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Rosenthal PJ, Asua V, Bailey JA, Conrad MD, Ishengoma DS, Kamya MR, Rasmussen C, Tadesse FG, Uwimana A, Fidock DA. The emergence of artemisinin partial resistance in Africa: how do we respond? THE LANCET. INFECTIOUS DISEASES 2024; 24:e591-e600. [PMID: 38552654 DOI: 10.1016/s1473-3099(24)00141-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/17/2024] [Accepted: 02/19/2024] [Indexed: 04/21/2024]
Abstract
Malaria remains one of the most important infectious diseases in the world, with the greatest burden in sub-Saharan Africa, primarily from Plasmodium falciparum infection. The treatment and control of malaria is challenged by resistance to most available drugs, but partial resistance to artemisinins (ART-R), the most important class for the treatment of malaria, was until recently confined to southeast Asia. This situation has changed, with the emergence of ART-R in multiple countries in eastern Africa. ART-R is mediated primarily by single point mutations in the P falciparum kelch13 protein, with several mutations present in African parasites that are now validated resistance mediators based on clinical and laboratory criteria. Major priorities at present are the expansion of genomic surveillance for ART-R mutations across the continent, more frequent testing of the efficacies of artemisinin-based regimens against uncomplicated and severe malaria in trials, more regular assessment of ex-vivo antimalarial drug susceptibilities, consideration of changes in treatment policy to deter the spread of ART-R, and accelerated development of new antimalarial regimens to overcome the impacts of ART-R. The emergence of ART-R in Africa is an urgent concern, and it is essential that we increase efforts to characterise its spread and mitigate its impact.
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Affiliation(s)
- Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, CA, USA.
| | - Victor Asua
- Infectious Diseases Research Collaboration, Kampala, Uganda; University of Tübingen, Tübingen, Germany
| | - Jeffrey A Bailey
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA; Departments of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Melissa D Conrad
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania; Department of Biochemistry, Kampala International University in Tanzania, Dar es Salaam, Tanzania; School of Public Health, Harvard University, Boston, MA, USA
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda; Department of Medicine, Makerere University, Kampala, Uganda
| | | | - Fitsum G Tadesse
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia; London School of Hygiene and Tropical Medicine, London, UK
| | - Aline Uwimana
- Rwanda Biomedical Center, Kigali, Rwanda; Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - David A Fidock
- Department of Microbiology and Immunology and Center for Malaria Therapeutics and Antimicrobial Resistance, Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
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Rosenthal PJ, Asua V, Conrad MD. Emergence, transmission dynamics and mechanisms of artemisinin partial resistance in malaria parasites in Africa. Nat Rev Microbiol 2024; 22:373-384. [PMID: 38321292 DOI: 10.1038/s41579-024-01008-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2024] [Indexed: 02/08/2024]
Abstract
Malaria, mostly due to Plasmodium falciparum infection in Africa, remains one of the most important infectious diseases in the world. Standard treatment for uncomplicated P. falciparum malaria is artemisinin-based combination therapy (ACT), which includes a rapid-acting artemisinin derivative plus a longer-acting partner drug, and standard therapy for severe P. falciparum malaria is intravenous artesunate. The efficacy of artemisinins and ACT has been threatened by the emergence of artemisinin partial resistance in Southeast Asia, mediated principally by mutations in the P. falciparum Kelch 13 (K13) protein. High ACT treatment failure rates have occurred when resistance to partner drugs is also seen. Recently, artemisinin partial resistance has emerged in Rwanda, Uganda and the Horn of Africa, with independent emergences of different K13 mutants in each region. In this Review, we summarize our current knowledge of artemisinin partial resistance and focus on the emergence of resistance in Africa, including its epidemiology, transmission dynamics and mechanisms. At present, the clinical impact of emerging resistance in Africa is unclear and most available evidence suggests that the efficacies of leading ACTs remain excellent, but there is an urgent need to better appreciate the extent of the problem and its consequences for the treatment and control of malaria.
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Affiliation(s)
| | - Victor Asua
- Infectious Diseases Research Collaboration, Kampala, Uganda
- University of Tübingen, Tübingen, Germany
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Ngasala BE, Chiduo MG, Mmbando BP, Francis FT, Bushukatale S, Makene T, Mandara CI, Ishengoma DS, Kamugisha E, Ahmed M, Mahende MK, Kavishe RA, Muro F, Molteni F, Reaves E, Kitojo C, Greer G, Nyinondi S, Kabula B, Lalji S, Chacky F, Njau RJ, Warsame M, Mohamed A. Efficacy and safety of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in mainland Tanzania, 2019. Malar J 2024; 23:101. [PMID: 38594679 PMCID: PMC11005286 DOI: 10.1186/s12936-024-04931-0] [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: 12/21/2023] [Accepted: 04/04/2024] [Indexed: 04/11/2024] Open
Abstract
BACKGROUND Artemisinin-based combination therapy (ACT) has been a major contributor to the substantial reductions in global malaria morbidity and mortality over the last decade. In Tanzania, artemether-lumefantrine (AL) was introduced as the first-line treatment for uncomplicated Plasmodium falciparum malaria in 2006. The World Health Organization (WHO) recommends regular assessment and monitoring of the efficacy of the first-line treatment, specifically considering that artemisinin resistance has been confirmed in the Greater Mekong sub-region. This study's main aim was to assess the efficacy and safety of AL for treating uncomplicated P. falciparum malaria in Tanzania. METHODS This was a single-arm prospective antimalarial drug efficacy trial conducted in four of the eight National Malaria Control Programme (NMCP) sentinel sites in 2019. The trial was carried out in outpatient health facilities in Karume-Mwanza region, Ipinda-Mbeya region, Simbo-Tabora region, and Nagaga-Mtwara region. Children aged six months to 10 years with microscopy confirmed uncomplicated P. falciparum malaria who met the inclusion criteria were recruited based on the WHO protocol. The children received AL (a 6-dose regimen of AL twice daily for three days). Clinical and parasitological parameters were monitored during follow-up over 28 days to evaluate drug efficacy. RESULTS A total of 628 children were screened for uncomplicated malaria, and 349 (55.6%) were enrolled between May and September 2019. Of the enrolled children, 343 (98.3%) completed the 28-day follow-up or attained the treatment outcomes. There were no early treatment failures; recurrent infections during follow-up were common at two sites (Karume 29.5%; Simbo 18.2%). PCR-corrected adequate clinical and parasitological response (ACPR) by survival analysis to AL on day 28 of follow-up varied from 97.7% at Karume to 100% at Ipinda and Nagaga sites. The commonly reported adverse events were cough, skin pallor, and abdominal pain. The drug was well tolerated, and no serious adverse event was reported. CONCLUSION This study showed that AL had adequate efficacy and safety for the treatment of uncomplicated falciparum malaria in Tanzania in 2019. The high recurrent infections were mainly due to new infections, highlighting the potential role of introducing alternative artemisinin-based combinations that offer improved post-treatment prophylaxis, such as artesunate-amodiaquine (ASAQ).
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Affiliation(s)
- Billy E Ngasala
- Department of Parasitology, School of Public Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
| | - Mercy G Chiduo
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Bruno P Mmbando
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Filbert T Francis
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Samwel Bushukatale
- Department of Parasitology, School of Public Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Twilumba Makene
- Department of Parasitology, School of Public Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Celine I Mandara
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Deus S Ishengoma
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Erasmus Kamugisha
- Catholic University of Health and Allied Sciences, Bugando Medical Centre, Mwanza, Tanzania
| | - Maimuna Ahmed
- Catholic University of Health and Allied Sciences, Bugando Medical Centre, Mwanza, Tanzania
| | | | - Reginald A Kavishe
- Kilimanjaro Christian Medical Centre, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Florida Muro
- Kilimanjaro Christian Medical Centre, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | | | - Erik Reaves
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention, Dar es Salaam, Tanzania
| | - Chonge Kitojo
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - George Greer
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | | | | | | | - Frank Chacky
- National Malaria Control Program, Dodoma, Tanzania
| | - Ritha J Njau
- Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania
| | | | - Ally Mohamed
- National Malaria Control Program, Dodoma, Tanzania
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Somé AF, Conrad MD, Kabré Z, Fofana A, Yerbanga RS, Bazié T, Neya C, Somé M, Kagambega TJ, Legac J, Garg S, Bailey JA, Ouédraogo JB, Rosenthal PJ, Cooper RA. Ex vivo drug susceptibility and resistance mediating genetic polymorphisms of Plasmodium falciparum in Bobo-Dioulasso, Burkina Faso. Antimicrob Agents Chemother 2024; 68:e0153423. [PMID: 38411062 PMCID: PMC10989024 DOI: 10.1128/aac.01534-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 01/31/2024] [Indexed: 02/28/2024] Open
Abstract
Malaria remains a leading cause of morbidity and mortality in Burkina Faso, which utilizes artemether-lumefantrine as the principal therapy to treat uncomplicated malaria and seasonal malaria chemoprevention with monthly sulfadoxine-pyrimethamine plus amodiaquine in children during the transmission season. Monitoring the activities of available antimalarial drugs is a high priority. We assessed the ex vivo susceptibility of Plasmodium falciparum to 11 drugs in isolates from patients presenting with uncomplicated malaria in Bobo-Dioulasso in 2021 and 2022. IC50 values were derived using a standard 72 h growth inhibition assay. Parasite DNA was sequenced to characterize known drug resistance-mediating polymorphisms. Isolates were generally susceptible, with IC50 values in the low-nM range, to chloroquine (median IC5010 nM, IQR 7.9-24), monodesethylamodiaquine (22, 14-46) piperaquine (6.1, 3.6-9.2), pyronaridine (3.0, 1.3-5.5), quinine (50, 30-75), mefloquine (7.1, 3.7-10), lumefantrine (7.1, 4.5-12), dihydroartemisinin (3.7, 2.2-5.5), and atovaquone (0.2, 0.1-0.3) and mostly resistant to cycloguanil (850, 543-1,290) and pyrimethamine (33,200, 18,400-54,200), although a small number of outliers were seen. Considering genetic markers of resistance to aminoquinolines, most samples had wild-type PfCRT K76T (87%) and PfMDR1 N86Y (95%) sequences. For markers of resistance to antifolates, established PfDHFR and PfDHPS mutations were highly prevalent, the PfDHPS A613S mutation was seen in 19% of samples, and key markers of high-level resistance (PfDHFR I164L; PfDHPS K540E) were absent or rare (A581G). Mutations in the PfK13 propeller domain known to mediate artemisinin partial resistance were not detected. Overall, our results suggest excellent susceptibilities to drugs now used to treat malaria and moderate, but stable, resistance to antifolates used to prevent malaria.
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Affiliation(s)
- A. Fabrice Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - Melissa D. Conrad
- Department of Medicine, University of California, San Francisco, California, USA
| | - Zachari Kabré
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - Aminata Fofana
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - R. Serge Yerbanga
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
- Institut des Sciences et Techniques, Bobo-Dioulasso, Burkina Faso
| | - Thomas Bazié
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - Catherine Neya
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - Myreille Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - Tegawinde Josue Kagambega
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l’Ouest, Bobo-Dioulasso, Burkina Faso
| | - Jenny Legac
- Department of Medicine, University of California, San Francisco, California, USA
| | - Shreeya Garg
- Department of Medicine, University of California, San Francisco, California, USA
| | - Jeffrey A. Bailey
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | | | - Philip J. Rosenthal
- Department of Medicine, University of California, San Francisco, California, USA
| | - Roland A. Cooper
- Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, California, USA
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Ishengoma DS, Mandara CI, Madebe RA, Warsame M, Ngasala B, Kabanywanyi AM, Mahende MK, Kamugisha E, Kavishe RA, Muro F, Mandike R, Mkude S, Chacky F, Njau R, Martin T, Mohamed A, Bailey JA, Fola AA. Microsatellites reveal high polymorphism and high potential for use in anti-malarial efficacy studies in areas with different transmission intensities in mainland Tanzania. Malar J 2024; 23:79. [PMID: 38491359 PMCID: PMC10943981 DOI: 10.1186/s12936-024-04901-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 03/04/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Tanzania is currently implementing therapeutic efficacy studies (TES) in areas of varying malaria transmission intensities as per the World Health Organization (WHO) recommendations. In TES, distinguishing reinfection from recrudescence is critical for the determination of anti-malarial efficacy. Recently, the WHO recommended genotyping polymorphic coding genes, merozoite surface proteins 1 and 2 (msp1 and msp2), and replacing the glutamate-rich protein (glurp) gene with one of the highly polymorphic microsatellites in Plasmodium falciparum to adjust the efficacy of antimalarials in TES. This study assessed the polymorphisms of six neutral microsatellite markers and their potential use in TES, which is routinely performed in Tanzania. METHODS Plasmodium falciparum samples were obtained from four TES sentinel sites, Kibaha (Pwani), Mkuzi (Tanga), Mlimba (Morogoro) and Ujiji (Kigoma), between April and September 2016. Parasite genomic DNA was extracted from dried blood spots on filter papers using commercial kits. Genotyping was done using six microsatellites (Poly-α, PfPK2, TA1, C3M69, C2M34 and M2490) by capillary method, and the data were analysed to determine the extent of their polymorphisms and genetic diversity at the four sites. RESULTS Overall, 83 (88.3%) of the 94 samples were successfully genotyped (with positive results for ≥ 50.0% of the markers), and > 50.0% of the samples (range = 47.6-59.1%) were polyclonal, with a mean multiplicity of infection (MOI) ranging from 1.68 to 1.88 among the four sites. There was high genetic diversity but limited variability among the four sites based on mean allelic richness (RS = 7.48, range = 7.27-8.03, for an adjusted minimum sample size of 18 per site) and mean expected heterozygosity (He = 0.83, range = 0.80-0.85). Cluster analysis of haplotypes using STRUCTURE, principal component analysis, and pairwise genetic differentiation (FST) did not reveal population structure or clustering of parasites according to geographic origin. Of the six markers, Poly-α was the most polymorphic, followed by C2M34, TA1 and C3M69, while M2490 was the least polymorphic. CONCLUSION Microsatellite genotyping revealed high polyclonality and genetic diversity but no significant population structure. Poly-α, C2M34, TA1 and C3M69 were the most polymorphic markers, and Poly-α alone or with any of the other three markers could be adopted for use in TES in Tanzania.
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Affiliation(s)
- Deus S Ishengoma
- National Institute for Medical Research, Dar es Salaam, Tanzania.
- Faculty of Pharmaceutical Sciences, Monash University, Melbourne, Australia.
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA.
| | - Celine I Mandara
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Rashid A Madebe
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | | | - Billy Ngasala
- Department of Parasitology, School of Public Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
- Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden
| | | | | | - Erasmus Kamugisha
- Bugando Medical Centre, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Reginald A Kavishe
- Kilimanjaro Christian Medical Centre, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Florida Muro
- Kilimanjaro Christian Medical Centre, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Renata Mandike
- National Malaria Control Programme, Ministry of Health, Dodoma, Tanzania
| | - Sigsbert Mkude
- National Malaria Control Programme, Ministry of Health, Dodoma, Tanzania
| | - Frank Chacky
- National Malaria Control Programme, Ministry of Health, Dodoma, Tanzania
| | - Ritha Njau
- Malariologist and Public Health Specialist, Dar es Salaam, Tanzania
| | - Troy Martin
- HIV Vaccine Trials Network, Fred Hutch Cancer Research Centre, Seattle, WA, USA
| | - Ally Mohamed
- National Malaria Control Programme, Ministry of Health, Dodoma, Tanzania
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Abebe A Fola
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
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Gunasekera KT, Premaratne RG, Handunnetti SM, Weerasena J, Premawansa S, Fernando DS. msp1, msp2, and glurp genotyping to differentiate Plasmodium falciparum recrudescence from reinfections during prevention of reestablishment phase, Sri Lanka, 2014-2019. Malar J 2024; 23:35. [PMID: 38281044 PMCID: PMC10821543 DOI: 10.1186/s12936-024-04858-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/22/2024] [Indexed: 01/29/2024] Open
Abstract
BACKGROUND Sri Lanka after eliminating malaria in 2012, is in the prevention of re-establishment (POR) phase. Being a tropical country with high malariogenic potential, maintaining vigilance is important. All malaria cases are investigated epidemiologically and followed up by integrated drug efficacy surveillance (iDES). Occasionally, that alone is not adequate to differentiate Plasmodium falciparum reinfections from recrudescences. This study evaluated the World Health Organization and Medicines for Malaria Venture (MMV) recommended genotyping protocol for the merozoite surface proteins (msp1, msp2) and the glutamate-rich protein (glurp) to discriminate P. falciparum recrudescence from reinfection in POR phase. METHODS All P. falciparum patients detected from April 2014 to December 2019 were included in this study. Patients were treated and followed up by iDES up to 28 days and were advised to get tested if they develop fever at any time over the following year. Basic socio-demographic information including history of travel was obtained. Details of the malariogenic potential and reactive entomological and parasitological surveillance carried out by the Anti Malaria Campaign to exclude the possibility of local transmission were also collected. The msp1, msp2, and glurp genotyping was performed for initial and any recurrent infections. Classification of recurrent infections as recrudescence or reinfection was done based on epidemiological findings and was compared with the genotyping outcome. RESULTS Among 106 P. falciparum patients, six had recurrent infections. All the initial infections were imported, with a history of travel to malaria endemic countries. In all instances, the reactive entomological and parasitological surveillance had no evidence for local transmission. Five recurrences occurred within 28 days of follow-up and were classified as recrudescence. They have not travelled to malaria endemic countries between the initial and recurrent infections. The other had a recurrent infection after 105 days. It was assumed a reinfection, as he had travelled to the same malaria endemic country in between the two malaria attacks. Genotyping confirmed the recrudescence and the reinfection. CONCLUSIONS The msp1, msp2 and glurp genotyping method accurately differentiated reinfections from recrudescence. Since reinfection without a history of travel to a malaria endemic country would mean local transmission, combining genotyping outcome with epidemiological findings will assist classifying malaria cases without any ambiguity.
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Affiliation(s)
- Kumudunayana T Gunasekera
- Anti Malaria Campaign, Ministry of Health, 555/5 Public Health Complex, Elvitigala Mawatha, Colombo 5, Sri Lanka.
| | | | - Shiroma M Handunnetti
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka
| | - Jagathpriya Weerasena
- Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka
| | - Sunil Premawansa
- Department of Zoology and Environmental Science, University of Colombo, Colombo, Sri Lanka
| | - Deepika S Fernando
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
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Stauning MA, Jensen CS, Staalsøe T, Kurtzhals JAL. Detection and quantification of Plasmodium falciparum in human blood by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a proof of concept study. Malar J 2023; 22:285. [PMID: 37752504 PMCID: PMC10523782 DOI: 10.1186/s12936-023-04719-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/13/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) has revolutionized identification of bacteria and is becoming available in an increasing number of laboratories in malaria-endemic countries. The purpose of this proof-of-concept study was to explore the potential of MALDI-TOF as a diagnostic tool for direct detection and quantification of Plasmodium falciparum in human blood. METHODS Three different P. falciparum strains (3D7, HB3 and IT4) were cultured and synchronized following standard protocols. Ring-stages were diluted in fresh blood group 0 blood drawn in EDTA from healthy subjects to mimic clinical samples. Samples were treated with saponin and washed in PBS to concentrate protein material. Samples were analysed using a Microflex LT MALDI-TOF and resulting mass spectra were compared using FlexAnalysis software. RESULTS More than 10 peaks specific for P. falciparum were identified. The identified peaks were consistent among the three genetically unrelated strains. Identification was possible in clinically relevant concentrations of 0.1% infected red blood cells, and a close relationship between peak intensity and the percentage of infected red blood cells was seen. CONCLUSION The findings indicate that the method has the potential to detect and quantify P. falciparum at clinically relevant infection intensities and provides proof-of-concept for MALDI-TOF-based diagnosis of human malaria. Further research is needed to include other Plasmodium spp., wildtype parasite isolates and to increase sensitivity. MALDI-TOF may be a useful tool for mass-screening purposes and for diagnosis of malaria in settings where it is readily available.
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Affiliation(s)
- Marius Ahm Stauning
- Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
| | - Christian Salgård Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Trine Staalsøe
- Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen A L Kurtzhals
- Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
- Centre for Medical Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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