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Ladu AI, Kadaura MU, Dauda M, Baba AS, Zango NG, Jeffery C, Farate A, Adekile A, Bates I. Malaria Infection in Patients with Sickle Cell Disease in Nigeria: Association with Markers of Hyposplenism. Hemoglobin 2024; 48:15-23. [PMID: 38247354 DOI: 10.1080/03630269.2023.2285881] [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: 05/19/2023] [Accepted: 11/15/2023] [Indexed: 01/23/2024]
Abstract
Malaria is considered an important cause of morbidity and mortality among people living with sickle cell disease (SCD). This has partly been attributed to the loss of splenic function that occurs early in the disease process. We conducted a cross-sectional study and determined the frequency of malaria infection among SCD patients and explored the association with spleen's presence on ultrasonography and spleen function assessed using the frequency of Howell-Jolly bodies (HJBs). A total of 395 participants consisting of 119 acutely-ill SCD patients, 168 steady-state SCD controls, and 108 healthy non-SCD controls were studied. The prevalence of Plasmodium falciparum parasitemia was 51.3% in acutely-ill SCD patients, 31.7% in steady-state SCD controls, and 11.0% in the healthy non-SCD controls; however, the mean parasite density was significantly higher in the non-SCD controls compared to both SCD groups (p = 0.0001). Among the acutely-ill SCD patients, the prevalence of clinical malaria and severe malaria anemia were highest in children <5 years of age. The prevalence of parasitemia (p = 0.540) and parasite density (p = 0.975) showed no association with spleen presence or absence on ultrasonography. Similarly, the frequency of HJB red cells was not associated with the presence of parasitemia (p = 0.183). Our study highlights the frequency and role of malaria infection in acutely-ill SCD patients, especially in those younger than five years. Although we have found no evidence of an increased risk of malaria parasitemia or parasite density with markers of hyposplenism, the role played by an underlying immunity to malaria among SCD patients in malaria-endemic region is not clear and needs further studies.
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Affiliation(s)
- Adama Isah Ladu
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Haematology, Faculty of Basic Clinical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - Mairo Usman Kadaura
- Department of Microbiology, Faculty of Basic Clinical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - Mohammed Dauda
- Department of Microbiology, Faculty of Basic Clinical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - Abubakar Sadiq Baba
- Department of Microbiology, Faculty of Basic Clinical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - Nasir Garba Zango
- Department of Microbiology, Faculty of Basic Clinical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - Caroline Jeffery
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Liverpool, UK
| | - Abubakar Farate
- Department of Radiology, Faculty of Clinical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - Adekunle Adekile
- Department of Paediatrics, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Imelda Bates
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
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van Bergen KJM, Stuitje AR, Akkers RC, Vermeer HJ, Castel R, Mank TG. Performance of a novel melting curve-based qPCR assay for malaria parasites in routine clinical practice in non-endemic setting. Malar J 2023; 22:191. [PMID: 37349789 DOI: 10.1186/s12936-023-04617-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/06/2023] [Indexed: 06/24/2023] Open
Abstract
BACKGROUND High-quality malaria diagnosis is essential for effective treatment and clinical disease management. Microscopy and rapid diagnostic tests are the conventional methods performed as first-line malaria diagnostics in non-endemic countries. However, these methods lack the characteristic to detect very low parasitaemia, and accurate identification of the Plasmodium species can be difficult. This study evaluated the performance of the MC004 melting curve-based qPCR for the diagnosis of malaria in routine clinical practice in non-endemic setting. METHODS AND RESULTS Whole blood samples were collected from 304 patients with clinical suspicion of malaria and analysed by both the MC004 assay and conventional diagnostics. Two discrepancies were found between the MC004 assay and microscopy. Repeated microscopic analysis confirmed the qPCR results. Comparison of the parasitaemia of nineteen Plasmodium falciparum samples determined by both microscopy and qPCR showed the potential of the MC004 assay to estimate the parasite load of P. falciparum. Eight Plasmodium infected patients were followed after anti-malarial treatment by the MC004 assay and microscopy. The MC004 assay still detected Plasmodium DNA although no parasites were seen with microscopy in post-treatment samples. The rapid decline in Plasmodium DNA showed the potential for therapy-monitoring. CONCLUSION Implementation of the MC004 assay in non-endemic clinical setting improved the diagnosis of malaria. The MC004 assay demonstrated superior Plasmodium species identification, the ability to indicate the Plasmodium parasite load, and can potentially detect submicroscopic Plasmodium infections.
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Affiliation(s)
- Kim J M van Bergen
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands.
| | - Antoine R Stuitje
- MRC Holland, Willem Schoutenstraat 1, 1057 DL, Amsterdam, The Netherlands
| | - Robert C Akkers
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Henricus J Vermeer
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Rob Castel
- Result Laboratorium, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3300 AK, Dordrecht, The Netherlands
| | - Theo G Mank
- Regional Laboratory for Medical Microbiology and Public Health, Boerhaavelaan 26, 2035 RC, Haarlem, The Netherlands
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Wynberg E, Commons RJ, Humphreys G, Ashurst H, Burrow R, Adjei GO, Adjuik M, Anstey NM, Anvikar A, Baird KJ, Barber BE, Barennes H, Baudin E, Bell DJ, Bethell D, Binh TQ, Borghini-Fuhrer I, Chu CS, Daher A, D’Alessandro U, Das D, Davis TME, de Vries PJ, Djimde AA, Dondorp AM, Dorsey G, Faucher JFF, Fogg C, Gaye O, Grigg M, Hatz C, Kager PA, Lacerda M, Laman M, Mårtensson A, Menan HIE, Monteiro WM, Moore BR, Nosten F, Ogutu B, Osorio L, Penali LK, Pereira DB, Rahim AG, Ramharter M, Sagara I, Schramm B, Seidlein L, Siqueira AM, Sirima SB, Starzengruber P, Sutanto I, Taylor WR, Toure OA, Utzinger J, Valea I, Valentini G, White NJ, William T, Woodrow CJ, Richmond CL, Guerin PJ, Price RN, Stepniewska K. Variability in white blood cell count during uncomplicated malaria and implications for parasite density estimation: a WorldWide Antimalarial Resistance Network individual patient data meta-analysis. Malar J 2023; 22:174. [PMID: 37280686 DOI: 10.1186/s12936-023-04583-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/07/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND The World Health Organization (WHO) recommends that when peripheral malarial parasitaemia is quantified by thick film microscopy, an actual white blood cell (WBC) count from a concurrently collected blood sample is used in calculations. However, in resource-limited settings an assumed WBC count is often used instead. The aim of this study was to describe the variability in WBC count during acute uncomplicated malaria, and estimate the impact of using an assumed value of WBC on estimates of parasite density and clearance. METHODS Uncomplicated malaria drug efficacy studies that measured WBC count were selected from the WorldWide Antimalarial Resistance Network data repository for an individual patient data meta-analysis of WBC counts. Regression models with random intercepts for study-site were used to assess WBC count variability at presentation and during follow-up. Inflation factors for parasitaemia density, and clearance estimates were calculated for methods using assumed WBC counts (8000 cells/µL and age-stratified values) using estimates derived from the measured WBC value as reference. RESULTS Eighty-four studies enrolling 27,656 patients with clinically uncomplicated malaria were included. Geometric mean WBC counts (× 1000 cells/µL) in age groups < 1, 1-4, 5-14 and ≥ 15 years were 10.5, 8.3, 7.1, 5.7 and 7.5, 7.0, 6.5, 6.0 for individuals with falciparum (n = 24,978) and vivax (n = 2678) malaria, respectively. At presentation, higher WBC counts were seen among patients with higher parasitaemia, severe anaemia and, for individuals with vivax malaria, in regions with shorter regional relapse periodicity. Among falciparum malaria patients, using an assumed WBC count of 8000 cells/µL resulted in parasite density underestimation by a median (IQR) of 26% (4-41%) in infants < 1 year old but an overestimation by 50% (16-91%) in adults aged ≥ 15 years. Use of age-stratified assumed WBC values removed systematic bias but did not improve precision of parasitaemia estimation. Imprecision of parasite clearance estimates was only affected by the within-patient WBC variability over time, and remained < 10% for 79% of patients. CONCLUSIONS Using an assumed WBC value for parasite density estimation from a thick smear may lead to underdiagnosis of hyperparasitaemia and could adversely affect clinical management; but does not result in clinically consequential inaccuracies in the estimation of the prevalence of prolonged parasite clearance and artemisinin resistance.
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Rogers CL, Bain BJ, Garg M, Fernandes S, Mooney C, Chiodini PL. British Society for Haematology guidelines for the laboratory diagnosis of malaria. Br J Haematol 2022; 197:271-282. [PMID: 35262915 DOI: 10.1111/bjh.18092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Claire L Rogers
- The London School of Hygiene and Tropical Medicine, London, UK
| | - Barbara J Bain
- St Mary's Hospital Campus of Imperial College London, London, UK
| | - Mamta Garg
- University Hospitals of Leicester NHS Trust, Leicester, UK
| | | | | | - Peter L Chiodini
- The London School of Hygiene and Tropical Medicine, London, UK.,The Hospital for Tropical Diseases, London, UK
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Dhorda M, Ba EH, Kevin Baird J, Barnwell J, Bell D, Carter JY, Dondorp A, Ekawati L, Gatton M, González I, Guérin PJ, Incardona S, Lilley K, Menard D, Nosten F, Obare P, Ogutu B, Olliaro PL, Price RN, Proux S, Ramsay AR, Reeder JC, Silamut K, Sokhna C. Towards harmonization of microscopy methods for malaria clinical research studies. Malar J 2020; 19:324. [PMID: 32887612 PMCID: PMC7471592 DOI: 10.1186/s12936-020-03352-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 07/28/2020] [Indexed: 01/13/2023] Open
Abstract
Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies. These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.
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Affiliation(s)
- Mehul Dhorda
- WorldWide Antimalarial Resistance Network, 60th Anniversary Chalermprakhiat Building 3rd Floor, 420/6 Ratchawithi Road, Ratchathewi, Bangkok, 10400 Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - El Hadji Ba
- UMR 257 IRD VITROME, Campus IRD-UCAD, Dakar, Senegal
| | - J. Kevin Baird
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.418754.b0000 0004 1795 0993Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
| | - John Barnwell
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, Atlanta, USA
| | - David Bell
- Independent consultant, Issaquah, WA USA
| | - Jane Y. Carter
- grid.413353.30000 0004 0621 4210Amref Health Africa Headquarters, Nairobi, Kenya
| | - Arjen Dondorp
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lenny Ekawati
- grid.418754.b0000 0004 1795 0993Eijkman-Oxford Clinical Research Unit, Jakarta, Indonesia
| | - Michelle Gatton
- grid.1024.70000000089150953Queensland University of Technology, Brisbane, Australia
| | - Iveth González
- grid.475489.30000 0001 2364 5600Terre des Hommes Foundation, Geneva, Switzerland
| | - Philippe J. Guérin
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.499581.8WorldWide Antimalarial Resistance Network, Oxford, UK
| | | | - Ken Lilley
- Australian Defence Force Malaria and Infectious Disease Institute, Enoggera, Australia
| | - Didier Menard
- grid.418537.cInstitut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - François Nosten
- grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.10223.320000 0004 1937 0490Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Peter Obare
- grid.33058.3d0000 0001 0155 5938Kenya Medical Research Institute, Kisumu, Kenya
| | - Bernhards Ogutu
- grid.33058.3d0000 0001 0155 5938Kenya Medical Research Institute, Kisumu, Kenya
| | - Piero L. Olliaro
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ric N. Price
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.499581.8WorldWide Antimalarial Resistance Network, Oxford, UK ,grid.1043.60000 0001 2157 559XGlobal Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, NT Australia
| | - Stéphane Proux
- grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand ,grid.10223.320000 0004 1937 0490Shoklo Malaria Research Unit, Mae Sot, Thailand
| | - Andrew R. Ramsay
- grid.11914.3c0000 0001 0721 1626School of Medicine, University of St Andrews, St Andrews, UK
| | - John C. Reeder
- Special Programme for Research and Training in Tropical Diseases (TDR), a Co-sponsored Programme of UNICEF, UNDP, the World Bank and WHO, Geneva, Switzerland
| | - Kamolrat Silamut
- grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Cheikh Sokhna
- UMR 257 IRD VITROME, Campus IRD-UCAD, Dakar, Senegal
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Zhao OS, Kolluri N, Anand A, Chu N, Bhavaraju R, Ojha A, Tiku S, Nguyen D, Chen R, Morales A, Valliappan D, Patel JP, Nguyen K. Convolutional neural networks to automate the screening of malaria in low-resource countries. PeerJ 2020; 8:e9674. [PMID: 32832279 PMCID: PMC7413078 DOI: 10.7717/peerj.9674] [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] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/16/2020] [Indexed: 12/27/2022] Open
Abstract
Malaria is an infectious disease caused by Plasmodium parasites, transmitted through mosquito bites. Symptoms include fever, headache, and vomiting, and in severe cases, seizures and coma. The World Health Organization reports that there were 228 million cases and 405,000 deaths in 2018, with Africa representing 93% of total cases and 94% of total deaths. Rapid diagnosis and subsequent treatment are the most effective means to mitigate the progression into serious symptoms. However, many fatal cases have been attributed to poor access to healthcare resources for malaria screenings. In these low-resource settings, the use of light microscopy on a thin blood smear with Giemsa stain is used to examine the severity of infection, requiring tedious and manual counting by a trained technician. To address the malaria endemic in Africa and its coexisting socioeconomic constraints, we propose an automated, mobile phone-based screening process that takes advantage of already existing resources. Through the use of convolutional neural networks (CNNs), we utilize a SSD multibox object detection architecture that rapidly processes thin blood smears acquired via light microscopy to isolate images of individual red blood cells with 90.4% average precision. Then we implement a FSRCNN model that upscales 32 × 32 low-resolution images to 128 × 128 high-resolution images with a PSNR of 30.2, compared to a baseline PSNR of 24.2 through traditional bicubic interpolation. Lastly, we utilize a modified VGG16 CNN that classifies red blood cells as either infected or uninfected with an accuracy of 96.5% in a balanced class dataset. These sequential models create a streamlined screening platform, giving the healthcare provider the number of malaria-infected red blood cells in a given sample. Our deep learning platform is efficient enough to operate exclusively on low-tier smartphone hardware, eliminating the need for high-speed internet connection.
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Affiliation(s)
- Oliver S Zhao
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Nikhil Kolluri
- Department of Electrical & Computer Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Anagata Anand
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Nicholas Chu
- Department of Electrical & Computer Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Ravali Bhavaraju
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Aditya Ojha
- Department of Electrical & Computer Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Sandhya Tiku
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Dat Nguyen
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Ryan Chen
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Adriane Morales
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Deepti Valliappan
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, United States of America
| | - Juhi P Patel
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States of America
| | - Kevin Nguyen
- Department of Psychology, The University of Texas at Austin, Austin, TX, United States of America
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7
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Manescu P, Shaw MJ, Elmi M, Neary‐Zajiczek L, Claveau R, Pawar V, Kokkinos I, Oyinloye G, Bendkowski C, Oladejo OA, Oladejo BF, Clark T, Timm D, Shawe‐Taylor J, Srinivasan MA, Lagunju I, Sodeinde O, Brown BJ, Fernandez‐Reyes D. Expert-level automated malaria diagnosis on routine blood films with deep neural networks. Am J Hematol 2020; 95:883-891. [PMID: 32282969 DOI: 10.1002/ajh.25827] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 11/09/2022]
Abstract
Over 200 million malaria cases globally lead to half a million deaths annually. Accurate malaria diagnosis remains a challenge. Automated imaging processing approaches to analyze Thick Blood Films (TBF) could provide scalable solutions, for urban healthcare providers in the holoendemic malaria sub-Saharan region. Although several approaches have been attempted to identify malaria parasites in TBF, none have achieved negative and positive predictive performance suitable for clinical use in the west sub-Saharan region. While malaria parasite object detection remains an intermediary step in achieving automatic patient diagnosis, training state-of-the-art deep-learning object detectors requires the human-expert labor-intensive process of labeling a large dataset of digitized TBF. To overcome these challenges and to achieve a clinically usable system, we show a novel approach. It leverages routine clinical-microscopy labels from our quality-controlled malaria clinics, to train a Deep Malaria Convolutional Neural Network classifier (DeepMCNN) for automated malaria diagnosis. Our system also provides total Malaria Parasite (MP) and White Blood Cell (WBC) counts allowing parasitemia estimation in MP/μL, as recommended by the WHO. Prospective validation of the DeepMCNN achieves sensitivity/specificity of 0.92/0.90 against expert-level malaria diagnosis. Our approach PPV/NPV performance is of 0.92/0.90, which is clinically usable in our holoendemic settings in the densely populated metropolis of Ibadan. It is located within the most populous African country (Nigeria) and with one of the largest burdens of Plasmodium falciparum malaria. Our openly available method is of importance for strategies aimed to scale malaria diagnosis in urban regions where daily assessment of thousands of specimens is required.
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Affiliation(s)
- Petru Manescu
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Michael J. Shaw
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Muna Elmi
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Lydia Neary‐Zajiczek
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Remy Claveau
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Vijay Pawar
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Iasonas Kokkinos
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Gbeminiyi Oyinloye
- Department of Paediatrics, College of Medicine University of IbadanUniversity College Hospital Ibadan Nigeria
- Childhood Malaria Research GroupCollege of Medicine University of Ibadan, University College Hospital Ibadan Nigeria
| | - Christopher Bendkowski
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Olajide A. Oladejo
- Department of Computer ScienceUniversity of Ibadan Ibadan Nigeria
- African Computational Sciences Centre for Health and DevelopmentUniversity of Ibadan Ibadan Nigeria
| | - Bolanle F. Oladejo
- Department of Computer ScienceUniversity of Ibadan Ibadan Nigeria
- African Computational Sciences Centre for Health and DevelopmentUniversity of Ibadan Ibadan Nigeria
| | - Tristan Clark
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Denis Timm
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - John Shawe‐Taylor
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Mandayam A. Srinivasan
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
| | - Ikeoluwa Lagunju
- Department of Paediatrics, College of Medicine University of IbadanUniversity College Hospital Ibadan Nigeria
- Childhood Malaria Research GroupCollege of Medicine University of Ibadan, University College Hospital Ibadan Nigeria
- African Computational Sciences Centre for Health and DevelopmentUniversity of Ibadan Ibadan Nigeria
| | - Olugbemiro Sodeinde
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
- Department of Paediatrics, College of Medicine University of IbadanUniversity College Hospital Ibadan Nigeria
- Childhood Malaria Research GroupCollege of Medicine University of Ibadan, University College Hospital Ibadan Nigeria
| | - Biobele J. Brown
- Department of Paediatrics, College of Medicine University of IbadanUniversity College Hospital Ibadan Nigeria
- Childhood Malaria Research GroupCollege of Medicine University of Ibadan, University College Hospital Ibadan Nigeria
- African Computational Sciences Centre for Health and DevelopmentUniversity of Ibadan Ibadan Nigeria
| | - Delmiro Fernandez‐Reyes
- Department of Computer Science, Faculty of Engineering SciencesUniversity College London London UK
- Department of Paediatrics, College of Medicine University of IbadanUniversity College Hospital Ibadan Nigeria
- Childhood Malaria Research GroupCollege of Medicine University of Ibadan, University College Hospital Ibadan Nigeria
- African Computational Sciences Centre for Health and DevelopmentUniversity of Ibadan Ibadan Nigeria
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8
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Okyere B, Owusu-Ofori A, Ansong D, Buxton R, Benson S, Osei-Akoto A, Owiredu EW, Adjei C, Xorse Amuzu E, Marfo Boaheng J, Dickerson T. Point prevalence of asymptomatic Plasmodium infection and the comparison of microscopy, rapid diagnostic test and nested PCR for the diagnosis of asymptomatic malaria among children under 5 years in Ghana. PLoS One 2020; 15:e0232874. [PMID: 32716936 PMCID: PMC7384639 DOI: 10.1371/journal.pone.0232874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/23/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasmodium infection among children is a serious public health problem. Asymptomatic malaria infection among humans serves as a significant reservoir for transmitting Plasmodium to uninfected Anopheles mosquitoes, fueling malaria endemicity and asymptomatic malaria may progress to clinical malaria. Therefore, prompt and accurate diagnosis of malaria infection is crucial for the management and control of malaria, especially in endemic areas. This study assessed the point prevalence of asymptomatic malaria infection and evaluated the performance of malaria Rapid Diagnostic Tests (RDT), light microscopy and nested PCR (nPCR) for the diagnosis of asymptomatic malaria infection in a paediatric population in the Atwima Nwabiagya North district, Ghana. METHODS This cross-sectional study enrolled 500 asymptomatic children aged ≤ 5 years. After consent was obtained from a parent, blood samples were collected from each participant to assess for Plasmodium infection based on histidine rich protein-2 (pfHRP-2)-based malaria RDT, light microscopy and nPCR. RESULTS The point prevalence of asymptomatic malaria by microscopy, RDT, and nPCR were 116/500 (23.2%), 156/500 (31.2%), and 184/500 (36.8%), respectively. Using nPCR as the reference, RDT presented with a perfect sensitivity (100.0%), specificity (100.0%), accuracy (100.0%), and reliability (100.0%) in detecting asymptomatic P. falciparum infection. Likewise, microscopy presented with an excellent specificity and high accuracy in detecting both P. falciparum (100.0%; 85.6%) and P. malariae (100.0%; 100.0%). However, the sensitivity (56.4%) and reliability (56.4%) of microscopy was low for both P. falciparum. CONCLUSION The findings of this study indicate a high point prevalence of asymptomatic Plasmodium infection among children in Atwima Nwabiagya North district, Ghana. In the absence of the more sensitive PCR, pfHRP-2-based malaria RDT provides substantial diagnostic sensitivity, specificity, accuracy and reliability and is superior to microscopy.
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Affiliation(s)
- Bismark Okyere
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Alex Owusu-Ofori
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Daniel Ansong
- Department of Child Health, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Rebecca Buxton
- Medical Laboratory Science Division, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Scott Benson
- Division of Public Health, Department of Family and Preventive Medicine, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Alex Osei-Akoto
- Department of Child Health, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Eddie-Williams Owiredu
- Department of Molecular Medicine, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Collins Adjei
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Evans Xorse Amuzu
- Research and Development Unit, Komfo Anokye Teaching Hospital, Kumasi, Ghana
| | | | - Ty Dickerson
- Division of Pediatric Inpatient Medicine, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
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Ngasala B, Bushukatale S. Evaluation of malaria microscopy diagnostic performance at private health facilities in Tanzania. Malar J 2019; 18:375. [PMID: 31771572 PMCID: PMC6880513 DOI: 10.1186/s12936-019-2998-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 11/11/2019] [Indexed: 12/04/2022] Open
Abstract
Background The World Health Organization (WHO) recommends use of parasitological diagnosis of malaria for all age groups in all malaria transmission settings. Many private health facilities rely on malaria microscopy for malaria diagnosis. However, quality of malaria microscopy is affected by number of factors including availability of skilled laboratory microscopists and lack of quality assurance systems in many malaria endemic countries. This study was carried out to assess quality of malaria microscopy in selected private health facilities in Tanzania. Methods A cross sectional study was conducted from August to September, 2017. A total of 40 private health laboratories in five regions were invited to participate in the study. Data were collected by distributing standardized pre-validated malaria slide-panels to each health facility. Sensitivity, specificity, and strength of agreement (with kappa score) were calculated to assess performance in detecting and quantification of Plasmodium species. Results Among the 40 health facilities, 31 (77.5%) returned their results to the reference centre (Muhimbili University of Health and Allied Sciences). Overall, the measures of malaria diagnostic accuracy were high, i.e. the sensitivity and specificity of malaria parasite detection by microscopy in the health facilities were 84.3% (95% CI 77–90) and 90.8% (95% CI 83.3–95.7), respectively. There was substantial agreement in parasite detection with (Kappa value: 0.74 (95% 0.65–0.83). However, only 17.8% (24 of 134) of blood slides were interpreted correctly at the health facilities in terms of parasite density counts. Conclusion Although there was substantial agreement between the private health microscopists and experienced microscopists in malaria parasite detection, there was poor performance in parasite counts. This calls for regular in-service training and external quality assessments at private health facilities to enhance the skills of private health facility microscopists in malaria microscopy.
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Affiliation(s)
- Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania. .,Department of Women's and Children's Health, International Maternal and Child Health (IMCH), Uppsala University, Uppsala, Sweden.
| | - Samweli Bushukatale
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
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Evaluation of the CellaVision DM96 advanced RBC application for screening and follow-up of malaria infection. Diagn Microbiol Infect Dis 2018; 90:253-256. [DOI: 10.1016/j.diagmicrobio.2017.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 11/15/2017] [Accepted: 12/02/2017] [Indexed: 12/16/2022]
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Grossman T, Schwartz E, Vainer J, Agmon V, Glazer Y, Goldmann D, Marva E. Contribution of real-time PCR to Plasmodium species identification and to clinical decisions: a nationwide study in a non-endemic setting. Eur J Clin Microbiol Infect Dis 2016; 36:671-675. [PMID: 27966198 DOI: 10.1007/s10096-016-2844-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/11/2016] [Indexed: 12/28/2022]
Abstract
Treatment choice for patients with malaria in Israeli hospitals is based on microscopy and rapid diagnostic tests (RDTs). Here, we demonstrate the cumulative value of real-time polymerase chain reaction (PCR) in optimizing the treatment of malaria. Between January 2009 and December 2015, 451 samples from 357 patients were tested in our laboratory using a real-time PCR assay. Hospital laboratory results (without real-time PCR) were compared to those obtained in our laboratory. A total of 307 patients had a malaria-positive laboratory finding in the hospital. Out of those, 288 were confirmed positive and 19 negative using real-time PCR. Two negative hospital results were found to be positive by real-time PCR. More specifically, of 153 cases positive for Plasmodium falciparum by real-time PCR, only 138 (90%) had been correctly identified at the hospitals. Similarly, 66 (67%) of 99 cases positive for P. vivax, 2 (11%) of 18 cases positive for P. ovale, and 3 (30%) of 10 cases positive for P. malariae had been correctly identified. Of 10 cases of mixed infection, only one had been identified as such at the hospital. Thus, real-time PCR was required for correct identification in 81 (28%) out of 290 positive cases. In 52 (18%) of those, there was an erroneous categorization of relapsing versus non-relapsing parasites. In a nationwide study, we found that the use of real-time PCR is definitely beneficial and may change the decision regarding the choice of treatment.
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Affiliation(s)
- T Grossman
- Reference Parasitology Laboratory, Central Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel.
| | - E Schwartz
- Center for Geographic Medicine and Tropical Diseases, Sheba Medical Center, and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - J Vainer
- Reference Parasitology Laboratory, Central Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - V Agmon
- Reference Parasitology Laboratory, Central Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - Y Glazer
- Epidemiological Division, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - D Goldmann
- Epidemiological Division, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - E Marva
- Reference Parasitology Laboratory, Central Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel
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Grimberg BT, Grimberg KO. Hemozoin detection may provide an inexpensive, sensitive, 1-minute malaria test that could revolutionize malaria screening. Expert Rev Anti Infect Ther 2016; 14:879-83. [PMID: 27530228 PMCID: PMC5224914 DOI: 10.1080/14787210.2016.1222900] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 08/08/2016] [Indexed: 12/25/2022]
Abstract
Malaria remains widespread throughout the tropics and is a burden to the estimated 3.5 billion people who are exposed annually. The lack of a fast and accurate diagnostic method contributes to preventable malaria deaths and its continued transmission. In many areas diagnosis is made solely based on clinical presentation. Current methods for malaria diagnosis take more than 20 minutes from the time blood is drawn and are frequently inaccurate. The introduction of an accurate malaria diagnostic that can provide a result in less than 1 minute would allow for widespread screening and treatment of endemic populations, and enable regions that have gained a foothold against malaria to prevent its return. Using malaria parasites' waste product, hemozoin, as a biomarker for the presence of malaria could be the tool needed to develop this rapid test.
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Affiliation(s)
- Brian T Grimberg
- a School of Medicine - Center for Global Health and Diseases , Case Western Reserve University , Cleveland , OH , USA
| | - Kerry O Grimberg
- b School of Medicine, Department of Radiology , Case Western Reserve University , Cleveland , OH , USA
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Shaw-Saliba K, Thomson-Luque R, Obaldía N, Nuñez M, Dutary S, Lim C, Barnes S, Kocken CHM, Duraisingh MT, Adams JH, Pasini EM. Insights into an Optimization of Plasmodium vivax Sal-1 In Vitro Culture: The Aotus Primate Model. PLoS Negl Trop Dis 2016; 10:e0004870. [PMID: 27463518 PMCID: PMC4963040 DOI: 10.1371/journal.pntd.0004870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/30/2016] [Indexed: 01/03/2023] Open
Abstract
Malaria is one of the most significant tropical diseases, and of the Plasmodium species that cause human malaria, P. vivax is the most geographically widespread. However, P. vivax remains a relatively neglected human parasite since research is typically limited to laboratories with direct access to parasite isolates from endemic field settings or from non-human primate models. This restricted research capacity is in large part due to the lack of a continuous P. vivax in vitro culture system, which has hampered the ability for experimental research needed to gain biological knowledge and develop new therapies. Consequently, efforts to establish a long-term P. vivax culture system are confounded by our poor knowledge of the preferred host cell and essential nutrients needed for in vitro propagation. Reliance on very heterogeneous P. vivax field isolates makes it difficult to benchmark parasite characteristics and further complicates development of a robust and reliable culture method. In an effort to eliminate parasite variability as a complication, we used a well-defined Aotus-adapted P. vivax Sal-1 strain to empirically evaluate different short-term in vitro culture conditions and compare them with previous reported attempts at P. vivax in vitro culture Most importantly, we suggest that reticulocyte enrichment methods affect invasion efficiency and we identify stabilized forms of nutrients that appear beneficial for parasite growth, indicating that P. vivax may be extremely sensitive to waste products. Leuko-depletion methods did not significantly affect parasite development. Formatting changes such as shaking and static cultures did not seem to have a major impact while; in contrast, the starting haematocrit affected both parasite invasion and growth. These results support the continued use of Aotus-adapted Sal-1 for development of P. vivax laboratory methods; however, further experiments are needed to optimize culture conditions to support long-term parasite development.
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Affiliation(s)
- Kathryn Shaw-Saliba
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Richard Thomson-Luque
- Center for Global Health & Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Nicanor Obaldía
- Center for the Evaluation of Antimalarial Drugs and Vaccines, Tropical Medicine Research / Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, Panamá
| | - Marlon Nuñez
- Center for the Evaluation of Antimalarial Drugs and Vaccines, Tropical Medicine Research / Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, Panamá
| | - Sahir Dutary
- Center for the Evaluation of Antimalarial Drugs and Vaccines, Tropical Medicine Research / Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá, Panamá
| | - Caeul Lim
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Samantha Barnes
- Center for Global Health & Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | | | - Manoj T. Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
- * E-mail: (MTD); (JHA); (EMP)
| | - John H. Adams
- Center for Global Health & Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida, United States of America
- * E-mail: (MTD); (JHA); (EMP)
| | - Erica M. Pasini
- Biomedical Primate Research Centre, Rijswijk, The Netherlands
- * E-mail: (MTD); (JHA); (EMP)
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Muñoz J, Rojo-Marcos G, Ramírez-Olivencia G, Salas-Coronas J, Treviño B, Perez Arellano JL, Torrús D, Muñoz Vilches MJ, Ramos JM, Alegría I, López-Vélez R, Aldasoro E, Perez-Molina JA, Rubio JM, Bassat Q. Diagnóstico y tratamiento de la malaria importada en España: recomendaciones del Grupo de Trabajo de Malaria de la Sociedad Española de Medicina Tropical y Salud Internacional (SEMTSI). Enferm Infecc Microbiol Clin 2015; 33:e1-e13. [DOI: 10.1016/j.eimc.2013.12.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/21/2013] [Accepted: 12/25/2013] [Indexed: 01/05/2023]
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Valente ARS, Jesus LMT, Hall A, Leahy M. Event- and interval-based measurement of stuttering: a review. INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS 2015; 50:14-30. [PMID: 24919948 DOI: 10.1111/1460-6984.12113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
BACKGROUND Event- and interval-based measurements are two different ways of computing frequency of stuttering. Interval-based methodology emerged as an alternative measure to overcome problems associated with reproducibility in the event-based methodology. No review has been made to study the effect of methodological factors in interval-based absolute reliability data or to compute the agreement between the two methodologies in terms of inter-judge, intra-judge and accuracy (i.e., correspondence between raters' scores and an established criterion). AIMS To provide a review related to reproducibility of event-based and time-interval measurement, and to verify the effect of methodological factors (training, experience, interval duration, sample presentation order and judgment conditions) on agreement of time-interval measurement; in addition, to determine if it is possible to quantify the agreement between the two methodologies METHODS & PROCEDURES The first two authors searched for articles on ERIC, MEDLINE, PubMed, B-on, CENTRAL and Dissertation Abstracts during January-February 2013 and retrieved 495 articles. Forty-eight articles were selected for review. Content tables were constructed with the main findings. MAIN CONTRIBUTION Articles related to event-based measurements revealed values of inter- and intra-judge greater than 0.70 and agreement percentages beyond 80%. The articles related to time-interval measures revealed that, in general, judges with more experience with stuttering presented significantly higher levels of intra- and inter-judge agreement. Inter- and intra-judge values were beyond the references for high reproducibility values for both methodologies. Accuracy (regarding the closeness of raters' judgements with an established criterion), intra- and inter-judge agreement were higher for trained groups when compared with non-trained groups. Sample presentation order and audio/video conditions did not result in differences in inter- or intra-judge results. A duration of 5 s for an interval appears to be an acceptable agreement. Explanation for high reproducibility values as well as parameter choice to report those data are discussed. CONCLUSIONS & IMPLICATIONS Both interval- and event-based methodologies used trained or experienced judges for inter- and intra-judge determination and data were beyond the references for good reproducibility values. Inter- and intra-judge values were reported in different metric scales among event- and interval-based methods studies, making it unfeasible to quantify the agreement between the two methods.
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Affiliation(s)
- Ana Rita S Valente
- Institute of Electronics and Informatics Engineering of Aveiro (IEETA), University of Aveiro, Aveiro, Portugal; Department of Education (DE), University of Aveiro, Aveiro, Portugal
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Sathpathi S, Mohanty AK, Satpathi P, Mishra SK, Behera PK, Patel G, Dondorp AM. Comparing Leishman and Giemsa staining for the assessment of peripheral blood smear preparations in a malaria-endemic region in India. Malar J 2014; 13:512. [PMID: 25551376 PMCID: PMC4320490 DOI: 10.1186/1475-2875-13-512] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Accepted: 11/27/2014] [Indexed: 11/10/2022] Open
Abstract
Background Microscopy of peripheral blood thin and thick films remains the reference for malaria diagnosis. Although Giemsa staining is most commonly used, the Leishman staining method provides better visualization of the nuclear chromatin pattern of cells. It is less well known whether accuracy of parasitaemia assessment is equally accurate with the latter method. Methods Peripheral blood thin and thick smears from consecutive febrile patients admitted to Ispat General hospital, Rourkela, Odhisa, India, were stained with Giemsa and Leishman stain. Methods were compared for species identification, parasite quantification, and ability for identification of alternative diagnoses. Results Blood films from 1,180 fever patients were compared according to staining method, of which 111 were identified as parasitaemic using Giemsa and 110 with Leishman staining. The Kappa value as a measure of agreement between methods was 0.995 (p < 0.001), and the log10parasitaemia between methods were strongly correlated (r2 = 0.9981). In parasite negative patients, thin smear assessment contributed to making a diagnosis in 276/1,180 (23%) of cases. These assessments were better made in Leishman-stained preparations, especially for the assessment of morphological changes in red and white cells. Conclusion Leishman’s staining method for thin and thick smears is a good alternative to Giemsa’s stain for identifying Plasmodium parasites. The Leishman method is superior for visualization of red and white blood cell morphology.
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Affiliation(s)
| | | | | | | | | | | | - Arjen M Dondorp
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Maganda BA, Minzi OMS, Kamuhabwa AAR, Ngasala B, Sasi PG. Outcome of artemether-lumefantrine treatment for uncomplicated malaria in HIV-infected adult patients on anti-retroviral therapy. Malar J 2014; 13:205. [PMID: 24885714 PMCID: PMC4051371 DOI: 10.1186/1475-2875-13-205] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 05/23/2014] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Malaria and HIV infections are both highly prevalent in sub-Saharan Africa, with HIV-infected patients being at higher risks of acquiring malaria. The majority of antiretroviral (ART) and anti-malarial drugs are metabolized by the CYP450 system, creating a chance of drug-drug interaction upon co-administration. Limited data are available on the effectiveness of the artemether-lumefantrine combination (AL) when co-administered with non-nucleoside reverse transcriptase inhibitors (NNRTIs). The aim of this study was to compare anti-malarial treatment responses between HIV-1 infected patients on either nevirapine- or efavirenz-based treatment and those not yet on ART (control-arm) with uncomplicated falciparum malaria, treated with AL. METHOD This was a prospective, non-randomized, open-label study conducted in Bagamoyo district, with three arms of HIV-infected adults: efavirenz-based treatment arm (EFV-arm) n = 66, nevirapine-based treatment arm (NVP-arm) n = 128, and control-arm n = 75, with uncomplicated malaria. All patients were treated with AL and followed up for 28 days. The primary outcome measure was an adequate clinical and parasitological response (ACPR) after treatment with AL by day 28. RESULTS Day 28 ACPR was 97.6%, 82.5% and 94.5% for the NVP-arm, EFV-arm and control-arm, respectively. No early treatment or late parasitological failure was reported. The cumulative risk of recurrent parasitaemia was >19-fold higher in the EFV-arm than in the control-arm (Hazard ratio [HR], 19.11 [95% confidence interval {CI}, 10.5-34.5]; P < 0.01). The cumulative risk of recurrent parasitaemia in the NVP-arm was not significantly higher than in the control-arm ([HR], 2.44 [95% {CI}, 0.79-7.6]; P = 0.53). The median (IQR) day 7 plasma concentrations of lumefantrine for the three arms were: 1,125 ng/m (638.8-1913), 300.4 ng/ml (220.8-343.1) and 970 ng/ml (562.1-1729) for the NVP-arm, the EFV-arm and the control-arm, respectively (P < 0.001). In all three arms, the reported adverse events were mostly mild. CONCLUSION After 28 days of follow-up, AL was statistically safe and effective in the treatment of uncomplicated malaria in the NVP-arm. The results of this study also provide an indication of the possible impact of EFV on the performance of AL and the likelihood of it affecting uncomplicated falciparum malaria treatment outcome.
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Affiliation(s)
| | - Omary M S Minzi
- Unit of Pharmacology and Therapeutics, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P,O, BOX 65013, Dar es Salaam, Tanzania.
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Bailey JW, Williams J, Bain BJ, Parker-Williams J, Chiodini PL. Guideline: the laboratory diagnosis of malaria. General Haematology Task Force of the British Committee for Standards in Haematology. Br J Haematol 2013; 163:573-80. [PMID: 24219330 DOI: 10.1111/bjh.12572] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/15/2013] [Indexed: 11/30/2022]
Abstract
UK National External Quality Assessment Service surveys indicate continuing problems in malaria diagnosis: inaccurate calculation of parasitaemia or failure to estimate it altogether, difficulty distinguishing Plasmodium vivax from P. ovale, reporting malaria parasites when none were present and misidentification of P. falciparum as another species still occur. Therefore, the British Committee for Standards in Haematology Guidelines for the Laboratory Diagnosis of Malaria have been revised. They are intended for use in the UK but may also prove useful in other non-endemic areas. Routine use of thick and thin films is advised for malaria diagnosis. Thick films should be stained using Giemsa or Field stain. Thin films should be stained with Giemsa stain or Leishman stain. Thick films should be examined by two observers, each viewing a minimum of 200 high power fields. If thick films are positive, the species should be determined by examination of a thin film. In the case of P. falciparum or P. knowlesi infection, the percentage of parasitized cells or the number of parasites per microlitre (/μl) should be estimated and reported. Rapid diagnostic tests (RDTs) for malarial antigen cannot replace microscopy but are indicated as a supplementary test when malaria diagnosis is performed by relatively inexperienced staff. Malaria RDTs are negative in babesiosis.
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Affiliation(s)
- J Wendi Bailey
- Clinical Diagnostic Parasitology Laboratory, Liverpool School of Tropical Medicine, Liverpool, UK
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Manser M, Olufsen C, Andrews N, Chiodini PL. Estimating the parasitaemia of Plasmodium falciparum: experience from a national EQA scheme. Malar J 2013; 12:428. [PMID: 24261625 PMCID: PMC4222811 DOI: 10.1186/1475-2875-12-428] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 11/12/2013] [Indexed: 11/24/2022] Open
Abstract
Background To examine performance of the identification and estimation of percentage parasitaemia of Plasmodium falciparum in stained blood films distributed in the UK National External Quality Assessment Scheme (UKNEQAS) Blood Parasitology Scheme. Methods Analysis of performance for the diagnosis and estimation of the percentage parasitaemia of P. falciparum in Giemsa-stained thin blood films was made over a 15-year period to look for trends in performance. Results An average of 25% of participants failed to estimate the percentage parasitaemia, 17% overestimated and 8% underestimated, whilst 5% misidentified the malaria species present. Conclusions Although the results achieved by participants for other blood parasites have shown an overall improvement, the level of performance for estimation of the parasitaemia of P. falciparum remains unchanged over 15 years. Possible reasons include incorrect calculation, not examining the correct part of the film and not examining an adequate number of microscope fields.
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Affiliation(s)
- Monika Manser
- UKNEQAS Parasitology, Department of Clinical Parasitology, Hospital for Tropical Diseases, Mortimer Market, Capper Street, London WC1E 6JB, UK.
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Billo MA, Diakité M, Dolo A, Diallo M, Poudiougou B, Diawara SI, Johnson ES, Rice JC, Krogstad DJ, Doumbo OK. Inter-observer agreement according to malaria parasite density. Malar J 2013; 12:335. [PMID: 24053719 PMCID: PMC3849530 DOI: 10.1186/1475-2875-12-335] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 09/15/2013] [Indexed: 11/21/2022] Open
Abstract
Background Recent developments in diagnostic techniques for malaria, particularly DNA probes and sero-immunology, have raised questions as to how these techniques might be used to facilitate malaria diagnosis at the most peripheral levels of the primary health care system. At present, malaria diagnosis is based on the standard microscopic examination of blood films in most field epidemiologic studies and is likely to remain so in the immediate future in Africa. The objective of this study was to assess inter-observer agreement for the examination of Giemsa-stained slides for Plasmodium falciparum parasites. Methods Children aged 0 to 10 years were enrolled yearly in Bancoumana village (West Africa), mainly during the transmission season (June to October). The blood smears obtained from the persistently negative children in June 1996, August 1996, October 1996 and March 1997 were systematically re-examined. A stratified random sample (10%) proportional to the following parasite density classes 1–100, 101–5000, and 5001 and over was taken from the slides collected. The kappa statistics and the intra-class correlation were used as measures of agreement the first and the second slide examinations. Results The weighted kappa statistic, widely used as a chance-corrected measure for nominal agreement, showed excellent inter-observer agreement (κw=0.7926; 95% CI [0.7588, 0.8263]; p=0.01). The intra-class correlation co-efficient had the same value of 0.7926 confirming the appropriateness of the weighted kappa statistic. Inter-observer agreement for slides read as negative by one observer, or as containing more than 100 parasites per μl, was excellent: 97% (493/506) and 92% (145/158), respectively. In contrast, the inter-observer agreement for slides read by one observer as containing 1–100 parasites/μl was poor, 36% (96/268). Conclusions In field conditions in Mali, there was a high reproducibility for slides reported as negative or as having more than 100 parasites per μl. However, smears with readings of 1–100 parasites per μl were less reproducible and should be re-examined carefully.
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Abeles SR, Chuquiyauri R, Tong C, Vinetz JM. Human host-derived cytokines associated with Plasmodium vivax transmission from acute malaria patients to Anopheles darlingi mosquitoes in the Peruvian Amazon. Am J Trop Med Hyg 2013; 88:1130-7. [PMID: 23478585 DOI: 10.4269/ajtmh.12-0752] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Infection of mosquitoes by humans is not always successful in the setting of patent gametocytemia. This study tested the hypothesis that pro- or anti-inflammatory cytokines are associated with transmission of Plasmodium vivax to Anopheles darlingi mosquitoes in experimental infection. Blood from adults with acute, non-severe P. vivax malaria was fed to laboratory-reared F1 An. darlingi mosquitoes. A panel of cytokines at the time of mosquito infection was assessed in patient sera and levels compared among subjects who did and did not infect mosquitoes. Overall, blood from 43 of 99 (43%) subjects led to mosquito infection as shown by oocyst counts. Levels of IL-10, IL-6, TNF-α, and IFN-γ were significantly elevated in vivax infection and normalized 3 weeks later. The anti-inflammatory cytokine IL-10 was significantly higher in nontransmitters compared with top transmitters but was not in TNF-α and IFN-γ. The IL-10 elevation during acute malaria was associated with P. vivax transmission blocking.
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Jelinek T. Artemisinin based combination therapy in travel medicine. Travel Med Infect Dis 2013; 11:23-8. [PMID: 23465532 DOI: 10.1016/j.tmaid.2013.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 01/25/2013] [Accepted: 01/25/2013] [Indexed: 12/13/2022]
Abstract
A steadily increasing number of Western travellers are exposed to malaria. Also, numbers of migrants from malarious areas are increasing. Fast and effective treatment options are needed to ensure effective malaria treatment in these groups in the future. Artemisinin combinations are well tolerated and have shown high efficacy in malaria endemic areas. Since 2001, 42 malaria endemic countries, 23 of them in Africa, have adopted artemisinin based combination therapies recommended by WHO. An additional 14 countries are in the process of changing their malaria treatment policy. Studies in non-immune travellers confirm a rapid parasite clearance time and very low rate of side effects. Outpatient clinics and hospitals in non-endemic countries should have standard operating procedures for diagnosing and managing patients with malaria. In this setting, artemisinin combinations should be available for treatment of uncomplicated malaria as they are clearly superior to any other oral antimalarial in their fast reduction of parasite biomass and in decreasing clinical symptoms. Also, they are the drugs of choice for travellers who are advised to carry stand-by emergency treatment during their journey.
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Affiliation(s)
- Tomas Jelinek
- Berlin Center for Travel & Tropical Medicine, Berlin, Germany.
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23
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Askling HH, Bruneel F, Burchard G, Castelli F, Chiodini PL, Grobusch MP, Lopez-Vélez R, Paul M, Petersen E, Popescu C, Ramharter M, Schlagenhauf P. Management of imported malaria in Europe. Malar J 2012; 11:328. [PMID: 22985344 PMCID: PMC3489857 DOI: 10.1186/1475-2875-11-328] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 08/19/2012] [Indexed: 11/10/2022] Open
Abstract
In this position paper, the European Society for Clinical Microbiology and Infectious Diseases, Study Group on Clinical Parasitology, summarizes main issues regarding the management of imported malaria cases. Malaria is a rare diagnosis in Europe, but it is a medical emergency. A travel history is the key to suspecting malaria and is mandatory in patients with fever. There are no specific clinical signs or symptoms of malaria although fever is seen in almost all non-immune patients. Migrants from malaria endemic areas may have few symptoms.Malaria diagnostics should be performed immediately on suspicion of malaria and the gold- standard is microscopy of Giemsa-stained thick and thin blood films. A Rapid Diagnostic Test (RDT) may be used as an initial screening tool, but does not replace urgent microscopy which should be done in parallel. Delays in microscopy, however, should not lead to delayed initiation of appropriate treatment. Patients diagnosed with malaria should usually be hospitalized. If outpatient management is preferred, as is the practice in some European centres, patients must usually be followed closely (at least daily) until clinical and parasitological cure. Treatment of uncomplicated Plasmodium falciparum malaria is either with oral artemisinin combination therapy (ACT) or with the combination atovaquone/proguanil. Two forms of ACT are available in Europe: artemether/lumefantrine and dihydroartemisinin/piperaquine. ACT is also effective against Plasmodium vivax, Plasmodium ovale, Plasmodium malariae and Plasmodium knowlesi, but these species can be treated with chloroquine. Treatment of persistent liver forms in P. vivax and P. ovale with primaquine is indicated after excluding glucose 6 phosphate dehydrogenase deficiency. There are modified schedules and drug options for the treatment of malaria in special patient groups, such as children and pregnant women. The potential for drug interactions and the role of food in the absorption of anti-malarials are important considerations in the choice of treatment.Complicated malaria is treated with intravenous artesunate resulting in a much more rapid decrease in parasite density compared to quinine. Patients treated with intravenous artesunate should be closely monitored for haemolysis for four weeks after treatment. There is a concern in some countries about the lack of artesunate produced according to Good Manufacturing Practice (GMP).
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Affiliation(s)
- Helena H Askling
- Department of Medicine Solna/Unit for Infectious Diseases, Karolinska Institutet, Stockholm, Sweden
- Department of Communicable Disease Control and Prevention, Stockholm County Council, Stockholm, Sweden
| | - Fabrice Bruneel
- Intensive Care Unit, Centre Hospitalier de Versailles, Site André Mignot, 177 rue de Versailles, Le Chesnay 78150, France
| | - Gerd Burchard
- Bernhard-Nocht-Institut für Tropenmedizin, Hamburg, Germany
| | - Francesco Castelli
- University Division of Infectious and Tropical Diseases, University of Brescia and Spedali Civili General Hospital, Brescia, Italy
| | - Peter L Chiodini
- Hospital for Tropical Diseases and London School of Hygiene and Tropical Medicine, London, UK
| | - Martin P Grobusch
- Center for Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rogelio Lopez-Vélez
- Tropical Medicine & Clinical Parasitology. Infectious Diseases Department.Hospital Ramón y Cajal, Madrid, Spain
| | - Margaret Paul
- Department and Clinic of Tropical and Parasitic Diseases, University of Medical Sciences, Poznan, Poland
| | - Eskild Petersen
- Department of Infectious Diseases, Aarhus University Hospital Skejby, Aarhus, Denmark
| | - Corneliu Popescu
- Clinical Hospital of Infectious and Tropical Diseases "Dr.Victor Babes", University of Medicine and Pharmacy "Carol Davila" Bucharest, Bucharest, Romania
| | - Michael Ramharter
- Department. of Medicine I, Div. of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Patricia Schlagenhauf
- University of Zürich, Centre for Travel Medicine, Division of Epidemiology and Communicable Diseases, Zürich, Switzerland
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24
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Somsak V, Srichairatanakool S, Yuthavong Y, Kamchonwongpaisan S, Uthaipibull C. Flow cytometric enumeration of Plasmodium berghei-infected red blood cells stained with SYBR Green I. Acta Trop 2012; 122:113-8. [PMID: 22222185 DOI: 10.1016/j.actatropica.2011.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 12/19/2011] [Accepted: 12/21/2011] [Indexed: 01/21/2023]
Abstract
High-throughput methods for evaluation of in vivo efficacy of candidate compounds against Plasmodium parasites are necessary during the antimalarial drug development process. It is essential that enumeration of parasitemia in the infected blood from experimental host animals is accurate and reliable. Flow cytometric enumeration of parasitized cells stained with fluorescent dye is a rapid alternative method to conventional microscopic counting. In this study, a protocol for flow cytometric enumeration of rodent malaria parasite Plasmodium berghei-infected red blood cells (RBC) stained with SYBR Green I was developed. The optimal concentration of SYBR Green I used to stain infected RBC was 4× for 30 min. This SYBR Green I staining protocol in combination with the bi-dimensional FL-1(530)/FL-3(620) detection method accurately detects parasitemia above 0.02%. The dye is stable during the prolonged incubation period necessary for accurate enumeration of parasitemia, with no loss of fluorescent signal over a period of hours. This protocol was validated in an antimalarial assay and the result was comparable to that obtained from conventional microscopic counting. The SYBR Green I flow cytometric protocol is thus a rapid and precise tool for high-throughput in vivo antimalarial drug screening.
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Affiliation(s)
- Voravuth Somsak
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Pathumthani 12120, Thailand
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25
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Abstract
Parasite clearance rates are important measures of anti-malarial drug efficacy. They are particularly important in the assessment of artemisinin resistance. The slope of the log-linear segment in the middle of the parasite clearance curve has the least inter-individual variance and is the focus of therapeutic assessment. The factors affecting parasite clearance are reviewed. Methods of presentation and the approaches to analysis are discussed.
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Affiliation(s)
- N J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Andrade BB, Reis-Filho A, Barros AM, Souza-Neto SM, Nogueira LL, Fukutani KF, Camargo EP, Camargo LMA, Barral A, Duarte A, Barral-Netto M. Towards a precise test for malaria diagnosis in the Brazilian Amazon: comparison among field microscopy, a rapid diagnostic test, nested PCR, and a computational expert system based on artificial neural networks. Malar J 2010; 9:117. [PMID: 20459613 PMCID: PMC2883547 DOI: 10.1186/1475-2875-9-117] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 05/06/2010] [Indexed: 11/10/2022] Open
Abstract
Background Accurate malaria diagnosis is mandatory for the treatment and management of severe cases. Moreover, individuals with asymptomatic malaria are not usually screened by health care facilities, which further complicates disease control efforts. The present study compared the performances of a malaria rapid diagnosis test (RDT), the thick blood smear method and nested PCR for the diagnosis of symptomatic malaria in the Brazilian Amazon. In addition, an innovative computational approach was tested for the diagnosis of asymptomatic malaria. Methods The study was divided in two parts. For the first part, passive case detection was performed in 311 individuals with malaria-related symptoms from a recently urbanized community in the Brazilian Amazon. A cross-sectional investigation compared the diagnostic performance of the RDT Optimal-IT, nested PCR and light microscopy. The second part of the study involved active case detection of asymptomatic malaria in 380 individuals from riverine communities in Rondônia, Brazil. The performances of microscopy, nested PCR and an expert computational system based on artificial neural networks (MalDANN) using epidemiological data were compared. Results Nested PCR was shown to be the gold standard for diagnosis of both symptomatic and asymptomatic malaria because it detected the major number of cases and presented the maximum specificity. Surprisingly, the RDT was superior to microscopy in the diagnosis of cases with low parasitaemia. Nevertheless, RDT could not discriminate the Plasmodium species in 12 cases of mixed infections (Plasmodium vivax + Plasmodium falciparum). Moreover, the microscopy presented low performance in the detection of asymptomatic cases (61.25% of correct diagnoses). The MalDANN system using epidemiological data was worse that the light microscopy (56% of correct diagnoses). However, when information regarding plasma levels of interleukin-10 and interferon-gamma were inputted, the MalDANN performance sensibly increased (80% correct diagnoses). Conclusions An RDT for malaria diagnosis may find a promising use in the Brazilian Amazon integrating a rational diagnostic approach. Despite the low performance of the MalDANN test using solely epidemiological data, an approach based on neural networks may be feasible in cases where simpler methods for discriminating individuals below and above threshold cytokine levels are available.
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