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van Schalkwyk DA, Pratt S, Nolder D, Stewart LB, Liddy H, Muwanguzi-Karugaba J, Beshir KB, Britten D, Victory E, Rogers C, Millard J, Brown M, Nabarro LE, Taylor A, Young BC, Chiodini PL, Sutherland CJ. Treatment Failure in a UK Malaria Patient Harboring Genetically Variant Plasmodium falciparum From Uganda With Reduced In Vitro Susceptibility to Artemisinin and Lumefantrine. Clin Infect Dis 2024; 78:445-452. [PMID: 38019958 PMCID: PMC10874266 DOI: 10.1093/cid/ciad724] [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: 08/18/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND Recent cases of clinical failure in malaria patients in the United Kingdom (UK) treated with artemether-lumefantrine have implications for malaria chemotherapy worldwide. METHODS Parasites were isolated from an index case of confirmed Plasmodium falciparum treatment failure after standard treatment, and from comparable travel-acquired UK malaria cases. Drug susceptibility in vitro and genotypes at 6 resistance-associated loci were determined for all parasite isolates and compared with clinical outcomes for each parasite donor. RESULTS A traveler, who returned to the UK from Uganda in 2022 with Plasmodium falciparum malaria, twice failed treatment with full courses of artemether-lumefantrine. Parasites from the patient exhibited significantly reduced susceptibility to artemisinin (ring-stage survival, 17.3% [95% confidence interval {CI}, 13.6%-21.1%]; P < .0001) and lumefantrine (effective concentration preventing 50% of growth = 259.4 nM [95% CI, 130.6-388.2 nM]; P = .001). Parasite genotyping identified an allele of pfk13 encoding both the A675V variant in the Pfk13 propeller domain and a novel L145V nonpropeller variant. In vitro susceptibility testing of 6 other P. falciparum lines of Ugandan origin identified reduced susceptibility to artemisinin and lumefantrine in 1 additional line, also from a 2022 treatment failure case. These parasites did not harbor a pfk13 propeller domain variant but rather the novel nonpropeller variant T349I. Variant alleles of pfubp1, pfap2mu, and pfcoronin were also identified among the 7 parasite lines. CONCLUSIONS We confirm, in a documented case of artemether-lumefantrine treatment failure imported from Uganda, the presence of pfk13 mutations encoding L145V and A675V. Parasites with reduced susceptibility to both artemisinin and lumefantrine may be emerging in Uganda.
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Affiliation(s)
- Donelly A van Schalkwyk
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sade Pratt
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Debbie Nolder
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Lindsay B Stewart
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Helen Liddy
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Julian Muwanguzi-Karugaba
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Khalid B Beshir
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Dawn Britten
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Emma Victory
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Claire Rogers
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - James Millard
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Michael Brown
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Laura E Nabarro
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Andrew Taylor
- Department of Infectious Diseases, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Bernadette C Young
- Department of Infectious Diseases, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Peter L Chiodini
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Colin J Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- UK Health Security Agency Malaria Reference Laboratory, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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2
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Paris L, Tackie RG, Beshir KB, Tampuori J, Awandare GA, Binka FN, Urban BC, Dinko B, Sutherland CJ. Parasite clearance dynamics in children hospitalised with severe malaria in the Ho Teaching Hospital, Volta Region, Ghana. Parasite Epidemiol Control 2022; 19:e00276. [PMID: 36263093 PMCID: PMC9574762 DOI: 10.1016/j.parepi.2022.e00276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 08/07/2022] [Accepted: 09/30/2022] [Indexed: 11/21/2022] Open
Abstract
Background Over 90% of severe malaria (SM) cases occur in African children. Parenteral artesunate is currently the recommended treatment for SM. Studies of parasite clearance in paediatric SM cases are needed for assessment of therapeutic outcomes but are lacking in Africa. Methods Severe malaria patients were recruited in the children's emergency ward at Ho Teaching Hospital, Ghana, in 2018. Blood samples were taken upon admission, every 24 h for 3 days and 1 week after treatment, and DNA extracted. Parasitaemia and parasite densities were performed by microscopy at enrolment and the follow-up days wherever possible. Relative parasite density was measured at each timepoint by duplex qPCR and parameters of parasite clearance estimated. Results Of 25 evaluable SM patients, clearance of qPCR-detectable parasites occurred within 48 h for 17 patients, but three out of the remaining eight were still qPCR-positive on day 3. Increased time to parasite clearance was seen in children ≥5 years old, those with lower haemoglobin levels and those with a high number of previous malaria diagnoses, but these associations were not statistically significant. Conclusion We examined parasite clearance dynamics among paediatric cases of SM. Our observations suggest that daily sampling for qPCR estimation of P. falciparum peripheral density is a useful method for assessing treatment response in hospitalised SM cases. The study demonstrated varied parasite clearance response, thus illuminating the complex nature of the mechanism in this important patient group, and further investigations utilizing larger sample sizes are needed to confirm our findings.
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Affiliation(s)
- Laura Paris
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Richmond G. Tackie
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Khalid B. Beshir
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - John Tampuori
- Department of Urology, Ho Teaching Hospital, Ho, Ghana
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Fred N. Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Ghana
| | - Britta C. Urban
- Department of Tropical Disease Biology, Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Colin J. Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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3
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Deletions of the Plasmodium falciparum histidine-rich protein 2/3 genes are common in field isolates from north-eastern Tanzania. Sci Rep 2022; 12:5802. [PMID: 35388127 PMCID: PMC8987040 DOI: 10.1038/s41598-022-09878-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/30/2022] [Indexed: 11/26/2022] Open
Abstract
Plasmodium falciparum parasites lacking histidine-rich protein 2 and 3 (pfhrp2/3) genes have been reported in several parts of the world. These deletions are known to compromise the effectiveness of HRP2-based malaria rapid diagnostic tests (HRP2-RDT). The National Malaria Control Programme (NMCP) in Tanzania adopted HRP2-RDTs as a routine tool for malaria diagnosis in 2009 replacing microscopy in many Health facilities. We investigated pfhrp2/3 deletions in 122 samples from two areas with diverse malaria transmission intensities in Northeastern Tanzania. Pfhrp2 deletion was confirmed in 1.6% of samples while pfhrp3 deletion was confirmed in 50% of samples. We did not find parasites with both pfhrp2 and pfhrp3 deletions among our samples. Results from this study highlight the need for systematic surveillance of pfhrp2/3 deletions in Tanzania to understand their prevalence and determine their impact on the performance of mRDT.
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4
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Hosch S, Yoboue CA, Donfack OT, Guirou EA, Dangy JP, Mpina M, Nyakurungu E, Blöchliger K, Guerra CA, Phiri WP, Ayekaba MO, García GA, Tanner M, Daubenberger C, Schindler T. Analysis of nucleic acids extracted from rapid diagnostic tests reveals a significant proportion of false positive test results associated with recent malaria treatment. Malar J 2022; 21:23. [PMID: 35073934 PMCID: PMC8785039 DOI: 10.1186/s12936-022-04043-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 01/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Surveillance programmes often use malaria rapid diagnostic tests (RDTs) to determine the proportion of the population carrying parasites in their peripheral blood to assess the malaria transmission intensity. Despite an increasing number of reports on false-negative and false-positive RDT results, there is a lack of systematic quality control activities for RDTs deployed in malaria surveillance programmes. METHODS The diagnostic performance of field-deployed RDTs used for malaria surveys was assessed by retrospective molecular analysis of the blood retained on the tests. RESULTS Of the 2865 RDTs that were collected in 2018 on Bioko Island and analysed in this study, 4.7% had a false-negative result. These false-negative RDTs were associated with low parasite density infections. In 16.6% of analysed samples, masked pfhrp2 and pfhrp3 gene deletions were identified, in which at least one Plasmodium falciparum strain carried a gene deletion. Among all positive RDTs analysed, 28.4% were tested negative by qPCR and therefore considered to be false-positive. Analysing the questionnaire data collected from the participants, this high proportion of false-positive RDTs could be explained by P. falciparum histidine rich protein 2 (PfHRP2) antigen persistence after recent malaria treatment. CONCLUSION Malaria surveillance depending solely on RDTs needs well-integrated quality control procedures to assess the extent and impact of reduced sensitivity and specificity of RDTs on malaria control programmes.
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Affiliation(s)
- Salome Hosch
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Charlene Aya Yoboue
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | | | - Etienne A Guirou
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Maxmillian Mpina
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.,Laboratorio de Investigaciones de Baney, Baney, Equatorial Guinea
| | - Elizabeth Nyakurungu
- Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.,Laboratorio de Investigaciones de Baney, Baney, Equatorial Guinea
| | - Koranan Blöchliger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Carlos A Guerra
- Medical Care Development International, Malabo, Equatorial Guinea
| | - Wonder P Phiri
- Medical Care Development International, Malabo, Equatorial Guinea
| | | | | | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Claudia Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Laboratorio de Investigaciones de Baney, Baney, Equatorial Guinea.
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Manirakiza G, Kassaza K, Taremwa IM, Bazira J, Byarugaba F. Molecular identification and anti-malarial drug resistance profile of Plasmodium falciparum from patients attending Kisoro Hospital, southwestern Uganda. Malar J 2022; 21:21. [PMID: 35033082 PMCID: PMC8761270 DOI: 10.1186/s12936-021-04023-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 12/14/2021] [Indexed: 11/22/2022] Open
Abstract
Background The evolution of malaria infection has necessitated the development of highly sensitive diagnostic assays, as well as the use of dried blood spots (DBS) as a potential source of deoxyribonucleic acid (DNA) yield for polymerase chain reaction (PCR) assays. This study identified the different Plasmodium species in malaria-positive patients, and the anti-malarial drug resistance profile for Plasmodium falciparum using DBS samples collected from patients attending Kisoro Hospital in Kisoro district, Southwestern Uganda. Methods The blood samples were prospectively collected from patients diagnosed with malaria to make DBS, which were then used to extract DNA for real-time PCR and high-resolution melting (HRM) analysis. Plasmodium species were identified by comparing the control and test samples using HRM-PCR derivative curves. Plasmodium falciparum chloroquine (CQ) resistance transporter (pfcrt) and kelch13 to screen the samples for anti-malarial resistance markers. The HRM-PCR derivative curve was used to present a summary distribution of the different Plasmodium species as well as the anti-malarial drug profile. Results Of the 152 participants sampled, 98 (64.5%) were females. The average age of the participants was 34.9 years (range: 2 months–81 years). There were 134 samples that showed PCR amplification, confirming the species as Plasmodium. Plasmodium falciparum (N = 122), Plasmodium malariae (N = 6), Plasmodium ovale (N = 4), and Plasmodium vivax (N = 2) were the various Plasmodium species and their proportions. The results showed that 87 (71.3%) of the samples were sensitive strains/wild type (CVMNK), 4 (3.3%) were resistant haplotypes (SVMNT), and 31 (25.4%) were resistant haplotypes (CVIET). Kelch13 C580Y mutation was not detected. Conclusion The community served by Kisoro hospital has a high Plasmodium species burden, according to this study. Plasmodium falciparum was the dominant species, and it has shown that resistance to chloroquine is decreasing in the region. Based on this, molecular identification of Plasmodium species is critical for better clinical management. Besides, DBS is an appropriate medium for DNA preservation and storage for future epidemiological studies.
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Affiliation(s)
- Godfrey Manirakiza
- Department of Microbiology, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda.
| | - Kennedy Kassaza
- Department of Microbiology, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Ivan Mugisha Taremwa
- Institute of Allied Health Sciences, Clarke International University, Kampala, Uganda
| | - Joel Bazira
- Department of Microbiology, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Fredrick Byarugaba
- Department of Microbiology, Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda
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6
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Persistent Submicroscopic Plasmodium falciparum Parasitemia 72 Hours after Treatment with Artemether-Lumefantrine Predicts 42-Day Treatment Failure in Mali and Burkina Faso. Antimicrob Agents Chemother 2021; 65:e0087321. [PMID: 34060901 PMCID: PMC8284475 DOI: 10.1128/aac.00873-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A recent randomized controlled trial, the WANECAM (West African Network for Clinical Trials of Antimalarial Drugs) trial, conducted at seven centers in West Africa, found that artemether-lumefantrine, artesunate-amodiaquine, pyronaridine-artesunate, and dihydroartemisinin-piperaquine all displayed good efficacy. However, artemether-lumefantrine was associated with a shorter interval between clinical episodes than the other regimens. In a further comparison of these therapies, we identified cases of persisting submicroscopic parasitemia by quantitative PCR (qPCR) at 72 h posttreatment among WANECAM participants from 5 sites in Mali and Burkina Faso, and we compared treatment outcomes for this group to those with complete parasite clearance by 72 h. Among 552 evaluable patients, 17.7% had qPCR-detectable parasitemia at 72 h during their first treatment episode. This proportion varied among sites, reflecting differences in malaria transmission intensity, but did not differ among pooled drug treatment groups. However, patients who received artemether-lumefantrine and were qPCR positive at 72 h were significantly more likely to have microscopically detectable recurrent Plasmodium falciparum parasitemia by day 42 than those receiving other regimens and experienced, on average, a shorter interval before the next clinical episode. Haplotypes of pfcrt and pfmdr1 were also evaluated in persisting parasites. These data identify a possible threat to the parasitological efficacy of artemether-lumefantrine in West Africa, over a decade since it was first introduced on a large scale.
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7
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O'Flaherty K, Oo WH, Zaloumis SG, Cutts JC, Aung KZ, Thein MM, Drew DR, Razook Z, Barry AE, Parischa N, Zaw NN, Thu HK, Thi A, Htay WYM, Soe AP, Simpson JA, Beeson JG, Agius PA, Fowkes FJI. Community-based molecular and serological surveillance of subclinical malaria in Myanmar. BMC Med 2021; 19:121. [PMID: 34044836 PMCID: PMC8161608 DOI: 10.1186/s12916-021-01993-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/27/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND In the Greater Mekong Subregion (GMS), current malaria surveillance strategies rely on a network of village health volunteers (VHVs) reporting the results of rapid diagnostic tests (RDTs), known to miss many asymptomatic infections. Integration of more sensitive diagnostic molecular and serological measures into the VHV network may improve surveillance of residual malaria transmission in hard-to-reach areas in the region and inform targeted interventions and elimination responses. However, data on residual malaria transmission that would be captured by these measures in the VHV-led testing and treatment surveillance network in the GMS is unknown. METHODS A total of 114 VHVs were trained to collect dried blood spots from villagers undergoing routine RDTs as part of VHV-led active and passive case detection from April 2015 to June 2016. Samples were subjected to molecular testing (quantitative polymerase chain reaction [qPCR]) to determine Plasmodium falciparum and P. vivax infection and serological testing (against P. falciparum and P. vivax antigens) to determine exposure to P. falciparum and P. vivax. RESULTS Over 15 months, 114 VHVs performed 32,194 RDTs and collected samples for molecular (n = 13,157) and serological (n = 14,128) testing. The prevalence of molecular-detectable P. falciparum and P. vivax infection was 3.2% compared to the 0.16% prevalence of Plasmodium spp. by RDT, highlighting the large burden of infections undetected by standard surveillance. Peaks in anti-P. falciparum, but not P. vivax, merozoite IgG seroprevalence coincided with seasonal P. falciparum transmission peaks, even in those with no molecularly detectable parasites. At the individual level, antibody seropositivity was associated with reduced odds of contemporaneous P. falciparum (OR for PfCSP 0.51 [95%CI 0.35, 0.76], p = 0.001, PfAMA1 0.70 [95%CI 0.52, 0.93], p = 0.01, and PfMSP2 0.81 [95%CI 0.61, 1.08], p = 0.15), but not P. vivax infection (OR PvAMA1 1.02 [95%CI 0.73, 1.43], p = 0.89) indicating a potential role of immunity in protection against molecular-detectable P. falciparum parasitaemia. CONCLUSIONS We demonstrated that integration and implementation of sample collection for molecular and serological surveillance into networks of VHV servicing hard-to-reach populations in the GMS is feasible, can capture significant levels of ongoing undetected seasonal malaria transmission and has the potential to supplement current routine RDT testing. Improving malaria surveillance by advancing the integration of molecular and serological techniques, through centralised testing approaches or novel point-of-contact tests, will advance progress, and tracking, towards malaria elimination goals in the GMS.
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Affiliation(s)
- Katherine O'Flaherty
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Win Han Oo
- Burnet Institute Myanmar, Yangon, Myanmar
| | - Sophie G Zaloumis
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Julia C Cutts
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia.,Department of Medicine, University of Melbourne, Melbourne, Australia
| | | | | | - Damien R Drew
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Zahra Razook
- School of Medicine, Deakin University, Geelong, Australia
| | - Alyssa E Barry
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia.,Department of Medicine, University of Melbourne, Melbourne, Australia.,School of Medicine, Deakin University, Geelong, Australia
| | - Naanki Parischa
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | | | | | - Aung Thi
- Department of Public Health, Myanmar Ministry of Health, Nay Pyi Taw, Myanmar
| | | | | | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - James G Beeson
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia.,Department of Medicine, University of Melbourne, Melbourne, Australia.,Department of Microbiology and Central Clinical School, Monash University, Melbourne, Australia
| | - Paul A Agius
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia.,Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia.,Judith Lumley Centre, La Trobe University, Melbourne, Australia
| | - Freya J I Fowkes
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia. .,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia. .,Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia. .,Department of Infectious Diseases, Monash University, Melbourne, Australia.
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8
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Nolder D, Stewart L, Tucker J, Ibrahim A, Gray A, Corrah T, Gallagher C, John L, O'Brien E, Aggarwal D, Benavente ED, van Schalkwyk D, Henriques G, Sepúlveda N, Campino S, Chiodini P, Sutherland C, Beshir KB. Failure of rapid diagnostic tests in Plasmodium falciparum malaria cases among travelers to the UK and Ireland: Identification and characterisation of the parasites. Int J Infect Dis 2021; 108:137-144. [PMID: 33991679 PMCID: PMC8295040 DOI: 10.1016/j.ijid.2021.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Our objective was to systematically investigate false-negative histidine-rich protein 2 rapid diagnostic tests (HRP2-RDT) in imported Plasmodium falciparum malaria cases from travelers to the UK and the Republic of Ireland (RoI). METHODS Five imported malaria cases in travellers returning to the UK and RoI from East Africa were reported to the PHE Malaria Reference Laboratory as negative according to histidine-rich protein (HRP2)-RDT. The cases were systematically investigated using microscopic, RDT, molecular, genomic, and in in vitro approaches. RESULTS In each case, HRP2-RDT was negative, whereas microscopy confirmed the presence of P. falciparum. Further analysis revealed that the genes encoding HRP2 and HRP3 were deleted in three of the five cases. Whole-genome sequencing in one of these isolates confirmed deletions in P. falciparum chromosomes 8 and 13. Our study produced evidence that the fourth case, which had high parasitemia at clinical presentation, was a rare example of antigen saturation ('prozone-like effect'), leading to a false negative in the HRP2-RDT, while the fifth case was due to low parasitemia. CONCLUSIONS False-negative HRP2-RDT results with P. falciparum are concerning. Our findings emphasise the necessity of supporting the interpretation of RDT results with microscopy, in conjunction with clinical observations, and sets out a systematic approach to identifying parasites carrying pfhrp2 and pfhrp3 deletions.
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Affiliation(s)
- Debbie Nolder
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Lindsay Stewart
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Julie Tucker
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Amy Ibrahim
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Adam Gray
- Department of Infectious Diseases, Northwick Park Hospital, London North West University Healthcare NHS Trust, London HA1 3UJ, UK
| | - Tumena Corrah
- Department of Infectious Diseases, Northwick Park Hospital, London North West University Healthcare NHS Trust, London HA1 3UJ, UK
| | - Carmel Gallagher
- Department of Infectious Diseases, Northwick Park Hospital, London North West University Healthcare NHS Trust, London HA1 3UJ, UK
| | - Laurence John
- Department of Infectious Diseases, Northwick Park Hospital, London North West University Healthcare NHS Trust, London HA1 3UJ, UK
| | - Edel O'Brien
- Haematology Lab, University Hospital Limerick, Ireland
| | - Dinesh Aggarwal
- Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK
| | - Ernest Diez Benavente
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Donelly van Schalkwyk
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Gisela Henriques
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Nuno Sepúlveda
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; CEAUL - Centro de Estatística e Aplicações da Universidade de Lisboa, Lisbon, Portugal
| | - Susana Campino
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Peter Chiodini
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Department of Clinical Parasitology, Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, UK
| | - Colin Sutherland
- PHE Malaria Reference Laboratory, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Khalid B Beshir
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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9
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Guirou EA, Schindler T, Hosch S, Donfack OT, Yoboue CA, Krähenbühl S, Deal A, Cosi G, Gondwe L, Mwangoka G, Masuki H, Salim N, Mpina M, Said J, Abdulla S, Hoffman SL, Nlavo BM, Maas C, Falla CC, Phiri WP, Garcia GA, Tanner M, Daubenberger C. Molecular malaria surveillance using a novel protocol for extraction and analysis of nucleic acids retained on used rapid diagnostic tests. Sci Rep 2020; 10:12305. [PMID: 32703999 PMCID: PMC7378824 DOI: 10.1038/s41598-020-69268-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 07/10/2020] [Indexed: 11/09/2022] Open
Abstract
The use of malaria rapid diagnostic tests (RDTs) as a source for nucleic acids that can be analyzed via nucleic acid amplification techniques has several advantages, including minimal amounts of blood, sample collection, simplified storage and shipping conditions at room temperature. We have systematically developed and extensively evaluated a procedure to extract total nucleic acids from used malaria RDTs. The co-extraction of DNA and RNA molecules from small volumes of dried blood retained on the RDTs allows detection and quantification of P. falciparum parasites from asymptomatic patients with parasite densities as low as 1 Pf/µL blood using reverse transcription quantitative PCR. Based on the extraction protocol we have developed the ENAR (Extraction of Nucleic Acids from RDTs) approach; a complete workflow for large-scale molecular malaria surveillance. Using RDTs collected during a malaria indicator survey we demonstrated that ENAR provides a powerful tool to analyze nucleic acids from thousands of RDTs in a standardized and high-throughput manner. We found several, known and new, non-synonymous single nucleotide polymorphisms in the propeller region of the kelch 13 gene among isolates circulating on Bioko Island, Equatorial Guinea.
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Affiliation(s)
- Etienne A Guirou
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Tobias Schindler
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Salome Hosch
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Charlene Aya Yoboue
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Silvan Krähenbühl
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Anna Deal
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Glenda Cosi
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Linda Gondwe
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Ifakara Health Institute, Bagamoyo Branch, United Republic of Tanzania
| | - Grace Mwangoka
- Ifakara Health Institute, Bagamoyo Branch, United Republic of Tanzania
| | - Heavenlight Masuki
- Department of Paediatrics and Child Health, Muhimbili University of Health and Allied Sciences, Dar Es Salaam, Tanzania
| | - Nahya Salim
- Department of Paediatrics and Child Health, Muhimbili University of Health and Allied Sciences, Dar Es Salaam, Tanzania
| | - Maxmillian Mpina
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland.,Ifakara Health Institute, Bagamoyo Branch, United Republic of Tanzania
| | - Jongo Said
- Ifakara Health Institute, Bagamoyo Branch, United Republic of Tanzania
| | - Salim Abdulla
- Ifakara Health Institute, Bagamoyo Branch, United Republic of Tanzania
| | | | | | - Carl Maas
- Marathon EG Production Ltd, Malabo, Equatorial Guinea
| | | | - Wonder P Phiri
- Medical Care Development International, Malabo, Equatorial Guinea
| | | | - Marcel Tanner
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Claudia Daubenberger
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
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10
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Srisutham S, Suwannasin K, Mathema VB, Sriprawat K, Smithuis FM, Nosten F, White NJ, Dondorp AM, Imwong M. Utility of Plasmodium falciparum DNA from rapid diagnostic test kits for molecular analysis and whole genome amplification. Malar J 2020; 19:193. [PMID: 32460780 PMCID: PMC7251736 DOI: 10.1186/s12936-020-03259-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) have become the most common diagnostic tool for detection of Plasmodium falciparum malaria, in particular in remote areas. RDT blood spots provide a source of parasite DNA for molecular analysis. In this study, the utility of RDTs for molecular analysis and the performance of different methods for whole genome amplification were investigated. Methods Positive P. falciparum RDTs were collected from Kayin, Myanmar from August 2014 to January 2016. The RDT samples were stored for 6 months, 9 months, 20 months, 21 months, and 32 months before DNA extraction and subsequent molecular analysis of P. falciparum kelch 13 (pfkelch13) mutations, P. falciparum multidrug resistance 1 (pfmdr1), and P. falciparum plasmepsin 2 (pfplasmepsin2) gene amplification. In addition, performance of four whole genome amplification (WGA) kits were compared, including REPLI-g®, MALBACTM, PicoPLEX®, and GenomePlex®, for which DNA quantity and quality were compared between original DNA and post-WGA products. Results The proportion of successful amplification of the different molecular markers was similar between blood spots analysed from RDTs stored for 6, 9, 20, 21, or 32 months. Successful amplification was dependent on the molecular markers fragment length (p value < 0.05): 18% for a 1245 bp fragment of pfkelch13, 71% for 364 bp of pfkelch13, 81% for 87 bp of pfmdr1, 81% for 108 bp of pfplasmepsin2. Comparison of the four WGA assay kits showed that REPLI-g®, MALBACTM, and PicoPLEX® increased the quantity of DNA 60 to 750-fold, whereas the ratio of parasite DNA amplification over human DNA was most favourable for MALBAC®. Sequencing results of pfkelch13, P. falciparum chloroquine resistance transporter (pfcrt), P. falciparum dihydrofolate reductase (pfdhfr) and six microsatellite markers assessed from the post-WGA product was the same as from the original DNA. Conclusions Blood spots from RDTs are a good source for molecular analysis of P. falciparum, even after storage up to 32 months. WGA of RDT-derived parasite DNA reliably increase DNA quantity with sufficient quality for molecular analysis of resistance markers.
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Affiliation(s)
- Suttipat Srisutham
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Vivek Bhakta Mathema
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kanlaya Sriprawat
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Frank M Smithuis
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.,Medical Action Myanmar, Yangon, Myanmar
| | - Francois Nosten
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mallika Imwong
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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11
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Grignard L, Nolder D, Sepúlveda N, Berhane A, Mihreteab S, Kaaya R, Phelan J, Moser K, van Schalkwyk DA, Campino S, Parr JB, Juliano JJ, Chiodini P, Cunningham J, Sutherland CJ, Drakeley C, Beshir KB. A novel multiplex qPCR assay for detection of Plasmodium falciparum with histidine-rich protein 2 and 3 (pfhrp2 and pfhrp3) deletions in polyclonal infections. EBioMedicine 2020; 55:102757. [PMID: 32403083 PMCID: PMC7218259 DOI: 10.1016/j.ebiom.2020.102757] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/13/2020] [Accepted: 03/30/2020] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND Many health facilities in malaria endemic countries are dependent on Rapid diagnostic tests (RDTs) for diagnosis and some National Health Service (NHS) hospitals without expert microscopists rely on them for diagnosis out of hours. The emergence of P. falciparum lacking the gene encoding histidine-rich protein 2 and 3 (HRP2 and HRP3) and escaping RDT detection threatens progress in malaria control and elimination. Currently, confirmation of RDT negative due to the deletion of pfhrp2 and pfhrp3, which encodes a cross-reactive protein isoform, requires a series of PCR assays. These tests have different limits of detection and many laboratories have reported difficulty in confirming the absence of the deletions with certainty. METHODS We developed and validated a novel and rapid multiplex real time quantitative (qPCR) assay to detect pfhrp2, pfhrp3, confirmatory parasite and human reference genes simultaneously. We also applied the assay to detect pfhrp2 and pfhrp3 deletion in 462 field samples from different endemic countries and UK travellers. RESULTS The qPCR assay demonstrated diagnostic sensitivity of 100% (n = 19, 95% CI= (82.3%; 100%)) and diagnostic specificity of 100% (n = 31; 95% CI= (88.8%; 100%)) in detecting pfhrp2 and pfhrp3 deletions. In addition, the assay estimates P. falciparum parasite density and accurately detects pfhrp2 and pfhrp3 deletions masked in polyclonal infections. We report pfhrp2 and pfhrp3 deletions in parasite isolates from Kenya, Tanzania and in UK travellers. INTERPRETATION The new qPCR is easily scalable to routine surveillance studies in countries where P. falciparum parasites lacking pfhrp2 and pfhrp3 are a threat to malaria control.
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Affiliation(s)
- Lynn Grignard
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Debbie Nolder
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom; PHE Malaria Reference Laboratory, London School of Hygiene & Tropical Medicine, United Kingdom
| | - Nuno Sepúlveda
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom; Centre of Statistics and Applications of University of Lisbon, Portugal
| | - Araia Berhane
- Communicable Diseases Control Division, Ministry of Health, Eritrea
| | - Selam Mihreteab
- Communicable Diseases Control Division, Ministry of Health, Eritrea
| | - Robert Kaaya
- Kilimanjaro Christian Medical University College, Tanzania
| | - Jody Phelan
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Kara Moser
- University of North Carolina at Chapel Hill, United States
| | - Donelly A van Schalkwyk
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Susana Campino
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | | | - Peter Chiodini
- PHE Malaria Reference Laboratory, London School of Hygiene & Tropical Medicine, United Kingdom; UCL Hospital for Tropical Diseases, United Kingdom
| | | | - Colin J Sutherland
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Chris Drakeley
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Khalid B Beshir
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom.
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12
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Guiguemde KT, Dieye Y, Lô AC, Ndiaye M, Lam A, Manga IA, Sow GD, Diop M, Souané T, Diouf MP, Tine RCK, Faye B. Molecular detection and quantification of Plasmodium falciparum gametocytes carriage in used RDTs in malaria elimination settings in northern Senegal. Malar J 2020; 19:123. [PMID: 32228599 PMCID: PMC7106854 DOI: 10.1186/s12936-020-03204-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/23/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Malaria surveillance requires powerful tools and strategies to achieve malaria elimination. Rapid diagnostic tests for malaria (RDTs) are easily deployed on a large scale and are helpful sources of parasite DNA. The application of sensitive molecular techniques to these RDTs is a modern tool for improving malaria case detection and drug resistance surveillance. Several studies have made it possible to extract the DNA of Plasmodium falciparum from RDTs. The knowledge of gametocyte carriage in the population is important to better assess the level of parasite transmission in elimination settings. The aim of this study was to detect P. falciparum gametocytes from used RDTs by quantitative PCR for molecular monitoring of malaria transmission. METHODS DNA was extracted from 303 RDT devices (SD Bioline Malaria Pf) using the Chelex-100 protocol. qPCR was performed in a 20 μL reaction to detect and quantify transcripts of the pfs25 gene. The cycle threshold (Ct) was determined by the emission fluorescence corresponding to the initial amount of amplified DNA. RESULTS The study found an overall prevalence of 53.47% with an average Ct of 32.12 ± 4.28 cycles. In 2018, the prevalence of gametocytes was higher in the Ranérou district (76.24%) than in the Saint-Louis district (67.33%) where an increase in the number of gametocyte carriers in 2018 was noted, in comparison with 2017. CONCLUSIONS RDTs are a good source of DNA for molecular monitoring of gametocyte carriage. This method is a simple and effective tool to better understand the level of malaria transmission with a view to elimination.
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Affiliation(s)
| | - Yakou Dieye
- PATH, Malaria Control and Evaluation Partnership (MACEPA), Dakar, Senegal
| | - Aminata Collé Lô
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
| | - Magatte Ndiaye
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
| | - Aminata Lam
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
| | - Isaac Akhénaton Manga
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
| | - Gnagna Dieng Sow
- PATH, Malaria Control and Evaluation Partnership (MACEPA), Dakar, Senegal
| | - Moussa Diop
- PATH, Malaria Control and Evaluation Partnership (MACEPA), Dakar, Senegal
| | - Tamba Souané
- PATH, Malaria Control and Evaluation Partnership (MACEPA), Dakar, Senegal
| | - Marie Pièrre Diouf
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
| | - Roger Clément Kouly Tine
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
| | - Babacar Faye
- Department of Medical Parasitology, Medical Faculty, Cheikh Anta Diop University, Dakar, Senegal
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