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Rizzo A, Grosso S, Faggion I, Gigantiello A, Salari F, Niero F, Passerini S, Mariani C, Antinori S, Gismondo MR. Multiple episodes of Plasmodium malariae despite antimalarial treatment: "Quartana te teneat"? Travel Med Infect Dis 2023; 56:102671. [PMID: 38016529 DOI: 10.1016/j.tmaid.2023.102671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/06/2023] [Accepted: 11/18/2023] [Indexed: 11/30/2023]
Affiliation(s)
- Alberto Rizzo
- Laboratory of Clinical Microbiology, Virology and Bioemergencies, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Silvia Grosso
- Laboratory of Clinical Microbiology, Virology and Bioemergencies, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Ivano Faggion
- Department of Infectious Diseases, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Anna Gigantiello
- Laboratory of Clinical Microbiology, Virology and Bioemergencies, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Federica Salari
- Laboratory of Clinical Microbiology, Virology and Bioemergencies, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Fosca Niero
- Department of Infectious Diseases, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Simone Passerini
- Department of Infectious Diseases, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Chiara Mariani
- Department of Infectious Diseases, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Spinello Antinori
- Department of Infectious Diseases, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy; Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, via G. B. Grassi 74, 20157, Milano, Italy.
| | - Maria Rita Gismondo
- Laboratory of Clinical Microbiology, Virology and Bioemergencies, ASST Fatebenefratelli Sacco - L. Sacco Hospital, via G. B. Grassi 74, 20157, Milano, Italy; Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, via G. B. Grassi 74, 20157, Milano, Italy.
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2
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Oyegoke OO, Maharaj L, Akoniyon OP, Kwoji I, Roux AT, Adewumi TS, Maharaj R, Oyebola BT, Adeleke MA, Okpeku M. Malaria diagnostic methods with the elimination goal in view. Parasitol Res 2022; 121:1867-1885. [PMID: 35460369 PMCID: PMC9033523 DOI: 10.1007/s00436-022-07512-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/01/2022] [Indexed: 01/08/2023]
Abstract
Malaria control measures have been in use for years but have not completely curbed the spread of infection. Ultimately, global elimination is the goal. A major playmaker in the various approaches to reaching the goal is the issue of proper diagnosis. Various diagnostic techniques were adopted in different regions and geographical locations over the decades, and these have invariably produced diverse outcomes. In this review, we looked at the various approaches used in malaria diagnostics with a focus on methods favorably used during pre-elimination and elimination phases as well as in endemic regions. Microscopy, rapid diagnostic testing (RDT), loop-mediated isothermal amplification (LAMP), and polymerase chain reaction (PCR) are common methods applied depending on prevailing factors, each with its strengths and limitations. As the drive toward the elimination goal intensifies, the search for ideal, simple, fast, and reliable point-of-care diagnostic tools is needed more than ever before to be used in conjunction with a functional surveillance system supported by the ideal vaccine.
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Affiliation(s)
- Olukunle O Oyegoke
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Leah Maharaj
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Oluwasegun P Akoniyon
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Illiya Kwoji
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Alexandra T Roux
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Taiye S Adewumi
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Rajendra Maharaj
- Office of Malaria Research, Medical Research Council, Durban, South Africa
| | | | - Matthew A Adeleke
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa
| | - Moses Okpeku
- Discipline of Genetics School of Life Sciences, University of KwaZulu-Natal, Westville, Durban, South Africa.
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3
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Malaria. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2022; 65:512-524. [PMID: 35119479 PMCID: PMC8814801 DOI: 10.1007/s00103-022-03490-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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4
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Kingston DGI, Cassera MB. Antimalarial Natural Products. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2022; 117:1-106. [PMID: 34977998 DOI: 10.1007/978-3-030-89873-1_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Natural products have made a crucial and unique contribution to human health, and this is especially true in the case of malaria, where the natural products quinine and artemisinin and their derivatives and analogues, have saved millions of lives. The need for new drugs to treat malaria is still urgent, since the most dangerous malaria parasite, Plasmodium falciparum, has become resistant to quinine and most of its derivatives and is becoming resistant to artemisinin and its derivatives. This volume begins with a short history of malaria and follows this with a summary of its biology. It then traces the fascinating history of the discovery of quinine for malaria treatment and then describes quinine's biosynthesis, its mechanism of action, and its clinical use, concluding with a discussion of synthetic antimalarial agents based on quinine's structure. The volume then covers the discovery of artemisinin and its development as the source of the most effective current antimalarial drug, including summaries of its synthesis and biosynthesis, its mechanism of action, and its clinical use and resistance. A short discussion of other clinically used antimalarial natural products leads to a detailed treatment of other natural products with significant antiplasmodial activity, classified by compound type. Although the search for new antimalarial natural products from Nature's combinatorial library is challenging, it is very likely to yield new antimalarial drugs. The chapter thus ends by identifying over ten natural products with development potential as clinical antimalarial agents.
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Affiliation(s)
- David G I Kingston
- Department of Chemistry and the Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Maria Belen Cassera
- Department of Biochemistry and Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA, 30602, USA
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5
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Markus MB. Safety and Efficacy of Tafenoquine for Plasmodium vivax Malaria Prophylaxis and Radical Cure: Overview and Perspectives. Ther Clin Risk Manag 2021; 17:989-999. [PMID: 34526770 PMCID: PMC8435617 DOI: 10.2147/tcrm.s269336] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/20/2021] [Indexed: 11/23/2022] Open
Abstract
This article is inter alia a brief, first-stop guide to possible adverse events (AEs) associated with tafenoquine (TQ) intake. Safety and efficacy findings for TQ in Plasmodium vivax malaria prophylaxis and radical cure are summarized and some of the latest TQ-related studies (published in 2020 and 2021) are highlighted. In addition, little-known biological and other matters concerning malaria parasites and 8-aminoquinoline (8-AQ) drug action are discussed and some correct terminology pertinent to malaria is explained.
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Affiliation(s)
- Miles B Markus
- School of Animal, Plant and Environmental Sciences, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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6
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Akala HM, Watson OJ, Mitei KK, Juma DW, Verity R, Ingasia LA, Opot BH, Okoth RO, Chemwor GC, Juma JA, Mwakio EW, Brazeau N, Cheruiyot AC, Yeda RA, Maraka MN, Okello CO, Kateete DP, Managbanag JR, Andagalu B, Ogutu BR, Kamau E. Plasmodium interspecies interactions during a period of increasing prevalence of Plasmodium ovale in symptomatic individuals seeking treatment: an observational study. LANCET MICROBE 2021; 2:e141-e150. [DOI: 10.1016/s2666-5247(21)00009-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 12/07/2020] [Accepted: 01/15/2021] [Indexed: 11/28/2022]
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7
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Holbrook Z, Bean TP, Lynch SA, Hauton C. What do the terms resistance, tolerance, and resilience mean in the case of Ostrea edulis infected by the haplosporidian parasite Bonamia ostreae. J Invertebr Pathol 2021; 182:107579. [PMID: 33811850 DOI: 10.1016/j.jip.2021.107579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 01/21/2021] [Accepted: 02/25/2021] [Indexed: 12/29/2022]
Abstract
The decline of the European flat oyster Ostrea edulis represents a loss to European coastal economies both in terms of food security and by affecting the Good Environmental Status of the marine environment as set out by the European Council's Marine Strategy Framework Directive (2008/56/EC). Restoration of O. edulis habitat is being widely discussed across Europe, addressing key challenges such as the devastating impact of the haplosporidian parasite Bonamia ostreae. The use of resistant, tolerant, or resilient oysters as restoration broodstock has been proposed by restoration practitioners, but the definitions and implications of these superficially familiar terms have yet to be defined and agreed by all stakeholders. This opinion piece considers the challenges of differentiating Bonamia resistance, tolerance, and resilience; challenges which impede the adoption of robust definitions. We argue that, disease-resistance is reduced susceptibility to infection by the parasite, or active suppression of the parasites ability to multiply and proliferate. Disease-tolerance is the retention of fitness and an ability to neutralise the virulence of the parasite. Disease-resilience is the ability to recover from illness and, at population level, tolerance could be interpreted as resilience. We concede that further work is required to resolve practical uncertainty in applying these definitions, and argue for a collaboration of experts to achieve consensus. Failure to act now might result in the future dispersal of this disease into new locations and populations, because robust definitions are important components of regulatory mechanisms that underpin marine management.
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Affiliation(s)
- Zoë Holbrook
- Ocean and Earth Science, University of Southampton Waterfront Campus, National Oceanography Centre Southampton, UK
| | - Tim P Bean
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Sharon A Lynch
- School of Biological, Earth and Environmental Sciences, Aquaculture and Fisheries Development Centre, and Environmental Research Institute, University College Cork, Ireland
| | - Chris Hauton
- Ocean and Earth Science, University of Southampton Waterfront Campus, National Oceanography Centre Southampton, UK.
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8
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Monteiro W, Brito-Sousa JD, Elizalde-Torrent A, Bôtto-Menezes C, Melo GC, Fernandez-Becerra C, Lacerda M, Del Portillo HA. Cryptic Plasmodium chronic infections: was Maurizio Ascoli right? Malar J 2020; 19:440. [PMID: 33256745 PMCID: PMC7708240 DOI: 10.1186/s12936-020-03516-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 11/20/2020] [Indexed: 12/02/2022] Open
Abstract
Cryptic Plasmodium niches outside the liver possibly represent a major source of hypnozoite-unrelated recrudescences in malaria. Maurizio Ascoli, an Italian physician and scientist, suggested that infection was maintained as a result of the persistence of endoerythrocytic parasites in the circulatory bed of some internal organs, mainly the spleen. This would explain a proportion of the recurrences in patients, regardless of the Plasmodium species. Ascoli proposed a method that included the co-administration of adrenaline, in order to induce splenic contraction, and quinine to clear expelled forms in major vessels. Driven by controversy regarding safety and effectiveness, along with the introduction of new drugs, the Ascoli method was abandoned and mostly forgotten by the malaria research community. To date, however, the existence of cryptic parasites outside the liver is gaining supportive data. This work is a historical retrospective of cryptic malaria infections and the Ascoli method, highlighting key knowledge gaps regarding these possible parasite reservoirs.
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Affiliation(s)
- Wuelton Monteiro
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado (FMT-HVD), Manaus, Amazonas, Brazil. .,Universidade Do Estado Do Amazonas (UEA), Manaus, Amazonas, Brazil.
| | - José Diego Brito-Sousa
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado (FMT-HVD), Manaus, Amazonas, Brazil.,Universidade Do Estado Do Amazonas (UEA), Manaus, Amazonas, Brazil
| | - Aleix Elizalde-Torrent
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.,Institut D'Investigació Germans Trias I Pujol (IGTP), Badalona, Barcelona, Spain.,IrsiCaixa AIDS Research Institute, Badalona, Catalonia, Spain
| | - Camila Bôtto-Menezes
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado (FMT-HVD), Manaus, Amazonas, Brazil.,Universidade Do Estado Do Amazonas (UEA), Manaus, Amazonas, Brazil
| | - Gisely Cardoso Melo
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado (FMT-HVD), Manaus, Amazonas, Brazil.,Universidade Do Estado Do Amazonas (UEA), Manaus, Amazonas, Brazil
| | - Carmen Fernandez-Becerra
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.,Institut D'Investigació Germans Trias I Pujol (IGTP), Badalona, Barcelona, Spain
| | - Marcus Lacerda
- Fundação de Medicina Tropical Dr Heitor Vieira Dourado (FMT-HVD), Manaus, Amazonas, Brazil.,Instituto Leônidas & Maria Deane (ILMD), Fiocruz, Manaus, Amazonas, Brazil
| | - Hernando A Del Portillo
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain. .,Institut D'Investigació Germans Trias I Pujol (IGTP), Badalona, Barcelona, Spain. .,Institució Catalana de Recerca I Estudis Avançats (ICREA), Barcelona, Spain.
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9
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Groger M, Veletzky L, Lalremruata A, Cattaneo C, Mischlinger J, Manego Zoleko R, Kim J, Klicpera A, Meyer EL, Blessborn D, Winterberg M, Adegnika AA, Agnandji ST, Kremsner PG, Mordmüller B, Mombo-Ngoma G, Fuehrer HP, Ramharter M. Prospective Clinical and Molecular Evaluation of Potential Plasmodium ovale curtisi and wallikeri Relapses in a High-transmission Setting. Clin Infect Dis 2020; 69:2119-2126. [PMID: 31066448 PMCID: PMC6880329 DOI: 10.1093/cid/ciz131] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Indexed: 01/02/2023] Open
Abstract
Background Plasmodium ovale curtisi and wallikeri are perceived as relapsing malarial parasites. Contrary to Plasmodium vivax, direct evidence for this hypothesis is scarce. The aim of this prospective study was to characterize the reappearance patterns of ovale parasites. Methods P. ovale spp. infected patients were treated with artemether-lumefantrine and followed biweekly for up to 1 year for the detection of reappearing parasitemia. Molecular analysis of reappearing isolates was performed to identify homologous isolates by genotyping and to define cases of relapse following predefined criteria. Results At inclusion, 26 participants were positive for P. ovale curtisi and/or P. ovale wallikeri. The median duration of follow-up was 35 weeks. Reappearance of the same P. ovale species was observed in 46% of participants; 61% of P. ovale curtisi and 19% of P. ovale wallikeri infection-free intervals were estimated to end with reappearance by week 32. Based on the predefined criteria, 23% of participants were identified with 1 or 2 relapses, all induced by P. ovale curtisi. Conclusion These findings are in line with the currently accepted relapse theory inasmuch as the reappearance of P. ovale curtisi strains following initial blood clearance was conclusively demonstrated. Interestingly, no relapse of P. ovale wallikeri was observed.
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Affiliation(s)
- Mirjam Groger
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Germany
| | - Luzia Veletzky
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | | | | | - Johannes Mischlinger
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Germany
| | - Rella Manego Zoleko
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | - Johanna Kim
- Centre de Recherches Médicales de Lambaréné, Gabon
| | | | - Elias L Meyer
- Center for Medical Statistics, Informatics, and Intelligent Systems, Section for Medical Statistics, Medical University of Vienna, Austria
| | - Daniel Blessborn
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Markus Winterberg
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ayola A Adegnika
- Centre de Recherches Médicales de Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Germany.,German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | | | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Germany.,German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné, Gabon.,Institut für Tropenmedizin, Universität Tübingen, Germany.,German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Ghyslain Mombo-Ngoma
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | - Hans-Peter Fuehrer
- Institute of Parasitology, University of Veterinary Medicine Vienna, Austria
| | - Michael Ramharter
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine and I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon.,German Center for Infection Research (DZIF), partner site Hamburg-Luebeck-Borstel, Hamburg, Germany
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10
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Chen M, Dong Y, Deng Y, Xu Y, Liu Y, Zhang C, Huang H. Polymorphism analysis of propeller domain of k13 gene in Plasmodium ovale curtisi and Plasmodium ovale wallikeri isolates original infection from Myanmar and Africa in Yunnan Province, China. Malar J 2020; 19:246. [PMID: 32660505 PMCID: PMC7359257 DOI: 10.1186/s12936-020-03317-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 07/04/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Eighteen imported ovale malaria cases imported from Myanmar and various African countries have been reported in Yunnan Province, China from 2013 to 2018. All of them have been confirmed by morphological examination and 18S small subunit ribosomal RNA gene (18S rRNA) based PCR in YNRL. Nevertheless, the subtypes of Plasmodium ovale could not be identified based on 18S rRNA gene test, thus posing challenges on its accurate diagnosis. To help establish a more sensitive and specific method for the detection of P. ovale genes, this study performs sequence analysis on k13-propeller polymorphisms in P. ovale. METHODS Dried blood spots (DBS) from ovale malaria cases were collected from January 2013 to December 2018, and the infection sources were confirmed according to epidemiological investigation. DNA was extracted, and the coding region (from 206th aa to 725th aa) in k13 gene propeller domain was amplified using nested PCR. Subsequently, the amplified products were sequenced and compared with reference sequence to obtain CDS. The haplotypes and mutation loci of the CDS were analysed, and the spatial structure of the amino acid peptide chain of k13 gene propeller domain was predicted by SWISS-MODEL. RESULTS The coding region from 224th aa to 725th aa of k13 gene from P. ovale in 83.3% of collected samples (15/18) were amplified. Three haplotypes were observed in 15 samples, and the values of Ka/Ks, nucleic acid diversity index (π) and expected heterozygosity (He) were 3.784, 0.0095, and 0.4250. Curtisi haplotype, Wallikeri haplotype, and mutant type accounted for 73.3% (11/15), 20.0% (3/15), and 6.7% (1/15). The predominant haplotypes of P. ovale curtisi were determined in all five Myanmar isolates. Of the ten African isolates, six were identified as P. o. curtisi, three were P. o. wallikeri and one was mutant type. Base substitutions between the sequences of P. o. curtisi and P. o. wallikeri were determined at 38 loci, such as c.711. Moreover, the A > T base substitution at c.1428 was a nonsynonymous mutation, resulting in amino acid variation of T476S in the 476th position. Compared with sequence of P. o. wallikeri, the double nonsynonymous mutations of G > A and A > T at the sites of c.1186 and c.1428 leads to the variations of D396N and T476S for the 396th and 476th amino acids positions. For P. o. curtisi and P. o. wallikeri, the peptide chains in the coding region from 224th aa to 725th aa of k13 gene merely formed a monomeric spatial model, whereas the double-variant peptide chains of D396N and T476S formed homodimeric spatial model. CONCLUSION The propeller domain of k13 gene in the P. ovale isolates imported into Yunnan Province from Myanmar and Africa showed high differentiation. The sequences of Myanmar-imported isolates belong to P. o. curtisi, while the sequences of African isolates showed the sympatric distribution from P. o. curtisi, P. o. wallikeri and mutant isolates. The CDS with a double base substitution formed a dimeric spatial model to encode the peptide chain, which is completely different from the monomeric spatial structure to encode the peptide chain from P. o. curtisi and P. o. wallikeri.
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Affiliation(s)
- Mengni Chen
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China
| | - Ying Dong
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China.
| | - Yan Deng
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China
| | - Yanchun Xu
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China
| | - Yan Liu
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China
| | - Canglin Zhang
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China
| | - Herong Huang
- Yunnan Institute of Parasitic Diseases, Yunnan Provincial Key Laboratory of Vector-Borne Diseases Control and Research, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Expert Workstation of Professor Jiang Lubin, Pu'er, 665000, China
- School of Basic Medical Sciences, Dali University, Dali, 667000, China
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11
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Grande R, Antinori S, Meroni L, Menegon M, Severini C. A case of Plasmodium malariae recurrence: recrudescence or reinfection? Malar J 2019; 18:169. [PMID: 31088460 PMCID: PMC6515619 DOI: 10.1186/s12936-019-2806-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/07/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Plasmodium malariae is the most neglected of the six human malaria species and it is still unknown which is the mechanism underlying the long latency of this Plasmodium. CASE PRESENTATION A case of PCR-confirmed P. malariae recurrence in a 52-year old Italian man was observed 5 months after a primary attack. In the interval between the two observed episodes of malaria the patient denied any further stay in endemic areas except for a visit to Libya, a country considered malaria-free. Genomic DNA of the P. malariae strain using five microsatellites (PM2, PM9, PM11, PM25, PM34) and the antigen marker of circumsporozoite (csp) was amplified and sequenced. Analysis of polymorphisms of the P. malariae csp central repeat region showed differences between the strains responsible of the first and second episode of malaria. A difference in the allele size was also observed for the sequence analysis of PM2 microsatellites. CONCLUSIONS Plasmodium malariae is a challenging human malaria parasite and even with the use of molecular techniques the pathogenesis of recurrent episodes cannot be precisely explained.
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Affiliation(s)
- Romualdo Grande
- Clinical Microbiology, Virology and Bioemergency, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milan, Italy
| | - Spinello Antinori
- Department of Biomedical and Clinical Sciences "Luigi Sacco", University of Milan, Milan, Italy.
- III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milan, Italy.
| | - Luca Meroni
- III Division of Infectious Diseases, ASST Fatebenefratelli Sacco, Luigi Sacco Hospital, Milan, Italy
| | - Michela Menegon
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Carlo Severini
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
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12
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Molecular and cellular characterization of apoptosis in flat oyster a key mechanisms at the heart of host-parasite interactions. Sci Rep 2018; 8:12494. [PMID: 30131502 PMCID: PMC6104086 DOI: 10.1038/s41598-018-29776-x] [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: 04/05/2018] [Accepted: 07/14/2018] [Indexed: 01/09/2023] Open
Abstract
Bonamia ostreae has been associated with the decline of flat oyster Ostrea edulis populations in some European countries. This obligatory intracellular parasite persists and multiplies into hemocytes. Previous in vitro experiments showed that apoptosis is activated in hemocytes between 1 h and 4 h of contact with the parasite. The flat oyster uses the apoptosis pathway to defend against B. ostreae. However, the parasite might be also able to modulate this response in order to survive in its host. In order to investigate this hypothesis the apoptotic response of the host was evaluated using flow cytometry, transmission electron microscopy and by measuring the response of genes involved in the apoptotic pathway after 4 h. In parallel, the parasite response was investigated by measuring the expression of B. ostreae genes involved in different biological functions including cell cycle and cell death. Obtained results allow describing molecular apoptotic pathways in O. edulis and confirm that apoptosis is early activated in hemocytes after a contact with B. ostreae. Interestingly, at cellular and molecular levels this process appeared downregulated after 44 h of contact. Concurrently, parasite gene expression appeared reduced suggesting that the parasite could inhibit its own metabolism to escape the immune response.
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13
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Yavne Y, Leshem E, Paran Y, Nadir E, Weinberger M, Stein M, Petersiel N, Yahav D, Grossman T, Schwartz E. Plasmodium malariae in Israeli Travelers: A Nationwide Study. Clin Infect Dis 2018; 65:1516-1522. [PMID: 29020345 DOI: 10.1093/cid/cix560] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/18/2017] [Indexed: 11/13/2022] Open
Abstract
Background Little is known about Plasmodium malariae, a relatively rare cause of malaria in returned travelers. Recently, polymerase chain reaction (PCR) use for malaria diagnosis has enhanced specificity of P. malariae detection. The study objective was to describe the unique aspects of P. malariae diagnosis and clinical course in travelers. Methods Malaria is a reportable disease in Israel. All PCR-proven P. malariae monoinfections in Israeli travelers between January 2008 and January 2017 were retrieved from the Ministry of Health Reference Parasitology Laboratory. Data regarding method and timing of diagnosis, clinical characteristics, and laboratory testing were collected from patient charts. Results Eighteen patients with P. malariae were included. All cases were acquired in Africa. During the study period, the relative proportion of P. malariae increased (2%-10% of all malaria cases). Malaria was identified by blood smear in 10 of 18 patients (56%) on admission, and by rapid antigen test in 5 of 18 (29%) patients only, while P. malariae speciation was correctly identified by smear in 2 of 18 (11%) patients. Though all patients reported fever, only 4 of 18 (22%) described a quartan fever course. In 7 of 18 (39%) patients, malaria was contracted despite prophylactic treatment. Five patients had prolonged prepatent periods (median, 55 days), all of whom received prior prophylaxis. Conclusions The relative proportion of P. malariae is on the rise. Diagnosis in routine clinical settings is inadequate due to the low sensitivity and specificity of blood smears. PCR should be considered when clinical suspicion is high. Prophylaxis failure, which caused delayed clinical presentation, was documented.
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Affiliation(s)
- Yarden Yavne
- Sackler Faculty of Medicine, Tel-Aviv University
| | - Eyal Leshem
- Sackler Faculty of Medicine, Tel-Aviv University.,Center for Geographic Medicine and Department of Medicine C, Chaim Sheba Medical Center, Tel Hashomer
| | - Yael Paran
- Sackler Faculty of Medicine, Tel-Aviv University.,Infectious Diseases Unit, Sourasky Medical Center, Tel Aviv
| | - Eyal Nadir
- Infectious Diseases Unit, Kaplan Medical Center, Rehovot, affiliated to the School of Medicine, Hebrew University and Hadassah, Jerusalem
| | - Miriam Weinberger
- Sackler Faculty of Medicine, Tel-Aviv University.,Infectious Diseases Unit, Assaf Harofeh Medical Center
| | - Michal Stein
- Infectious Diseases Unit, Hillel Yaffe Medical Center, Hadera
| | - Neta Petersiel
- Unit of Infectious Diseases and Internal Medicine B, Rambam Medical Center and Bruce Rappaport Faculty of Medicine, Technion, Haifa
| | - Dafna Yahav
- Unit of Infectious Diseases, Rabin Medical Center, Beilinson Hospital, Petah-Tikva
| | - Tamar Grossman
- Reference Parasitology Laboratory, Central Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - Eli Schwartz
- Sackler Faculty of Medicine, Tel-Aviv University.,Center for Geographic Medicine and Department of Medicine C, Chaim Sheba Medical Center, Tel Hashomer
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14
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Abstract
A curious aspect of the evolution of the hypnozoite theory of malarial relapse is its transmogrification from theory into 'fact', this being of historical, linguistic, scientific and sociological interest. As far as it goes, the hypnozoite explanation for relapse is almost certainly correct. I contend, however, that many of the genotypically homologous, non-reinfection, relapse-like Plasmodium vivax recurrences that researchers ascribe to hypnozoite activation are probably hypnozoite-independent. Indeed, some malariologists are starting to recognize that homologous P. vivax recurrences have most likely been overattributed to activation of hypnozoites. Hitherto identified, non-hypnozoite, possible plasmodial sources of recurrence that must be considered, besides circulating erythrocytic stages, include parasites in splenic dendritic cells, other cells in the spleen (in addition to infected erythrocytes there), bone marrow (importantly) and the skin. I argue that we need to take into account the possibility of a dual or multiple extra-vascular origin of P. vivax non-reinfection recurrences, not arbitrarily discount it. The existence of a P. vivax reservoir(s) is a topical subject and one of practical importance for malaria eradication. Pertinent drug-associated matters are also discussed, as is the dormancy-related significance of clues provided by blood-stage-induced malarial infection.
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15
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Veletzky L, Groger M, Lagler H, Walochnik J, Auer H, Fuehrer HP, Ramharter M. Molecular evidence for relapse of an imported Plasmodium ovale wallikeri infection. Malar J 2018; 17:78. [PMID: 29426330 PMCID: PMC5807828 DOI: 10.1186/s12936-018-2226-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/07/2018] [Indexed: 11/12/2022] Open
Abstract
Background Malaria caused by Plasmodium ovale spp. has been neglected by and large from research and has received only little scientific attention during the past decades. Ovale malaria is considered to feature relapses by liver hypnozoites although scientific evidence for this paradigm is scarce. Case presentation Here, the case of a 16-year-old male, who presented with fevers to the outpatient department in Vienna, Austria, after travelling to Uganda and Papua New Guinea is described. Infection with Plasmodium malariae was diagnosed by microscopy and the patient was treated accordingly with a full course of supervised artemether–lumefantrine. He was discharged in good clinical condition with a negative blood smear. One month after initial diagnosis, he returned complaining of fever. Thick blood smear was positive again for malaria parasites, which were confirmed as P. ovale wallikeri by PCR. Retrospective analysis revealed the identical Plasmodium spp. in the initial blood samples. Molecular analysis of various gene loci (nuclear porbp2, 18S rRNA and potra genes) gave identical results providing further evidence for relapse by an identical parasite genotype. Consecutively, the patient was retreated with artemether–lumefantrine and received a regimen of primaquine according to WHO guidelines. Conclusion Conclusive evidence for relapses with P. ovale spp. is rare. The presented case provides convincing confirmation for the relapse paradigm based on re-appearing parasitaemia following supervised treatment in a non-endemic region with a parasite strain of identical genotype.
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Affiliation(s)
- Luzia Veletzky
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria.,Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
| | - Mirjam Groger
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Heimo Lagler
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Julia Walochnik
- Institute for Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Herbert Auer
- Institute for Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Hans-Peter Fuehrer
- Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Michael Ramharter
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany. .,Bernhard Nocht Hospital for Tropical Diseases, Bernhard Nocht Institute for Tropical Medicine and University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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16
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Markus MB. Malaria Eradication and the Hidden Parasite Reservoir. Trends Parasitol 2017; 33:492-495. [DOI: 10.1016/j.pt.2017.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 11/28/2022]
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17
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Groger M, Fischer HS, Veletzky L, Lalremruata A, Ramharter M. A systematic review of the clinical presentation, treatment and relapse characteristics of human Plasmodium ovale malaria. Malar J 2017; 16:112. [PMID: 28284211 PMCID: PMC5346189 DOI: 10.1186/s12936-017-1759-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/28/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Despite increased efforts to control and ultimately eradicate human malaria, Plasmodium ovale malaria is for the most part outside the focus of research or public health programmes. Importantly, the understanding of P. ovale-nowadays regarded as the two distinct species P. ovale wallikeri and P. ovale curtisi-largely stems from case reports and case series lacking study designs providing high quality evidence. Consecutively, there is a lack of systematic evaluation of the clinical presentation, appropriate treatment and relapse characteristics of P. ovale malaria. The aim of this systematic review is to provide a systematic appraisal of the current evidence for severe manifestations, relapse characteristics and treatment options for human P. ovale malaria. METHODS AND RESULTS This systematic review was performed according to the PRISMA guidelines and registered in the international prospective register for systematic reviews (PROSPERO 2016:CRD42016039214). P. ovale mono-infection was a strict inclusion criterion. Of 3454 articles identified by the literature search, 33 articles published between 1922 and 2015 met the inclusion criteria. These articles did not include randomized controlled trials. Five prospective uncontrolled clinical trials were performed on a total of 58 participants. P. ovale was sensitive to all tested drugs within the follow-up periods and on interpretable in vitro assays. Since its first description in 1922, only 18 relapsing cases of P. ovale with a total of 28 relapse events were identified in the scientific literature. There was however no molecular evidence for a causal relationship between dormant liver stages and subsequent relapses. A total of 22 severe cases of P. ovale malaria were published out of which five were fatal. Additionally, two cases of congenital P. ovale malaria were reported. CONCLUSIONS Current knowledge of P. ovale malaria is based on small trials with minor impact, case reports and clinical observations. This systematic review highlights that P. ovale is capable of causing severe disease, severe congenital malaria and may even lead to death. Evidence for relapses in patients with P. ovale malaria adds up to only a handful of cases. Nearly 100 years after P. ovale's first description by Stephens the evidence for the clinical characteristics, relapse potential and optimal treatments for P. ovale malaria is still scarce.
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Affiliation(s)
- Mirjam Groger
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Hannah S. Fischer
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Luzia Veletzky
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | | | - Michael Ramharter
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine I, Medical University of Vienna, Vienna, Austria
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany
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18
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Rogier E, Moss DM, Chard AN, Trinies V, Doumbia S, Freeman MC, Lammie PJ. Evaluation of Immunoglobulin G Responses to Plasmodium falciparum and Plasmodium vivax in Malian School Children Using Multiplex Bead Assay. Am J Trop Med Hyg 2016; 96:312-318. [PMID: 27895279 DOI: 10.4269/ajtmh.16-0476] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/21/2016] [Indexed: 12/23/2022] Open
Abstract
Malaria serology through assaying for IgG against Plasmodium spp. antigens provides evidence into the infection history for an individual. The multiplex bead assay (MBA) allows for detection of IgG against multiple Plasmodium spp., and can be especially useful in many regions where Plasmodium falciparum is of primary clinical focus, but other species are co-endemic. Dried blood spots were collected from 805 Malian children attending 42 elementary schools in the regions of Mopti, Sikasso, Koulikoro, and Bamako capital district, and IgG assayed by MBA. As southern Mali is known to be holoendemic for P. falciparum, merozoite surface protein 1 19-kDa subunit (MSP-142) and apical membrane antigen 1 (AMA-1) antigens were included for serology against this parasite. Responses to these antigens both provided high estimates for lifetime exposure, with 730 (90%) children with IgG antibodies for MSP-142, 737 (91%) for AMA-1, and 773 (96%) positive for either or both. Also included was the antigen Plasmodium vivax MSP-119, against which 140 (17.4%) children were found to have antibodies. Increases in antibody titers with older age were clearly seen with the P. falciparum antigens, but not with the P. vivax antigen, likely indicating more of a sporadic, rather than sustained transmission for this species. The MBA provides effective opportunities to evaluate malaria transmission through serological analysis for multiple Plasmodium species.
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Affiliation(s)
- Eric Rogier
- Division of Parasitic Diseases and Malaria, Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia.
| | - Delynn M Moss
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Anna N Chard
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Victoria Trinies
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Seydou Doumbia
- Malaria Research and Training Center, Faculty of Medicine and Odontostomatology, University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | - Matthew C Freeman
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Patrick J Lammie
- Division of Parasitic Diseases and Malaria, Centers for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
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19
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Stanton A, Harris LM, Graham G, Merrick CJ. Recombination events among virulence genes in malaria parasites are associated with G-quadruplex-forming DNA motifs. BMC Genomics 2016; 17:859. [PMID: 27809775 PMCID: PMC5093961 DOI: 10.1186/s12864-016-3183-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/21/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria parasites of the genus Plasmodium possess large hyper-variable families of antigen-encoding genes. These are often variantly-expressed and are major virulence factors for immune evasion and the maintenance of chronic infections. Recombination and diversification of these gene families occurs readily, and may be promoted by G-quadruplex (G4) DNA motifs within and close to the variant genes. G4s have been shown to cause replication fork stalling, DNA breakage and recombination in model systems, but these motifs remain largely unstudied in Plasmodium. Results We examined the nature and distribution of putative G4-forming sequences in multiple Plasmodium genomes, finding that their co-distribution with variant gene families is conserved across different Plasmodium species that have different types of variant gene families. In P. falciparum, where a large set of recombination events that occurred over time in cultured parasites has been mapped, we found a strong spatial association between these recombination events and putative G4-forming sequences. Finally, we searched Plasmodium genomes for the three classes of helicase that can unwind G4s: Plasmodium spp. have no identifiable homologue of the highly efficient G4 helicase PIF1, but they do encode two putative RecQ helicases and one homologue of the RAD3-family helicase FANCJ. Conclusions Our analyses, conducted at the whole-genome level in multiple species of Plasmodium, support the concept that G4s are likely to be involved in recombination and diversification of antigen-encoding gene families in this important protozoan pathogen. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3183-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam Stanton
- School of Computing and Mathematics, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK
| | - Lynne M Harris
- Centre for Applied Entomology and Parasitology, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK
| | - Gemma Graham
- School of Medicine, Keele University, Keele, Staffordshire, ST55BG, UK
| | - Catherine J Merrick
- Centre for Applied Entomology and Parasitology, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK.
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