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Oyegoke OO, Akoniyon OP, Maharaj L, Adewumi TS, Malgwi SA, Aderoju SA, Fatoba AJ, Adeleke MA, Maharaj R, Okpeku M. Molecular detection of sub-microscopic infections and Plasmodium falciparum histidine-rich protein-2 and 3 gene deletions in pre-elimination settings of South Africa. Sci Rep 2024; 14:16024. [PMID: 38992085 PMCID: PMC11239831 DOI: 10.1038/s41598-024-60007-8] [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: 08/17/2023] [Accepted: 04/17/2024] [Indexed: 07/13/2024] Open
Abstract
South Africa's efforts toward eliminating malaria have positioned the country in the pre-elimination stage. Imported and sub-microscopic cases still contribute to the persistence of malaria in regions of low transmission as identified in this study where diagnostics is built largely on the use of Rapid Diagnostic Test (RDT). However, the presence of Pfhrp2/3 gene deletion is known to interfere with the accuracy of diagnosis with the use of RDT. Malaria elimination and detection of Pfhrp2/3 gene deletion in the pre-elimination setting requires accurate molecular surveillance. With the core objective of this study being the determination of the presence sub-microscopic malaria cases and deleted Pfhrp2/3 gene markers, a total of 354 samples were collected from five districts of KwaZulu Natal, South Africa. These samples were prepared for molecular analysis using primers and PCR conditions specific for amplification of 18S rRNA and msp-1gene. Positive amplicons were analysed for the presence of Pfhrp2/3 and flanking genes, along with Sanger sequencing and phylogenetic studies. Out of 354 samples collected 339 were tested negative with PfHRP2 based RDTs. Of these Pfhrp2 and Pfhrp3 gene deletions were confirmed in 94.7% (18/19) and 100% (19/19) respectively. High migration rate (75%) among the study participants was noted and phylogenetic analysis of sequenced isolates showed close evolutionary relatedness with India, United Kingdom, Iran, and Myanmar and China isolates. Molecular-based test is recommended as an essential surveillance tool for malaria management programs as the target focuses on elimination.
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Affiliation(s)
- Olukunle O Oyegoke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Olusegun P Akoniyon
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Leah Maharaj
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Taiye S Adewumi
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66046, USA
| | - Samson A Malgwi
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Samuel A Aderoju
- Department of Mathematics and Statistics, Kwara State University, Ilorin, Nigeria
| | - Abiodun J Fatoba
- Department of Genetics, Genomics and Bioinformatics, University of Tennessee Health Science Centre, Memphis, TN, 38016, USA
| | - Matthew A Adeleke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Rajendra Maharaj
- Malaria Research Unit, South African Medical Research Council, Durban, South Africa
| | - Moses Okpeku
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa.
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Mshani IH, Jackson FM, Mwanga RY, Kweyamba PA, Mwanga EP, Tambwe MM, Hofer LM, Siria DJ, González-Jiménez M, Wynne K, Moore SJ, Okumu F, Babayan SA, Baldini F. Screening of malaria infections in human blood samples with varying parasite densities and anaemic conditions using AI-Powered mid-infrared spectroscopy. Malar J 2024; 23:188. [PMID: 38880870 PMCID: PMC11181574 DOI: 10.1186/s12936-024-05011-z] [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] [Received: 05/04/2024] [Accepted: 06/05/2024] [Indexed: 06/18/2024] Open
Abstract
BACKGROUND Effective testing for malaria, including the detection of infections at very low densities, is vital for the successful elimination of the disease. Unfortunately, existing methods are either inexpensive but poorly sensitive or sensitive but costly. Recent studies have shown that mid-infrared spectroscopy coupled with machine learning (MIRs-ML) has potential for rapidly detecting malaria infections but requires further evaluation on diverse samples representative of natural infections in endemic areas. The aim of this study was, therefore, to demonstrate a simple AI-powered, reagent-free, and user-friendly approach that uses mid-infrared spectra from dried blood spots to accurately detect malaria infections across varying parasite densities and anaemic conditions. METHODS Plasmodium falciparum strains NF54 and FCR3 were cultured and mixed with blood from 70 malaria-free individuals to create various malaria parasitaemia and anaemic conditions. Blood dilutions produced three haematocrit ratios (50%, 25%, 12.5%) and five parasitaemia levels (6%, 0.1%, 0.002%, 0.00003%, 0%). Dried blood spots were prepared on Whatman™ filter papers and scanned using attenuated total reflection-Fourier Transform Infrared (ATR-FTIR) for machine-learning analysis. Three classifiers were trained on an 80%/20% split of 4655 spectra: (I) high contrast (6% parasitaemia vs. negative), (II) low contrast (0.00003% vs. negative) and (III) all concentrations (all positive levels vs. negative). The classifiers were validated with unseen datasets to detect malaria at various parasitaemia levels and anaemic conditions. Additionally, these classifiers were tested on samples from a population survey in malaria-endemic villages of southeastern Tanzania. RESULTS The AI classifiers attained over 90% accuracy in detecting malaria infections as low as one parasite per microlitre of blood, a sensitivity unattainable by conventional RDTs and microscopy. These laboratory-developed classifiers seamlessly transitioned to field applicability, achieving over 80% accuracy in predicting natural P. falciparum infections in blood samples collected during the field survey. Crucially, the performance remained unaffected by various levels of anaemia, a common complication in malaria patients. CONCLUSION These findings suggest that the AI-driven mid-infrared spectroscopy approach holds promise as a simplified, sensitive and cost-effective method for malaria screening, consistently performing well despite variations in parasite densities and anaemic conditions. The technique simply involves scanning dried blood spots with a desktop mid-infrared scanner and analysing the spectra using pre-trained AI classifiers, making it readily adaptable to field conditions in low-resource settings. In this study, the approach was successfully adapted to field use, effectively predicting natural malaria infections in blood samples from a population-level survey in Tanzania. With additional field trials and validation, this technique could significantly enhance malaria surveillance and contribute to accelerating malaria elimination efforts.
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Affiliation(s)
- Issa H Mshani
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK.
| | - Frank M Jackson
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Rehema Y Mwanga
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Prisca A Kweyamba
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123, Allschwil, Switzerland
- University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Emmanuel P Mwanga
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK
| | - Mgeni M Tambwe
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Lorenz M Hofer
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123, Allschwil, Switzerland
- University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Doreen J Siria
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK
| | - Mario González-Jiménez
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK
- School of Chemistry, The University of Glasgow, Glasgow, G128QQ, UK
| | - Klaas Wynne
- School of Chemistry, The University of Glasgow, Glasgow, G128QQ, UK
| | - Sarah J Moore
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, 4123, Allschwil, Switzerland
- University of Basel, Petersplatz 1, 4001, Basel, Switzerland
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
| | - Fredros Okumu
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
- School of Public Health, The University of the Witwatersrand, Park Town, Johannesburg, South Africa
| | - Simon A Babayan
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK
| | - Francesco Baldini
- Environmental Health, and Ecological Sciences Department, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, The University of Glasgow, Glasgow, UK
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Jebiwott S, Gutapaka N, Sumari D, Loss G, Athuman T, Nyandele JP, Cummins H, Chemba M, Benjamin-Chung J, Gangar P, Wu X, Smith J, Chen I, Dorsey G, Fink G, Olotu A, Hsiang M. Child Health and Infection with Low Density (CHILD) malaria: a protocol for a randomised controlled trial to assess the long-term health and socioeconomic impacts of testing and treating low-density malaria infection among children in Tanzania. BMJ Open 2024; 14:e082227. [PMID: 38538037 PMCID: PMC10982758 DOI: 10.1136/bmjopen-2023-082227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/15/2024] [Indexed: 04/04/2024] Open
Abstract
INTRODUCTION As malaria declines, low-density malaria infections (LMIs) represent an increasing proportion of infections and may have negative impacts on child health and cognition, necessitating development of targeted and effective solutions. This trial assesses the health, cognitive and socioeconomic impact of two strategies for detecting and treating LMI in a low transmission setting. METHODS AND ANALYSIS The study is a 3-arm open-label individually randomised controlled trial enrolling 600 children aged 6 months to 10 years in Bagamoyo district, Tanzania. Children are randomised to one of three arms: active case detection with molecular (ACDm) testing by high volume quantitative PCR (qPCR), passive case detection also with molecular testing (PCDm) and a control of standard PCD using rapid diagnostics tests (RDTs). Over the 2-year trial, ACDm participants receive malaria testing using RDT and qPCR three times annually, and malaria testing by RDT only when presenting with fever. PCDm and PCD participants receive malaria testing by RDT and qPCR or RDT only, respectively, when presenting with fever. RDT or qPCR positive participants with uncomplicated malaria are treated with artemether lumefantrine. The primary outcome is cumulative incidence of all-cause sick visits. Secondary outcomes include fever episodes, clinical failure after fever episodes, adverse events, malaria, non-malarial infection, antibiotic use, anaemia, growth faltering, cognition and attention, school outcomes, immune responses, and socioeconomic effects. Outcomes are assessed through monthly clinical assessments and testing, and baseline and endline neurodevelopmental testing. The trial is expected to provide key evidence and inform policy on health, cognitive and socioeconomic impact of interventions targeting LMI in children. ETHICS AND DISSEMINATION Study is approved by Tanzania NatHREC and institutional review boards at University of California San Francisco and Ifakara Health Institute. Findings will be reported on ClinicalTrials.gov, in peer-reviewed journals and through stakeholder meetings. TRIAL REGISTRATION NUMBER NCT05567016.
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Affiliation(s)
- Sylvia Jebiwott
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
| | | | - Deborah Sumari
- Ifakara Health Institute, Bagamoyo, Tanzania, United Republic of
| | - Georg Loss
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Thabit Athuman
- Ifakara Health Institute, Bagamoyo, Tanzania, United Republic of
| | | | - Hannah Cummins
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Mwajuma Chemba
- Ifakara Health Institute, Bagamoyo, Tanzania, United Republic of
| | - Jade Benjamin-Chung
- Epidemiology and Population Health, Stanford University School of Medicine, Stanford, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Pamela Gangar
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Xue Wu
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Jennifer Smith
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Ingrid Chen
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Günther Fink
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Ally Olotu
- Ifakara Health Institute, Bagamoyo, Tanzania, United Republic of
| | - Michelle Hsiang
- Malaria Elimination Initiative, Institute of Global Health Sciences, University of California, San Francisco, San Francisco, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, USA
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, USA
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Adeniji YR, Jalo I, Okonkwo I, Poksireni MR, Manga M, Wariri O, Alhassan HA, Warnow EI. Diagnostic value of rapid test for malaria among febrile neonates in a tertiary hospital in North-East Nigeria: a prospective cross-sectional study. Arch Dis Child 2023; 109:11-15. [PMID: 37879855 PMCID: PMC10803997 DOI: 10.1136/archdischild-2023-325906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 08/30/2023] [Indexed: 10/27/2023]
Abstract
OBJECTIVE The WHO recommends testing using microscopy or rapid diagnostic test (RDT) before treatment for malaria. However, the use of RDT to diagnose neonatal malaria has not been widely validated with most studies limited to the first week of life. Thus, we conducted this study to determine the utility of RDT in the diagnosis of congenital and acquired malaria in febrile neonates in Nigeria. DESIGN This prospective cross-sectional descriptive study consecutively recruited 131 febrile neonates at the Special Care Baby Unit (SCBU) of the Federal Teaching Hospital Gombe, Nigeria. All study participants concurrently had RDT (HRP2, LDH) and malaria microscopy. The performance of both methods was then compared. RESULT Seventy-eight of 131 neonates tested for malaria by blood smear microscopy demonstrated malaria parasites; a prevalence of 59.5%. Parasite count ranged from 16 to 520 /μL and the median parasite count was 81.0 /μL with IQR (40.0-134.5). The majority of patients (93.5%) had low-density parasitaemia (≤2+). All species identified were Plasmodium falciparum. None of the 131 neonates tested positive on RDT. The sensitivity and positive predictive value of RDT for neonatal malaria was zero. Congenital malaria was the most common form of neonatal malaria, accounting for 75.6%, while acquired and transfusion-related malaria were estimated at 12.8% and 11.6%, respectively. CONCLUSION The RDT used in this study was not sensitive in the diagnosis of congenital or acquired neonatal malaria; therefore, microscopy remains the preferred method of diagnosis of neonatal malaria.
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Affiliation(s)
| | - Iliya Jalo
- Department of Paediatrics, Federal Teaching Hospital Gombe, Gombe, Nigeria
| | - Ikechukwu Okonkwo
- Department of Child Health, University of Benin Teaching Hospital, Benin City, Nigeria
| | | | - Mohammed Manga
- Medical Microbiology, Federal Teaching Hospital Gombe, Gombe, Nigeria
| | - Oghenebrume Wariri
- Vaccines and Immunity Theme, MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | | | - Elon Isaac Warnow
- Department of Paediatrics, Federal Teaching Hospital Gombe, Gombe, Nigeria
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Paica IC, Rusu I, Popescu O, Brînzan A, Pencea I, Dobrinescu C, Kelemen B. Tentative indicators of malaria in archaeological skeletal samples, a pilot study testing different methods. INTERNATIONAL JOURNAL OF PALEOPATHOLOGY 2023; 40:109-116. [PMID: 36724549 DOI: 10.1016/j.ijpp.2023.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
OBJECTIVE This study attempts to integrate multiple methods to investigate the presence of malaria in human skeletal samples from an archaeological context. MATERIALS 33 well preserved human remains originating from a 17th-century archaeological site in southeastern Romania. METHODS The human bone samples were analyzed using rapid diagnostic tests for malaria antigens and PCR amplification of Plasmodium falciparum apical membrane antigen 1. A preliminary test was performed to identify and briefly characterize the presence of hemozoin using a combination of TEM imaging and diffraction. RESULTS The rapid diagnostic tests indicated that more than half of the examined samples were positive for Plasmodium antigens, but no traces of the parasites' genetic material were detected despite repeated attempts. The TEM images indicated that hemozoin might be a promising diagnostic marker of malaria in ancient bones. CONCLUSIONS The indisputable identification of malaria in the analyzed archaeological population was not possible as none of the applied methodological strategies turned out to be straightforward. SIGNIFICANCE This study reinforces the intricacy and limitations of unequivocally identifying malaria in past populations and sets the stage for future studies on such life-threatening infectious disease in a geographical space, which is currently underrepresented in the bioarchaeological literature. LIMITATIONS The low sample size and the lack of consistency across all assays hindered understanding the role of malaria in the studied population. SUGGESTIONS FOR FURTHER RESEARCH Further thorough multidisciplinary approaches on malaria detection in ancient settlements would be appropriate to inform our knowledge of its origins, frequency, and pathogen changes over centuries.
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Affiliation(s)
| | - Ioana Rusu
- Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeș-Bolyai University, Cluj-Napoca, 400006, Romania; Molecular Biology Centre, Interdisciplinary Research Institute on Bio-Nano-Sciences, Babeș-Bolyai University, Cluj-Napoca, 400271, Romania.
| | - Octavian Popescu
- Institute of Biology Bucharest of Romanian Academy, Bucharest, 060031, Romania; Molecular Biology Centre, Interdisciplinary Research Institute on Bio-Nano-Sciences, Babeș-Bolyai University, Cluj-Napoca, 400271, Romania; Emil G. Racoviță Institute, Babeș-Bolyai University, Cluj-Napoca, 400006, Romania
| | - Alexandru Brînzan
- Institute of Biology Bucharest of Romanian Academy, Bucharest, 060031, Romania
| | - Ion Pencea
- Department of Metallic Material Science and Physical Metallurgy, University Politehnica of Bucharest, Bucharest, 060042, Romania
| | - Cătălin Dobrinescu
- Department of Research-Development and Projects, Museum of National History and Archaeology, Constanţa, 900745, Romania
| | - Beatrice Kelemen
- Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeș-Bolyai University, Cluj-Napoca, 400006, Romania; Molecular Biology Centre, Interdisciplinary Research Institute on Bio-Nano-Sciences, Babeș-Bolyai University, Cluj-Napoca, 400271, Romania
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Awosolu OB, Yahaya ZS, Farah Haziqah MT, Olusi TA. Performance Evaluation of Nested Polymerase Chain Reaction (Nested PCR), Light Microscopy, and Plasmodium falciparum Histidine-Rich Protein 2 Rapid Diagnostic Test (PfHRP2 RDT) in the Detection of Falciparum Malaria in a High-Transmission Setting in Southwestern Nigeria. Pathogens 2022; 11:1312. [PMID: 36365063 PMCID: PMC9694681 DOI: 10.3390/pathogens11111312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 11/01/2022] [Accepted: 11/02/2022] [Indexed: 09/16/2023] Open
Abstract
Malaria remains a major public health challenge worldwide. In order to ensure a prompt and accurate malaria diagnosis, the World Health Organization recommended the confirmatory parasitological diagnosis of malaria by microscopy and malaria rapid diagnostic test (RDT) prior to antimalarial administration and treatment. This study was designed to evaluate the performance of nested polymerase chain reaction (nested PCR), light microscopy, and Plasmodium falciparum histidine-rich protein 2 rapid diagnostic test (PfHRP2 RDT) in the detection of falciparum malaria in Akure, Nigeria. A cross-sectional and hospital-based study involving 601 febrile volunteer participants was conducted in Akure, Nigeria. Approximately 2-3 mL venous blood samples were obtained from each study participant for parasitological confirmation by microscopy and PfHRP2-based malaria RDT. Thick and thin films were prepared and viewed under the light microscope for parasite detection, parasite density quantification, and species identification, respectively. Dry blood spot samples were prepared on 3MM Whatman filter paper for nested PCR. The overall prevalence of microscopy, PfHRP2 RDT, and nested PCR were 64.89% (390/601), 65.7% (395/601), and 67.39% (405/601), respectively. The estimates of sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and Youden's j index of microscopy and RDT were 96.30, 100.00, 100.00, 92.89, 97.50, 0.963, and 95.06, 94.90, 97.47, 90.29, 95.01, and 0.899, respectively. Malaria RDT recorded higher false negativity, compared microscopy (4.94% vs. 3.70%). A near perfect agreement was reported between microscopy and nested PCR, and between PfHRP2 RDT and nested PCR with Cohen's kappa (k) values of 0.94 and 0.88, respectively. This study revealed that PfHRP2 RDT and microscopy continues to remain sensitive and specific for falciparum malaria diagnosis in the study area.
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Affiliation(s)
- Oluwaseun Bunmi Awosolu
- School of Biological Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia
- Vector Control Research Unit, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia
- Department of Biology, Federal University of Technology, Akure 340252, Nigeria
| | - Zary Shariman Yahaya
- School of Biological Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia
- Vector Control Research Unit, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia
| | | | - Titus Adeniyi Olusi
- Vector Control Research Unit, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia
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7
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Martiáñez-Vendrell X, Skjefte M, Sikka R, Gupta H. Factors Affecting the Performance of HRP2-Based Malaria Rapid Diagnostic Tests. Trop Med Infect Dis 2022; 7:tropicalmed7100265. [PMID: 36288006 PMCID: PMC9611031 DOI: 10.3390/tropicalmed7100265] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/14/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022] Open
Abstract
The recent COVID-19 pandemic has profoundly impacted global malaria elimination programs, resulting in a sharp increase in malaria morbidity and mortality. To reduce this impact, unmet needs in malaria diagnostics must be addressed while resuming malaria elimination activities. Rapid diagnostic tests (RDTs), the unsung hero in malaria diagnosis, work to eliminate the prevalence of Plasmodium falciparum malaria through their efficient, cost-effective, and user-friendly qualities in detecting the antigen HRP2 (histidine-rich protein 2), among other proteins. However, the testing mechanism and management of malaria with RDTs presents a variety of limitations. This paper discusses the numerous factors (including parasitic, host, and environmental) that limit the performance of RDTs. Additionally, the paper explores outside factors that can hinder RDT performance. By understanding these factors that affect the performance of HRP2-based RDTs in the field, researchers can work toward creating and implementing more effective and accurate HRP2-based diagnostic tools. Further research is required to understand the extent of these factors, as the rapidly changing interplay between parasite and host directly hinders the effectiveness of the tool.
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Affiliation(s)
- Xavier Martiáñez-Vendrell
- Molecular Virology Laboratory, Department of Medical Microbiology, LUMC Center for Infectious Diseases (LU-CID), Leiden University Medical Center, 2333 ZA Leiden, The Netherlands or
| | - Malia Skjefte
- Department of Global Health and Population, Harvard TH Chan School of Public Health, Boston, MA 02115, USA
| | - Ruhi Sikka
- Department of Biotechnology, Institute of Applied Sciences & Humanities, GLA University, Mathura 281406, UP, India
| | - Himanshu Gupta
- Department of Biotechnology, Institute of Applied Sciences & Humanities, GLA University, Mathura 281406, UP, India
- Correspondence: or
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8
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Leonard CM, Assefa A, McCaffery JN, Herman C, Plucinski M, Sime H, Mohammed H, Kebede A, Solomon H, Haile M, Murphy M, Hwang J, Rogier E. Investigation of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions and performance of a rapid diagnostic test for identifying asymptomatic malaria infection in northern Ethiopia, 2015. Malar J 2022; 21:70. [PMID: 35246151 PMCID: PMC8895513 DOI: 10.1186/s12936-022-04097-7] [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: 10/14/2021] [Accepted: 02/18/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rapid diagnostic tests (RDTs) are widely used for malaria diagnosis of both symptomatic and asymptomatic infections. Although RDTs are a reliable and practical diagnostic tool, the sensitivity of histidine-rich protein 2 (HRP2)-based RDTs can be reduced if pfhrp2 or pfhrp3 (pfhrp2/3) gene deletions exist in the Plasmodium falciparum parasite population. This study evaluated dried blood spot (DBS) samples collected from a national household survey to investigate the presence of pfhrp2/3 deletions and the performance of the RDT used in the cross-sectional survey in a low transmission setting. METHODS The 2015 Ethiopia Malaria Indicator Survey tested household members by RDT and collected DBS samples. DBS (n = 2648) from three regions in northern Ethiopia were tested by multiplex bead-based antigen detection assay after completion of the survey. The multiplex assay detected pan-Plasmodium lactate dehydrogenase (LDH), pAldolase, and HRP2 antigens in samples. Samples suspected for pfhrp2/3 gene deletions (pLDH and/or pAldolase positive but low or absent HRP2) were further investigated by molecular assays for gene deletions. Antigen results were also compared to each individual's RDT results. Dose-response logistic regression models were fit to estimate RDT level of detection (LOD) antigen concentrations at which 50, 75, 90, and 95% of the RDTs returned a positive result during this survey. RESULTS Out of 2,648 samples assayed, 29 were positive for pLDH or pAldolase antigens but low or absent for HRP2 signal, and 15 of these samples (51.7%) were successfully genotyped for pfhrp2/3. Of these 15 P. falciparum infections, eight showed single deletions in pfhrp3, one showed a single pfhrp2 deletion, and six were pfhrp2/3 double-deletions. Six pfhrp2 deletions were observed in Tigray and one in Amhara. Twenty-five were positive for HRP2 by the survey RDT while the more sensitive bead assay detected 30 HRP2-positive samples. A lower concentration of HRP2 antigen generated a positive test result by RDT compared to pLDH (95% LOD: 16.9 ng/mL vs. 319.2 ng/mL, respectively). CONCLUSIONS There is evidence of dual pfhrp2/3 gene deletions in the Tigray and Amhara regions of Ethiopia in 2015. As the prevalence of malaria was very low (< 2%), it is difficult to make strong conclusions on RDT performance, but these results challenge the utility of biomarkers in household surveys in very low transmission settings.
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Affiliation(s)
- Colleen M Leonard
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.,Oak Ridge Institute for Science and Education, US. Department of Energy, Oak Ridge, TN, 37831, USA
| | - Ashenafi Assefa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia.,Infectious Disease Ecology and Epidemiology Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Jessica N McCaffery
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.,Oak Ridge Institute for Science and Education, US. Department of Energy, Oak Ridge, TN, 37831, USA
| | - Camelia Herman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Mateusz Plucinski
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.,U.S. President's Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Heven Sime
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Amha Kebede
- African Society for Laboratory Medicine, Addis Ababa, Ethiopia
| | - Hiwot Solomon
- Ethiopian Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Matt Murphy
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.,U.S. President's Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Jimee Hwang
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.,U.S. President's Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Eric Rogier
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA.
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9
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Plasmodium falciparum histidine-rich protein 2 and 3 genes deletion in global settings (2010–2021): a systematic review and meta-analysis. Malar J 2022; 21:26. [PMID: 35093092 PMCID: PMC8800273 DOI: 10.1186/s12936-022-04051-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/17/2022] [Indexed: 01/10/2023] Open
Abstract
Background The usefulness of histidine-rich protein-2/3 (HRP2/3)-based rapid diagnostic tests of malaria due to Plasmodium falciparum has been threatened by the appearance of mutant PfHRP2/3 genes. This study was undertaken to determine the global pooled estimates of PfHRP2/3gene deletions. Methods Relevant publications were identified from electronic databases such as; PubMed, EMBASE, and MEDLINE online. Besides, all the relevant literatures were retrieved through Google and Google Scholar. STATA software was used for data analysis. The pooled estimates were calculated using random effect model. The summary estimates were presented using forest plots and tables. Results A total of 27 studies were included in the systematic review. However, only 24 and 17 studies were included for PfHRP2 and 3 gene deletion meta-analysis, respectively. The prevalence of PfHRP2 gene deletion across the individual studies ranged from the highest 100% to the lowest 0%. However, the meta-analysis result showed that the global pooled prevalence of PfHRP2 and PfHRP3 gene deletions were 21.30% and 34.50%, respectively. The pooled proportion of PfHRP2 gene deletion among false negative PfHRP2-based RDTs results was found to be 41.10%. The gene deletion status was higher in South America and followed by Africa. The pooled estimate of PfHRP2 gene deletion among studies, which did not follow the WHO PfHRP2/3 gene deletion analysis protocol was higher than their counter parts (21.3% vs 10.5%). Conclusions This review showed that there is a high pooled prevalence of PfHRP2/3 gene deletions in Plasmodium falciparum confirmed isolates and also a high proportion of their deletions among false-negative malaria cases using PfHRP2-based RDT results. Hence, malaria diagnosis based on PfHRP2-based rapid tests seems to be less sensitive and warrants further evaluation of PfHRP2/3 gene deletions.
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10
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Mwenda MC, Fola AA, Ciubotariu II, Mulube C, Mambwe B, Kasaro R, Hawela MB, Hamainza B, Miller JM, Carpi G, Bridges DJ. Performance evaluation of RDT, light microscopy, and PET-PCR for detecting Plasmodium falciparum malaria infections in the 2018 Zambia National Malaria Indicator Survey. Malar J 2021; 20:386. [PMID: 34583692 PMCID: PMC8477358 DOI: 10.1186/s12936-021-03917-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/14/2021] [Indexed: 11/29/2022] Open
Abstract
Background Zambia continues to advance on the path to elimination with significant reductions in malaria morbidity and mortality. Crucial components that have contributed to progress thus far and are necessary for achieving the national malaria elimination goals include properly identifying and treating all malaria cases through accurate diagnosis. This study sought to compare and assess the diagnostic performance of Rapid Diagnostic Tests (RDT) and Light Microscopy (LM) with photo-induced electron transfer polymerase chain reaction (PET-PCR) as the gold standard using 2018 Malaria Indicator Survey (MIS) data across Zambia to better understand diagnostic accuracy metrics and how these vary across a transmission gradient. Methods Cross-sectional samples collected in a nationally representative survey from 7 provinces in Zambia were tested for the presence of malaria parasites by light microscopy (LM), rapid diagnostic test (RDT) and the gold standard PET-PCR. Diagnostic performance was assessed including sensitivity, specificity, negative- and positive-predictive values across a wide malaria transmission spectrum. Diagnostic accuracy metrics were measured, and statistically significant differences were calculated between test methods for different outcome variables. Results From the individuals included in the MIS, the overall prevalence of Plasmodium falciparum malaria was 32.9% by RDT, 19.4% by LM, and 23.2% by PET-PCR. Herein, RDT and LM diagnostic performance was compared against gold standard PET-PCR with LM displaying a higher diagnostic accuracy than RDTs (91.3% vs. 84.6% respectively) across the transmission spectrum in Zambia. However, the performance of both diagnostics was significantly reduced in low parasitaemia samples. Consistent with previous studies, RDT diagnostic accuracy was predominantly affected by a high rate of false positives. Conclusions RDTs and LM both perform well across a range of transmission intensities within their respective target applications, i.e., in the community, for the former, where ease of use and speed of result is critical, and at the health facility, for the latter, where accuracy is prioritized. However, the performance of both diagnostic methods is adversely affected by low parasitaemia infections. As Zambia moves towards elimination more sensitive tools may be required to identify the last cases. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03917-6.
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Affiliation(s)
- Mulenga C Mwenda
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Abebe A Fola
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Conceptor Mulube
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Brenda Mambwe
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Rachael Kasaro
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Moonga B Hawela
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Busiku Hamainza
- National Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - John M Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia
| | - Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Indiana, USA
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia.
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11
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Molina-de la Fuente I, Pastor A, Herrador Z, Benito A, Berzosa P. Impact of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions on malaria control worldwide: a systematic review and meta-analysis. Malar J 2021; 20:276. [PMID: 34158065 PMCID: PMC8220794 DOI: 10.1186/s12936-021-03812-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022] Open
Abstract
Background Deletion of pfhrp2 and/or pfhrp3 genes cause false negatives in malaria rapid diagnostic test (RDT) and threating malaria control strategies. This systematic review aims to assess the main methodological aspects in the study of pfhrp2 and pfhrp3 gene deletions and its global epidemiological status, with special focus on their distribution in Africa; and its possible impact in RDT. Methods The systematic review was conducted by examining the principal issues of study design and methodological workflow of studies addressing pfhrp2 deletion. Meta-analysis was applied to represent reported prevalences of pfhrp2 and pfhrp3 single and double deletion in the World Health Organization (WHO) region. Pooled-prevalence of deletions was calculated using DerSimonnian-Laird random effect model. Then, in-deep analysis focused on Africa was performed to assess possible variables related with these deletions. Finally, the impact of these deletions in RDT results was analysed combining reported information about RDT sensitivity and deletion prevalences. Results 49 articles were included for the systematic review and 37 for the meta-analysis, 13 of them placed in Africa. Study design differs significantly, especially in terms of population sample and information reported, resulting in high heterogeneity between studies that difficulties comparisons and merged conclusions. Reported prevalences vary widely in all the WHO regions, significantly higher deletion were reported in South-Central America, following by Africa and Asia. Pfhrp3 deletion is more prevalent (43% in South-Central America; 3% in Africa; and 1% in Asia) than pfhrp2 deletion (18% in South-Central America; 4% in Africa; and 3% in Asia) worldwide. In Africa, there were not found differences in deletion prevalence by geographical or population origin of samples. The prevalence of deletion among false negatives ranged from 0 to 100% in Africa, but in Asia and South-Central America was only up to 90% and 48%, respectively, showing substantial relation between deletions and false negatives. Conclusion The concerning prevalence of pfhrp2, pfhrp3 and pfhrp2/3 gene deletions, as its possible implications in malaria control, highlights the importance of regular and systematic surveillance of these deletions. This review has also outlined that a standardized methodology could play a key role to ensure comparability between studies to get global conclusions. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03812-0.
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Affiliation(s)
- Irene Molina-de la Fuente
- Department of Biomedicine and Biotechnology, School of Pharmacy, University of Alcalá, Alcalá de Henares, Madrid, Spain. .,Malaria and Neglected Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, 28029, Madrid, Spain. .,Public Health and Epidemiology Research Group, School of Medicine, University of Alcalá, 28871, Alcalá de Henares, Madrid, Spain.
| | - Andrea Pastor
- Public Health and Epidemiology Research Group, School of Medicine, University of Alcalá, 28871, Alcalá de Henares, Madrid, Spain
| | - Zaida Herrador
- National Centre of Epidemiology, Institute of Health Carlos III, 28029, Madrid, Spain.,Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Agustín Benito
- Malaria and Neglected Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, 28029, Madrid, Spain.,Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Pedro Berzosa
- Malaria and Neglected Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, 28029, Madrid, Spain.,Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
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12
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Minakawa N, Kongere JO, Sonye GO, Lutiali PA, Awuor B, Kawada H, Isozumi R, Futami K. Long-Lasting Insecticidal Nets Incorporating Piperonyl Butoxide Reduce the Risk of Malaria in Children in Western Kenya: A Cluster Randomized Controlled Trial. Am J Trop Med Hyg 2021; 105:461-471. [PMID: 34125699 PMCID: PMC8437186 DOI: 10.4269/ajtmh.20-1069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 03/22/2021] [Indexed: 11/10/2022] Open
Abstract
Malaria vectors have acquired an enzyme that metabolizes pyrethroids. To tackle this problem, we evaluated long-lasting insecticidal nets incorporating piperonyl butoxide (PBO-LLINs) with a community-based cluster randomized control trial in western Kenya. The primary endpoints were anopheline density and Plasmodium falciparum polymerase chain reaction (PCR)-positive prevalence (PCRpfPR) of children aged 7 months to 10 years. Four clusters were randomly selected for each of the treatment and control arms (eight clusters in total) from 12 clusters, and PBO-LLINs and standard LLINs were distributed in February 2011 to 982 and 1,028 houses for treatment and control arms, respectively. Entomological surveys targeted 20 houses in each cluster, and epidemiological surveys targeted 150 children. Cluster-level permutation tests evaluated the effectiveness using the fitted values from individual level regression models adjusted for baseline. Bootstrapping estimated 95% confidence intervals (CIs). The medians of anophelines per house were 1.4 (interquartile range [IQR]: 2.3) and 3.4 (IQR: 3.7) in the intervention and control arms after 3 months, and 0.4 (IQR: 0.2) and 1.6 (IQR: 0.5) after 10 months, respectively. The differences were -2.5 (95% CI: -6.4 to -0.6) and -1.3 (95% CI: -2.0 to -0.7), respectively. The datasets of 861 and 775 children were analyzed in two epidemiological surveys. The median PCRpfPRs were 25% (IQR: 11%) in the intervention arm and 52% (IQR: 11%) in the control arm after 5 months and 33% (IQR: 11%) and 45% (IQR: 5%) after 12 months. The PCRpfPR ratios were 0.67 (95% CI: 0.38, 0.91) and 0.74 (95% CI: 0.53, 0.90), respectively. We confirmed the superiority of PBO-LLINs.
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Affiliation(s)
- Noboru Minakawa
- Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - James O. Kongere
- Kenya Medical Research Institute, Nairobi, Kenya
- Center for Research in Tropical Medicine and Community Development (CRTMCD), Nairobi, Kenya
| | | | - Peter A. Lutiali
- Kenya Medical Research Institute, Nairobi, Kenya
- Center for Research in Tropical Medicine and Community Development (CRTMCD), Nairobi, Kenya
| | | | - Hitoshi Kawada
- Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Rie Isozumi
- Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Kyoko Futami
- Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
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13
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Peterson I, Kapito-Tembo A, Bauleni A, Nyirenda O, Pensulo P, Still W, Valim C, Cohee L, Taylor T, Mathanga DP, Laufer MK. Overdiagnosis of Malaria Illness in an Endemic Setting: A Facility-Based Surveillance Study in Malawi. Am J Trop Med Hyg 2021; 104:2123-2130. [PMID: 33939628 PMCID: PMC8176516 DOI: 10.4269/ajtmh.20-1209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 03/03/2021] [Indexed: 11/07/2022] Open
Abstract
In endemic settings where asymptomatic malaria infections are common, malaria infection can complicate fever diagnosis. Factors influencing fever misdiagnosis, including accuracy of malaria rapid diagnostic tests (mRDTs) and the malaria-attributable fraction of fevers (MAF), require further investigation. We conducted facility-based surveillance in Malawi, from January 2012 through December 2013 in settings of high perennial (Chikhwawa), high seasonal (Thoylo), and moderate seasonal (Ndirande) malaria transmission. Consecutive patients presenting to outpatient departments were screened; those with suspected malaria illness were tested by mRDT or routine thick-smear microscopy. Test positivity rates (TPRs), positive predictive value (PPVs) of mRDTs, and MAFs were calculated by site, age, and season. Of 41,471 patients, 10,052 (24.2%) tested positive for malaria. The TPR was significantly greater in Chikhwawa (29.9%; 95% CI, 28.6-30.0) compared with Thyolo (13.2%; 95% CI, 12.5-13.7) and Ndirande (13.1%; 95% CI, 12.2-14.4). The overall PPV was 77.8% (95% CI, 76.8-78.7); it was lowest among infants (69.9%; 95% CI, 65.5-74.2) and highest among school-age children (81.9%; 95% CI, 80.3-83.4). Malaria infection accounted for about 50% of fevers in children younger than 5 years old with microscopy-confirmed Plasmodium falciparum infection, and less than 20% of such fevers in school-age children. Outpatient settings in Malawi had a high burden of malaria illness, but also possible overdiagnosis of malaria illness. Interventions to reduce malaria transmission and rapid testing for other common febrile illness may improve diagnostic clarity among outpatients in malaria endemic settings.
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Affiliation(s)
- Ingrid Peterson
- Center for Vaccine Development and Global Health, University of Maryland Baltimore, Baltimore, Maryland
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Atupele Kapito-Tembo
- Malaria Alert Center, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Andrew Bauleni
- Malaria Alert Center, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Osward Nyirenda
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Paul Pensulo
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
| | - William Still
- Center for Vaccine Development and Global Health, University of Maryland Baltimore, Baltimore, Maryland
| | - Clarissa Valim
- Department of Global Health, Boston University School of Public Health, Boston, Massachusetts
| | - Lauren Cohee
- Center for Vaccine Development and Global Health, University of Maryland Baltimore, Baltimore, Maryland
| | - Terrie Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Don P. Mathanga
- Malaria Alert Center, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Miriam K. Laufer
- Center for Vaccine Development and Global Health, University of Maryland Baltimore, Baltimore, Maryland
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14
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Malaria Rapid Diagnostic Tests: Literary Review and Recommendation for a Quality Assurance, Quality Control Algorithm. Diagnostics (Basel) 2021; 11:diagnostics11050768. [PMID: 33922917 PMCID: PMC8145891 DOI: 10.3390/diagnostics11050768] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 01/24/2023] Open
Abstract
Malaria rapid diagnostic tests (RDTs) have had an enormous global impact which contributed to the World Health Organization paradigm shift from empiric treatment to obtaining a parasitological diagnosis prior to treatment. Microscopy, the classic standard, requires significant expertise, equipment, electricity, and reagents. Alternatively, RDT’s lower complexity allows utilization in austere environments while achieving similar sensitivities and specificities. Worldwide, there are over 200 different RDT brands that utilize three antigens: Plasmodium histidine-rich protein 2 (PfHRP-2), Plasmodium lactate dehydrogenase (pLDH), and Plasmodium aldolase (pALDO). pfHRP-2 is produced exclusively by Plasmodium falciparum and is very Pf sensitive, but an alternative antigen or antigen combination is required for regions like Asia with significant Plasmodium vivax prevalence. RDT sensitivity also decreases with low parasitemia (<100 parasites/uL), genetic variability, and prozone effect. Thus, proper RDT selection and understanding of test limitations are essential. The Center for Disease Control recommends confirming RDT results by microscopy, but this is challenging, due to the utilization of clinical laboratory standards, like the College of American Pathologists (CAP) and the Clinical Lab Improvement Act (CLIA), and limited recourses. Our focus is to provide quality assurance and quality control strategies for resource-constrained environments and provide education on RDT limitations.
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15
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High Prevalence of Low-Level Parasitemia With Plasmodium vivax in Makira-Ulawa Province Presents a Challenge for the Diagnosis and Eradication of Malaria in Solomon Islands. Ochsner J 2021; 21:76-80. [PMID: 33828428 PMCID: PMC7993419 DOI: 10.31486/toj.20.0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background: Malaria remains endemic in Solomon Islands, but data on malaria in the provinces of Solomon Islands are limited. This study from Makira-Ulawa Province aimed to identify the most prevalent strain of malaria and assess if the available rapid diagnostic test (RDT) was effective in Kirakira Hospital. Methods: Forty-five patients who presented to Kirakira Hospital with symptoms of fever had a positive malaria parasite smear during a 4-week period in 2017. The parasite count for each smear was calculated. Simultaneous testing using the CareStart Malaria HRP2/pLDH (Pf/pan) Combo RDT was conducted. The data for all malaria parasite smears performed in Makira-Ulawa Province in 2016 were collated for comparison. Results: All 45 patients diagnosed with malaria in a 4-week period in 2017 were positive for Plasmodium vivax. The median parasite load was 280 parasites per μL (range, 160 to 640 parasites per μL). None of the 45 CareStart RDTs performed was positive. In 2016, 5,505 of 17,195 patients (32.0%) screened had malaria parasites detected on a malaria parasite smear. P vivax was detected in 5,212 (94.7%) and Plasmodium falciparum in 285 (5.2%) of patients with malaria. Conclusion:P vivax is the predominant strain of malaria present in Makira-Ulawa Province. RDTs were not helpful in the diagnosis of malaria at Kirakira Hospital. The parasite load detected in the 45 patients diagnosed with malaria in this study was low. A focus on attempting to eradicate P vivax in the community through improved compliance with treatment protocols is suggested as a possible way forward to best manage malaria in Makira-Ulawa Province.
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16
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Hsiang MS, Ntshalintshali N, Kang Dufour MS, Dlamini N, Nhlabathi N, Vilakati S, Malambe C, Zulu Z, Maphalala G, Novotny J, Murphy M, Schwartz A, Sturrock H, Gosling R, Dorsey G, Kunene S, Greenhouse B. Active Case Finding for Malaria: A 3-Year National Evaluation of Optimal Approaches to Detect Infections and Hotspots Through Reactive Case Detection in the Low-transmission Setting of Eswatini. Clin Infect Dis 2021; 70:1316-1325. [PMID: 31095677 PMCID: PMC7318780 DOI: 10.1093/cid/ciz403] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 05/15/2019] [Indexed: 11/15/2022] Open
Abstract
Background Reactive case detection (RACD) is a widely practiced malaria elimination intervention whereby close contacts of index cases receive malaria testing to inform treatment and other interventions. However, the optimal diagnostic and operational approaches for this resource-intensive strategy are not clear. Methods We conducted a 3-year prospective national evaluation of RACD in Eswatini, a malaria elimination setting. Loop-mediated isothermal amplification (LAMP) was compared to traditional rapid diagnostic testing (RDT) for the improved detection of infections and for hotspots (RACD events yielding ≥1 additional infection). The potential for index case–, RACD-, and individual-level factors to improve efficiencies was also evaluated. Results Among 377 RACD events, 10 890 participants residing within 500 m of index cases were tested. Compared to RDT, LAMP provided a 3-fold and 2.3-fold higher yield to detect infections (1.7% vs 0.6%) and hotspots (29.7% vs 12.7%), respectively. Hotspot detection improved with ≥80% target population coverage and response times within 7 days. Proximity to the index case was associated with a dose-dependent increased infection risk (up to 4-fold). Individual-, index case–, and other RACD-level factors were considered but the simple approach of restricting RACD to a 200-m radius maximized yield and efficiency. Conclusions We present the first large-scale national evaluation of optimal RACD approaches from a malaria elimination setting. To inform delivery of antimalarial drugs or other interventions, RACD, when conducted, should utilize more sensitive diagnostics and clear context-specific operational parameters. Future studies of RACD’s impact on transmission may still be needed.
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Affiliation(s)
- Michelle S Hsiang
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas.,Malaria Elimination Initiative, Global Health Group.,Department of Pediatrics, University of California, San Francisco (UCSF)
| | | | | | | | | | | | | | | | | | - Joseph Novotny
- Clinton Health Access Initiative, Eswatini Office, Mbabane
| | - Maxwell Murphy
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
| | - Alanna Schwartz
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
| | | | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group
| | - Grant Dorsey
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
| | | | - Bryan Greenhouse
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
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17
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Dalimi A, Mosawi SH. The Comparison of Real-time-PCR-HRM and Microscopy Methods for Detection of Mixed Plasmodium spp. Infections in Laghman Province, Afghanistan. Infect Disord Drug Targets 2021; 21:399-404. [PMID: 32614757 DOI: 10.2174/1871526520666200702134555] [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: 03/07/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Laghman province, in the east of Afghanistan, is one of the most malaria endemic regions with prominence of Plasmodium vivax and Plasmodium falciparum. So far, no study has been conducted to investigate the extent of mixed infections in this area. OBJECTIVE In this study, we aimed to evaluate the prevalence of mixed infections of malaria in Laghman province by using a new and highly sensitive molecular method (real-time polymerase chain reaction high resolution melting analysis) and compare its results with microscopically confirmed cases of malaria. METHODS In general, 347 infected individuals have been referred to Khalwati laboratory that is located in the center of Laghman province from May to November of 2018. Microscopic analysis was performed on prepared thick and thin blood films under ×100 lens with oil immersion. The real- time-PCR-HRM assay was performed using an ABI 7500 Fast Real-time PCR system. RESULTS In a microscopic examination, out of 347 patients referred to the Center, 267 (76.94%) cases were detected to be Plasmodium vivax, 79 (22.76%) Plasmodium falciparum and 1 (0.28%) case of mixed of two species. However, by using Real-time PCR-HRM technique, 249 (71.75%) were detected Plasmodium vivax, 79 (22.76%) were Plasmodium falciparum and 19 (5.47%) were mixed of two species. CONCLUSION Our result indicated that the Real-time PCR-HRM method is more accurate and more reliable than microscopic method in the diagnosis of malaria mixed infections.
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Affiliation(s)
- Abdolhossein Dalimi
- Department of Medical Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Sayed Hussain Mosawi
- Department of Medical Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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18
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Conner RO, Dieye Y, Hainsworth M, Tall A, Cissé B, Faye F, Sy MD, Ba A, Sene D, Ba S, Doucouré E, Thiam T, Diop M, Schneider K, Cissé M, Ba M, Earle D, Guinot P, Steketee RW, Guinovart C. Mass testing and treatment for malaria followed by weekly fever screening, testing and treatment in Northern Senegal: feasibility, cost and impact. Malar J 2020; 19:252. [PMID: 32664939 PMCID: PMC7362450 DOI: 10.1186/s12936-020-03313-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 07/04/2020] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Population-wide interventions using malaria testing and treatment might decrease the reservoir of Plasmodium falciparum infection and accelerate towards elimination. Questions remain about their effectiveness and evidence from different transmission settings is needed.
Methods
A pilot quasi-experimental study to evaluate a package of population-wide test and treat interventions was conducted in six health facility catchment areas (HFCA) in the districts of Kanel, Linguère, and Ranérou (Senegal). Seven adjacent HFCAs were selected as comparison. Villages within the intervention HFCAs were stratified according to the 2013 incidences of passively detected malaria cases, and those with an incidence ≥ 15 cases/1000/year were targeted for a mass test and treat (MTAT) in September 2014. All households were visited, all consenting individuals were tested with a rapid diagnostic test (RDT), and, if positive, treated with dihydroartemisinin-piperaquine. This was followed by weekly screening, testing and treatment of fever cases (PECADOM++) until the end of the transmission season in January 2015. Villages with lower incidence received only PECADOM++ or case investigation. To evaluate the impact of the interventions over that transmission season, the incidence of passively detected, RDT-confirmed malaria cases was compared between the intervention and comparison groups with a difference-in-difference analysis using negative binomial regression with random effects on HFCA.
Results
During MTAT, 89% (2225/2503) of households were visited and 86% (18,992/22,170) of individuals were tested, for a combined 77% effective coverage. Among those tested, 291 (1.5%) were RDT positive (range 0–10.8 by village), of whom 82% were < 20 years old and 70% were afebrile. During the PECADOM++ 40,002 visits were conducted to find 2784 individuals reporting fever, with an RDT positivity of 6.5% (170/2612). The combination of interventions resulted in an estimated 38% larger decrease in malaria case incidence in the intervention compared to the comparison group (adjusted incidence risk ratio = 0.62, 95% CI 0.45–0.84, p = 0.002). The cost of the MTAT was $14.3 per person.
Conclusions
It was operationally feasible to conduct MTAT and PECADOM++ with high coverage, although PECADOM++ was not an efficient strategy to complement MTAT. The modest impact of the intervention package suggests a need for alternative or complementary strategies.
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19
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Morang'a CM, Amenga-Etego L, Bah SY, Appiah V, Amuzu DSY, Amoako N, Abugri J, Oduro AR, Cunnington AJ, Awandare GA, Otto TD. Machine learning approaches classify clinical malaria outcomes based on haematological parameters. BMC Med 2020; 18:375. [PMID: 33250058 PMCID: PMC7702702 DOI: 10.1186/s12916-020-01823-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/22/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Malaria is still a major global health burden, with more than 3.2 billion people in 91 countries remaining at risk of the disease. Accurately distinguishing malaria from other diseases, especially uncomplicated malaria (UM) from non-malarial infections (nMI), remains a challenge. Furthermore, the success of rapid diagnostic tests (RDTs) is threatened by Pfhrp2/3 deletions and decreased sensitivity at low parasitaemia. Analysis of haematological indices can be used to support the identification of possible malaria cases for further diagnosis, especially in travellers returning from endemic areas. As a new application for precision medicine, we aimed to evaluate machine learning (ML) approaches that can accurately classify nMI, UM, and severe malaria (SM) using haematological parameters. METHODS We obtained haematological data from 2,207 participants collected in Ghana: nMI (n = 978), SM (n = 526), and UM (n = 703). Six different ML approaches were tested, to select the best approach. An artificial neural network (ANN) with three hidden layers was used for multi-classification of UM, SM, and uMI. Binary classifiers were developed to further identify the parameters that can distinguish UM or SM from nMI. Local interpretable model-agnostic explanations (LIME) were used to explain the binary classifiers. RESULTS The multi-classification model had greater than 85% training and testing accuracy to distinguish clinical malaria from nMI. To distinguish UM from nMI, our approach identified platelet counts, red blood cell (RBC) counts, lymphocyte counts, and percentages as the top classifiers of UM with 0.801 test accuracy (AUC = 0.866 and F1 score = 0.747). To distinguish SM from nMI, the classifier had a test accuracy of 0.96 (AUC = 0.983 and F1 score = 0.944) with mean platelet volume and mean cell volume being the unique classifiers of SM. Random forest was used to confirm the classifications, and it showed that platelet and RBC counts were the major classifiers of UM, regardless of possible confounders such as patient age and sampling location. CONCLUSION The study provides proof of concept methods that classify UM and SM from nMI, showing that the ML approach is a feasible tool for clinical decision support. In the future, ML approaches could be incorporated into clinical decision-support algorithms for the diagnosis of acute febrile illness and monitoring response to acute SM treatment particularly in endemic settings.
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Affiliation(s)
- Collins M Morang'a
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Lucas Amenga-Etego
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana.
| | - Saikou Y Bah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana.,Florey Institute, Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Vincent Appiah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Dominic S Y Amuzu
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Nicholas Amoako
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - James Abugri
- Department of Applied Chemistry and Biochemistry, C. K Tedam University of Technology and Applied Sciences, Navrongo, Ghana
| | - Abraham R Oduro
- Ministry of Health, Navrongo Health Research Centre (NHRC), Navrongo, Ghana
| | - Aubrey J Cunnington
- Section of Pediatric Infectious Disease, Department of Infectious Disease, Imperial College London, London, UK
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Thomas D Otto
- Institute of Infection, Immunity & Inflammation, MVLS, University of Glasgow, Glasgow, UK.
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20
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Daniels RF, Schaffner SF, Bennett A, Porter TR, Yukich JO, Mulube C, Mambwe B, Mwenda MC, Chishimba S, Bridges DJ, Moonga H, Hamainza B, Chizema Kawesha E, Miller JM, Steketee RW, Wirth DF, Eisele TP, Hartl DL, Volkman SK. Evidence for Reduced Malaria Parasite Population after Application of Population-Level Antimalarial Drug Strategies in Southern Province, Zambia. Am J Trop Med Hyg 2020; 103:66-73. [PMID: 32618255 PMCID: PMC7416975 DOI: 10.4269/ajtmh.19-0666] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A mass drug administration trial was carried out in Southern Province, Zambia, between 2014 and 2016, in conjunction with a standard of care package that included improved surveillance, increased access to malaria case management, and sustained high levels of vector control coverage. This was preceded by mass test and treatment in the same area from 2011 to 2013. Concordant decreases in malaria prevalence in Southern Province and deaths attributed to malaria in Zambia over this time suggest that these strategies successfully reduced the malaria burden. Genetic epidemiological studies were used to assess the consequences of these interventions on parasite population structure. Analysis of parasite material derived from 1,620 rapid diagnostic test (RDT)-positive individuals obtained from studies to evaluate trial outcomes revealed a reduction in the average complexity of infection and consequential increase in the proportion of infections that harbored a single parasite genome (monogenomic infections). Highly related parasites, consistent with inbreeding, were detected after interventions were deployed. Geographical analysis indicated that the highly related infections were both clustered focally and dispersed across the study area. These findings provide genetic evidence for a reduced parasite population, with indications of inbreeding following the application of comprehensive interventions, including drug-based campaigns, that reduced the malaria burden in Southern Province. Genetic data additionally revealed the relationship between individual infections in the context of these population-level patterns, which has the potential to provide useful data for stratification and targeting of interventions to reduce the malaria burden.
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Affiliation(s)
- Rachel F Daniels
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Stephen F Schaffner
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California
| | - Travis R Porter
- Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Joshua O Yukich
- Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Conceptor Mulube
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), Lusaka, Zambia
| | - Brenda Mambwe
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), Lusaka, Zambia
| | - Mulenga C Mwenda
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), Lusaka, Zambia
| | - Sandra Chishimba
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), Lusaka, Zambia
| | - Daniel J Bridges
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), Lusaka, Zambia
| | - Hawela Moonga
- National Malaria Elimination Centre, Zambia Ministry of Health, Lusaka, Zambia
| | - Busiku Hamainza
- National Malaria Elimination Centre, Zambia Ministry of Health, Lusaka, Zambia
| | | | - John M Miller
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), Lusaka, Zambia
| | | | - Dyann F Wirth
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Thomas P Eisele
- Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Daniel L Hartl
- Harvard University, Cambridge, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Sarah K Volkman
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,Simmons University, Boston, Massachusetts
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21
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Du YQ, Ling XX, Jin JJ, Zhou HY, Zhu S, Zhu GD, Wang W, Cao J, Huang JY. Cost-effectiveness analysis of malaria rapid diagnostic test in the elimination setting. Infect Dis Poverty 2020; 9:135. [PMID: 32993762 PMCID: PMC7523355 DOI: 10.1186/s40249-020-00745-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/20/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND As more and more countries approaching the goal of malaria elimination, malaria rapid diagnostic tests (RDT) was recomendated to be a diagnostic strategy to achieve and maintain the statute of malaria free, as it's less requirments on equipment and experitise than microscopic examination. But there are very few economic evaluations to confirm whether RDT was cost-effective in the setting of malaria elimination. This research aimed to offer evidence for helping decision making on malaria diagnosis strategy. METHODS A cost-effectiveness analysis was conducted to compare RDT with microscopy examination for malaria diagnosis, by using a decision tree model. There were three strategies of malaria diagnostic testing evaluated in the model, 1) microscopy, 2) RDT, 3) RDT followed by microscopy. The effect indicator was defined as the number of malaria cases treated appropriately. Based on the joint perspective of health sector and patient, costs data were collected from hospital information systems, key informant interviews, and patient surveys. Data collection was conducted in Jiangsu from September 2018 to January 2019. Epidemiological data were obtained from local malaria surveillance reports. A hypothetical cohort of 300 000 febrile patients were simulated to calculate the total cost and effect of each strategy. One-way, two-way, and probabilistic sensitivity analysis were performed to test the robustness of the result. RESULTS The results showed that RDT strategy was the most effective (245 cases) but also the most costly (United States Dollar [USD] 4.47 million) compared to using microscopy alone (238 cases, USD 3.63 million), and RDT followed by microscopy (221 cases, USD 2.75 million). There was no strategy dominated. One-way sensitivity analysis reflected that the result was sensitive to the change in labor cost and two-way sensitivity analysis indicated that the result was not sensitive to the proportion of falciparum malaria. The result of Monte Carlo simulation showed that RDT strategy had higher effects and higher cost than other strategies with a high probability. CONCLUSIONS Compared to microscopy and RDT followed by microscopy, RDT strategy had higher effects and higher cost in the setting of malaria elimination.
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Affiliation(s)
- Yan-Qiu Du
- Key Lab of Health Technology Assessment, National Health Commission, School of Public Health, Fudan University, Shanghai, 200433, China
| | - Xiao-Xiao Ling
- Department of Statistical Science, University College London, WC1E 6BT, London, UK
| | - Jia-Jie Jin
- Key Lab of Health Technology Assessment, National Health Commission, School of Public Health, Fudan University, Shanghai, 200433, China
| | - Hua-Yun Zhou
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory of Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Si Zhu
- Key Lab of Health Technology Assessment, National Health Commission, School of Public Health, Fudan University, Shanghai, 200433, China
| | - Guo-Ding Zhu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory of Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China.,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China.,Public Health Research Center, Jiangnan University, Wuxi, 214122, China
| | - Wei Wang
- Key Lab of Health Technology Assessment, National Health Commission, School of Public Health, Fudan University, Shanghai, 200433, China
| | - Jun Cao
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory of Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China. .,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China. .,Public Health Research Center, Jiangnan University, Wuxi, 214122, China.
| | - Jia-Yan Huang
- Key Lab of Health Technology Assessment, National Health Commission, School of Public Health, Fudan University, Shanghai, 200433, China.
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22
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Hartley MA, Hofmann N, Keitel K, Kagoro F, Antunes Moniz C, Mlaganile T, Samaka J, Masimba J, Said Z, Temba H, Gonzalez I, Felger I, Genton B, D’Acremont V. Clinical relevance of low-density Plasmodium falciparum parasitemia in untreated febrile children: A cohort study. PLoS Med 2020; 17:e1003318. [PMID: 32956354 PMCID: PMC7505590 DOI: 10.1371/journal.pmed.1003318] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 08/13/2020] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Low-density (LD) Plasmodium infections are missed by standard malaria rapid diagnostic tests (standard mRDT) when the blood antigen concentration is below the detection threshold. The clinical impact of these LD infections is unknown. This study investigates the clinical presentation and outcome of untreated febrile children with LD infections attending primary care facilities in a moderately endemic area of Tanzania. METHODS/FINDINGS This cohort study includes 2,801 febrile pediatric outpatients (median age 13.5 months [range 2-59], female:male ratio 0.8:1.0) recruited in Dar es Salaam, Tanzania between 01 December 2014 and 28 February 2016. Treatment decisions were guided by a clinical decision support algorithm run on a mobile app, which also collected clinical data. Only standard mRDT+ cases received antimalarials. Outcomes (clinical failure, secondary hospitalization, and death) were collected in follow-up visits or interviews on days 3, 7, and 28. After patient recruitment had ended, frozen blood from all 2,801 patients was tested for Plasmodium falciparum (Pf) by ultrasensitive-quantitative polymerase chain reaction (qPCR), standard mRDT, and "ultrasensitive" mRDT. As the latter did not improve sensitivity beyond standard mRDT, it is hereafter excluded. Clinical features and outcomes in LD patients (standard mRDT-/ultrasensitive-qPCR+, not given antimalarials) were compared with those with no detectable (ND) parasitemia (standard mRDT-/ultrasensitive-qPCR-) or high-density (HD) infections (standard mRDT+/ultrasensitive-qPCR+, antimalarial-treated). Pf positivity rate was 7.1% (n = 199/2,801) and 9.8% (n = 274/2,801) by standard mRDT and ultrasensitive qPCR, respectively. Thus, 28.0% (n = 76/274) of ultrasensitive qPCR+ cases were not detected by standard mRDT and labeled "LD". LD patients were, on average, 10.6 months younger than those with HD infections (95% CI 7.0-14.3 months, p < 0.001). Compared with ND, LD patients more frequently had the diagnosis of undifferentiated fever of presumed viral origin (risk ratio [RR] = 2.0, 95% CI 1.3-3.1, p = 0.003) and were more often suffering from severe malnutrition (RR = 3.2, 95% CI 1.1-7.5, p = 0.03). Despite not receiving antimalarials, outcomes for the LD group did not differ from ND regarding clinical failures (2.6% [n = 2/76] versus 4.0% [n = 101/2,527], RR = 0.7, 95% CI 0.2-3.5, p = 0.7) or secondary hospitalizations (2.6% [n = 2/76] versus 2.8% [n = 72/2,527], RR = 0.7,95% CI 0.2-3.2, p = 0.9), and no deaths were reported in any Pf-positive groups. HD patients experienced more secondary hospitalizations (10.1% [n = 20/198], RR = 0.3, 95% CI 0.1-1.0, p = 0.005) than LD patients. All the patients in this cohort were febrile children; thus, the association between parasitemia and fever cannot be investigated, nor can the conclusions be extrapolated to neonates and adults. CONCLUSIONS During a 28-day follow-up period, we did not find evidence of a difference in negative outcomes between febrile children with untreated LD Pf parasitemia and those without Pf parasitemia. These findings suggest LD parasitemia may either be a self-resolving fever or an incidental finding in children with other infections, including those of viral origin. These findings do not support a clinical benefit nor additional risk (e.g. because of missed bacterial infections) to using ultrasensitive malaria diagnostics at a primary care level.
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Affiliation(s)
- Mary-Anne Hartley
- Centre for Primary Care and Public Health, University of Lausanne, Lausanne Switzerland
- EPFL, Machine Learning and Optimization Laboratory, Lausanne, Switzerland
| | - Natalie Hofmann
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Kristina Keitel
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Frank Kagoro
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Clara Antunes Moniz
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Tarsis Mlaganile
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Josephine Samaka
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
- Amana hospital, Dar es Salaam, United Republic of Tanzania
| | - John Masimba
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Zamzam Said
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Hosiana Temba
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Iveth Gonzalez
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Blaise Genton
- Centre for Primary Care and Public Health, University of Lausanne, Lausanne Switzerland
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Valérie D’Acremont
- Centre for Primary Care and Public Health, University of Lausanne, Lausanne Switzerland
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
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23
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Opuni KFM, Koy C, Russ M, Reepmeyer M, Danquah BD, Weresow M, Alef A, Lorenz P, Thiesen HJ, Glocker MO. ITEM-THREE analysis of a monoclonal anti-malaria antibody reveals its assembled epitope on the pfMSP1 19 antigen. J Biol Chem 2020; 295:14987-14997. [PMID: 32848020 DOI: 10.1074/jbc.ra120.014802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/18/2020] [Indexed: 11/06/2022] Open
Abstract
Rapid diagnostic tests are first-line assays for diagnosing infectious diseases, such as malaria. To minimize false positive and false negative test results in population-screening assays, high-quality reagents and well-characterized antigens and antibodies are needed. An important property of antigen-antibody binding is recognition specificity, which best can be estimated by mapping an antibody's epitope on the respective antigen. We have cloned a malarial antigen-containing fusion protein, MBP-pfMSP119, in Escherichia coli, which then was structurally and functionally characterized before and after high pressure-assisted enzymatic digestion. We then used our previously developed method, intact transition epitope mapping-targeted high-energy rupture of extracted epitopes (ITEM-THREE), to map the area on the MBP-pfMSP119 antigen surface that is recognized by the anti-pfMSP119 antibody G17.12. We identified three epitope-carrying peptides, 386GRNISQHQCVKKQCPQNSGCFRHLDE411, 386GRNISQHQCVKKQCPQNSGCFRHLDEREE414, and 415CKCLLNYKQE424, from the GluC-derived peptide mixture. These peptides belong to an assembled (conformational) epitope on the MBP-pfMSP119 antigen whose identification was substantiated by positive and negative control experiments. In conclusion, our data help to establish a workflow to obtain high-quality control data for diagnostic assays, including the use of ITEM-THREE as a powerful analytical tool. Data are available via ProteomeXchange: PXD019717.
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Affiliation(s)
- Kwabena F M Opuni
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany; Department of Pharmaceutical Chemistry, School of Pharmacy, College of Health, University of Ghana, Legon, Ghana
| | - Cornelia Koy
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | - Manuela Russ
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | - Maren Reepmeyer
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | - Bright D Danquah
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany
| | | | | | - Peter Lorenz
- Institute for Immunology, University Medicine Rostock, Rostock, Germany
| | | | - Michael O Glocker
- Proteome Center Rostock, University Medicine Rostock and University of Rostock, Rostock, Germany.
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24
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Pickens C, Wunderink RG, Qi C, Mopuru H, Donnelly H, Powell K, Sims MD. A multiplex polymerase chain reaction assay for antibiotic stewardship in suspected pneumonia. Diagn Microbiol Infect Dis 2020; 98:115179. [PMID: 32927409 PMCID: PMC7428672 DOI: 10.1016/j.diagmicrobio.2020.115179] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 02/06/2023]
Abstract
Background Multiplexed molecular rapid diagnostic tests (RDTs) may allow for rapid and accurate diagnosis of the microbial etiology of pneumonia. However, little data are available on multiplexed RDTs in pneumonia and their impact on clinical practice. Methods This retrospective study analyzed 659 hospitalized patients for microbiological diagnosis of suspected pneumonia. Results The overall sensitivity of the Unyvero LRT Panel was 85.7% (95% CI 82.3–88.7) and the overall specificity was 98.4% (95% CI 98.2–98.7) with a negative predictive value of 97.9% (95% CI 97.6–98.1). The LRT Panel result predicted no change in antibiotics in 12.4% of cases but antibiotic de-escalation in 65.9% (405/615) of patients, of whom 278/405 (69%) had unnecessary MRSA coverage and 259/405 (64%) had unnecessary P. aeruginosa coverage. Interpretation In hospitalized adults with suspected pneumonia, use of an RDT on respiratory samples can allow for early adjustment of initial antibiotics, most commonly de-escalation.
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Affiliation(s)
- Chiagozie Pickens
- Northwestern University Feinberg School of Medicine, Department of Medicine, Pulmonary and Critical Care Division, Chicago, IL.
| | - Richard G Wunderink
- Northwestern University Feinberg School of Medicine, Department of Medicine, Pulmonary and Critical Care Division, Chicago, IL
| | - Chao Qi
- Northwestern University Feinberg School of Medicine, Department of Pathology, Chicago, IL
| | - Haritha Mopuru
- Beaumont Hospital, Royal Oak, Section of Infectious Diseases and International Medicine, Royal Oak, MI
| | - Helen Donnelly
- Northwestern University Feinberg School of Medicine, Department of Medicine, Pulmonary and Critical Care Division, Chicago, IL
| | - Kimberly Powell
- Beaumont Hospital, Royal Oak, Section of Infectious Diseases and International Medicine, Royal Oak, MI
| | - Matthew D Sims
- Beaumont Hospital, Royal Oak, Section of Infectious Diseases and International Medicine, Royal Oak, MI; Oakland University William Beaumont School of Medicine, Department of Internal Medicine, Rochester, MI
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25
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Jang IK, Tyler A, Lyman C, Rek JC, Arinaitwe E, Adrama H, Murphy M, Imwong M, Proux S, Haohankhunnatham W, Barney R, Rashid A, Kalnoky M, Kahn M, Golden A, Nosten F, Greenhouse B, Gamboa D, Domingo GJ. Multiplex Human Malaria Array: Quantifying Antigens for Malaria Rapid Diagnostics. Am J Trop Med Hyg 2020; 102:1366-1369. [PMID: 32189616 PMCID: PMC7253106 DOI: 10.4269/ajtmh.19-0763] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Malaria antigen detection through rapid diagnostic tests (RDTs) is widely used to diagnose malaria and estimate prevalence. To support more sensitive next-generation RDT development and screen asymptomatic malaria, we developed and evaluated the Q-Plex™ Human Malaria Array (Quansys Biosciences, Logan, UT), which quantifies the antigens commonly used in RDTs—Plasmodium falciparum–specific histidine-rich protein 2 (HRP2), P. falciparum-specific lactate dehydrogenase (Pf LDH), Plasmodium vivax–specific LDH (Pv LDH), and Pan malaria lactate dehydrogenase (Pan LDH), and human C-reactive protein (CRP), a biomarker of severity in malaria. At threshold levels yielding 99.5% or more diagnostic specificity, diagnostic sensitivities against polymerase chain reaction–confirmed malaria for HRP2, Pf LDH, Pv LDH, and Pan LDH were 92.7%, 71.5%, 46.1%, and 83.8%, respectively. P. falciparum culture strains and samples from Peru indicated that HRP2 and Pf LDH combined improves detection of P. falciparum parasites with hrp2 and hrp3 deletions. This array can be used for antigen-based malaria screening and detecting hrp2/3 deletion mutants of P. falciparum.
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Affiliation(s)
| | | | | | - John C Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Harriet Adrama
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Maxwell Murphy
- Department of Medicine, University of California at San Francisco, San Francisco, California
| | - Mallika Imwong
- Faculty of Tropical Medicine, Department of Molecular Tropical Medicine and Genetics, Mahidol University, Bangkok, Thailand
| | - Stephane Proux
- Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Shoklo Malaria Research Unit, Mahidol University, Mae Sot, Thailand
| | - Warat Haohankhunnatham
- Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Shoklo Malaria Research Unit, Mahidol University, Mae Sot, Thailand
| | | | | | | | | | | | - François Nosten
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom.,Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Shoklo Malaria Research Unit, Mahidol University, Mae Sot, Thailand
| | - Bryan Greenhouse
- Department of Medicine, University of California at San Francisco, San Francisco, California
| | - Dionicia Gamboa
- Department of Cellular and Molecular Sciences, Institute of Tropical Medicine Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
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Thomson R, Parr JB, Cheng Q, Chenet S, Perkins M, Cunningham J. Prevalence of Plasmodium falciparum lacking histidine-rich proteins 2 and 3: a systematic review. Bull World Health Organ 2020; 98:558-568F. [PMID: 32773901 PMCID: PMC7411324 DOI: 10.2471/blt.20.250621] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 05/14/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023] Open
Abstract
Objective To calculate prevalence estimates and evaluate the quality of studies reporting Plasmodium falciparum lacking histidine-rich proteins 2 and 3, to inform an international response plan. Methods We searched five online databases, without language restriction, for articles reporting original data on Plasmodium falciparum-infected patients with deletions of the pfhrp2 and/or pfhrp3 genes (pfhrp2/3). We calculated prevalence estimates of pfhrp2/3 deletions and mapped the data by country. The denominator was all P. falciparum-positive samples testing positive by microscopy and confirmed positive by species-specific polymerase chain reaction testing (PCR). If microscopy was not performed, we used the number of samples based on a different diagnostic method or PCR alone. We scored studies for risk of bias and the quality of laboratory methods using a standardized scoring system. Findings A total of 38 articles reporting 55 studies from 32 countries and one territory worldwide were included in the review. We found considerable heterogeneity in the populations studied, methods used and estimated prevalence of P. falciparum parasites with pfhrp2/3 deletions. The derived prevalence of pfhrp2 deletions ranged from 0% to 100%, including focal areas in South America and Africa. Only three studies (5%) fulfilled all seven criteria for study quality. Conclusion The lack of representative surveys or consistency in study design impairs evaluations of the risk of false-negative results in malaria diagnosis due to pfhrp2/3 deletions. Accurate mapping and strengthened monitoring of the prevalence of pfhrp2/3 deletions is needed, along with harmonized methods that facilitate comparisons across studies.
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Affiliation(s)
| | - Jonathan B Parr
- Division of Infectious Diseases, University of North Carolina, Chapel Hill, United States of America
| | - Qin Cheng
- Australian Defence Force Malaria and Infectious Disease Institute, Queensland, Australia
| | - Stella Chenet
- Instituto de Enfermedades Tropicales, Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas, Chachapoyas, Peru
| | - Mark Perkins
- Department of Emergency Preparedness, World Health Organization, Geneva, Switzerland
| | - Jane Cunningham
- Global Malaria Programme, World Health Organization, avenue Appia 20, 1211 Geneva 27, Switzerland
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Plasmodium falciparum Histidine-Rich Protein 2 and 3 Gene Deletions and Their Implications in Malaria Control. Diseases 2020; 8:diseases8020015. [PMID: 32443811 PMCID: PMC7349124 DOI: 10.3390/diseases8020015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/25/2020] [Accepted: 05/05/2020] [Indexed: 01/15/2023] Open
Abstract
Malaria remains the biggest threat to public health, especially among pregnant women and young children in sub-Saharan Africa. Prompt and accurate diagnosis is critical for effective case management and detection of drug resistance. Conventionally, microscopy and rapid diagnostic tests (RDTs) are the tools of choice for malaria diagnosis. RDTs are simple to use and have been extensively used in the diagnosis of malaria among travelers to malaria-endemic regions, routine case management, and surveillance studies. Most RDTs target the histidine-rich protein (PfHRP) which is exclusively found in Plasmodium falciparum and a metabolic enzyme Plasmodium lactate dehydrogenase (pLDH) which is common among all Plasmodium species. Other RDTs incorporate the enzyme aldolase that is produced by all Plasmodium species. Recently, studies have reported false-negative RDTs primarily due to the deletion of the histidine-rich protein (pfhrp2 and pfhrp3) genes in field isolates of P. falciparum. Herein, we review published literature to establish pfhrp2/pfhrp3 deletions, the extent of these deletions in different geographical regions, and the implication in malaria control. We searched for publications on pfhrp2/pfhrp3 deletions and retrieved all publications that reported on this subject. Overall, 20 publications reported on pfhrp2/pfhrp3 deletions, and most of these studies were done in Central and South America, with very few in Asia and Africa. The few studies in Africa that reported on the occurrence of pfhrp2/pfhrp3 deletions rarely evaluated deletions on the flanking genes. More studies are required to evaluate the existence and extent of these gene deletions, whose presence may lead to delayed or missed treatment. This information will guide appropriate diagnostic approaches in the respective areas.
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Bhondoekhan FRP, Searle KM, Hamapumbu H, Lubinda M, Matoba J, Musonda M, Katowa B, Shields TM, Kobayashi T, Norris DE, Curriero FC, Stevenson JC, Thuma PE, Moss WJ. Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: a cross-sectional study. Malar J 2020; 19:175. [PMID: 32381005 PMCID: PMC7206707 DOI: 10.1186/s12936-020-03245-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/23/2020] [Indexed: 01/20/2023] Open
Abstract
Background Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitaemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighbouring (secondary) households within a 140-m radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitaemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitaemic residents, environmental risk factors and a larger screening radius (250 m) were assessed in a region of low malaria endemicity. Methods Between January 12, 2015 and July 26, 2017, 4170 individuals residing in 158 index and 531 secondary households were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using PfHRP2 RDTs and quantitative PCR (qPCR). A Quickbird™ high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitaemic individuals. Results The parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. Overall, 8.5% (n = 45) of secondary households had at least one resident with parasitaemia by qPCR or RDT. The risk of a secondary household having a parasitaemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97 (95% CI 1.04–8.42) and 2.30 (95% CI 1.04–5.09), respectively, and that for distance to index households for each 50 m was 1.24 (95% CI 0.98–1.58). Conclusion Applying proximity to streams as a screening tool, 16% (n = 3) more malaria-positive secondary households were identified compared to using a 140-m circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency.
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Affiliation(s)
- Fiona R P Bhondoekhan
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Kelly M Searle
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, USA
| | | | | | | | | | - Ben Katowa
- Macha Research Trust, Choma District, Zambia
| | - Timothy M Shields
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Tamaki Kobayashi
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Douglas E Norris
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Frank C Curriero
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Philip E Thuma
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - William J Moss
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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Comparision of the various routine diagnostic modalities of malaria and a new method: the Parasight™ platform. J Parasit Dis 2020; 44:528-535. [PMID: 32801504 DOI: 10.1007/s12639-020-01221-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 04/07/2020] [Indexed: 10/24/2022] Open
Abstract
Malaria is one of most important parasitic disease, which is still much prevalent in India. The burden of malaria in India is complex and the proportions of Plasmodium vivax and Plasmodium falciparum vary across India, because of the highly variable malaria eco-epidemiological profiles, transmission factors, and the presence of multiple Plasmodium species and Anopheles vectors. The diagnostic modalities which were being used currently, are at the risk of missing potential malaria cases, if a single test is being used for a given sample. There are some extremely sensitive and specific diagnostic methods available (e.g. PCR, LAMP), but they are expensive, complex, and not readily available in all healthcare setups. Therefore, this study aimed to compare three different types of routinely used diagnostic methods and a novel testing method, the Parasight™ platform, and compare them with the detection ability of the most accurate diagnostic method, that is, PCR. A total of 111 consecutive malaria-positive (proven positive by PCR) patients were taken and tested by the immunochromatographic test or the rapid diagnostic test (RDT), thin and thick blood smears, quantitative buffy coat (QBC). In the last year of study period, 26 PCR positive samples were also taken up for the Parasight™ platform diagnostic test, along with the other routine tests. Among 111 PCR-positive cases, 78.4% samples were positive by Giemsa-stained blood film examination, 80.2% by QBC, 87.4% by RDT. In the last year of study period, among the 26 PCR-positive malaria samples, 80.8% were positive by blood film examination, 84.6% by QBC, 96.2% by RDT and 100% by the Parasight™ platform test. A combination of tests is preferable than a single method, for better detection of Plasmodium species including automated methods. The new testing method, the Parasight™ platform, is emerging to be a very sensitive test for detection of Plasmodium spp., results of which are comparable to PCR.
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Hu X, Wang C, Zhang M, Zhao F, Zeng B. Ionic liquid assisted molecular self-assemble and molecular imprinting on gold nanoparticles decorated boron-doped ordered mesoporous carbon for the detection of zearalenone. Talanta 2020; 217:121032. [PMID: 32498821 DOI: 10.1016/j.talanta.2020.121032] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/06/2020] [Accepted: 04/10/2020] [Indexed: 01/05/2023]
Abstract
Accurate and early diagnosis of zearalenone (ZEN) is particularly significant to the food safety. Herein, we propose an ionic liquid assisted self-assembly molecular imprinting strategy for ZEN based on ionic liquid functionalized boron-doped ordered mesoporous carbon -gold nanoparticles composite (BOMC-IL-Au NPs). During the composite synthesis, increased well-dispersed and uniform Au NPs are deposited on the surface of IL modified BOMC, due to the strong electrostatic interaction between AuCl4- and positively charged IL. For molecular imprinting, the BOMC-IL-Au NPs/GCE is immersed into p-aminothiophenol (p-ATP) solution and template solution in turn. Thus, the mercapto group contained p-ATP self-assembles on the Au NPs. Subsequently, the template molecules self-assemble onto the composite to form dense template layer, because of the hydrophobic interaction, π-π and hydrogen bond between template and IL/or p-ATP. After electropolymerization, the template layer is embedded into the p-ATP polymer membrane and produces lots of imprinting sites. Hence, the obtained sensor exhibits high sensitivity and selectivity. Under the optimal conditions, zearalenone can be quantified from 5 × 10-4 to 1 ng mL-1 with the low detection limit of 1 × 10-4 ng mL-1, by using [Fe(CN)6]3-/4- probe and square wave voltammetry. This strategy can also be employed to construct sensors for the detection of other substances.
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Affiliation(s)
- Xiaopeng Hu
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 30072, Hubei Province, PR China
| | - Caiyun Wang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 30072, Hubei Province, PR China
| | - Meng Zhang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 30072, Hubei Province, PR China
| | - Faqiong Zhao
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 30072, Hubei Province, PR China
| | - Baizhao Zeng
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 30072, Hubei Province, PR China.
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Kojom LP, Singh V. Prevalence of Plasmodium falciparum field isolates with deletions in histidine-rich protein 2 and 3 genes in context with sub-Saharan Africa and India: a systematic review and meta-analysis. Malar J 2020; 19:46. [PMID: 31992330 PMCID: PMC6986054 DOI: 10.1186/s12936-019-3090-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/25/2019] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND In 2017, nearly 80% of malaria morbidity and mortality occurred in sub-Saharan African (SSA) countries and India. Rapid diagnostic tests (RDTs), especially those targeting histidine-rich protein 2 (PfHRP2) of Plasmodium falciparum, have become an important diagnostic tool in these malaria-endemic areas. However, the chances of RDT-oriented successful treatment are increasingly jeopardized by the appearance of mutants with deletions in pfhrp2 and pfhrp3 genes. This systematic review and meta-analysis determines the prevalence of field P. falciparum isolates with deletion in pfhrp2 and/or pfhrp3 genes and their proportion among false-negative results in the PfHRP2-based RDTs in SSA and India. METHODS Eight electronic databases were used for searching potentially relevant publications for the systematic review analysis, wherein the main methodological aspects of included studies were analysed and some missing links in the included studies were identified. RESULTS A total of 19 studies were included, 16 from SSA and 3 from India. The pooled prevalence of pfhrp2 deletions was 8 and 5% while 16 and 4% for pfhrp3 gene deletions in Africa and India, respectively. The pooled proportion of pfhrp2 gene deletions found among false negative PfHRP2-based RDTs results was about 27.0 and 69.0% in Africa and India, respectively. CONCLUSIONS This review study indicates a relatively high proportion of both pfhrp2/3 genes deletions in P. falciparum isolates and among false-negative malaria cases using PfHRP2-based RDT results in SSA and India. Recently the deletions in pfhrp2/3 genes have also been reported from two African countries (Nigeria and Sudan). This review emphasizes the importance of more extensive studies and standardization of studies addressing the pfhrp2/3 gene deletions in malarious areas.
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Affiliation(s)
- Loick P Kojom
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India
| | - Vineeta Singh
- Cell Biology Laboratory and Malaria Parasite Bank, ICMR-National Institute of Malaria Research, Sector 8, Dwarka, New Delhi, 110077, India.
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Dong Y, Liu S, Deng Y, Xu Y, Chen M, Liu Y, Xue J. Genetic polymorphism of histidine rich protein 2 in Plasmodium falciparum isolates from different infection sources in Yunnan Province, China. Malar J 2019; 18:446. [PMID: 31888663 PMCID: PMC6937805 DOI: 10.1186/s12936-019-3084-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 12/21/2019] [Indexed: 11/22/2022] Open
Abstract
Background Failed diagnoses of some falciparum malaria cases by RDTs are constantly reported in recent years. Plasmodium falciparum histidine-rich protein 2 (pfhpr2) gene deficiency has been found to be the major reason of RDTs failure in many countries. This article analysed the deletion of pfhpr2 gene of falciparum malaria cases isolated in Yunnan Province, China. Methods Blood samples from falciparum malaria cases diagnosed in Yunnan Province were collected. Plasmodium genomic DNA was extracted and the pfhrp2 gene exon2 region was amplified via nested PCR. The haplotype of the DNA sequence, the nucleic acid diversity index (PI) and expected heterozygosity (He) were analyzed. Count PfHRP2 amino acid peptide sequence repeat and its times, and predict the properties of PfHRP2 peptide chain reaction to RDTs testing. Results A total of 306 blood samples were collected, 84.9% (259/306) from which pfhrp2 PCR amplification products (gene exon2) were obtained, while the remaining 47 samples were false amplification. The length of the 250 DNA sequences ranged from 345 - 927 bp, with 151 haplotypes, with PI and He values of 0.169 and 0.983, respectively. The length of the PfHRP2 peptide chain translated from 250 DNA sequences ranged from 115 to 309 aa. All peptide chains had more than an amino acid codon deletion. All 250 PfHRP2 strands ended with a type 12 amino acid repeat, 98.0% (245/250) started with a type 1 repetition and 2.0% (5/250) with a type 2 repetition. The detection rate for type 2 duplicates was 100% (250/250). Prediction of RDT sensitivity of PfHRP2 peptide chains based on type 2 and type 7 repeats showed that 9.60% (24/250), 50.0% (125/250), 13.20% (33/250) and 27.20.5% (68/250) of the 250 peptide chains were very sensitive, sensitive, borderline and non-sensitive, respectively. Conclusion The diversified polymorphism of the pfhrp2 gene deletion from different infection sources in the Yunnan province are extremely complex. The cause of the failure of pfhrp2 exon2 amplification is still to be investigated. The results of this study appeal to Yunnan Province for a timely evaluation of the effectiveness and applicability of RDTs in the diagnosis of malaria.
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Affiliation(s)
- Ying Dong
- Yunnan Institute of Parasitic Diseases Control, Yunnan Provincial Key Laboratory, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Pu'er, 665000, China.
| | - Shuping Liu
- Yunnan Institute of Parasitic Diseases Control, Yunnan Provincial Key Laboratory, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Pu'er, 665000, China.,School of Basic Medical Sciences, Dali University, Dali, 667000, China
| | - Yan Deng
- Yunnan Institute of Parasitic Diseases Control, Yunnan Provincial Key Laboratory, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Pu'er, 665000, China
| | - Yanchun Xu
- Yunnan Institute of Parasitic Diseases Control, Yunnan Provincial Key Laboratory, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Pu'er, 665000, China
| | - Mengni Chen
- Yunnan Institute of Parasitic Diseases Control, Yunnan Provincial Key Laboratory, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Pu'er, 665000, China
| | - Yan Liu
- Yunnan Institute of Parasitic Diseases Control, Yunnan Provincial Key Laboratory, Yunnan Centre of Malaria Research, Academician Workstation of Professor Jin Ningyi, Pu'er, 665000, China
| | - Jingpo Xue
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025, China
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Coldiron ME, Assao B, Langendorf C, Sayinzoga-Makombe N, Ciglenecki I, de la Tour R, Piriou E, Yarima Bako M, Mumina A, Guindo O, Page AL, Grais RF. Clinical diagnostic evaluation of HRP2 and pLDH-based rapid diagnostic tests for malaria in an area receiving seasonal malaria chemoprevention in Niger. Malar J 2019; 18:443. [PMID: 31878947 PMCID: PMC6933886 DOI: 10.1186/s12936-019-3079-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/17/2019] [Indexed: 11/27/2022] Open
Abstract
Background Rapid diagnostic tests (RDT) for malaria are common, but their performance varies. Tests using histidine-rich protein 2 (HRP2) antigen are most common, and many have high sensitivity. HRP2 tests can remain positive for weeks after treatment, limiting their specificity and usefulness in high-transmission settings. Tests using Plasmodium lactate dehydrogenase (pLDH) have been less widely used but have higher specificity, mostly due to a much shorter time to become negative. Methods A prospective, health centre-based, diagnostic evaluation of two malaria RDTs was performed in rural Niger during the high malaria transmission season (3–28 October, 2017) and during the low transmission season (28 January–31 March, 2018). All children under 5 years of age presenting with fever (axillary temperature > 37.5 °C) or history of fever in the previous 24 h were eligible. Capillary blood was collected by finger prick. The SD Bioline HRP2 (catalog: 05FK50) and the CareStart pLDH(pan) (catalog: RMNM-02571) were performed in parallel, and thick and thin smears were prepared. Microscopy was performed at Epicentre, Maradi, Niger, with external quality control. The target sample size was 279 children with microscopy-confirmed malaria during each transmission season. Results In the high season, the sensitivity of both tests was estimated at > 99%, but the specificity of both tests was lower: 58.0% (95% CI 52.1–63.8) for the pLDH test and 57.4% (95% CI 51.5–63.1) for the HRP2 test. The positive predictive value was 66.3% (95% CI 61.1–71.2) for both tests. In the low season, the sensitivity of both tests dropped: 91.0% (95% CI 85.3–95.0) for the pLDH test and 85.8% (95% CI 79.3–90.9) for the HRP2 test. The positive predictive value remained low for both tests in the low season: 60.5% (95% CI 53.9–66.8) for the pLDH test and 61.9% (55.0–68.4) for the HRP2 test. Performance was similar across different production lots, gender, age of the children, and, during the high season, time since the most recent distribution of seasonal malaria chemoprevention. Conclusions The low specificity of the pLDH RDT in this setting was unexpected and is not easily explained. As the pLDH test continues to be introduced into new settings, the questions raised by this study will need to be addressed.
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Affiliation(s)
| | | | | | | | - Iza Ciglenecki
- Médecins Sans Frontières, 70 rue de Lausanne, Geneva, Switzerland
| | | | - Erwan Piriou
- Médecins Sans Frontières, Naritaweg 10, Amsterdam, The Netherlands
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Prevalence of Asymptomatic Malaria among Children in the Tamale Metropolis: How Does the PfHRP2 CareStart™ RDT Perform against Microscopy? J Trop Med 2019; 2019:6457628. [PMID: 31933652 PMCID: PMC6942882 DOI: 10.1155/2019/6457628] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/24/2019] [Accepted: 11/26/2019] [Indexed: 11/30/2022] Open
Abstract
Background Asymptomatic carriage of the malaria parasites, likewise its misdiagnosis, especially false negatives, due to the use of substandard rapid diagnosis tests (RDTs) has been shown to hinder the progress of the fight against malaria. Method The study assessed the prevalence of asymptomatic malaria as well as the performance of Plasmodium falciparum-specific protein and histidine-rich protein 2 (PfHRP2) CareStart™ RDT against standard microscopy in the detection of malaria infection among 345 children (1–15 yrs) from two (2) basic schools in Tamale Metropolis. Results From the microscopy (considered as gold standard), prevalence of malaria among the asymptomatic children was found to be 2.6%, with sensitivity and specificity of CareStart™ RDT in detecting P. falciparum infections found to be 55.6% and 93.8%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of CareStart™ RDT were found to be 19.23% and 98.45%, respectively. There was an evidence showing a significant relation between CareStart™ RDT and microscopy in determining malaria infection (χ2 = 30.579, p < 0.001). Conclusion Prevalence of asymptomatic malaria among children was found to be 2.6%. The study reported low sensitivity and PPV for PfHRP2 CareStart™ RDT in an asymptomatic population at instances of low parasitaemia.
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Spatiotemporal clustering of malaria in southern-central Ethiopia: A community-based cohort study. PLoS One 2019; 14:e0222986. [PMID: 31568489 PMCID: PMC6768540 DOI: 10.1371/journal.pone.0222986] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/11/2019] [Indexed: 01/08/2023] Open
Abstract
Introduction Understanding the spatiotemporal clustering of malaria transmission would help target interventions in settings of low malaria transmission. The aim of this study was to assess whether malaria infections were clustered in areas with long-lasting insecticidal nets (LLINs) alone, indoor residual spraying (IRS) alone, or a combination of LLINs and IRS interventions, and to determine the risk factors for the observed malaria clustering in southern-central Ethiopia. Methods A cohort of 34,548 individuals residing in 6,071 households was followed for 121 weeks, from October 2014 to January 2017. Both active and passive case detection mechanisms were used to identify clinical malaria episodes, and there were no geographic heterogeneity in data collection methods. Using SaTScan software v 9.4.4, a discrete Poisson model was used to identify high rates of spatial, temporal, and spatiotemporal malaria clustering. A multilevel logistic regression model was fitted to identify predictors of spatial malaria clustering. Results The overall incidence of malaria was 16.5 per 1,000 person-year observations. Spatial, temporal, and spatiotemporal clustering of malaria was detected in all types of malaria infection (P. falciparum, P. vivax, or mixed). Spatial clustering was identified in all study arms: for LLIN + IRS arm, a most likely cluster size of 169 cases in 305 households [relative risk (RR) = 4.54, P<0.001]; for LLIN alone arm a cluster size of 88 cases in 103 households (RR = 5.58, P<0.001); for IRS alone arm a cluster size of 58 cases in 50 households (RR = 7.15, P<0.001), and for control arm a cluster size of 147 cases in 377 households (RR = 2.78, P<0.001). Living 1 km closer to potential vector breeding sites increased the odds of being in spatial clusters by 41.32 fold (adjusted OR = 41.32, 95% CI = 3.79–138.89). Conclusions The risk of malaria infection varied significantly between kebeles, within kebeles, and even among households in areas targeted for different types of malaria control interventions in low malaria transmission setting. The results of this study can be used in planning and implementation of malaria control strategies at micro-geographic scale. Trial registration PACT R2014 11000 882128 (8 September 2014).
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Development of a film-based immunochromatographic microfluidic device for malaria diagnosis. Biomed Microdevices 2019; 21:86. [PMID: 31451957 DOI: 10.1007/s10544-019-0431-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this study, a novel film-based immunochromatographic microfluidic device (IMD) has been developed for malaria diagnosis. A microfluidic channel was patterned on a polyethylene terephthalate (PET) double-sided adhesive film using a plotting cutter and was assembled with a polycarbonate (PC) film. The PC film used for the probe immobilization layer was activated using oxygen plasma treatment to modify the film surface with avidin-biotin linker to immobilize a capture antibody. A fluorescent labeled Pan type mAb conjugate was prepared for signal indicator after undergoing a sandwich enzyme-linked immunosorbent assay (ELISA). Target antigens include Plasmodium falciparum (P. falciparum) lactate dehydrogenase (LDH) and Plasmodium vivax (P. vivax) LDH which were injected into the sample inlet. Target antigens combined with the conjugate and then flowed to the detection chamber where two test dots and a control dot (Ctrl) exist. In the presence of P. falciparum LDH, three detection dots including test dot 1 (T1), test dot 2 (T2) and Ctrl revealed fluorescence signals where P. falciparum mAb, Pan type pLDH mAb and goat anti-mouse IgG were immobilized, respectively. When P. vivax LDH was present, T2 and Ctrl dots showed fluorescence signals while no signal was detected with the negative control. P. falciparum LDH and P. vivax LDH were successfully detected on the IMD with a detection limit of 50 ng/mL and 100 ng/mL, respectively. The IMD provides a point-of-care diagnosis platform which is able to analyze pathogenic bacteria and viruses that can be applied in the field of clinical diagnosis and food safety testing.
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Baltzell KA, Maglior A, Bangu K, Mngadi N, Prach LM, Whittemore B, Ntshalintshali N, Saini M, Dlamini N, Kunene S, Hsiang MS. "We were afraid of the lion that has roared next to us"; community response to reactive focal mass drug administration for malaria in Eswatini (formerly Swaziland). Malar J 2019; 18:238. [PMID: 31307494 PMCID: PMC6631448 DOI: 10.1186/s12936-019-2877-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 07/09/2019] [Indexed: 11/25/2022] Open
Abstract
Background Reactive focal mass drug administration (rfMDA), or presumptive treatment without malaria testing of household members and neighbours of a passively identified malaria case, is currently being explored as a possible malaria elimination strategy in low transmission settings. One of the primary factors determining the effectiveness of rfMDA on reducing or interrupting transmission is achieving high coverage of the target population with drug administration. This study aims to explore the acceptability of rfMDA and identify facilitators and barriers to its potential implementation, as well as the community’s general knowledge, attitudes and beliefs with regard to malaria elimination. Methods A qualitative study was performed using focus group discussions (FGDs) among villagers that received rfMDA through the National Malaria Control Programme in the low transmission setting of Eswatini as part of a 2-year clinical trial. FGDs were audio-recorded, transcribed and translated into English. All transcripts were managed in Dedoose and underwent qualitative content analysis. Results The majority of participants perceived their community to be at high risk of malaria. Witnessing others in their community suffer from malaria, proximity to Mozambique, various ecological factors, and the presence of mosquitoes contributed to this perception. The greatest motivator of participation in rfMDA was witnessing someone else suffer from malaria, since most participants had not personally experienced malaria themselves. Participants valued the education on rfMDA and on malaria in general, particularly when communicated by nurses and other health workers from the Ministry of Health. Participants were overwhelmingly motivated to participate in rfMDA in order to obtain protection from malaria. Most participants did not understand the concept of sub-clinical infection and, therefore, did not perceive the anti-malarial medication given in rfMDA to be a treatment medication. Conclusions Perceived risk for malaria was a major driver of acceptability; therefore, future intervention campaigns could aim to better quantify risk to inform interventions and encourage uptake. There were misunderstandings about the asymptomatic reservoir of parasites in humans. Given that this phenomenon is the rationale for rfMDA, this misunderstanding could threaten the uptake of the intervention if it persists in the community. Using local authorities to deliver messaging, additional education on this concept with re-inforcement that risk of malaria is ongoing, even in the absence of frequent cases, may help to maximize and maintain acceptability.
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Affiliation(s)
- Kimberly A Baltzell
- Dept of Family Health Care Nursing, UCSF, San Francisco, CA, USA. .,Institute for Global Health Sciences, UCSF, San Francisco, CA, USA.
| | - Alysse Maglior
- Institute for Global Health Sciences, UCSF, San Francisco, CA, USA
| | - Khaya Bangu
- National Malaria Programme, Eswatini Ministry of Health, Manzini, Swaziland
| | - Nontokozo Mngadi
- Clinton Health Access Initiative, Eswatini Office, Mbabane, Swaziland
| | - Lisa M Prach
- Malaria Elimination Initiative, Global Health Group, UCSF, San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Manik Saini
- Clinton Health Access Initiative, Eswatini Office, Mbabane, Swaziland
| | - Nomcebo Dlamini
- National Malaria Programme, Eswatini Ministry of Health, Manzini, Swaziland
| | - Simon Kunene
- National Malaria Programme, Eswatini Ministry of Health, Manzini, Swaziland
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, UCSF, San Francisco, CA, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Pediatrics, UCSF, San Francisco, CA, USA
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Talapko J, Škrlec I, Alebić T, Jukić M, Včev A. Malaria: The Past and the Present. Microorganisms 2019; 7:microorganisms7060179. [PMID: 31234443 PMCID: PMC6617065 DOI: 10.3390/microorganisms7060179] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/28/2019] [Accepted: 06/19/2019] [Indexed: 02/07/2023] Open
Abstract
Malaria is a severe disease caused by parasites of the genus Plasmodium, which is transmitted to humans by a bite of an infected female mosquito of the species Anopheles. Malaria remains the leading cause of mortality around the world, and early diagnosis and fast-acting treatment prevent unwanted outcomes. It is the most common disease in Africa and some countries of Asia, while in the developed world malaria occurs as imported from endemic areas. The sweet sagewort plant was used as early as the second century BC to treat malaria fever in China. Much later, quinine started being used as an antimalaria drug. A global battle against malaria started in 1955, and Croatia declared 1964 to be the year of eradication of malaria. The World Health Organization carries out a malaria control program on a global scale, focusing on local strengthening of primary health care, early diagnosis of the disease, timely treatment, and disease prevention. Globally, the burden of malaria is lower than ten years ago. However, in the last few years, there has been an increase in the number of malaria cases around the world. It is moving towards targets established by the WHO, but that progress has slowed down.
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Affiliation(s)
- Jasminka Talapko
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, Crkvena 21, HR-31000 Osijek, Croatia.
| | - Ivana Škrlec
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, Crkvena 21, HR-31000 Osijek, Croatia.
| | - Tamara Alebić
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Josipa Huttlera 4, HR-31000 Osijek, Croatia.
| | - Melita Jukić
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Josipa Huttlera 4, HR-31000 Osijek, Croatia.
- General Hospital Vukovar, Županijska 35, HR-32000 Vukovar, Croatia.
| | - Aleksandar Včev
- Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, Crkvena 21, HR-31000 Osijek, Croatia.
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, Josipa Huttlera 4, HR-31000 Osijek, Croatia.
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Hawash Y, Ismail K, Alsharif K, Alsanie W. Malaria Prevalence in a Low Transmission Area, Jazan District of Southwestern Saudi Arabia. THE KOREAN JOURNAL OF PARASITOLOGY 2019; 57:233-242. [PMID: 31284345 PMCID: PMC6616166 DOI: 10.3347/kjp.2019.57.3.233] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/24/2019] [Accepted: 05/03/2019] [Indexed: 11/23/2022]
Abstract
Detailed description of malaria in low transmission areas is crucial for elimination. The current study aimed to provide a comprehensive description for malaria transmission in Jazan, a low transmission district, southwestern Saudi Arabia. Patients at a tertiary care hospital were recruited in our study between August 2016 and September 2018. Malaria diagnosis was performed through a species-specific nested polymerase chain reaction (nested PCR), microscopy and Paramax-3TM rapid detection test (RDT). Malaria was detected in 30 patients by the PCR, with point prevalence of 10.9%. Of these malaria infections, 80% was imported, 26.6% was asymptomatic and 23.3% was sub-microscopic. Malaria was reported throughout the year, with February/March and September/October peaks. Infection was significantly more in males than in females (P=0.01). Likewise, infections were detected more in febrile than in non-febrile patients (P=0.01). Adult aged 15-24 years, fever and travel were identified as high-risk factors. Malaria was primarily attributed to Plasmodium falciparum mono-infections, followed by P. vivax mono-infections and lastly to falciparum/vivax mixed infections accounting 76.6%, 16.6%, and 6.6% of PCR-confirmed malaria cases, respectively. The nested PCR was superior to the smear microscopy (sensitivity 76.6%; specificity 100%) and the RDT (sensitivity 83.3%, specificity 94.2%). The overall percent agreement between microscopy and the RDT was 92.7% (kappa=0.63). High proportion of imported malaria including sub-microscopic and sub-patent cases were described. We suggest that incorporation of molecular tool into the conventional malaria diagnosis is beneficial in Jazan district.
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Affiliation(s)
- Yousry Hawash
- Clinical Laboratories Sciences Department, College of Applied Medical Science, Taif University, Taif,
Saudi Arabia
- Parasitology Department, National Liver Institute, Menoufia University, Menoufia,
Egypt
| | - Khadiga Ismail
- Clinical Laboratories Sciences Department, College of Applied Medical Science, Taif University, Taif,
Saudi Arabia
- Parasitology Department, Faculty of Medicine, Ain-Shams University, Cairo,
Egypt
| | - Khalaf Alsharif
- Clinical Laboratories Sciences Department, College of Applied Medical Science, Taif University, Taif,
Saudi Arabia
| | - Walaa Alsanie
- Clinical Laboratories Sciences Department, College of Applied Medical Science, Taif University, Taif,
Saudi Arabia
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Rossi G, De Smet M, Khim N, Kindermans JM, Menard D. Performance of Rapid Diagnostic Testing in Patients with Suspected Malaria in Cambodia, a Low-Endemicity Country Aiming for Malaria Elimination. Clin Infect Dis 2019; 65:1769-1770. [PMID: 29020315 DOI: 10.1093/cid/cix625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Martin De Smet
- Médecins Sans Frontières, Phnom Penh, Cambodia.,Médecins Sans Frontières Operational Center, Brussels, Belgium
| | | | - Jean-Marie Kindermans
- Médecins Sans Frontières, Phnom Penh, Cambodia.,Médecins Sans Frontières Operational Center, Brussels, Belgium
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Plasmodium falciparum histidine-rich protein (PfHRP2 and 3) diversity in Western and Coastal Kenya. Sci Rep 2019; 9:1709. [PMID: 30737461 PMCID: PMC6368535 DOI: 10.1038/s41598-018-38175-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 12/21/2018] [Indexed: 01/24/2023] Open
Abstract
Plasmodium falciparum histidine-rich proteins 2 (PfHRP2) based RDTs are advocated in falciparum malaria-endemic regions, particularly when quality microscopy is not available. However, diversity and any deletion in the pfhrp2 and pfhrp3 genes can affect the performance of PfHRP2-based RDTs. A total of 400 samples collected from uncomplicated malaria cases from Kenya were investigated for the amino acid repeat profiles in exon 2 of pfhrp2 and pfhrp3 genes. In addition, PfHRP2 levels were measured in 96 individuals with uncomplicated malaria. We observed a unique distribution pattern of amino acid repeats both in the PfHRP2 and PfHRP3. 228 PfHRP2 and 124 PfHRP3 different amino acid sequences were identified. Of this, 214 (94%) PfHRP2 and 81 (65%) PfHRP3 amino acid sequences occurred only once. Thirty-nine new PfHRP2 and 20 new PfHRP3 amino acid repeat types were identified. PfHRP2 levels were not correlated with parasitemia or the number of PfHRP2 repeat types. This study shows the variability of PfHRP2, PfHRP3 and PfHRP2 concentration among uncomplicated malaria cases. These findings will be useful to understand the performance of PfHRP2-based RDTs in Kenya.
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Vilay P, Nonaka D, Senamonty P, Lao M, Iwagami M, Kobayashi J, Hernandez PM, Phrasisombath K, Kounnavong S, Hongvanthong B, Brey PT, Kano S. Malaria prevalence, knowledge, perception, preventive and treatment behavior among military in Champasak and Attapeu provinces, Lao PDR: a mixed methods study. Trop Med Health 2019; 47:11. [PMID: 30700970 PMCID: PMC6347756 DOI: 10.1186/s41182-019-0138-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/14/2019] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major health problem in Lao People's Democratic Republic (Lao PDR) with high transmission in remote and forest areas, particularly in the South. The military is at risk of malaria infection especially those deployed in forest areas. This study determined the prevalence of malaria infection and assessed knowledge, perception, and preventive and treatment behavior regarding malaria among military personnel in two southern provinces in Lao PDR. Methods Quantitative and qualitative approaches were undertaken in Champasak and Attapeu provinces in 2017. From 313 military personnel, quantitative data were collected through questionnaire-based interviews and blood samples used for parasite detection by polymerase chain reaction (PCR). Qualitative data were collected through 7 focus group discussions and 17 in-depth interviews among 49 military personnel. Fisher's exact test and Mann-Whitney U test were used to assess the association between malaria infection and participant characteristics. Content analysis for qualitative data was performed to explore perception and treatment behaviors regarding malaria. Results The prevalence of malaria infection was 11.2% (Plasmodium falciparum: 1.3%, Plasmodium vivax: 9.3% and mixed infections: 0.6%). Many participants understood that malaria is transmitted through mosquito bites, although they did not necessarily know the name of vector mosquitoes (Anopheles). Surprisingly, more than a half also believed that malaria is transmitted through drinking stream water. One-third of the participants used long-lasting insecticidal nets. Due to limited supply, participants were often unable to use mosquito repellent and coils when necessary. Because participants were unable to receive timely diagnosis and appropriate treatment for malaria in their camps, they commonly practiced self-treatment using antibiotics, painkillers, and/or traditional medicines. They only go to a healthcare facility through their supervisor if their conditions worsen. Conclusions The prevalence of symptomatic and asymptomatic malaria was conspicuous among military in forest areas. Many participants believed that malaria is transmitted not only by mosquito bites but also from drinking stream water. Preventive equipment was often insufficient. Self-treatment was practiced before referring to healthcare facility. To further prevent military from contracting malaria, the National Malaria Control Program and military body should provide adequate and suitable health education, protective equipment, and on-site malaria case management.
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Affiliation(s)
- Phoutnalong Vilay
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,2Center of Malariology, Parasitology and Entomology, Ministry of Health, Vientiane, Lao PDR.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Daisuke Nonaka
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Phosadeth Senamonty
- Military Institute of Diseases Prevention, Department of Military Medical, Ministry of Defense, Vientiane, Lao PDR
| | - Malayvanh Lao
- Military Institute of Diseases Prevention, Department of Military Medical, Ministry of Defense, Vientiane, Lao PDR
| | - Moritoshi Iwagami
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,5Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655 Japan.,6Institut Pasteur du Laos, Ministry of Health, Vientiane, Lao PDR
| | - Jun Kobayashi
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Paul Michael Hernandez
- 1Department of Global Health, Graduate School of Health Sciences, University of the Ryukyus, 207 Uehara-cho, Okinawa, 903-0215 Japan.,7Department of Environmental and Occupational Health, College of Public Health, University of the Philippines Manila, 625 Pedro Gil Street, Ermita, 1000 Manila, Philippines
| | | | - Sengchanh Kounnavong
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,9Lao Tropical and Public Health Institute, Ministry of Health, Vientiane, Lao PDR
| | - Bouasy Hongvanthong
- 2Center of Malariology, Parasitology and Entomology, Ministry of Health, Vientiane, Lao PDR.,SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR
| | - Paul T Brey
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,6Institut Pasteur du Laos, Ministry of Health, Vientiane, Lao PDR
| | - Shigeyuki Kano
- SATREPS Project for Parasitic Diseases, Vientiane, Lao PDR.,5Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655 Japan
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Development of an aptamer-based field effect transistor biosensor for quantitative detection of Plasmodium falciparum glutamate dehydrogenase in serum samples. Biosens Bioelectron 2018; 123:30-35. [PMID: 30308419 DOI: 10.1016/j.bios.2018.09.085] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/13/2018] [Accepted: 09/25/2018] [Indexed: 02/07/2023]
Abstract
There has been a continuous strive to develop portable, stable, sensitive and low cost detection system for malaria to meet the demand of effective screening actions in developing countries where the disease is most endemic. Herein, we report an aptamer-based field effect transistor (aptaFET) biosensor, developed by using an extended gate field effect transistor with inter-digitated gold microelectrodes (IDµE) for the detection of the malaria biomarker Plasmodium falciparum glutamate dehydrogenase (PfGDH) in serum samples. A 90 mer long ssDNA aptamer (NG3) selective to PfGDH was used in the aptaFET to capture the target protein. The intrinsic surface net charge of the captured protein led to change in gate potential of the aptaFET device, which could be correlated to the concentration of the protein. This biosensor exhibited a sensitive response in broad dynamic range of 100 fM -10 nM with limits of detection of 16.7 pM and 48.6 pM in spiked buffer and serum samples, respectively. The high selectivity of the biosensor for PfGDH was verified by testing relevant analogous human and parasitic proteins on the device. Overall, the results validated the application potential of the developed aptaFET for diagnosis of both symptomatic and asymptomatic malaria.
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Hsiang MS, Ranadive N, Chitundu S, Ntshalintshali N, Greenhouse B. Reply to Rossi et al. Clin Infect Dis 2017; 65:1770-1771. [PMID: 29020318 PMCID: PMC5850315 DOI: 10.1093/cid/cix627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Michelle S Hsiang
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas
- Malaria Elimination Initiative, Global Health Group
- Department of Pediatrics, University of California, San Francisco Benioff Children’s Hospital
| | - Nikhil Ranadive
- Global Health Sciences
- Emory University School of Medicine, Atlanta, Georgia
| | | | | | - Bryan Greenhouse
- Department of Medicine, San Francisco General Hospital, University of California
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Tejedor-Garavito N, Dlamini N, Pindolia D, Soble A, Ruktanonchai NW, Alegana V, Le Menach A, Ntshalintshali N, Dlamini B, Smith DL, Tatem AJ, Kunene S. Travel patterns and demographic characteristics of malaria cases in Swaziland, 2010-2014. Malar J 2017; 16:359. [PMID: 28886710 PMCID: PMC5591561 DOI: 10.1186/s12936-017-2004-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/30/2017] [Indexed: 11/17/2022] Open
Abstract
Background As Swaziland progresses towards national malaria elimination, the importation of parasites into receptive areas becomes increasingly important. Imported infections have the potential to instigate local transmission and sustain local parasite reservoirs. Methods Travel histories from Swaziland’s routine surveillance data from January 2010 to June 2014 were extracted and analysed. The travel patterns and demographics of rapid diagnostic test (RDT)-confirmed positive cases identified through passive and reactive case detection (RACD) were analysed and compared to those found to be negative through RACD. Results Of 1517 confirmed cases identified through passive surveillance, 67% reported travel history. A large proportion of positive cases reported domestic or international travel history (65%) compared to negative cases (10%). The primary risk factor for malaria infection in Swaziland was shown to be travel, more specifically international travel to Mozambique by 25- to 44-year old males, who spent on average 28 nights away. Maputo City, Inhambane and Gaza districts were the most likely travel destinations in Mozambique, and 96% of RDT-positive international travellers were either Swazi (52%) or Mozambican (44%) nationals, with Swazis being more likely to test negative. All international travellers were unlikely to have a bed net at home or use protection of any type while travelling. Additionally, paths of transmission, important border crossings and means of transport were identified. Conclusion Results from this analysis can be used to direct national and well as cross-border targeting of interventions, over space, time and by sub-population. The results also highlight that collaboration between neighbouring countries is needed to tackle the importation of malaria at the regional level. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-2004-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Adam Soble
- Clinton Health Access Initiative, Boston, MA, USA
| | - Nick W Ruktanonchai
- WorldPop, University of Southampton, Southampton, UK.,Flowminder Foundation, Stockholm, Sweden
| | - Victor Alegana
- WorldPop, University of Southampton, Southampton, UK.,Flowminder Foundation, Stockholm, Sweden
| | | | | | | | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, USA
| | - Andrew J Tatem
- WorldPop, University of Southampton, Southampton, UK.,Flowminder Foundation, Stockholm, Sweden
| | - Simon Kunene
- National Malaria Control Programme, Manzini, Swaziland
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Chuang TW, Soble A, Ntshalintshali N, Mkhonta N, Seyama E, Mthethwa S, Pindolia D, Kunene S. Assessment of climate-driven variations in malaria incidence in Swaziland: toward malaria elimination. Malar J 2017; 16:232. [PMID: 28571572 PMCID: PMC5455096 DOI: 10.1186/s12936-017-1874-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/24/2017] [Indexed: 12/01/2022] Open
Abstract
Background Swaziland aims to eliminate malaria by 2020. However, imported cases from neighbouring endemic countries continue to sustain local parasite reservoirs and initiate transmission. As certain weather and climatic conditions may trigger or intensify malaria outbreaks, identification of areas prone to these conditions may aid decision-makers in deploying targeted malaria interventions more effectively. Methods Malaria case-surveillance data for Swaziland were provided by Swaziland’s National Malaria Control Programme. Climate data were derived from local weather stations and remote sensing images. Climate parameters and malaria cases between 2001 and 2015 were then analysed using seasonal autoregressive integrated moving average models and distributed lag non-linear models (DLNM). Results The incidence of malaria in Swaziland increased between 2005 and 2010, especially in the Lubombo and Hhohho regions. A time-series analysis indicated that warmer temperatures and higher precipitation in the Lubombo and Hhohho administrative regions are conducive to malaria transmission. DLNM showed that the risk of malaria increased in Lubombo when the maximum temperature was above 30 °C or monthly precipitation was above 5 in. In Hhohho, the minimum temperature remaining above 15 °C or precipitation being greater than 10 in. might be associated with malaria transmission. Conclusions This study provides a preliminary assessment of the impact of short-term climate variations on malaria transmission in Swaziland. The geographic separation of imported and locally acquired malaria, as well as population behaviour, highlight the varying modes of transmission, part of which may be relevant to climate conditions. Thus, the impact of changing climate conditions should be noted as Swaziland moves toward malaria elimination. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1874-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ting-Wu Chuang
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, No. 250, Wuxing St. Sinyi District, Taipei, 100, Taiwan.
| | - Adam Soble
- Clinton Health Access Initiative, Manzini, Swaziland
| | | | - Nomcebo Mkhonta
- National Malaria Control Programme, Ministry of Health, Manzini, Swaziland
| | - Eric Seyama
- Swaziland Meteorological Service, Mbabane, Swaziland
| | - Steven Mthethwa
- National Malaria Control Programme, Ministry of Health, Manzini, Swaziland
| | | | - Simon Kunene
- National Malaria Control Programme, Ministry of Health, Manzini, Swaziland
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