Calabar, Nigeria
| | - Clara Menéndez
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Medicales de Lambarene, Lambarene, Gabon.,Institute for Tropical Medicine, University of Tubingen, Tubingen, Germany.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Clarissa Moreira
- WorldWide Antimalarial Resistance Network (WWARN), Oxford, UK.,Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Frederic Nikiema
- Institut de Recherche en Science de la Sante, Bobo-Dioulasso, Burkina Faso
| | - Jean B Ouédraogo
- Institut de Recherche en Science de la Sante, Bobo-Dioulasso, Burkina Faso
| | - Sarah G Staedke
- Department of Clinical Research, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Halidou Tinto
- Institut de Recherche en Science de la Sante, Nanoro, Burkina Faso
| | - Innocent Valea
- Institut de Recherche en Science de la Sante, Nanoro, Burkina Faso
| | - Adoke Yeka
- Uganda Malaria Surveillance Project, Kampala, Uganda
| | - Azra C Ghani
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Philippe J Guerin
- WorldWide Antimalarial Resistance Network (WWARN), Oxford, UK.,Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Lucy C Okell
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
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9
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Adegbite BR, Edoa JR, Honkpehedji YJ, Zinsou FJ, Dejon-Agobe JC, Mbong-Ngwese M, Lotola-Mougueni F, Koehne E, Lalremruata A, Kreidenweiss A, Nguyen TT, Kun J, Agnandji ST, Lell B, Safiou AR, Obone Atome FA, Mombo-Ngoma G, Ramharter M, Velavan TP, Mordmüller B, Kremsner PG, Adegnika AA. Monitoring of efficacy, tolerability and safety of artemether-lumefantrine and artesunate-amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Lambaréné, Gabon: an open-label clinical trial. Malar J 2019; 18:424. [PMID: 31842893 PMCID: PMC6916217 DOI: 10.1186/s12936-019-3015-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 11/20/2019] [Indexed: 02/01/2023] Open
Abstract
Background Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether–lumefantrine (AL) and artesunate–amodiaquine (AS–AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon. Methods A non-randomized clinical trial was conducted between October 2017 and March 2018 to assess safety, clinical and parasitological efficacy of fixed-doses of AL and AS–AQ administered to treat uncomplicated Plasmodium falciparum malaria in children aged from 6 months to 12 years. After 50 children were treated with AL, another 50 children received ASAQ. The 2009 World Health Organization protocol for monitoring of the efficacy of anti‑malarial drugs was followed. Molecular markers msp1 and msp2 were used to differentiate recrudescence and reinfection. For the investigation of artemisinin resistant markers, gene mutations in Pfk13 were screened. Results Per-protocol analysis on day 28 showed a PCR corrected cure rate of 97% (95% CI 86–100) and 95% (95% CI 84–99) for AL and AS–AQ, respectively. The most frequent adverse event in both groups was asthenia. No mutations in the kelch-13 gene associated with artemisinin resistance were identified. All participants had completed microscopic parasite clearance by day 3 post-treatment. Conclusion This study showed that AL and AS–AQ remain efficacious, well-tolerated, and are safe to treat uncomplicated malaria in children from Lambaréné. However, a regular monitoring of efficacy and a study of molecular markers of drug resistance to artemisinin in field isolates is essential. Trial registration ANZCTR, ACTRN12616001600437. Registered 18 November, http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12616001600437p&isBasic=True
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Affiliation(s)
- Bayode R Adegbite
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon
| | - Jean R Edoa
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon
| | - Yabo J Honkpehedji
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Frejus J Zinsou
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jean C Dejon-Agobe
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | - Erik Koehne
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Albert Lalremruata
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Andrea Kreidenweiss
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - The T Nguyen
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,Vietnamese-German Center for Medical Research, Hanoi, Vietnam
| | - Jutta Kun
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Selidji T Agnandji
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Division of Infectious Diseases and Tropical Medicine, Department of Medicine 1, Medical University of Vienna, Vienna, Austria
| | - Abdou R Safiou
- Programme National de Lutte contre le paludisme, Libreville, Gabon
| | | | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thirumalaisamy P Velavan
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,Vietnamese-German Center for Medical Research, Hanoi, Vietnam
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research, Tübingen, Germany
| | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,German Center for Infection Research, Tübingen, Germany
| | - Ayola A Adegnika
- Centre de Recherches Médicales de Lambaréné, BP: 242, Lambaréné, Gabon. .,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. .,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands. .,German Center for Infection Research, Tübingen, Germany.
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10
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Histone deacetylase inhibitors with high in vitro activities against Plasmodium falciparum isolates collected from Gabonese children and adults. Sci Rep 2019; 9:17336. [PMID: 31758015 PMCID: PMC6874535 DOI: 10.1038/s41598-019-53912-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/04/2019] [Indexed: 01/25/2023] Open
Abstract
Histone deacetylase (HDAC) enzymes are targets for the development of antimalarial drugs with a different mode of action to established antimalarials. Broad-spectrum HDAC-inhibitors show high potency against Plasmodium falciparum, but displayed some toxicity towards human cells. Inhibitors of human HDAC6 are new drug candidates with supposed reduced toxicity to human cells and favorable activities against laboratory P. falciparum strains. We investigated the potency of 12 peptoid-based HDAC-inhibitors against asexual stages of P. falciparum clinical isolates. Parasites representing different genetic backgrounds were isolated from adults and children with uncomplicated malaria in Gabon. Clinical studies on (non-HDAC-inhibitors) antimalarials, moreover, found lower drug efficacy in children, mainly attributed to acquired immunity with age in endemic areas. Therefore, we compared the in vitro sensitivity profiles of adult- and child-derived isolates to antimalarials (HDAC and standard drugs). All HDAC-inhibitors showed 50% inhibitory concentrations at nanomolar ranges with higher activities than the FDA approved reference HDAC-inhibitor SAHA. We propose peptoid-based HDAC6-inhibitors to be lead structures for further development as antimalarial chemotherapeutics. Our results further suggest no differences in activity of the tested antimalarials between P. falciparum parasites isolated from children and adults.
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11
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DNA recovery from archived RDTs for genetic characterization of Plasmodium falciparum in a routine setting in Lambaréné, Gabon. Malar J 2019; 18:336. [PMID: 31578142 PMCID: PMC6775649 DOI: 10.1186/s12936-019-2972-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/24/2019] [Indexed: 11/15/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) have been described as a source of genetic material to analyse malaria parasites in proof-of-concept studies. The increasing use of RDTs (e.g., in focal or mass screening and treatment campaigns) makes this approach particularly attractive for large-scale investigations of parasite populations. In this study, the complexity of Plasmodium falciparum infections, parasite load and chloroquine resistance transporter gene mutations were investigated in DNA samples extracted from positive RDTs, obtained in a routine setting and archived at ambient temperature. Methods A total of 669 archived RDTs collected from malaria cases in urban, semi-urban and rural areas of central Gabon were used for P. falciparum DNA extraction. Performance of RDTs as a source of DNA for PCR was determined using: (i) amplification of a single copy merozoite surface protein 1 (msp1) gene followed by highly sensitive and automated capillary electrophoresis; (ii) genotyping of the pfcrt gene locus 72–76 using haplotype-specific-probe-based real-time PCR to characterize chloroquine resistance; and, (iii) real-time PCR targeting 18S genes to detect and quantify Plasmodium parasites. Results Out of the 669 archived RDTs, amplification of P. falciparum nucleic materials had a success rate of 97% for 18S real-time PCR, and 88% for the msp1 gene. The multiplicity of infections (MOI) of the whole population was 2.6 (95% CI 2.5–2.8). The highest number of alleles detected in one infection was 11. The MOI decreased with increasing age (β = − 0.0046, p = 0.02) and residence in Lambaréné was associated with smaller MOIs (p < 0.001). The overall prevalence of mutations associated with chloroquine resistance was 78.5% and was not associated with age. In Lambaréné, prevalence of chloroquine resistance was lower compared to rural Moyen-Ogooué (β = − 0.809, p-value = 0.011). Conclusion RDT is a reliable source of DNA for P. falciparum detection and genotyping assays. Furthermore, the increasing use of RDTs allows them to be an alternative source of DNA for large-scale genetic epidemiological studies. Parasite populations in the study area are highly diverse and prevalence of chloroquine-resistant P. falciparum remains high, especially in rural areas.
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12
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Characterization of drug resistance and genetic diversity of Plasmodium falciparum parasites from Tripura, Northeast India. Sci Rep 2019; 9:13704. [PMID: 31548652 PMCID: PMC6757058 DOI: 10.1038/s41598-019-50152-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 09/06/2019] [Indexed: 01/23/2023] Open
Abstract
Monitoring of anti-malarial drug resistance is vital in Northeast India as this region shares its international border with Southeast Asia. Genetic diversity of Plasmodium parasites regulates transmission dynamics, disease severity and vaccine efficacy. P. falciparum chloroquine resistance transporter (Pfcrt), multidrug resistance-1 (Pfmdr-1) and kelch 13 propeller (PfK-13) genes which govern antimalarial drug resistance and three genetic diversity markers, merozoite surface protein 1 and 2 (Pfmsp-1, Pfmsp-2) and glutamate rich protein (Pfglurp) were evaluated from Tripura, Northeast India using molecular tools. In the Pfcrt gene, 87% isolates showed triple mutations at codons M74I, N75E and K76T. 12.5% isolates in Pfmdr-1 gene showed mutation at N86Y. No polymorphism in PfK-13 propeller was found. Polyclonal infections were observed in 53.85% isolates and more commonly in adults (p = 0.0494). In the Pfmsp-1 locus, the K1 allelic family was predominant (71.2%) followed by the 3D7/IC family (69.2%) in the Pfmsp-2 locus. RII region of Pfglurp exhibited nine alleles with expected heterozygosity of 0.85. The multiplicity of infection for Pfmsp-1, Pfmsp-2 and Pfglurp were 1.56, 1.31 and 1.06 respectively. Overall, the study demonstrated a high level of chloroquine resistance and extensive parasite diversity in the region, necessitating regular surveillance in this population group.
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13
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Woldearegai TG, Lalremruata A, Nguyen TT, Gmeiner M, Veletzky L, Tazemda-Kuitsouc GB, Matsiegui PB, Mordmüller B, Held J. Characterization of Plasmodium infections among inhabitants of rural areas in Gabon. Sci Rep 2019; 9:9784. [PMID: 31278305 PMCID: PMC6611864 DOI: 10.1038/s41598-019-46194-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/25/2019] [Indexed: 12/18/2022] Open
Abstract
Plasmodium infections in endemic areas are often asymptomatic, can be caused by different species and contribute significantly to transmission. We performed a cross-sectional study in February/March 2016 including 840 individuals ≥ 1 year living in rural Gabon (Ngounié and Moyen-Ogooué). Plasmodium parasitemia was measured by high-sensitive, real-time quantitative PCR. In a randomly chosen subset of P. falciparum infections, gametocyte carriage and prevalence of chloroquine-resistant genotypes were analysed. 618/834 (74%) individuals were positive for Plasmodium 18S-rRNA gene amplification, of these 553 (66.3%) carried P. falciparum, 193 (23%) P. malariae, 74 (8.9%) P. ovale curtisi and 38 (4.6%) P.ovale wallikeri. Non-falciparum infections mostly presented as mixed infections. P. malariae monoinfected individuals were significantly older (median age: 60 years) than coinfected (20 years) or P. falciparum monoinfected individuals (23 years). P. falciparum gametocyte carriage was confirmed in 109/223 (48.9%) individuals, prevalence of chloroquine-resistant genotypes was high (298/336, 89%), including four infections with a new SVMNK genotype. In rural Gabon, Plasmodium infections with all endemic species are frequent, emphasizing that malaria control efforts shall cover asymptomatic infections also including non-falciparum infections when aiming for eradication.
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Affiliation(s)
- Tamirat Gebru Woldearegai
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Albert Lalremruata
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - The Trong Nguyen
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Vietnamese - German Center of Excellence in Medical Research, Hanoi, Vietnam
| | - Markus Gmeiner
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Luzia Veletzky
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Dep. of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Pierre Blaise Matsiegui
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.,Centre de Recherches Médicales de la Ngounié, Fougamou, Gabon
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany. .,German Centre for Infection Research, partner site Tübingen, Tübingen, Germany. .,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon.
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14
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Staines HM, Burrow R, Teo BHY, Chis Ster I, Kremsner PG, Krishna S. Clinical implications of Plasmodium resistance to atovaquone/proguanil: a systematic review and meta-analysis. J Antimicrob Chemother 2019; 73:581-595. [PMID: 29237012 PMCID: PMC5890752 DOI: 10.1093/jac/dkx431] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 10/23/2017] [Indexed: 11/26/2022] Open
Abstract
Background Atovaquone/proguanil, registered as Malarone®, is a fixed-dose combination recommended for first-line treatment of uncomplicated Plasmodium falciparum malaria in non-endemic countries and its prevention in travellers. Mutations in the cytochrome bc1 complex are causally associated with atovaquone resistance. Methods This systematic review assesses the clinical efficacy of atovaquone/proguanil treatment of uncomplicated malaria and examines the extent to which codon 268 mutation in cytochrome b influences treatment failure and recrudescence based on published information. Results Data suggest that atovaquone/proguanil treatment efficacy is 89%–98% for P. falciparum malaria (from 27 studies including between 18 and 253 patients in each case) and 20%–26% for Plasmodium vivax malaria (from 1 study including 25 patients). The in vitro P. falciparum phenotype of atovaquone resistance is an IC50 value >28 nM. Case report analyses predict that recrudescence in a patient presenting with parasites carrying cytochrome b codon 268 mutation will occur on average at day 29 (95% CI: 22, 35), 19 (95% CI: 7, 30) days longer than if the mutation is absent. Conclusions Evidence suggests atovaquone/proguanil treatment for P. falciparum malaria is effective. Late treatment failure is likely to be associated with a codon 268 mutation in cytochrome b, though recent evidence from animal models suggests these mutations may not spread within the population. However, early treatment failure is likely to arise through alternative mechanisms, requiring further investigation.
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Affiliation(s)
- Henry M Staines
- Centre for Diagnostics and Antimicrobial Resistance, Institute for Infection & Immunity, St George's University of London, London, UK.,Institute for Infection & Immunity, St George's University of London, London, UK
| | - Rebekah Burrow
- Institute for Infection & Immunity, St George's University of London, London, UK
| | - Beatrix Huei-Yi Teo
- Institute for Infection & Immunity, St George's University of London, London, UK
| | - Irina Chis Ster
- Institute for Infection & Immunity, St George's University of London, London, UK
| | - Peter G Kremsner
- Institut für Tropenmedizin Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Sanjeev Krishna
- Centre for Diagnostics and Antimicrobial Resistance, Institute for Infection & Immunity, St George's University of London, London, UK.,Institute for Infection & Immunity, St George's University of London, London, UK.,Institut für Tropenmedizin Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon.,St George's University Hospitals NHS Foundation Trust, London, UK
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15
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Ocan M, Akena D, Nsobya S, Kamya MR, Senono R, Kinengyere AA, Obuku EA. Persistence of chloroquine resistance alleles in malaria endemic countries: a systematic review of burden and risk factors. Malar J 2019; 18:76. [PMID: 30871535 PMCID: PMC6419488 DOI: 10.1186/s12936-019-2716-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/08/2019] [Indexed: 12/18/2022] Open
Abstract
Background Chloroquine, a previous highly efficacious, easy to use and affordable anti-malarial agent was withdrawn from malaria endemic regions due to high levels of resistance. This review collated evidence from published-reviewed articles to establish prevalence of Pfcrt 76T and Pfmdr-1 86Y alleles in malaria affected countries following official discontinuation of chloroquine use. Methods A review protocol was developed, registered in PROSPERO (#CRD42018083957) and published in a peer-reviewed journal. Article search was done in PubMed, Scopus, Lilacs/Vhl and Embase databases by two experienced librarians (AK, RS) for the period 1990-to-Febuary 2018. Mesh terms and Boolean operators (AND, OR) were used. Data extraction form was designed in Excel spread sheet 2007. Data extraction was done by three reviewers (NL, BB and MO), discrepancies were resolved by discussion. Random effects analysis was done in Open Meta Analyst software. Heterogeneity was established using I2-statistic. Results A total of 4721 citations were retrieved from article search (Pubmed = 361, Lilac/vhl = 28, Science Direct = 944, Scopus = 3388). Additional targeted search resulted in three (03) eligible articles. After removal of duplicates (n = 523) and screening, 38 articles were included in the final review. Average genotyping success rate was 63.6% (18,343/28,820) for Pfcrt K76T and 93.5% (16,232/17,365) for Pfmdr-1 86Y mutations. Prevalence of Pfcrt 76T was as follows; East Africa 48.9% (2528/5242), Southern Africa 18.6% (373/2163), West Africa 58.3% (3321/6608), Asia 80.2% (1951/2436). Prevalence of Pfmdr-1 86Y was; East Africa 32.4% (1447/5722), Southern Africa 36.1% (544/1640), West Africa 52.2% (1986/4200), Asia 46.4% (1276/2217). Over half, 52.6% (20/38) of included studies reported continued unofficial chloroquine use following policy change. Studies done in Madagascar and Kenya reported re-emergence of chloroquine sensitive parasites (IC50 < 30.9 nM). The average time (years) since discontinuation of chloroquine use to data collection was 8.7 ± 7.4. There was high heterogeneity (I2 > 95%). Conclusion The prevalence of chloroquine resistance alleles among Plasmodium falciparum parasites have steadily declined since discontinuation of chloroquine use. However, Pfcrt K76T and Pfmdr-1 N86Y mutations still persist at moderate frequencies in most malaria affected countries.
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Affiliation(s)
- Moses Ocan
- Department of Pharmacology & Therapeutics, Makerere University, P.O. Box 7072, Kampala, Uganda. .,Africa Centre for Systematic Reviews and Knowledge Translation, Makerere University College of Health Sciences, P.O. Box 7072, Kampala, Uganda.
| | - Dickens Akena
- Department of Psychiatry, Makerere University, P.O. Box 7072, Kampala, Uganda.,Infectious Disease Institute, Makerere University, P. O. Box 22418, Kampala, Uganda
| | - Sam Nsobya
- Department of Medical Microbiology, Makerere University, P.O. Box 7072, Kampala, Uganda
| | - Moses R Kamya
- Department of Medicine, Makerere University, P.O. Box 7072, Kampala, Uganda
| | - Richard Senono
- Infectious Disease Institute, Makerere University, P. O. Box 22418, Kampala, Uganda.,Africa Centre for Systematic Reviews and Knowledge Translation, Makerere University College of Health Sciences, P.O. Box 7072, Kampala, Uganda
| | - Alison Annet Kinengyere
- Albert Cook Library, Makerere University, P.O. Box 7072, Kampala, Uganda.,Africa Centre for Systematic Reviews and Knowledge Translation, Makerere University College of Health Sciences, P.O. Box 7072, Kampala, Uganda
| | - Ekwaro A Obuku
- Clinical Epidemiology Unit, Department of Medicine, Makerere University, P.O. Box 7072, Kampala, Uganda.,Africa Centre for Systematic Reviews and Knowledge Translation, Makerere University College of Health Sciences, P.O. Box 7072, Kampala, Uganda.,Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
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16
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Bruske E, Otto TD, Frank M. Whole genome sequencing and microsatellite analysis of the Plasmodium falciparum E5 NF54 strain show that the var, rifin and stevor gene families follow Mendelian inheritance. Malar J 2018; 17:376. [PMID: 30348135 PMCID: PMC6198375 DOI: 10.1186/s12936-018-2503-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/03/2018] [Indexed: 12/30/2022] Open
Abstract
Background Plasmodium falciparum exhibits a high degree of inter-isolate genetic diversity in its variant surface antigen (VSA) families: P. falciparum erythrocyte membrane protein 1, repetitive interspersed family (RIFIN) and subtelomeric variable open reading frame (STEVOR). The role of recombination for the generation of this diversity is a subject of ongoing research. Here the genome of E5, a sibling of the 3D7 genome strain is presented. Short and long read whole genome sequencing (WGS) techniques (Ilumina, Pacific Bioscience) and a set of 84 microsatellites (MS) were employed to characterize the 3D7 and non-3D7 parts of the E5 genome. This is the first time that VSA genes in sibling parasites were analysed with long read sequencing technology. Results Of the 5733 E5 genes only 278 genes, mostly var and rifin/stevor genes, had no orthologues in the 3D7 genome. WGS and MS analysis revealed that chromosomal crossovers occurred at a rate of 0–3 per chromosome. var, stevor and rifin genes were inherited within the respective non-3D7 or 3D7 chromosomal context. 54 of the 84 MS PCR fragments correctly identified the respective MS as 3D7- or non-3D7 and this correlated with var and rifin/stevor gene inheritance in the adjacent chromosomal regions. E5 had 61 var and 189 rifin/stevor genes. One large non-chromosomal recombination event resulted in a new var gene on chromosome 14. The remainder of the E5 3D7-type subtelomeric and central regions were identical to 3D7. Conclusions The data show that the rifin/stevor and var gene families represent the most diverse compartments of the P. falciparum genome but that the majority of var genes are inherited without alterations within their respective parental chromosomal context. Furthermore, MS genotyping with 54 MS can successfully distinguish between two sibling progeny of a natural P. falciparum cross and thus can be used to investigate identity by descent in field isolates. Electronic supplementary material The online version of this article (10.1186/s12936-018-2503-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ellen Bruske
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany
| | - Thomas D Otto
- Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK. .,Centre of Immunobiology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Matthias Frank
- Institute of Tropical Medicine, University of Tuebingen, Wilhelmstr. 27, 72074, Tuebingen, Germany.
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17
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Voumbo-Matoumona DF, Kouna LC, Madamet M, Maghendji-Nzondo S, Pradines B, Lekana-Douki JB. Prevalence of Plasmodium falciparum antimalarial drug resistance genes in Southeastern Gabon from 2011 to 2014. Infect Drug Resist 2018; 11:1329-1338. [PMID: 30214253 PMCID: PMC6118251 DOI: 10.2147/idr.s160164] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE The introduction of artemisinin-based combination therapies (ACTs) in treating uncomplicated malaria and sulfadoxine-pyrimethamine (SP) as intermittent preventive treatment during pregnancy drastically decreased the burden of malarial disease around the world. However, ACTs are known to select for drug resistance markers. In Gabon, artemether-lumefantrine induced an increase in the prevalence of N86-Pfmdr1, which is associated with treatment failure. However, little data are available regarding resistance markers in Southeastern Gabon. This study aimed to evaluate the evolution of resistance haplotypes in the Pfcrt, Pfdhps, Pfdhfr, and PfK13 genes from 2011 to 2014 in Southeastern Gabon. METHODS A total of 233 Plasmodium falciparum DNA samples were collected from febrile pediatric patients in South Gabon: Franceville, an urban area; Koulamoutou, a semi-urban area; and Lastourville, a rural area. Pfcrt, Pfdhps, Pfdhfr, and the propeller domain of PfK13 were sequenced for all isolates. RESULTS The overall prevalence (3.7%-11.5%) of the wild-type haplotype Pfcrt 72-76 CVMNK was not significantly different between 2011 and 2014 in Southeast Gabon. For Pfdhfr (codons 51, 59, 108, 164), the IRNI triple-mutant haplotype was the most prevalent (>89.0%). The ICNI and NCNI mutant haplotypes and the NCSI wild-type haplotype showed a minor prevalence. There were no differences in the distributions of these haplotypes across the 4 years and the three study sites. For Pfdhps, the AAKAA and SGKAA mutant haplotypes and the SAKAA wild-type haplotype were similarly present in the three areas during the study period. The AGKAA double mutant was first observed in 2013 in Franceville and in 2014 in Koulamoutou and Lastourville. Interestingly, only the A578S mutation (0.4%) and two new A494V (0.4%) and V504A (0.9%) mutations were found in PfK13. CONCLUSION Despite the withdrawal of chloroquine, the frequency of the resistant allele 76T remained high in the south of Gabon. Moreover, a high level of resistant haplotypes against IPTp-SP was found.
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Affiliation(s)
- Dominique Fatima Voumbo-Matoumona
- Unit of Evolution, Epidemiology and Parasitic Resistances (UNEEREP), International Medical Research Center of Franceville (CIRMF), Franceville, Gabon,
- Parasitology and Entomology Unit, Department of Infectious Diseases, Biomedical Research Institute of Army, Marseille, France
- Regional Doctoral School of Central Africa in Tropical Infectiology, Franceville, Gabon
| | - Lady Charlène Kouna
- Department of Parasitology, Mycology and Tropical Medicine, University of Health Sciences, Libreville, Gabon,
| | - Marylin Madamet
- Parasitology and Entomology Unit, Department of Infectious Diseases, Biomedical Research Institute of Army, Marseille, France
- Research Unit on Infectious and Tropical Emerging Diseases, Aix Marseille University, Marseille, France
- National Malaria Reference Center, Marseille, France
| | - Sydney Maghendji-Nzondo
- Department of Parasitology, Mycology and Tropical Medicine, University of Health Sciences, Libreville, Gabon,
| | - Bruno Pradines
- Parasitology and Entomology Unit, Department of Infectious Diseases, Biomedical Research Institute of Army, Marseille, France
- Research Unit on Infectious and Tropical Emerging Diseases, Aix Marseille University, Marseille, France
- National Malaria Reference Center, Marseille, France
| | - Jean Bernard Lekana-Douki
- Unit of Evolution, Epidemiology and Parasitic Resistances (UNEEREP), International Medical Research Center of Franceville (CIRMF), Franceville, Gabon,
- Department of Parasitology, Mycology and Tropical Medicine, University of Health Sciences, Libreville, Gabon,
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18
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Voumbo-Matoumona DF, Akiana J, Madamet M, Kouna LC, Lekana-Douki JB, Pradines B. High prevalence of Plasmodium falciparum antimalarial drug resistance markers in isolates from asymptomatic patients from the Republic of the Congo between 2010 and 2015. J Glob Antimicrob Resist 2018; 14:277-283. [PMID: 30121345 DOI: 10.1016/j.jgar.2018.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES This study investigated the prevalence of haplotypes of the Pfdhps, Pfdhfr, Pfcrt, Pfmdr1 and PfK13 resistance markers in isolates from asymptomatic patients from the Republic of the Congo following implementation of artemisinin based-combination therapy (ACT). METHODS Peripheral blood was collected from asymptomatic children in 2010 and 2015 from Brazzaville in the south and in 2013 in the north of the Congo. Genotypes of Pfmdr1, Pfcrt, Pfdhps, Pfdhfr and PfK13 were assessed by PCR. RESULTS Children from 2010 were younger than those from 2015 (mean age 5.38 years vs. 8.67 years; P=0.003). The main Pfcrt haplotype was the wild-type CVMNK (84.85%) in 2010, whereas the mutant CVIET (61.64%) predominated in 2015 (P<0.001). In the north, 45.00% of samples were CVMNK and 10.00% were CVIET. Other samples harboured new haplotypes in the country or mixed alleles. No significant difference in Pfmdr1 haplotypes was observed in 2010 and 2015 and the main haplotypes were NYD and NFD (30.56% vs. 28.57% and 61.11% vs. 42.86% for 2010 and 2015, respectively). In the south, the Pfdhps haplotypes observed were AAKAA, AGKAA, SGKAA and SGEGA (87.50% vs. 0%, 12.50% vs. 33.33%, 0% vs. 33.33% and 0% vs. 33.33% for 2010 and 2015, respectively). For Pfdhfr, the IRNI haplotype was most prevalent (85.71% for 2010, 87.50% for 2013 and 100% for 2015). No PfK13 mutations were found. CONCLUSIONS Monitoring the efficacy of ACT and intermittent preventive treatment with sulfadoxine-pyrimethamine is necessary to ensure an epidemiological survey of asymptomatic malaria.
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Affiliation(s)
- Dominique Fatima Voumbo-Matoumona
- Unité d'Evolution, Epidémiologie et Résistances Parasitaires (UNEEREP), Centre International de Recherche Médicales de Franceville, BP 769 Franceville, Gabon; Unité Parasitologie et Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France; Ecole Doctorale Régionale d'Afrique Centrale en Infectiologie Tropicale, BP 876 Franceville, Gabon
| | - Jean Akiana
- Départements des Masters/Licences, Parcours-Types des Sciences Biologiques, Faculté des Sciences et Techniques, Université Marien Ngouabi, BP 69, Brazzaville, Congo; Direction de la Médecine Préventive et des Essais Cliniques, Laboratoire National de Santé Publique, BP 120 Brazzaville, Congo
| | - Marylin Madamet
- Unité Parasitologie et Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France; Aix-Marseille Univ., IRD, AP-HM, SSA, VITROME, IHU Méditerranée Infection, Marseille, France; Centre National de Référence du Paludisme, Marseille, France
| | - Lady Charlène Kouna
- Unité d'Evolution, Epidémiologie et Résistances Parasitaires (UNEEREP), Centre International de Recherche Médicales de Franceville, BP 769 Franceville, Gabon
| | - Jean Bernard Lekana-Douki
- Unité d'Evolution, Epidémiologie et Résistances Parasitaires (UNEEREP), Centre International de Recherche Médicales de Franceville, BP 769 Franceville, Gabon; Département de Parasitologie Mycologie et de Médecine Tropicale, Université des Science de la Santé, BP 4005 Libreville, Gabon
| | - Bruno Pradines
- Unité Parasitologie et Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France; Aix-Marseille Univ., IRD, AP-HM, SSA, VITROME, IHU Méditerranée Infection, Marseille, France; Centre National de Référence du Paludisme, Marseille, France.
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19
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Awandare GA, Nyarko PB, Aniweh Y, Ayivor-Djanie R, Stoute JA. Plasmodium falciparum strains spontaneously switch invasion phenotype in suspension culture. Sci Rep 2018; 8:5782. [PMID: 29636510 PMCID: PMC5893586 DOI: 10.1038/s41598-018-24218-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/28/2018] [Indexed: 01/11/2023] Open
Abstract
The extensive redundancy in the use of invasion ligands by Plasmodium falciparum, and its unique ability to switch between invasion pathways have hampered vaccine development. P. falciparum strains Dd2 and W2mef have been shown to change from sialic acid (SA)-dependent to SA-independent phenotypes when selected on neuraminidase-treated erythrocytes. Following an observation of increasing ability of Dd2 to invade neuraminidase-treated cells when cultured for several weeks, we systematically investigated this phenomenon by comparing invasion phenotypes of Dd2, W2mef and 3D7 strains of P. falciparum that were cultured with gentle shaking (Suspended) or under static (Static) conditions. While Static Dd2 and W2mef remained SA-dependent for the entire duration of the investigation, Suspended parasites spontaneously and progressively switched to SA-independent phenotype from week 2 onwards. Furthermore, returning Suspended cultures to Static conditions led to a gradual reversal to SA-dependent phenotype. The switch to SA-independent phenotype was accompanied by upregulation of the key invasion ligand, reticulocyte-binding homologue 4 (RH4), and the increased invasion was inhibited by antibodies to the RH4 receptor, CR1. Our data demonstrates a novel mechanism for inducing the switching of invasion pathways in P. falciparum parasites and may provide clues for understanding the mechanisms involved.
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Affiliation(s)
- Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana. .,Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana.
| | - Prince B Nyarko
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Yaw Aniweh
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Reuben Ayivor-Djanie
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana.,Department of Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - José A Stoute
- Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA
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20
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Reteng P, Vrisca V, Sukarno I, Djarkoni IH, Kalangi JA, Jacobs GE, Runtuwene LR, Eshita Y, Maeda R, Suzuki Y, Mongan AE, Warouw SM, Yamagishi J, Tuda J. Genetic polymorphisms in Plasmodium falciparum chloroquine resistance genes, pfcrt and pfmdr1, in North Sulawesi, Indonesia. BMC Res Notes 2017; 10:147. [PMID: 28376874 PMCID: PMC5379540 DOI: 10.1186/s13104-017-2468-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 03/24/2017] [Indexed: 01/25/2023] Open
Abstract
Background Malaria still poses one of the major threats to human health. Development of effective antimalarial drugs has decreased this threat; however, the emergence of drug-resistant Plasmodium falciparum, a cause of Malaria, is disconcerting. The antimalarial drug chloroquine has been effectively used, but resistant parasites have spread worldwide. Interestingly, the withdrawal of the drug reportedly leads to an increased population of susceptible parasites in some cases. We examined the prevalence of genomic polymorphisms in a malaria parasite P. falciparum, associated with resistance to an antimalarial drug chloroquine, after the withdrawal of the drug from Indonesia. Results Blood samples were collected from 95 malaria patients in North Sulawesi, Indonesia, in 2010. Parasite DNA was extracted and analyzed by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) for pfcrt and pfmdr1. In parallel, multiplex amplicon sequencing for the same genes was carried out with Illumina MiSeq. Of the 59 cases diagnosed as P. falciparum infection by microscopy, PCR–RFLP analysis clearly identified the genotype 76T in pfcrt in 44 cases. Sequencing analysis validated the identified genotypes in the 44 cases and demonstrated that the haplotype in the surrounding genomic region was exclusively SVMNT. Results of pfmdr1 were successfully obtained for 51 samples, where the genotyping results obtained by the two methods were completely consistent. In pfmdr1, the 86Y mutant genotype was observed in 45 cases (88.2%). Conclusions Our results suggest that the prevalence of the mutated genotypes remained dominant even 6 years after the withdrawal of chloroquine from this region. Diversified haplotype of the resistance-related locus, potentially involved in fitness costs, unauthorized usage of chloroquine, and/or a short post-withdrawal period may account for the observed high persistence of prevalence. Electronic supplementary material The online version of this article (doi:10.1186/s13104-017-2468-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Patrick Reteng
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Visia Vrisca
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Inka Sukarno
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Ilham Habib Djarkoni
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Jane Angela Kalangi
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - George Eduardo Jacobs
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Lucky Ronald Runtuwene
- Department of Medical Genome Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Yuki Eshita
- Faculty of Medicine, Oita University, Yufu, Oita, 879-5593, Japan.,Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.,Research Center for Zoonosis Control, Hokkaido University, North 20, West 10 Kita-ku, Sapporo, Hokkaido, 001-0020, Japan
| | - Ryuichiro Maeda
- Department of Human Sciences, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan
| | - Yutaka Suzuki
- Department of Medical Genome Sciences, University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Arthur Elia Mongan
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Sarah Maria Warouw
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
| | - Junya Yamagishi
- Research Center for Zoonosis Control, Hokkaido University, North 20, West 10 Kita-ku, Sapporo, Hokkaido, 001-0020, Japan. .,Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, North 20, West 10 Kita-ku, Sapporo, Hokkaido, 001-0020, Japan.
| | - Josef Tuda
- Department of Medicine, Sam Ratulangi University, Kampus Unsrat, Bahu, Manado, 95115, Indonesia
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21
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Bruske EI, Dimonte S, Enderes C, Tschan S, Flötenmeyer M, Koch I, Berger J, Kremsner P, Frank M. In Vitro Variant Surface Antigen Expression in Plasmodium falciparum Parasites from a Semi-Immune Individual Is Not Correlated with Var Gene Transcription. PLoS One 2016; 11:e0166135. [PMID: 27907004 PMCID: PMC5132323 DOI: 10.1371/journal.pone.0166135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 10/24/2016] [Indexed: 12/17/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is considered to be the main variant surface antigen (VSA) of Plasmodium falciparum and is mainly localized on electron-dense knobs in the membrane of the infected erythrocyte. Switches in PfEMP1 expression provide the basis for antigenic variation and are thought to be critical for parasite persistence during chronic infections. Recently, strain transcending anti-PfEMP1 immunity has been shown to develop early in life, challenging the role of PfEMP1 in antigenic variation during chronic infections. In this work we investigate how P. falciparum achieves persistence during a chronic asymptomatic infection. The infected individual (MOA) was parasitemic for 42 days and multilocus var gene genotyping showed persistence of the same parasite population throughout the infection. Parasites from the beginning of the infection were adapted to tissue culture and cloned by limiting dilution. Flow cytometry using convalescent serum detected a variable surface recognition signal on isogenic clonal parasites. Quantitative real-time PCR with a field isolate specific var gene primer set showed that the surface recognition signal was not correlated with transcription of individual var genes. Strain transcending anti-PfEMP1 immunity of the convalescent serum was demonstrated with CD36 selected and PfEMP1 knock-down NF54 clones. In contrast, knock-down of PfEMP1 did not have an effect on the antibody recognition signal in MOA clones. Trypsinisation of the membrane surface proteins abolished the surface recognition signal and immune electron microscopy revealed that antibodies from the convalescent serum bound to membrane areas without knobs and with knobs. Together the data indicate that PfEMP1 is not the main variable surface antigen during a chronic infection and suggest a role for trypsin sensitive non-PfEMP1 VSAs for parasite persistence in chronic infections.
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Affiliation(s)
- Ellen Inga Bruske
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
| | - Sandra Dimonte
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
| | - Corinna Enderes
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
| | - Serena Tschan
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
| | | | - Iris Koch
- Max Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Jürgen Berger
- Max Planck Institute for Developmental Biology, Tuebingen, Germany
| | - Peter Kremsner
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
- CERMEL (Centre de Recherche Médicale de Lambaréné), Lambaréné, Gabon
| | - Matthias Frank
- Institute of Tropical Medicine, University of Tuebingen, Tuebingen, Germany
- CERMEL (Centre de Recherche Médicale de Lambaréné), Lambaréné, Gabon
- * E-mail:
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22
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Kateera F, Nsobya SL, Tukwasibwe S, Hakizimana E, Mutesa L, Mens PF, Grobusch MP, van Vugt M, Kumar N. Molecular surveillance of Plasmodium falciparum drug resistance markers reveals partial recovery of chloroquine susceptibility but sustained sulfadoxine-pyrimethamine resistance at two sites of different malaria transmission intensities in Rwanda. Acta Trop 2016; 164:329-336. [PMID: 27647575 PMCID: PMC10600949 DOI: 10.1016/j.actatropica.2016.09.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 09/01/2016] [Accepted: 09/05/2016] [Indexed: 12/23/2022]
Abstract
Faced with intense levels of chloroquine (CQ) resistance in Plasmodium falciparum malaria, Rwanda replaced CQ with amodiaquine (AQ)+sulfadoxine-pyrimethamine (SP) in 2001, and subsequently with artemether-lumefantrine (AL) in 2006, as first-line treatments for uncomplicated malaria. Following years of discontinuation of CQ use, re-emergence of CQ-susceptible parasites has been reported in countries including Malawi, Kenya and Tanzania. In contrast, high levels of SP resistant mutant parasites continue to be reported even in countries of presumed reduced SP drug selection pressure. The prevalence and distributions of genetic polymorphisms linked with CQ and SP resistance at two sites of different malaria transmission intensities are described here to better understand drug-related genomic adaptations over time and exposure to varying drug pressures in Rwanda. Using filter paper blood isolates collected from P. falciparum infected patients, DNA was extracted and a nested PCR performed to identify resistance-mediating polymorphisms in the pfcrt, pfmdr1, pfdhps and pfdhfr genes. Amplicons from a total of 399 genotyped samples were analysed by ligase detection reaction fluorescent microsphere assay. CQ susceptible pfcrt 76K and pfmdr1 86N wild-type parasites were found in about 50% and 81% of isolates, respectively. Concurrently, SP susceptible pfdhps double (437G-540E), pfdhfr triple (108N-51I-59R), quintuple pfdhps 437G-540E/pfdhfr 51I-59R-108N and sextuple haplotypes were found in about 84%, 85%, 74% and 18% of isolates, respectively. High-level SP resistance associated pfdhfr 164L and pfdhps 581G mutant prevalences were noted to decline. Mutations pfcrt 76T, pfdhfr 59R and pfdhfr 164L were found differentially distributed between the two study sites with the pfdhfr 164L mutants found only at Ruhuha site, eastern Rwanda. Overall, sustained intense levels of SP resistance mutations and a recovery of CQ susceptible parasites were found in this study following 7 years and 14 years of drug withdrawal from use, respectively. Most likely, the sustained high prevalence of resistant parasites is due to the use of DHFR/DHPS inhibitors like trimethoprim-sulfamethoxazole (TS) for the treatment of and prophylaxis against bacterial infections among HIV infected individuals as well as the continued use of IPTp-SP within the East and Central African regions for malaria prevention among pregnant women. With regard to CQ, the slow recovery of CQ susceptible parasites may have been caused partly by the continued use of CQ and/or CQ mimicking antimalarial drugs like AQ in spite of policies to withdraw it from Rwanda and the neighbouring countries of Uganda and Tanzania. Continued surveillance of P. falciparum CQ and SP associated polymorphisms is recommended for guiding future rational drug policy-making and mitigation of future risk of anti-malaria drug resistance development.
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Affiliation(s)
- Fredrick Kateera
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda; Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
| | - Sam L Nsobya
- Molecular Research Laboratory, Infectious Disease Research Collaboration (IDRC), New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda; School of Biomedical Science, College of Medicine, Makerere University, Uganda.
| | - Steven Tukwasibwe
- Molecular Research Laboratory, Infectious Disease Research Collaboration (IDRC), New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda.
| | - Emmanuel Hakizimana
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda; Malaria & Other Parasitic Diseases Division, Rwanda Biomedical Centre, Kigali, Rwanda.
| | - Leon Mutesa
- College of Medicine & Health Sciences, University of Rwanda, PO Box 3286, Kigali, Rwanda.
| | - Petra F Mens
- Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands; Royal Tropical Institute/Koninklijk Instituutvoor de Tropen, KIT Biomedical Research, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands.
| | - Martin P Grobusch
- Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
| | - Michèle van Vugt
- Centre of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Division of Internal Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
| | - Nirbhay Kumar
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Vector-Borne Infectious Disease Research Centre, Tulane University, 333S Liberty Street, Mail code 8317, New Orleans, LA 70112, United States.
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23
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Maghendji-Nzondo S, Kouna LC, Mourembou G, Boundenga L, Imboumy-Limoukou RK, Matsiegui PB, Manego-Zoleko R, Mbatchi B, Raoult D, Toure-Ndouo F, Lekana-Douki JB. Malaria in urban, semi-urban and rural areas of southern of Gabon: comparison of the Pfmdr 1 and Pfcrt genotypes from symptomatic children. Malar J 2016; 15:420. [PMID: 27538948 PMCID: PMC4990874 DOI: 10.1186/s12936-016-1469-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/02/2016] [Indexed: 12/25/2022] Open
Abstract
Background Artesunate-amodiaquine (AS-AQ) and artemether-lumefantrine (AL) are first- and second-line treatments for uncomplicated Plasmodium falciparum malaria in Gabon. AL remains highly efficacious, but its widespread use has led to molecular selection of the NFD haplotype on Pfmdr1 and K76 in Pfcrt. In this study, plasmodial infection characteristics and the distribution of the Pfmdr1 and Pfcrt genotypes involved in reduced efficacy of artemisinin-based combination therapy (ACT) were investigated in four Gabonese localities. Methods A cross-sectional study was conducted in the paediatric units of rural (Lastourville and Fougamou), semi-urban (Koula-Moutou) and urban (Franceville) areas. Malaria was diagnosed with the rapid diagnostic test Optimal-IT® and confirmed by blood smear. Pfmdr1 codons 86, 184 and 1246 and Pfcrt codon 76 were genotyped by PCR–RFLP and sequencing. Results Among 1129 included children, the prevalence of plasmodial infection was 79.5 % at Lastourville, 53.6 % at Fougamou, 36.1 % at Koula-Moutou, and 21.2 % at Franceville. The prevalence was significantly higher among children over 60 months of age in both semi-urban (p = 0.01) and urban (p = 0.004) areas. The prevalence of Pfmdr1 wild-type N86 differed significantly between Lastourville (57.8 %) and Koula-Moutou (45.4 %) (p = 0.039). No difference in 184F-carrying parasites was found between Lastourville (73.8 %), Fougamou (81.6 %), Koula-Moutou (83.2 %), and Franceville (80.6 %) (p = 0.240). The prevalence of wild-type D1246 was significantly different between Lastourville (94.1 %), Koula-Moutou (85.6 %) and Franceville (87.3 %) (p = 0.01). The frequency of wild-type K76 was not significantly different across the four sites: Lastourville (16.5 %), Fougamou (27.8 %), Koula-Moutou (17.4 %), and Franceville (29.4 %) (p = 0.09). The mixed genotypes were only found in Lastourville and Franceville. The NFD, YFD and NYD haplotypes were mainly Lastourville (46.6, 25.8, 14.0 %), Fougamou (45.5, 9.1, 42.4 %), Koula-Moutou (35, 6.7, 40.4 %), and Franceville (40.0, 16.0, 32.0 %). Conclusion This study shows an increase in the prevalence of childhood plasmodial infection in Gabon according to the low socio-economic level, and a high frequency of markers associated with AL treatment failure. Close monitoring of ACT use is needed.
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Affiliation(s)
- Sydney Maghendji-Nzondo
- Unité d'Evolution Epidémiologie Résistance Parasitaire (UNEEREP), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769, Franceville, Gabon.,Département de Biologie, Université des Sciences et Techniques de Masuku, BP: 901, Franceville, Gabon
| | - Lady-Charlène Kouna
- Unité d'Evolution Epidémiologie Résistance Parasitaire (UNEEREP), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769, Franceville, Gabon
| | - Gaël Mourembou
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Larson Boundenga
- Unité d'Evolution Epidémiologie Résistance Parasitaire (UNEEREP), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769, Franceville, Gabon
| | - Romeo-Karl Imboumy-Limoukou
- Unité d'Evolution Epidémiologie Résistance Parasitaire (UNEEREP), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769, Franceville, Gabon
| | | | | | - Bertrand Mbatchi
- Département de Biologie, Université des Sciences et Techniques de Masuku, BP: 901, Franceville, Gabon
| | - Didier Raoult
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Fousseyni Toure-Ndouo
- Unité d'Evolution Epidémiologie Résistance Parasitaire (UNEEREP), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769, Franceville, Gabon
| | - Jean Bernard Lekana-Douki
- Unité d'Evolution Epidémiologie Résistance Parasitaire (UNEEREP), Centre International de Recherches Médicales de Franceville (CIRMF), B.P. 769, Franceville, Gabon. .,Département de Parasitologie-Mycologie Médecine Tropicale, Faculté de Médecine, Université des Sciences de la Santé, B.P. 4009, Libreville, Gabon.
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Huang B, Wang Q, Deng C, Wang J, Yang T, Huang S, Su XZ, Liu Y, Pan L, Li G, Li D, Zhang H, Bacar A, Abdallah KS, Attoumane R, Mliva AMSA, Zheng S, Xu Q, Lu F, Guan Y, Song J. Prevalence of crt and mdr-1 mutations in Plasmodium falciparum isolates from Grande Comore island after withdrawal of chloroquine. Malar J 2016; 15:414. [PMID: 27527604 PMCID: PMC4986190 DOI: 10.1186/s12936-016-1474-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 08/02/2016] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND In Comoros, the widespread of chloroquine (CQ)-resistant Plasmodium falciparum populations was a major obstacle to malaria control, which led to the official withdrawal of CQ in 2004. Continuous monitoring of CQ-resistant markers of the P. falciparum CQ resistant transporter (pfcrt) and the P. falciparum multiple drug resistance 1 (pfmdr-1) is necessary inder to obtain first-hand information on CQ susceptibility of parasite populations in the field. The objective of this study is to assess the prevalence and evolution of CQ-resistance in the P. falciparum populations on the Comoros' Grande Comore island after withdrawal of CQ. METHODS A total of 207 P. falciparum clinical isolates were collected from the island, including 118 samples from 2006 to 2007 and 89 samples from 2013 to 2014. Nucleotide substitutions in the pfcrt and pfmdr-1 genes linked to CQ response in parasite isolates were assessed using nested PCR and DNA sequencing. RESULTS From the pfcrt gene segment sequenced, we detected C72S, M74I, N75E, and K76T substitutions in the parasite isolates collected from both 2006-2007 to 2013-2014 periods. Significant decline of pfcrt resistant alleles at C72S (42.6 to 6.9 %), M74I (39.1 to 14.9 %), N75E (63.5 to 18.3 %), and K76T (72.2 to 19.5 %) from 2006-2007 to 2013-2014 were observed, and the frequency of pfcrt wild type allele was significantly increased from 19.1 % in 2006-2007 to 75.8 % in 2013-2014. Sequence analysis of pfmdr-1 also detected point mutations at codons N86Y, Y184F, and D1246Y, but not S1034C and N1042D, in the isolates collected from both examined periods. An increasing trend in the prevalence of the pfmdr-1 wild type allele (NYD, 4.3 % in 2006-2007; and 28.7 % in 2013-2014), and a decreasing trend for pfmdr-1 N86Y mutation (87.0 % in 2006-2007; and 40.2 % in 2013-2014) were observed in our samples. CONCLUSIONS The present data indicate that the prevalence and patterns of mutant pfcrt and pfmdr-1 dramatically decreased in the Grande Comore isolates from 2006 to 2014, suggesting that the CQ-sensitive P. falciparum strains have returned after the withdrawal of CQ. The data also suggests that the parasites with wild type pfcrt/pfdmr-1 genes may have growth and/or transmission advantages over the mutant parasites. The information obtained from this study will be useful for developing and updating anti-malarial treatment policy in Grande Comore island.
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Affiliation(s)
- Bo Huang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Qi Wang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Changsheng Deng
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Jianhua Wang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Tao Yang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Shiguang Huang
- School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China
| | - Xin-Zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.,State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361005, Fujian, People's Republic of China
| | - Yajun Liu
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Longhua Pan
- Guangdong Newsouth Artepharm Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China
| | - Guoming Li
- Guangdong Newsouth Artepharm Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China
| | - Di Li
- Guangdong Newsouth Artepharm Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China
| | - Hongying Zhang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Afane Bacar
- National Malaria Control Programme, BP 500, Moroni, Union of Comoros
| | | | - Rachad Attoumane
- National Malaria Control Programme, BP 500, Moroni, Union of Comoros
| | | | - Shaoqin Zheng
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Qin Xu
- Research Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Fangli Lu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, Guangdong, People's Republic of China
| | - Yezhi Guan
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
| | - Jianping Song
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
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Held J, Supan C, Salazar CLO, Tinto H, Bonkian LN, Nahum A, Moulero B, Sié A, Coulibaly B, Sirima SB, Siribie M, Otsyula N, Otieno L, Abdallah AM, Kimutai R, Bouyou-Akotet M, Kombila M, Koiwai K, Cantalloube C, Din-Bell C, Djeriou E, Waitumbi J, Mordmüller B, Ter-Minassian D, Lell B, Kremsner PG. Ferroquine and artesunate in African adults and children with Plasmodium falciparum malaria: a phase 2, multicentre, randomised, double-blind, dose-ranging, non-inferiority study. THE LANCET. INFECTIOUS DISEASES 2015; 15:1409-19. [DOI: 10.1016/s1473-3099(15)00079-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 04/02/2015] [Accepted: 05/27/2015] [Indexed: 10/23/2022]
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Cui L, Mharakurwa S, Ndiaye D, Rathod PK, Rosenthal PJ. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network. Am J Trop Med Hyg 2015; 93:57-68. [PMID: 26259943 PMCID: PMC4574275 DOI: 10.4269/ajtmh.15-0007] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs.
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Affiliation(s)
- Liwang Cui
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
| | | | | | | | - Philip J. Rosenthal
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
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27
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Rebelo M, Tempera C, Fernandes JF, Grobusch MP, Hänscheid T. Assessing anti-malarial drug effects ex vivo using the haemozoin detection assay. Malar J 2015; 14:140. [PMID: 25879757 PMCID: PMC4393616 DOI: 10.1186/s12936-015-0657-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 03/17/2015] [Indexed: 11/20/2022] Open
Abstract
Background In vitro sensitivity assays are crucial to detect and monitor drug resistance. Plasmodium falciparum has developed resistance to almost all anti-malarial drugs. Although different in vitro drug assays are available, some of their inherent characteristics limit their application, especially in the field. A recently developed approach based on the flow cytometric detection of haemozoin (Hz) allowed reagent-free monitoring of parasite maturation and detection of drug effects in culture-adapted parasites. In this study, the set-up, performance and usefulness of this novel assay were investigated under field conditions in Gabon. Methods An existing flow cytometer (Cyflow Blue) was modified on site to detect light depolarization caused by Hz. Blood from malaria patients was incubated for 72 hrs with increasing concentrations of chloroquine, artesunate and artemisinin. The percentage of depolarizing red blood cells (RBC) was used as maturation indicator and measured at 24, 48 and 72 hrs of incubation to determine parasite growth and drug effects. Results The flow cytometer was easily adapted on site to detect light depolarization caused by Hz. Analysis of ex vivo cultures of parasites, obtained from blood samples of malaria patients, showed four different growth profiles. In 39/46 samples, 50% inhibitory concentrations (IC50) were successfully determined. IC50 values for chloroquine were higher than 200 nM in 70% of the samples, indicating the presence of chloroquine-resistant parasites. For artesunate and artemisinin, IC50 values ranged from 0.9 to 60 nM and from 2.2 nM to 124 nM, respectively, indicating fully sensitive parasites. Conclusion Flow cytometric detection of Hz allowed the detection of drug effects in blood samples from malaria patients, without using additional reagents or complex protocols. Adjustment of the initial parasitaemia was not required, which greatly simplifies the protocol, although it may lead to different IC50 values. Further investigation of set-up conditions of the Hz assay, as well as future studies in various settings should be performed to further determine the usefulness of this assay as a tool for rapid resistance testing in malaria-endemic countries.
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Affiliation(s)
- Maria Rebelo
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, Lisbon, P-1649-028, Portugal. .,Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon.
| | - Carolina Tempera
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, Lisbon, P-1649-028, Portugal.
| | - José F Fernandes
- Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon. .,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. .,Centre of Tropical Medicine and Travel Medicine, Amsterdam Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
| | - Martin P Grobusch
- Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon. .,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. .,Centre of Tropical Medicine and Travel Medicine, Amsterdam Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
| | - Thomas Hänscheid
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Av Prof Egas Moniz, Lisbon, P-1649-028, Portugal. .,Centre de Recherches Médicales de Lambaréné - CERMEL, Albert Schweitzer Hospital, Lambaréné, Gabon. .,Instituto de Microbiologia, Faculdade de Medicina, Lisbon, Portugal.
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Assele V, Ndoh GE, Nkoghe D, Fandeur T. No evidence of decline in malaria burden from 2006 to 2013 in a rural Province of Gabon: implications for public health policy. BMC Public Health 2015; 15:81. [PMID: 25649228 PMCID: PMC4324784 DOI: 10.1186/s12889-015-1456-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 01/23/2015] [Indexed: 11/10/2022] Open
Abstract
Background The morbidity of malaria has steady declined in the urban regions of Gabon between 2000 and 2008, but caution should be exercised before generalizing this trend to the whole country because this finding has not been systematically confirmed in remote rural provinces. Methods We conducted a retrospective survey using data on malaria cases recorded in North Eastern Gabon between 2006 and 2013 at health facilities in Makokou. Malaria data were analyzed, and associations with annual variations and patient age were assessed. Results A global increase in clinical and confirmed malaria cases was observed over the study period. The rate of infection was significantly higher in children aged between 0 to 4 years than in children of 5 years and above, and in adults. Contrary to prior observations in urban and semi-urban areas of Gabon, malaria burden remained mostly unchanged or even increased in Makokou in the Ogooué-Ivindo province during these last 8 years. Conclusions The persistence of Plasmodium falciparum pockets of sustained malaria transmission in rural Gabon may be related to an inadequate coverage of key interventions, to poor treatment seeking behavior and/or to a decline efficacy of treatments. Our results highlight the need to better adapt malaria control strategies to local epidemiological contexts and to environmental constraints. Equitable delivery of health service to hard-to-reach populations constitutes a challenging issue for the health authorities of Gabon. Electronic supplementary material The online version of this article (doi:10.1186/s12889-015-1456-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vanessa Assele
- Unité de Parasitologie Médicale, Centre International de Recherches Médicales de Franceville, Franceville, BP 769, Gabon.
| | - Gildas Ella Ndoh
- Unité de Recherche et d'Analyses Médicales, Centre International de Recherches Médicales de Franceville, Franceville, Gabon.
| | - Dieudonné Nkoghe
- Unité de Recherche et d'Analyses Médicales, Centre International de Recherches Médicales de Franceville, Franceville, Gabon.
| | - Thierry Fandeur
- Unité de Parasitologie Médicale, Centre International de Recherches Médicales de Franceville, Franceville, BP 769, Gabon.
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Low Prevalence of Pfcrt Resistance Alleles among Patients with Uncomplicated Falciparum Malaria in Niger Six Years after Chloroquine Withdrawal. Malar Res Treat 2014; 2014:614190. [PMID: 25506465 PMCID: PMC4259070 DOI: 10.1155/2014/614190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/04/2014] [Indexed: 01/06/2023] Open
Abstract
Chloroquine (CQ) resistance is widespread in Africa, but few data are available for Niger. Pfcrt haplotypes (aa 56–118) and ex vivo responses to CQ and amodiaquine were characterized for 26 isolates collected in South Niger from children under 15 years of age suffering from uncomplicated falciparum malaria, six years after the introduction of artemisinin-based combinations and the withdrawal of CQ. The wild-type Pfcrt haplotype CVMNK was found in 22 of the 26 isolates, with CVIET sequences observed in only three of the samples. We also describe for the first time a new CVINT haplotype. The ex vivo responses were better for CVMNK than for CVIET parasites. Pfcrt sequence data were compared with those obtained for 26 additional parasitized blood samples collected in Gabon, from an area of CQ resistance used as a control. Our findings suggest that there has been a significant decline in CQ-resistant genotypes since the previous estimates for Niger were obtained. No such decline in molecular resistance to CQ was observed in the subset of samples collected in similar conditions from Gabon. These results have important implications for public health and support the policy implemented in Niger since 2005, which aims to increase the efficacy and availability of antimalarial drugs whilst controlling the spread of resistance.
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Mawili-Mboumba DP, Ndong Ngomo JM, Maboko F, Guiyedi V, Mourou Mbina JR, Kombila M, Bouyou Akotet MK. Pfcrt 76T and pfmdr1 86Y allele frequency in Plasmodium falciparum isolates and use of self-medication in a rural area of Gabon. Trans R Soc Trop Med Hyg 2014; 108:729-34. [PMID: 25249358 DOI: 10.1093/trstmh/tru147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Studies showed that chloroquine resistance may revert to sensitivity after its withdrawal mainly detected by a significant decrease of Plasmodium falciparum pfcrt 76T and pfmdr1 86Y alleles. Besides, self-medication is considered as a key factor of antimalarial drug resistance expansion. Thus, pfcrt 76T and pfmdr1 86Y allele frequency and its relationship with antimalarial drug self-medication was analyzed in P. falciparum isolates collected in Gabon. METHODS Samples were collected from febrile children screened for P. falciparum infection in 2005 and 2008 at the regional hospital of Oyem. Self-use of antimalarial drugs before the day of consultation was recorded. Polymorphic codons 76 and 86 of pfcrt and pfmdr1 genes were analyzed by PCR-RFLP. RESULTS The frequency of pfcrt 76T mutant allele was greater than 70.0% in 2005 and 2008. Wild type isolates were 1.7-fold more prevalent in 2008. The prevalence of pfmdr1 86Y mutant allele was comparable between 2005 and 2008 (p=0.1); the proportion of wild type allele reached 20.5% in 2008. The frequency of wild type allele pfcrt K76 or pfmdr1 N86 was higher among patients without anti-malarial drug self-medication compared to those who used it. CONCLUSIONS An increase of the frequency of P. falciparum wild type allele pfcrt 76K and pfmdr1 86N was observed within a short period after chloroquine withdrawal. The proportion of mutant genotypes is still high, mainly among patients using self-medication with antimalarial drugs.
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Affiliation(s)
- D P Mawili-Mboumba
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
| | - J M Ndong Ngomo
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
| | - F Maboko
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
| | - V Guiyedi
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
| | - J R Mourou Mbina
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
| | - M Kombila
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
| | - M K Bouyou Akotet
- Department of Parasitology-Mycology, Faculty of Medicine, Université des Sciences de la Santé, Libreville, Gabon, BP 4009 Libreville, Gabon
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Mharakurwa S, Sialumano M, Liu K, Scott A, Thuma P. Selection for chloroquine-sensitive Plasmodium falciparum by wild Anopheles arabiensis in Southern Zambia. Malar J 2013; 12:453. [PMID: 24354640 PMCID: PMC3878239 DOI: 10.1186/1475-2875-12-453] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/17/2013] [Indexed: 11/20/2022] Open
Abstract
Background The emergence of parasite drug resistance, especially Plasmodium falciparum, persists as a major obstacle for malaria control and elimination. To develop effective public health containment strategies, a clear understanding of factors that govern the emergence and spread of resistant parasites in the field is important. The current study documents selection for chloroquine-sensitive malaria parasites by wild Anopheles arabiensis in southern Zambia. Methods In a 2,000-sq km region, mosquitoes were collected from human sleeping rooms using pyrethrum spray catches during the 2006 malaria transmission season. After morphological examination and molecular confirmation, vector mosquitoes were dissected to separate head and thorax from the abdominal section, followed by PCR screening for P. falciparum infection. Human residents of all ages were tested for P. falciparum parasitaemia by microscopy and PCR. Plasmodium falciparum infections were genotyped at the chloroquine resistance-conferring amino acid codon 76 of the PfCRT gene, using PCR and restriction enzyme digestion. Results In the human population there was nearly 90% prevalence of the chloroquine-resistant PfCRT K76T mutant, with no significant differences in polymorphism among smear-positive and smear-negative (submicroscopic) infections (p = 0.323, n = 128). However, infections in both abdominal and salivary gland phases of the An. arabiensis vector exhibited wild type K76-bearing parasites with up to 9X higher odds (OR (95% CI): 9 (3.7-20.2), p < 0.0005, n = 125), despite having been acquired from humans within a few weeks. Conclusions Anopheles arabiensis selects for wild-type K76-bearing P. falciparum during both abdominal and salivary gland phases of parasite development. The rapid vectorial selection, also recently seen with antifolate resistance, is evidence for parasite fitness cost in the mosquito, and may underpin regional heterogeneity in the emergence, spread and waning of drug resistance. Understanding the nature and direction of vector selection could be instrumental for rational curtailment of the spread of drug resistance in integrated malaria control and elimination programmes.
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Van Tyne D, Dieye B, Valim C, Daniels RF, Sène PD, Lukens AK, Ndiaye M, Bei AK, Ndiaye YD, Hamilton EJ, Ndir O, Mboup S, Volkman SK, Wirth DF, Ndiaye D. Changes in drug sensitivity and anti-malarial drug resistance mutations over time among Plasmodium falciparum parasites in Senegal. Malar J 2013; 12:441. [PMID: 24314037 PMCID: PMC3924193 DOI: 10.1186/1475-2875-12-441] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 11/24/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria treatment efforts are hindered by the rapid emergence and spread of drug resistant parasites. Simple assays to monitor parasite drug response in direct patient samples (ex vivo) can detect drug resistance before it becomes clinically apparent, and can inform changes in treatment policy to prevent the spread of resistance. METHODS Parasite drug responses to amodiaquine, artemisinin, chloroquine and mefloquine were tested in approximately 400 Plasmodium falciparum malaria infections in Thiès, Senegal between 2008 and 2011 using a DAPI-based ex vivo drug resistance assay. Drug resistance-associated mutations were also genotyped in pfcrt and pfmdr1. RESULTS Parasite drug responses changed between 2008 and 2011, as parasites became less sensitive to amodiaquine, artemisinin and chloroquine over time. The prevalence of known resistance-associated mutations also changed over time. Decreased amodiaquine sensitivity was associated with sustained, highly prevalent mutations in pfcrt, and one mutation in pfmdr1 - Y184F - was associated with decreased parasite sensitivity to artemisinin. CONCLUSIONS Directly measuring ex vivo parasite drug response and resistance mutation genotyping over time are useful tools for monitoring parasite drug responses in field samples. Furthermore, these data suggest that the use of amodiaquine and artemisinin derivatives in combination therapies is selecting for increased drug tolerance within this population.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston 02115, USA.
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Nwakanma DC, Duffy CW, Amambua-Ngwa A, Oriero EC, Bojang KA, Pinder M, Drakeley CJ, Sutherland CJ, Milligan PJ, Macinnis B, Kwiatkowski DP, Clark TG, Greenwood BM, Conway DJ. Changes in malaria parasite drug resistance in an endemic population over a 25-year period with resulting genomic evidence of selection. J Infect Dis 2013; 209:1126-35. [PMID: 24265439 PMCID: PMC3952670 DOI: 10.1093/infdis/jit618] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background. Analysis of genome-wide polymorphism in many organisms has potential to identify genes under recent selection. However, data on historical allele frequency changes are rarely available for direct confirmation. Methods. We genotyped single nucleotide polymorphisms (SNPs) in 4 Plasmodium falciparum drug resistance genes in 668 archived parasite-positive blood samples of a Gambian population between 1984 and 2008. This covered a period before antimalarial resistance was detected locally, through subsequent failure of multiple drugs until introduction of artemisinin combination therapy. We separately performed genome-wide sequence analysis of 52 clinical isolates from 2008 to prospect for loci under recent directional selection. Results. Resistance alleles increased from very low frequencies, peaking in 2000 for chloroquine resistance-associated crt and mdr1 genes and at the end of the survey period for dhfr and dhps genes respectively associated with pyrimethamine and sulfadoxine resistance. Temporal changes fit a model incorporating likely selection coefficients over the period. Three of the drug resistance loci were in the top 4 regions under strong selection implicated by the genome-wide analysis. Conclusions. Genome-wide polymorphism analysis of an endemic population sample robustly identifies loci with detailed documentation of recent selection, demonstrating power to prospectively detect emerging drug resistance genes.
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Chauhan K, Pande V, Das A. Analyses of genetic variations at microsatellite loci present in-and-around the Pfcrt gene in Indian Plasmodium falciparum. INFECTION GENETICS AND EVOLUTION 2013; 20:476-87. [PMID: 24157593 DOI: 10.1016/j.meegid.2013.10.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/10/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
Abstract
Evolution and spread of chloroquine resistant (CQR) malaria parasite Plasmodium falciparum have posed great threat in malaria intervention across the globe. The occurrence of K76T mutation in the P. falciparum chloroquine resistance transporter (pfcrt) gene has been widely attributed to CQR with four neighboring mutations providing compensatory fitness benefit to the parasite survival. Understanding evolutionary patterns of the pfcrt gene is of great relevance not only for devising new malaria control measures but also could serve as a model to understand evolution and spread of other human drug-resistant pathogens. Several studies, mainly based on differential patterns of diversities of the microsatellite loci placed in-and-around the pfcrt gene have indicated the role of positive natural selection under the 'hitchhiking' model of molecular evolution. However, the studies were restricted to limited number of microsatellite loci present inside the pfcrt gene. Moreover, comparatively higher level of diversities in microsatellite loci present inside the pfcrt gene than the loci flanking the pfcrt gene are hallmarks of Indian P. falciparum, presenting contrasting evolutionary models to global isolates. With a view to infer evolutionary patterns of the pfcrt gene in Indian P. falciparum, we have adopted a unique sampling scheme of two types of populations (cultured and field collected) and utilized 20 polymorphic microsatellite loci (16 located inside the pfcrt gene and four in the two flanking regions) to disentangle between genetic drift (inbred cultured isolates) and natural selection (field isolates). Data analyses employing different population genetic tests could not straightforwardly explain either the model invoking 'genetic hitchhiking' or 'genetic drift'. However, complex evolutionary models influenced by both demography and natural selection or an alternative model of natural selection (e.g. diversifying/balancing selection) might better explain the observed microsatellite variation in-and-around the pfcrt gene in Indian P. falciparum.
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Affiliation(s)
- Kshipra Chauhan
- Evolutionary Genomics and Bioinformatics Laboratory, Division of Genomics and Bioinformatics, National Institute of Malaria Research, Sector 8, Dwarka, New Delhi 110077, India
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Babiker HA, Gadalla AAH, Ranford-Cartwright LC. The role of asymptomatic P. falciparum parasitaemia in the evolution of antimalarial drug resistance in areas of seasonal transmission. Drug Resist Updat 2013; 16:1-9. [PMID: 23510592 DOI: 10.1016/j.drup.2013.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 02/11/2013] [Indexed: 01/15/2023]
Abstract
In areas with seasonal transmission, proper management of acute malaria cases that arise in the transmission season can markedly reduce the disease burden. However, asymptomatic carriage of Plasmodium falciparum sustains a long-lasting reservoir in the transmission-free dry season that seeds cyclical malaria outbreaks. Clinical trials targeting asymptomatic parasitaemia in the dry season failed to interrupt the malaria epidemics that follow annual rains. These asymptomatic infections tend to carry multiple-clones, capable of producing gametocytes and infecting Anopheles mosquitoes. Different clones within an infection fluctuate consistently, indicative of interaction between clones during the long course of asymptomatic carriage. However, the therapy-free environment that prevails in the dry season dis-advantages the drug resistant lineages and favors the wild-type parasites. This review highlights some biological and epidemiological characteristics of asymptomatic parasitaemia and calls for consideration of policies to diminish parasite exposure to drugs "therapy-free" and allow natural selection to curb drug resistance in the above setting.
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Affiliation(s)
- Hamza A Babiker
- Biochemistry Department, Faculty of Medicine, Sultan Qaboos University, Oman.
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PfCRT and its role in antimalarial drug resistance. Trends Parasitol 2012; 28:504-14. [PMID: 23020971 DOI: 10.1016/j.pt.2012.08.002] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 08/09/2012] [Accepted: 08/13/2012] [Indexed: 12/15/2022]
Abstract
Plasmodium falciparum resistance to chloroquine, the former gold standard antimalarial drug, is mediated primarily by mutant forms of the chloroquine resistance transporter (PfCRT). These mutations impart upon PfCRT the ability to efflux chloroquine from the intracellular digestive vacuole, the site of drug action. Recent studies reveal that PfCRT variants can also affect parasite fitness, protect immature gametocytes against chloroquine action, and alter P. falciparum susceptibility to current first-line therapies. These results highlight the need to be vigilant in screening for the appearance of novel pfcrt alleles that could contribute to new multi-drug resistance phenotypes.
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Mang’era CM, Mbai FN, Omedo IA, Mireji PO, Omar SA. Changes in genotypes of Plasmodium falciparum human malaria parasite following withdrawal of chloroquine in Tiwi, Kenya. Acta Trop 2012; 123:202-7. [PMID: 22641431 DOI: 10.1016/j.actatropica.2012.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 10/28/2022]
Abstract
Chloroquine (CQ) drug was withdrawn in 1998 as a first-line treatment of uncomplicated malaria in Kenya. This was in response to resistance to the drug in Plasmodium falciparum malaria parasite. Investigations were conducted to determine prevalence of CQ resistance genotypes in the parasites in Tiwi, a malaria endemic town in Kenya, before and about a decade after the withdrawal of the drug. Blood samples were collected and spotted on filter papers in 1999 and 2008 from 75 and 77 out-patients respectively with uncomplicated malaria. The sampling was conducted using finger pricking technique. DNA was extracted from individual spots in the papers and screened for the presence of P. falciparum chloroquine resistance transporter (Pfcrt) and multi drug resistance (Pfmdr-1) markers using nested PCR. Nature of mutations (haplotypes) in the Pfcrt and Pfmdr-1 markers in the samples were confirmed using dot blot hybridization technique. Changes in pattern of CQ resistance in the parasite samples in 1999 and 2008 were assessed by Chi Square test. There was a significant (P<0.05) reduction in CQ resistant genotypes of the parasite between 1999 and 2008. Pfmdr and Pfcrt CQ resistant genotypes in 2008 reduced to 54.10 and 63.64% respectively, from 75.39 and 88.0% respectively in 1999. This reduction was accompanied by emergence of Pfcrt specific CQ sensitive (IEK) and intermediate/partially CQ resistant (MET) haplotypes. Results suggest significant reversal of the phenotype of the parasite from chloroquine resistant to wild/sensitive type. The novel haplotypes indicates transitional phase of the parasite to the wild type. Current prevalence of chloroquine resistant genotype is definitely above the threshold for efficacious re-introduction of chloroquine for treatment of malaria in Tiwi.
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Kamugisha E, Jing S, Minde M, Kataraihya J, Kongola G, Kironde F, Swedberg G. Efficacy of artemether-lumefantrine in treatment of malaria among under-fives and prevalence of drug resistance markers in Igombe-Mwanza, north-western Tanzania. Malar J 2012; 11:58. [PMID: 22369089 PMCID: PMC3305412 DOI: 10.1186/1475-2875-11-58] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 02/27/2012] [Indexed: 11/10/2022] Open
Abstract
Background Drug resistance to anti-malarials is a major public health problem worldwide. This study aimed at establishing the efficacy of artemether-lumefantrine (ACT) in Igombe-Mwanza, north-western Tanzania after a few years of ACT use, and establish the prevalence of mutations in key targets for artemisinin, chloroquine and sulphadoxine/pyrimetamine (SP) drugs. Methods A prospective single cohort study was conducted at Igombe health centre using artemether-lumefantrine combination therapy between February 2010 and March 2011. The follow-up period was 28 days and outcome measures were according to WHO guidelines. Blood was collected on Whatman filter paper for DNA analysis. DNA extraction was done using TRIS-EDTA method, and mutations in Pfcrt, Pfmdr1, Pfdhfr, Pfdhps and Pfatp6 were detected using PCR-RFLP methods established previously. Results A total of 103 patients completed the 28 days follow-up. The mean haemoglobin was 8.9 g/dl (range 5.0 to 14.5 g/dl) and mean parasite density was 5,608 parasites/μl. Average parasite clearance time was 34.7 hours and all patients cleared the parasites by day 3. There was no early treatment failure in this study. Late clinical failure was seen in three (2.9%) patients and late parasitological failure (LPF) was seen in two (1.9%). PCR-corrected LPF was 1% and adequate clinical and parasitological response was 96%. The majority of parasites have wild type alleles on pfcrt 76 and pfmdr1 86 positions being 87.8% and 93.7% respectively. Mutant parasites predominated at pfdhfr gene at the main three positions 108, 51 and 59 with prevalence of 94.8%, 75.3% and 82.5% respectively. Post-treatment parasites had more wild types of pfdhps at position 437 and 540 than pre-treatment parasites. No mutation was seen in pfatp6 769 in re-infecting or recrudescing parasites. Conclusion The efficacy of artemether-lumefantrine for treatment of uncomplicated malaria is still high in the study area although the rate of re-infection is higher than previously reported. Parasite clearance after 48 hours was lower compared to previous studies. The prevalence of wild type allele pfcrt 76 K and pfmdr1 86 N was high in the study area while markers for SP resistance is still high. Artemether-lumefantrine may be selecting for wild type alleles on both positions (437 and 540) of pfdhps.
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Affiliation(s)
- Erasmus Kamugisha
- Weill-Bugando University College of Health Sciences, Mwanza, Tanzania.
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