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Alemu G, Nibret E. Evaluation of the Urine POC-CCA Test Accuracy in the Detection of Schistosoma mansoni Infection: A Systematic Review and Meta-Analysis. J Trop Med 2024; 2024:5531687. [PMID: 39040853 PMCID: PMC11262874 DOI: 10.1155/2024/5531687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/07/2024] [Accepted: 06/27/2024] [Indexed: 07/24/2024] Open
Abstract
Background Schistosomiasis is a common public health problem throughout the world and Schistosoma mansoni is the most prevalent species in Africa. Most endemic countries use the Kato-Katz (KK) stool smear examination for diagnosis, mapping, and monitoring of intervention programs. However, its poor sensitivity calls for an urgency to evaluate and use more accurate diagnostic tools, of which detection of circulating cathodic antigen (CCA) in urine seems promising. Methods Studies published until May 2022 were searched from PubMed, Google Scholar, and grey literature for systematic review and meta-analysis following the PRISMA guideline. Eligible studies were selected based on preset inclusion and exclusion criteria. Quality of included studies was assessed using the QUADAS-2 tool. Heterogeneity between studies was assessed using Cochrane Q test and I 2 test statistics. Data were analyzed using Review Manager 5.4.1 and Meta-DiSc 1.4 software programs. Results Thirty-seven studies published in 29 papers and enrolling 21159 study participants were included for analysis. Overall analysis of Point-of-Care Circulating Cathodic Antigen (POC-CCA) test against KK reference standard revealed a pooled sensitivity and specificity of 0.86 (95% CI: 0.85-0.87) and 0.66 (95% CI: 0.65-0.67), respectively. Subgroup analysis among 24 studies comparing single POC-CCA with test single KK revealed a high sensitivity (0.88) but low specificity (0.66). Based on findings of 24 studies, the area under the curve (AUC) for the systematic receiver operating characteristic (SROC) curve was 0.7805, indicating that the POC-CCA test effectively separates those with the disease from those who do not have it. Higher sensitivity estimates of 0.93 and 0.90 were reported when comparisons were made between test results of 2 urine and 1 stool samples, and 3 urine and 3 stool samples, respectively. Single POC-CCA test resulted in a pooled sensitivity estimate of 0.81 (95% CI: 0.78-0.84) as evaluated by the polymerase chain reaction (PCR) reference test. Conclusions The POC-CCA test has higher sensitivity than KK and may serve as a routine diagnostic alternative for disease diagnosis, mapping, and monitoring of interventions. However, its accuracy should further be evaluated at different transmission settings and infection intensity.
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Affiliation(s)
- Getaneh Alemu
- Department of Medical Laboratory ScienceBahir Dar University, Bahir Dar, Ethiopia
- Biology DepartmentScience CollegeBahir Dar University, Bahir Dar, Ethiopia
| | - Endalkachew Nibret
- Biology DepartmentScience CollegeBahir Dar University, Bahir Dar, Ethiopia
- Health Biotechnology DivisionInstitute of Biotechnology (IoB)Bahir Dar University, Bahir Dar, Ethiopia
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Dos Santos M, de Faria MT, da Silva JO, Gandra IB, Ribeiro AJ, Silva KA, Nogueira LM, Machado JM, da Silveira Mariano RM, Gonçalves AAM, Ludolf F, Candia-Puma MA, Chávez-Fumagalli MA, Campos-da-Paz M, Giunchetti RC, Galdino AS. A Mini-Review on Elisa-Based Diagnosis of Schistosomiasis. Curr Mol Med 2024; 24:585-598. [PMID: 37143281 DOI: 10.2174/1566524023666230504140828] [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: 10/19/2022] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 05/06/2023]
Abstract
BACKGROUND Schistosomiasis is a neglected tropical parasitic disease caused by trematode worms of the genus schistosoma, which affects approximately 240 million people worldwide. the diagnosis of the disease can be performed by parasitological, molecular, and/or immunological methods, however, the development of new diagnostic methods still essential to guide policy decisions, monitor disease trends and assess the effectiveness of interventions. OBJECTIVE in this sense, the current work summarizes the findings of a systematic review regarding antigens applied in the enzyme-linked immunosorbent assay test, which were patented and published over the last ten years. METHODS the literature search strategy used medical subject heading (mesh) terms to define as descriptors. "schistosoma mansoni" was used in arrangement with the descriptors "immunoassay", "enzyme-linked immunosorbent assay", "elisa", and "antigens", using the "and" connector. the patent search was done using keywords, including diagnosis and schistosoma or schistosomiasis or schistosome. several databases were employed for the patent search, such as intellectual property national institute; european patent office; the united states patent and trademark office; patent scope, and google patents. RESULTS forty-one articles were retrieved, of which only five met the eligibility criteria. seventeen patents were taken from the databases, and a brief description of the most relevant inventions is given here. CONCLUSION schistosomiasis is considered the most important helminthic disease in worldwide. therefore, it is important to of searching for and develops diagnostic methods based on serology to reduce morbidity and mortality caused by the disease.
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Affiliation(s)
- Michelli Dos Santos
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Mariana Teixeira de Faria
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Jonatas Oliveira da Silva
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Isadora Braga Gandra
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Anna Julia Ribeiro
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Kamila Alves Silva
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Lais Moreira Nogueira
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Juliana Martins Machado
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Reysla Maria da Silveira Mariano
- Laboratório de Biologia das Interações Celulares, Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, MG, Brazil
| | - Ana Alice Maia Gonçalves
- Laboratório de Biologia das Interações Celulares, Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, MG, Brazil
| | - Fernanda Ludolf
- Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, 30130-100, Minas Gerais, Brazil
| | - Mayron Antonio Candia-Puma
- Computational Biology and Chemistry Research Group, Vicerrectorado de Investigación, Universidad Católica de Santa María, Urb. San José S/N, Umacollo, Arequipa, 04000, Peru
| | - Miguel Angel Chávez-Fumagalli
- Computational Biology and Chemistry Research Group, Vicerrectorado de Investigación, Universidad Católica de Santa María, Urb. San José S/N, Umacollo, Arequipa, 04000, Peru
| | - Mariana Campos-da-Paz
- Laboratório de Bioativos & NanoBiotecnologia, Universidade Federal de São João Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
| | - Rodolfo Cordeiro Giunchetti
- Laboratório de Biologia das Interações Celulares, Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, MG, Brazil
| | - Alexsandro Sobreira Galdino
- Laboratório de Biotecnologia de Microrganismos, Universidade Federal de São Joao Del-Rei, Sebastião Gonçalves Coelho, Divinópolis, 400, 35501-296, MG, Brazil
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3
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Clark J, Moses A, Nankasi A, Faust CL, Moses A, Ajambo D, Besigye F, Atuhaire A, Wamboko A, Carruthers LV, Francoeur R, Tukahebwa EM, Prada JM, Lamberton PHL. Reconciling Egg- and Antigen-Based Estimates of Schistosoma mansoni Clearance and Reinfection: A Modeling Study. Clin Infect Dis 2022; 74:1557-1563. [PMID: 34358299 PMCID: PMC9070857 DOI: 10.1093/cid/ciab679] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Despite decades of interventions, 240 million people have schistosomiasis. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity, affected treatment efficacy and reinfection rate estimates. The point-of-care circulating cathodic antigen (referred to from here as POC-CCA+) test is advocated as an improvement on the Kato-Katz method, but improved estimates are limited by ambiguities in the interpretation of trace results. METHOD We collected repeated Kato-Katz egg counts from 210 school-aged children and scored POC-CCA tests according to the manufacturer's guidelines (referred to from here as POC-CCA+) and the externally developed G score. We used hidden Markov models parameterized with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding trace interpretations. RESULTS Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79%-92%), 99% (POC-CCA+; 97%-100%) and 98% (G-Score; 95%-100%). Post-treatment, 93% (Kato-Katz; 88%-96%), 72% (POC-CCA+; 64%-79%) and 65% (G-Score; 57%-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27%-42%), 51% (POC-CCA+; 41%-62%) and 44% (G-Score; 33%-55%) were estimated to have been reinfected by 9-weeks. CONCLUSIONS Treatment impact was shorter-lived than Kato-Katz-based estimates alone suggested, with lower clearance and rapid reinfection. At 3 weeks after treatment, longer-term clearance dynamics are captured. At 9 weeks after treatment, reinfection was captured, but failed clearance could not be distinguished from rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.
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Affiliation(s)
- Jessica Clark
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | | | - Christina L Faust
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Adriko Moses
- Vector Control Division, Ministry of Health, Uganda
| | - Diana Ajambo
- Vector Control Division, Ministry of Health, Uganda
| | - Fred Besigye
- Vector Control Division, Ministry of Health, Uganda
| | | | | | - Lauren V Carruthers
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Rachel Francoeur
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Faculty of Science & Engineering, University of Chester, Chester, United Kingdom
| | | | - Joaquin M Prada
- Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Poppy H L Lamberton
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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4
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Chirambo AC, Nyirenda TS, Jambo N, Msefula C, Kamng'ona A, Molina S, Mandala WL, Heyderman RS, Iturizza-Gomara M, Henrion MYR, Gordon MA. Performance of molecular methods for the detection of Salmonella in human stool specimens. Wellcome Open Res 2021; 5:237. [PMID: 34017923 PMCID: PMC8108707 DOI: 10.12688/wellcomeopenres.16305.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2021] [Indexed: 11/28/2022] Open
Abstract
Background: The relationship between asymptomatic
Salmonella exposure within the gastrointestinal tract and
Salmonella bacteraemia is poorly understood, in part due to the low sensitivity of stool culture and the lack of validated molecular diagnostic tests for the detection of
Salmonella in the stool. The study aimed to determine a reliable molecular diagnostic test for
Salmonella in stool specimens. Methods: We optimised an in-house monoplex real-time polymerase chain reaction (PCR) for the detection of
Salmonellattr and
InvA genes in stool by including a selenite broth pre-culture step for
Salmonella before DNA extraction and validated their specificity against other local common pathogens. Then we assessed their performance against a well-validated multiplex PCR targeting the same
ttr and
InvA genes and against stool culture using clinical stool specimens collected from a cohort of 50 asymptomatic healthy Malawian children that were sampled at 1-month intervals over 12 months. We employed a latent Markov model to estimate the specificities and sensitivities of PCR methods. Results:
Ttr and
InvA primers were both able to detect all the different
Salmonella serovars tested and had superior limits of detection when DNA was extracted after selenite pre-culture. T
tr sensitivity and specificity for monoplex-PCR were (99.53%, 95.46%) and for multiplex-PCR (90.30%, 99.30%) respectively.
InvA specificity and specificity for using monoplex-PCR was (95.06%, 90.31%) and multiplex-PCRs (89.41%, 98.00%) respectively. Sensitivity and specificity for standard stool culture were 62.88% and 99.99%, respectively. Culture showed the highest PPV (99.73%), and monoplex-
ttr had the highest NPV (99.67%). Conclusion: Test methods demonstrated high concordance, although stool culture and monoplexed
ttr primers had superior specificity and sensitivity, respectively. The use of selenite pre-enrichment step increased
Salmonella detection rate. Taken together, molecular detection methods used here could be used to reveal the true extent of both asymptomatic and symptomatic
Salmonella exposure events.
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Affiliation(s)
- Angeziwa Chunga Chirambo
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Pathology Department, College of Medicine, Malawi, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Tonney S Nyirenda
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Pathology Department, College of Medicine, Malawi, Blantyre, Malawi
| | - Ndaru Jambo
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Pathology Department, College of Medicine, Malawi, Blantyre, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Chisomo Msefula
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Pathology Department, College of Medicine, Malawi, Blantyre, Malawi
| | - Arox Kamng'ona
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Biomedical Sciences Department, College of Medicine, Malawi, Blantyre, Malawi
| | - Sandra Molina
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Wilson L Mandala
- Malawi University of Science and Technology, Thyolo, +265, Malawi
| | - Robert S Heyderman
- Research Department of Infection, Division of Infection and Immunity, University College London, London, WC1E 6EJ, UK
| | - Miren Iturizza-Gomara
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
| | - Marc Y R Henrion
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome (MLW) Programme, Blantyre, +265, Malawi.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, L69 3BX, UK
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5
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Koukounari A, Jamil H, Erosheva E, Shiff C, Moustaki I. Latent Class Analysis: Insights about design and analysis of schistosomiasis diagnostic studies. PLoS Negl Trop Dis 2021; 15:e0009042. [PMID: 33539357 PMCID: PMC7888681 DOI: 10.1371/journal.pntd.0009042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 02/17/2021] [Accepted: 12/18/2020] [Indexed: 11/18/2022] Open
Abstract
Various global health initiatives are currently advocating the elimination of schistosomiasis within the next decade. Schistosomiasis is a highly debilitating tropical infectious disease with severe burden of morbidity and thus operational research accurately evaluating diagnostics that quantify the epidemic status for guiding effective strategies is essential. Latent class models (LCMs) have been generally considered in epidemiology and in particular in recent schistosomiasis diagnostic studies as a flexible tool for evaluating diagnostics because assessing the true infection status (via a gold standard) is not possible. However, within the biostatistics literature, classical LCM have already been criticised for real-life problems under violation of the conditional independence (CI) assumption and when applied to a small number of diagnostics (i.e. most often 3-5 diagnostic tests). Solutions of relaxing the CI assumption and accounting for zero-inflation, as well as collecting partial gold standard information, have been proposed, offering the potential for more robust model estimates. In the current article, we examined such approaches in the context of schistosomiasis via analysis of two real datasets and extensive simulation studies. Our main conclusions highlighted poor model fit in low prevalence settings and the necessity of collecting partial gold standard information in such settings in order to improve the accuracy and reduce bias of sensitivity and specificity estimates. Accurate schistosomiasis diagnosis is essential to assess the impact of large scale and repeated mass drug administration to control or even eliminate this disease. However, in schistosomiasis diagnostic studies, several inherent study design issues pose a real challenge for the currently available statistical tools used for diagnostic modelling and associated data analysis and conclusions. More specifically, those study design issues are: 1) the inclusion of small number of diagnostic tests (i.e. most often five), 2) non formal consensus about a schistosomiasis gold standard, 3) the contemporary use of relatively small sample sizes in relevant studies due to lack of research funding, 4) the differing levels of prevalence of the studied disease even within the same area of one endemic country and 5) other real world factors such as: the lack of appropriate equipment, the variability of certain methods due to biological phenomena and training of technicians across the endemic countries because of scarce financial resources contributing to the existing lack of a schistosomiasis gold standard. The current study aims to caution practitioners from blindly applying statistical models with small number of diagnostic tests and sample sizes, proposing design guidelines of future schistosomiasis diagnostic accuracy studies with recommendations for further research. While our study is centred around the diagnosis of schistosomiasis, we feel that the recommendations can be adapted to other major tropical infectious diseases as well.
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Affiliation(s)
- Artemis Koukounari
- Product Development Personalized Health Care, F. Hoffmann-La Roche Ltd., Welwyn Garden, United Kingdom
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Haziq Jamil
- Mathematical Sciences, Faculty of Science, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei
| | - Elena Erosheva
- Department of Statistics, School of Social Work, Center for Statistics and the Social Sciences, University of Washington, Seattle, Washington, United States of America
| | - Clive Shiff
- Molecular Microbiology and Immunology Department, John Hopkins Bloomberg School of Public Health
| | - Irini Moustaki
- Department of Statistics, London School of Economics and Political Science, London, United Kingdom
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6
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Chirambo AC, Nyirenda TS, Jambo N, Msefula C, Kamng'ona A, Molina S, Mandala WL, Heyderman RS, Iturizza-Gomara M, Henrion MY, Gordon MA. Performance of molecular methods for the detection of Salmonella in human stool specimens. Wellcome Open Res 2020; 5:237. [DOI: 10.12688/wellcomeopenres.16305.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 11/20/2022] Open
Abstract
Background: The relationship between asymptomatic Salmonella exposure within the gastrointestinal tract and Salmonella bacteraemia is poorly understood, in part due to the low sensitivity of stool culture, and the lack of validated molecular diagnostic tests for the detection of Salmonella in stool. The study aimed to determine a reliable molecular diagnostic test for Salmonella in stool specimens. Methods: We optimized an in-house monoplex real time polymerase chain reaction (PCR) for the detection of Salmonella TTR and InvA genes in stool by including a selenite broth pre-culture step for Salmonella before DNA extraction, and validated their specificity against other local common pathogens. Then we assessed their performance against a well-validated multiplex PCR targeting the same TTR and InvA genes, and against stool culture using clinical stool specimens collected from a cohort of 50 asymptomatic healthy Malawian children that were sampled at 1-month intervals over a period of 12 months. We employed a latent Markov model to estimate the specificities and sensitivities of PCR methods. Results: TTR and InvA primers were both able to detect all the different Salmonella serovars tested, and had superior limits of detection if DNA was extracted after selenite pre-culture. TTR sensitivity and specificity for monoplex-PCR were (99.53%, 95.46%) and for multiplex-PCR (90.30%, 99.30%) respectively. InvA specificity and specificity for using monoplex-PCR was (95.06%, 90.31%) and multiplex-PCRs (89.41%, 98.00%) respectively. Sensitivity and specificity for standard stool culture were 62.88% and 99.99% respectively. Culture showed the highest PPV (99.73%) and mono-TTR had the highest NPV (99.67%). Conclusion: Test methods demonstrated high concordance although stool culture and monoplexed TTR primers had superior specificity and sensitivity respectively. The use of selenite pre-enrichment step increased Salmonella detection rate. Taken together, molecular detection methods used here could be used to reveal the true extent of both asymptomatic and symptomatic Salmonella exposure events.
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7
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Midzi N, Bärenbold O, Manangazira P, Phiri I, Mutsaka-Makuvaza MJ, Mhlanga G, Utzinger J, Vounatsou P. Accuracy of different diagnostic techniques for Schistosoma haematobium to estimate treatment needs in Zimbabwe: Application of a hierarchical Bayesian egg count model. PLoS Negl Trop Dis 2020; 14:e0008451. [PMID: 32817650 PMCID: PMC7462259 DOI: 10.1371/journal.pntd.0008451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 09/01/2020] [Accepted: 06/04/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Treatment needs for Schistosoma haematobium are commonly evaluated using urine filtration with detection of parasite eggs under a microscope. A common symptom of S. haematobium is hematuria, the passing of blood in urine. Hence, the use of hematuria-based diagnostic techniques as a proxy for the assessment of treatment needs has been considered. This study evaluates data from a national survey in Zimbabwe, where three hematuria-based diagnostic techniques, that is microhematuria, macrohematuria, and an anamnestic questionnaire pertaining to self-reported blood in urine, have been included in addition to urine filtration in 280 schools across 70 districts. METHODOLOGY We developed an egg count model, which evaluates the infection intensity-dependent sensitivity and the specificity of each diagnostic technique without relying on a 'gold' standard. Subsequently, we determined prevalence thresholds for each diagnostic technique, equivalent to a 10% urine filtration-based prevalence and compared classification of districts according to treatment strategy based on the different diagnostic methods. PRINCIPAL FINDINGS A 10% urine filtration prevalence threshold corresponded to a 17.9% and 13.3% prevalence based on questionnaire and microhematuria, respectively. Both the questionnaire and the microhematuria showed a sensitivity and specificity of more than 85% for estimating treatment needs at the above thresholds. For diagnosis at individual level, the questionnaire showed the highest sensitivity (70.0%) followed by urine filtration (53.8%) and microhematuria (52.2%). CONCLUSIONS/SIGNIFICANCE The high sensitivity and specificity of a simple questionnaire to estimate treatment needs of S. haematobium suggests that it can be used as a rapid, low-cost method to estimate district prevalence. Our modeling approach can be expanded to include setting-dependent specificity of the technique and should be assessed in relation to other diagnostic methods due to potential cross-reaction with other diseases.
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Affiliation(s)
- Nicholas Midzi
- National Institute of Health Research, Ministry of Health and Child Care, Harare, Zimbabwe
| | - Oliver Bärenbold
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Portia Manangazira
- National Institute of Health Research, Ministry of Health and Child Care, Harare, Zimbabwe
| | - Isaac Phiri
- National Institute of Health Research, Ministry of Health and Child Care, Harare, Zimbabwe
| | - Masceline J. Mutsaka-Makuvaza
- National Institute of Health Research, Ministry of Health and Child Care, Harare, Zimbabwe
- Department of Medical Microbiology, University of Zimbabwe, Harare, Zimbabwe
| | - Gibson Mhlanga
- National Institute of Health Research, Ministry of Health and Child Care, Harare, Zimbabwe
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
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8
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Hoekstra PT, Casacuberta-Partal M, van Lieshout L, Corstjens PLAM, Tsonaka R, Assaré RK, Silué KD, Meité A, N’Goran EK, N’Gbesso YK, Amoah AS, Roestenberg M, Knopp S, Utzinger J, Coulibaly JT, van Dam GJ. Efficacy of single versus four repeated doses of praziquantel against Schistosoma mansoni infection in school-aged children from Côte d'Ivoire based on Kato-Katz and POC-CCA: An open-label, randomised controlled trial (RePST). PLoS Negl Trop Dis 2020; 14:e0008189. [PMID: 32196506 PMCID: PMC7112237 DOI: 10.1371/journal.pntd.0008189] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/01/2020] [Accepted: 03/02/2020] [Indexed: 11/21/2022] Open
Abstract
Background Preventive chemotherapy with praziquantel (PZQ) is the cornerstone of schistosomiasis control. However, a single dose of PZQ (40 mg/kg) does not cure all infections. Repeated doses of PZQ at short intervals might increase efficacy in terms of cure rate (CR) and intensity reduction rate (IRR). Here, we determined the efficacy of a single versus four repeated treatments with PZQ on Schistosoma mansoni infection in school-aged children from Côte d’Ivoire, using two different diagnostic tests. Methods An open-label, randomized controlled trial was conducted from October 2018 to January 2019. School-aged children with a confirmed S. mansoni infection based on Kato-Katz (KK) and point-of-care circulating cathodic antigen (POC-CCA) urine cassette test were randomly assigned to receive either a single or four repeated doses of PZQ, administered at two-week intervals. The primary outcome was the difference in CR between the two treatment arms, measured by triplicate KK thick smears 10 weeks after the first treatment. Secondary outcomes included CR estimated by POC-CCA, IRR by KK and POC-CCA, and safety of repeated PZQ administration. Principal findings During baseline screening, 1,022 children were assessed for eligibility of whom 153 (15%) had a detectable S. mansoni infection, and hence, were randomized to the standard treatment group (N = 70) and the intense treatment group (N = 83). Based on KK, the CR was 42% (95% confidence interval (CI) 31–52%) in the standard treatment group and 86% (95% CI 75–92%) in the intense treatment group. Observed IRR was 72% (95% CI 55–83%) in the standard treatment group and 95% (95% CI 85–98%) in the intense treatment group. The CR estimated by POC-CCA was 18% (95% CI 11–27%) and 36% (95% CI 26–46%) in the standard and intense treatment group, respectively. Repeated PZQ treatment did not result in a higher number of adverse events. Conclusion/significance The observed CR using KK was significantly higher after four repeated treatments compared to a single treatment, without an increase in adverse events. Using POC-CCA, the observed CR was significantly lower than measured by KK, indicating that PZQ may be considerably less efficacious as concluded by KK. Our findings highlight the need for reliable and more accurate diagnostic tools, which are essential for monitoring treatment efficacy, identifying changes in transmission, and accurately quantifying the intensity of infection in distinct populations. In addition, the higher CR in the intense treatment group suggests that more focused and intense PZQ treatment can help to advance schistosomiasis control. Trial registration www.clinicaltrials.govNCT02868385. The previously established efficacy of the widely used drug praziquantel (PZQ) against schistosomiasis might have been overestimated due to the use of inaccurate diagnostic methods. Repeated PZQ treatment at short intervals in areas with ongoing transmission could more effectively target non-susceptible schistosomula as they will have matured into drug susceptible worms within a few weeks. In the current study, we aimed to determine the cure rate (CR) of repeated PZQ, measured by the Kato-Katz (KK) technique and the point-of-care circulating cathodic antigen (POC-CCA) test, respectively. An open-label, randomized controlled trial was conducted assigning 153 school-aged children with a confirmed Schistosoma mansoni infection to two groups, one receiving a single PZQ treatment, while the second group received four repeated PZQ treatments, given at two-week intervals. Based on the KK test, the CR was significantly higher after four repeated treatments compared to a single treatment. When using POC-CCA, a diagnostic method that has not been utilized before in studies assessing the efficacy of four repeated PZQ treatments, the CR was much lower, even after four repeated PZQ treatments. Our results indicate that worms are still present after multiple PZQ treatments and that PZQ might be less efficacious than previously published.
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Affiliation(s)
- Pytsje T. Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
- * E-mail:
| | | | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Paul L. A. M. Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Roula Tsonaka
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Rufin K. Assaré
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Kigbafori D. Silué
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Aboulaye Meité
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Ministère de la Santé et de l’Hygiène Publique, Abidjan, Côte d’Ivoire
| | - Eliézer K. N’Goran
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Yves K. N’Gbesso
- Département d’Agboville, Centre de Santé Urbain d’Azaguié, Azaguié, Côte d’Ivoire
| | - Abena S. Amoah
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Malawi Epidemiology and Intervention Research Unit, Chilumba, Karonge District, Malawi
| | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, the Netherlands
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jean T. Coulibaly
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
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9
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Saelens G, Gabriël S. Currently Available Monitoring and Surveillance Systems for Taenia spp., Echinococcus spp., Schistosoma spp., and Soil-Transmitted Helminths at the Control/Elimination Stage: A Systematic Review. Pathogens 2020; 9:E47. [PMID: 31935916 PMCID: PMC7168685 DOI: 10.3390/pathogens9010047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/02/2020] [Accepted: 01/02/2020] [Indexed: 12/13/2022] Open
Abstract
An increasing global focus on neglected tropical diseases (NTDs) has resulted in the set up of numerous control and elimination activities worldwide. This is partly true for Taenia solium taeniasis/cysticercosis, the most important foodborne parasitic infection. Despite substantial progress, adequate monitoring and surveillance (M&S) are required to sustain a status of control/elimination. This is often lacking, especially for T. solium. Therefore, the objective was to conduct a systematic literature review of the currently available M&S systems at the control/elimination stage of the four top-ranked helminth NTDs. Specifically, Taenia spp., Echinococcus spp., Schistosoma spp., and soil-transmitted helminths (STHs) were considered to determine if there are any similarities between their M&S systems and whether certain approaches can be adopted from each other. The systematic review demonstrated that rigorous M&S systems have been designed for the control/elimination stage of both STHs and schistosomiasis, particularly in China. On the other hand, a concept of M&S for Taenia spp. and Echinococcus spp. has not been fully developed yet, due to a lack of epidemiological data and the fact that many endemic countries are far away from reaching control/elimination. Moreover, accurate diagnostic tools for all four diseases are still imperfect, which complicates proper M&S. Finally, there is an urgent need to develop and harmonize/standardize M&S activities in order to reliably determine and compare the epidemiological situation worldwide.
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Affiliation(s)
- Ganna Saelens
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke B-9820, Belgium
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10
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Assaré RK, Tra MBI, Ouattara M, Hürlimann E, Coulibaly JT, N'Goran EK, Utzinger J. Sensitivity of the Point-of-Care Circulating Cathodic Antigen Urine Cassette Test for Diagnosis of Schistosoma mansoni in Low-Endemicity Settings in Côte d'Ivoire. Am J Trop Med Hyg 2019; 99:1567-1572. [PMID: 30277203 PMCID: PMC6283482 DOI: 10.4269/ajtmh.18-0550] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The sensitivity of a point-of-care circulating cathodic antigen (POC-CCA) urine cassette test for diagnosis of Schistosoma mansoni in low-endemicity settings is poorly understood. We conducted a cross-sectional survey in 14 villages in western Côte d'Ivoire and diagnosed children aged 9-12 years for schistosomiasis. Two stool samples were subjected to triplicate Kato-Katz thick smears each for diagnosis of S. mansoni, whereas a single urine sample was examined by POC-CCA for S. mansoni, filtration for Schistosoma haematobium, and reagent strip for microhematuria. According to the Kato-Katz technique, we found 45 out of 681 children positive for S. mansoni (6.6%) with a mean intensity among infected children of 72.2 eggs per gram of stool. Point-of-care circulating cathodic antigen revealed a prevalence of S. mansoni of 33.0% when trace results were considered positive and 12.5% when trace results were considered negative. Eggs of S. haematobium were found in eight participants (1.2%), whereas the prevalence of microhematuria was 13.5%. A single POC-CCA urine cassette test revealed a several-fold higher prevalence of S. mansoni than multiple Kato-Katz thick smears in this low-endemicity area. Our findings have important ramifications for choosing an appropriate diagnostic tool in low-endemic areas that might be targeted for elimination.
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Affiliation(s)
- Rufin K Assaré
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Mathieu B I Tra
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Mamadou Ouattara
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Eveline Hürlimann
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jean T Coulibaly
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.,University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Eliézer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Jürg Utzinger
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
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11
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Repeated doses of Praziquantel in Schistosomiasis Treatment (RePST) - single versus multiple praziquantel treatments in school-aged children in Côte d'Ivoire: a study protocol for an open-label, randomised controlled trial. BMC Infect Dis 2018; 18:662. [PMID: 30547750 PMCID: PMC6295059 DOI: 10.1186/s12879-018-3554-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/23/2018] [Indexed: 11/30/2022] Open
Abstract
Background Large scale administration of the anthelminthic drug praziquantel (PZQ) to at-risk populations is the cornerstone of schistosomiasis control, although persisting high prevalence of infections in some areas and growing concerns of PZQ resistance have revealed the limitations of this strategy. Most studies assessing PZQ efficacy have used relatively insensitive parasitological diagnostics, such as the Kato-Katz (KK) and urine-filtration methods, thereby overestimating cure rates (CRs). This study aims to determine the efficacy of repeated PZQ treatments against Schistosoma mansoni infection in school-aged children in Côte d’Ivoire using the traditional KK technique, as well as more sensitive antigen- and DNA-detection methods. Methods An open-label, randomised controlled trial will be conducted in school-aged children (5 to 18 years) from the region of Taabo, Côte d’Ivoire, an area endemic for S. mansoni. This 8-week trial includes four two-weekly standard doses of PZQ in the “intense treatment” intervention group and one standard dose of PZQ in the “standard treatment” control group. The efficacy of PZQ will be evaluated in stool samples using the KK technique and real-time PCR as well as in urine using the point-of-care circulating cathodic antigen test and the up-converting phosphor, lateral flow, circulating anodic antigen assay. The primary outcome of the study will be the difference in CR of intense versus standard treatment with PZQ on individuals with a confirmed S. mansoni infection measured by KK. Secondary outcomes include the difference in CR and intensity reduction rate between the intense and standard treatment groups as measured by the other diagnostic tests, as well as the accuracy of the different diagnostic tests, and the safety of PZQ. Discussion This study will provide data on the efficacy of repeated PZQ treatment on the clearance of S. mansoni as measured by several diagnostic techniques. These findings will inform future mass drug administration policy and shed light on position of novel diagnostic tools to evaluate schistosomiasis control strategies. Trial registration The study is registered at EudraCT (2016–003017-10, date of registration: 22 July 2016) and (NCT02868385, date of registration: 16 August 2016). Electronic supplementary material The online version of this article (10.1186/s12879-018-3554-2) contains supplementary material, which is available to authorized users.
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12
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Surveillance of intestinal schistosomiasis during control: a comparison of four diagnostic tests across five Ugandan primary schools in the Lake Albert region. Parasitology 2018; 145:1715-1722. [PMID: 29560841 PMCID: PMC6533640 DOI: 10.1017/s003118201800029x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Programmatic surveillance of intestinal schistosomiasis during control can typically use four diagnostic tests, either singularly or in combination, but these have yet to be cross-compared directly. Our study assembled a complete diagnostic dataset, inclusive of infection intensities, from 258 children from five Ugandan primary schools. The schools were purposely selected as typical of the endemic landscape near Lake Albert and reflective of high- and low-transmission settings. Overall prevalence was: 44.1% (95% CI 38.0–50.2) by microscopy of duplicate Kato-Katz smears from two consecutive stools, 56.9% (95% CI 50.8–63.0) by urine-circulating cathodic antigen (CCA) dipstick, 67.4% (95% CI 61.6–73.1) by DNA-TaqMan® and 75.1% (95% CI 69.8–80.4) by soluble egg antigen enzyme-linked immunosorbent assay (SEA-ELISA). A cross-comparison of diagnostic sensitivities, specificities, positive and negative predictive values was undertaken, inclusive of a latent class analysis (LCA) with a LCA-model estimate of prevalence by each school. The latter ranged from 9.6% to 100.0%, and prevalence by school for each diagnostic test followed a static ascending order or monotonic series of Kato-Katz, urine-CCA dipstick, DNA-TaqMan® and SEA-ELISA. We confirm that Kato-Katz remains a satisfactory diagnostic standalone in high-transmission settings but in low-transmission settings should be augmented or replaced by urine-CCA dipsticks. DNA-TaqMan® appears suitable in both endemic settings though is only implementable if resources permit. In low-transmission settings, SEA-ELISA remains the method of choice to evidence an absence infection. We discuss the pros and cons of each method concluding that future surveillance of intestinal schistosomiasis would benefit from a flexible, context-specific approach both in choice and application of each diagnostic method, rather than a single one-size fits all approach.
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13
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Lindholz CG, Favero V, Verissimo CDM, Candido RRF, de Souza RP, dos Santos RR, Morassutti AL, Bittencourt HR, Jones MK, St. Pierre TG, Graeff-Teixeira C. Study of diagnostic accuracy of Helmintex, Kato-Katz, and POC-CCA methods for diagnosing intestinal schistosomiasis in Candeal, a low intensity transmission area in northeastern Brazil. PLoS Negl Trop Dis 2018; 12:e0006274. [PMID: 29518081 PMCID: PMC5843168 DOI: 10.1371/journal.pntd.0006274] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/26/2018] [Indexed: 11/19/2022] Open
Abstract
Control initiatives have successfully reduced the prevalence and intensity of schistosomiasis transmission in several localities around the world. However, individuals that release low numbers of eggs in their feces may not be detected by classical methods that are limited by low sensitivity. Given that accurate estimates of prevalence are key to implementing planning control actions for the elimination of schistosomiasis, new diagnostic tools are needed to effectively monitor infections and confirm transmission interruption. The World Health Organization recommends the Kato-Katz (KK) thick smear as a parasitological test for epidemiological surveys, even though this method has been demonstrated to underestimate prevalence when egg burdens are low. The point-of-care immunodiagnostic for detecting schistosome cathodic circulating antigen (POC-CCA) method has been proposed as a more sensitive substitute for KK in prevalence estimations. An alternative diagnostic, the Helmintex (HTX) method, isolates eggs from fecal samples with the use of paramagnetic particles in a magnetic field. Here, a population-based study involving 461 individuals from Candeal, Sergipe State, Brazil, was conducted to evaluate these three methods comparatively by latent class analysis (LCA). The prevalence of schistosomiasis mansoni was determined to be 71% with POC-CCA, 40.% with HTX and 11% with KK. Most of the egg burdens of the individuals tested (70%) were < 1 epg, thereby revealing a dissociation between prevalence and intensity in this locality. Therefore, the present results confirm that the HTX method is a highly sensitive egg detection procedure and support its use as a reference method for diagnosing intestinal schistosomiasis and for comparative evaluation of other tests.
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Affiliation(s)
- Catieli Gobetti Lindholz
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Vivian Favero
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carolina de Marco Verissimo
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | | | - Renata Perotto de Souza
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Renata Rosa dos Santos
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Alessandra Loureiro Morassutti
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Helio Radke Bittencourt
- Polytechnic School, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Malcolm K. Jones
- School of Veterinary Science, The University of Queensland, Queensland, Australia
| | - Timothy G. St. Pierre
- School of Physics, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carlos Graeff-Teixeira
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
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14
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Clements MN, Corstjens PLAM, Binder S, Campbell CH, de Dood CJ, Fenwick A, Harrison W, Kayugi D, King CH, Kornelis D, Ndayishimiye O, Ortu G, Lamine MS, Zivieri A, Colley DG, van Dam GJ. Latent class analysis to evaluate performance of point-of-care CCA for low-intensity Schistosoma mansoni infections in Burundi. Parasit Vectors 2018; 11:111. [PMID: 29475457 PMCID: PMC5824563 DOI: 10.1186/s13071-018-2700-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 02/06/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Kato-Katz examination of stool smears is the field-standard method for detecting Schistosoma mansoni infection. However, Kato-Katz misses many active infections, especially of light intensity. Point-of-care circulating cathodic antigen (CCA) is an alternative field diagnostic that is more sensitive than Kato-Katz when intensity is low, but interpretation of CCA-trace results is unclear. To evaluate trace results, we tested urine and stool specimens from 398 pupils from eight schools in Burundi using four approaches: two in Burundi and two in a laboratory in Leiden, the Netherlands. In Burundi, we used Kato-Katz and point-of-care CCA (CCAB). In Leiden, we repeated the CCA (CCAL) and also used Up-Converting Phosphor Circulating Anodic Antigen (CAA). METHODS We applied Bayesian latent class analyses (LCA), first considering CCA traces as negative and then as positive. We used the LCA output to estimate validity of the prevalence estimates of each test in comparison to the population-level infection prevalence and estimated the proportion of trace results that were likely true positives. RESULTS Kato-Katz yielded the lowest prevalence (6.8%), and CCAB with trace considered positive yielded the highest (53.5%). There were many more trace results recorded by CCA in Burundi (32.4%) than in Leiden (2.3%). Estimated prevalence with CAA was 46.5%. LCA indicated that Kato-Katz had the lowest sensitivity: 15.9% [Bayesian Credible Interval (BCI): 9.2-23.5%] with CCA-trace considered negative and 15.0% with trace as positive (BCI: 9.6-21.4%), implying that Kato-Katz missed approximately 85% of infections. CCAB underestimated disease prevalence when trace was considered negative and overestimated disease prevalence when trace was considered positive, by approximately 12 percentage points each way, and CAA overestimated prevalence in both models. Our results suggest that approximately 52.2% (BCI: 37.8-5.8%) of the CCAB trace readings were true infections. CONCLUSIONS Whether measured in the laboratory or the field, CCA outperformed Kato-Katz at the low infection intensities in Burundi. CCA with trace as negative likely missed many infections, whereas CCA with trace as positive overestimated prevalence. In the absence of a field-friendly gold standard diagnostic, the use of a variety of diagnostics with differing properties will become increasingly important as programs move towards elimination of schistosomiasis. It is clear that CCA is a valuable tool for the detection and mapping of S. mansoni infection in the field and CAA may be a valuable field tool in the future.
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Affiliation(s)
- Michelle N. Clements
- Schistosomiasis Control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Paul L. A. M. Corstjens
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Sue Binder
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA USA
| | - Carl H. Campbell
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA USA
| | - Claudia J. de Dood
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Alan Fenwick
- Schistosomiasis Control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Wendy Harrison
- Schistosomiasis Control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Donatien Kayugi
- Programme National Intégré de lutte contre les Maladies Tropicales Négligées et la Cécité (PNIMTNC), Ministère de la Santé Publique et de la Lutte contre le SIDA, Bujumbura, Burundi
| | - Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, OH USA
| | - Dieuwke Kornelis
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Onesime Ndayishimiye
- Programme National Intégré de lutte contre les Maladies Tropicales Négligées et la Cécité (PNIMTNC), Ministère de la Santé Publique et de la Lutte contre le SIDA, Bujumbura, Burundi
| | - Giuseppina Ortu
- Schistosomiasis Control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Mariama Sani Lamine
- Schistosomiasis Control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Antonio Zivieri
- Schistosomiasis Control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Daniel G. Colley
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA USA
| | - Govert J. van Dam
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
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15
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Prada JM, Touloupou P, Adriko M, Tukahebwa EM, Lamberton PHL, Hollingsworth TD. Understanding the relationship between egg- and antigen-based diagnostics of Schistosoma mansoni infection pre- and post-treatment in Uganda. Parasit Vectors 2018; 11:21. [PMID: 29310695 PMCID: PMC5759883 DOI: 10.1186/s13071-017-2580-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 12/06/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Schistosomiasis is a major socio-economic and public health problem in many sub-Saharan African countries. After large mass drug administration (MDA) campaigns, prevalence of infection rapidly returns to pre-treatment levels. The traditional egg-based diagnostic for schistosome infections, Kato-Katz, is being substituted in many settings by circulating antigen recognition-based diagnostics, usually the point-of-care circulating cathodic antigen test (CCA). The relationship between these diagnostics is poorly understood, particularly after treatment in both drug-efficacy studies and routine monitoring. RESULTS We created a model of schistosome infections to better understand and quantify the relationship between these two egg- and adult worm antigen-based diagnostics. We focused particularly on the interpretation of "trace" results after CCA testing. Our analyses suggest that CCA is generally a better predictor of prevalence, particularly after treatment, and that trace CCA results are typically associated with truly infected individuals. CONCLUSIONS Even though prevalence rises to pre-treatment levels only six months after MDAs, our model suggests that the average intensity of infection is much lower, and is probably in part due to a small burden of surviving juveniles from when the treatment occurred. This work helps to better understand CCA diagnostics and the interpretation of post-treatment prevalence estimations.
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Affiliation(s)
- Joaquín M. Prada
- Department of Mathematics, University of Warwick, Coventry, UK
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | | | - Moses Adriko
- Vector Control Division, Ministry of Health, Uganda, Kampala, Uganda
| | | | - Poppy H. L. Lamberton
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow, UK
| | - T. Déirdre Hollingsworth
- Department of Mathematics, University of Warwick, Coventry, UK
- Big Data Institute, University of Oxford, Oxford, UK
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Clements MN, Donnelly CA, Fenwick A, Kabatereine NB, Knowles SCL, Meité A, N'Goran EK, Nalule Y, Nogaro S, Phillips AE, Tukahebwa EM, Fleming FM. Interpreting ambiguous 'trace' results in Schistosoma mansoni CCA Tests: Estimating sensitivity and specificity of ambiguous results with no gold standard. PLoS Negl Trop Dis 2017; 11:e0006102. [PMID: 29220354 PMCID: PMC5738141 DOI: 10.1371/journal.pntd.0006102] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/20/2017] [Accepted: 11/07/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The development of new diagnostics is an important tool in the fight against disease. Latent Class Analysis (LCA) is used to estimate the sensitivity and specificity of tests in the absence of a gold standard. The main field diagnostic for Schistosoma mansoni infection, Kato-Katz (KK), is not very sensitive at low infection intensities. A point-of-care circulating cathodic antigen (CCA) test has been shown to be more sensitive than KK. However, CCA can return an ambiguous 'trace' result between 'positive' and 'negative', and much debate has focused on interpretation of traces results. METHODOLOGY/PRINCIPLE FINDINGS We show how LCA can be extended to include ambiguous trace results and analyse S. mansoni studies from both Côte d'Ivoire (CdI) and Uganda. We compare the diagnostic performance of KK and CCA and the observed results by each test to the estimated infection prevalence in the population. Prevalence by KK was higher in CdI (13.4%) than in Uganda (6.1%), but prevalence by CCA was similar between countries, both when trace was assumed to be negative (CCAtn: 11.7% in CdI and 9.7% in Uganda) and positive (CCAtp: 20.1% in CdI and 22.5% in Uganda). The estimated sensitivity of CCA was more consistent between countries than the estimated sensitivity of KK, and estimated infection prevalence did not significantly differ between CdI (20.5%) and Uganda (19.1%). The prevalence by CCA with trace as positive did not differ significantly from estimates of infection prevalence in either country, whereas both KK and CCA with trace as negative significantly underestimated infection prevalence in both countries. CONCLUSIONS Incorporation of ambiguous results into an LCA enables the effect of different treatment thresholds to be directly assessed and is applicable in many fields. Our results showed that CCA with trace as positive most accurately estimated infection prevalence.
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Affiliation(s)
| | - Christl A. Donnelly
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | | | - Sarah C. L. Knowles
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
- The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
| | - Aboulaye Meité
- Côte d'Ivoire Ministry of Health, National Program Against Filariasis, Schistosomiasis and Geohelminths, Abidjan, Côte d'Ivoire
| | - Eliézer K. N'Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abijan, Côte d'Ivoire
| | - Yolisa Nalule
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Sarah Nogaro
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Anna E. Phillips
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | | | - Fiona M. Fleming
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
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17
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Rapid clearance of Schistosoma mansoni circulating cathodic antigen after treatment shown by urine strip tests in a Ugandan fishing community - Relevance for monitoring treatment efficacy and re-infection. PLoS Negl Trop Dis 2017; 11:e0006054. [PMID: 29131820 PMCID: PMC5703575 DOI: 10.1371/journal.pntd.0006054] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 11/27/2017] [Accepted: 10/19/2017] [Indexed: 12/28/2022] Open
Abstract
Schistosomiasis control and elimination has priority in public health agendas in several sub-Saharan countries. However, achieving these goals remains a substantial challenge. In order to assess progress of interventions and treatment efficacy it is pertinent to have accurate, feasible and affordable diagnostic tools. Detection of Schistosoma mansoni infection by circulating cathodic antigen (CCA) in urine is an attractive option as this measure describes live worm infection noninvasively. In order to interpret treatment efficacy and re-infection levels, knowledge about clearance of this antigen is necessary. The current study aims to investigate, whether antigen clearance as a proxy for decreasing worm numbers is reflected in decreasing CCA levels in urine shortly after praziquantel treatment. Here CCA levels are measured 24 hours post treatment in response to both a single and two treatments. The study was designed as a series of cross-sectional urine and stool sample collections from 446 individuals nested in a two-arm randomised single blinded longitudinal clinical trial cohort matched by gender and age (ClinicalTrials.gov Identifier: NCT00215267) receiving one or two praziquantel treatments. CCA levels in urine were determined by carbon-conjugated monoclonal antibody lateral flow strip assay and eggs per gram faeces for S. mansoni and soil-transmitted helminths by Kato-Katz. Significant correlations between CCA levels and S. mansoni egg count at every measured time point were found and confirmed the added beneficial effect of a second treatment at two weeks after baseline. Furthermore, presence of hookworm was found not to be a confounder for CCA test specificity. Twenty-four hours post treatment measures of mean CCA scores showed significant reductions. In conclusion, removal of CCA in response to treatment is detectable as a decline in CCA in urine already after 24 hours. This has relevance for use and interpretation of laboratory based and point-of-care CCA tests in terms of treatment efficacy and re-infection proportions as this measure provides information on the presence of all actively feeding stages of S. mansoni, which conventional faecal microscopy methods do not accurately reflect. TRIAL REGISTRATION ClinicalTrials.gov NCT00215267.
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Vonghachack Y, Sayasone S, Khieu V, Bergquist R, van Dam GJ, Hoekstra PT, Corstjens PLAM, Nickel B, Marti H, Utzinger J, Muth S, Odermatt P. Comparison of novel and standard diagnostic tools for the detection of Schistosoma mekongi infection in Lao People's Democratic Republic and Cambodia. Infect Dis Poverty 2017; 6:127. [PMID: 28793922 PMCID: PMC5550959 DOI: 10.1186/s40249-017-0335-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/12/2017] [Indexed: 12/29/2022] Open
Abstract
Background Given the restricted distribution of Schistosoma mekongi in one province in Lao People’s Democratic Republic (Lao PDR) and two provinces in Cambodia, together with progress of the national control programmes aimed at reducing morbidity and infection prevalence, the elimination of schistosomiasis mekongi seems feasible. However, sensitive diagnostic tools will be required to determine whether elimination has been achieved. We compared several standard and novel diagnostic tools in S. mekongi-endemic areas. Methods The prevalence and infection intensity of S. mekongi were evaluated in 377 study participants from four villages in the endemic areas in Lao PDR and Cambodia using Kato-Katz stool examination, antibody detection based on an enzyme-linked immunosorbent assay (ELISA) and schistosome circulating antigen detection by lateral-flow tests. Two highly sensitive test systems for the detection of cathodic and anodic circulating antigens (CCA, CAA) in urine and serum were utilized. Results Stool microscopy revealed an overall prevalence of S. mekongi of 6.4% (one case in Cambodia and 23 cases in Lao PDR), while that of Opisthorchis viverrini, hookworm, Trichuris trichiura, Ascaris lumbricoides and Taenia spp. were 50.4%, 28.1%, 3.5%, 0.3% and 1.9%, respectively. In the urine samples, the tests for CCA and CAA detected S. mekongi infections in 21.0% and 38.7% of the study participants, respectively. In the serum samples, the CAA assay revealed a prevalence of 32.4%, while a combination of the CAA assay in serum and in urine revealed a prevalence of 43.2%. There was a difference between the two study locations with a higher prevalence reached in the samples from Lao PDR. Conclusions The CCA, CAA and ELISA results showed substantially higher prevalence estimates for S. mekongi compared to Kato-Katz thick smears. Active schistosomiasis mekongi in Lao PDR and Cambodia might thus have been considerably underestimated previously. Hence, sustained control efforts are still needed to break transmission of S. mekongi. The pivotal role of highly sensitive diagnostic assays in areas targeting elimination cannot be overemphasised. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0335-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Youthanavanh Vonghachack
- Faculty of Basic Sciences, University of Health Sciences, Ministry of Health, Vientiane, Lao People's Democratic Republic.,Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.,University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Somphou Sayasone
- National Institute of Public Health, Ministry of Health, Vientiane, Lao People's Democratic Republic
| | - Virak Khieu
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | | | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Paul L A M Corstjens
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Beatrice Nickel
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.,University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Hanspeter Marti
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.,University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.,University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Sinuon Muth
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Peter Odermatt
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, CH-4003, Basel, Switzerland.
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19
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Ferreira FT, Fidelis TA, Pereira TA, Otoni A, Queiroz LC, Amâncio FF, Antunes CM, Lambertucci JR. Sensitivity and specificity of the circulating cathodic antigen rapid urine test in the diagnosis of Schistosomiasis mansoni infection and evaluation of morbidity in a low- endemic area in Brazil. Rev Soc Bras Med Trop 2017; 50:358-364. [PMID: 28700054 DOI: 10.1590/0037-8682-0423-2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 05/16/2017] [Indexed: 12/28/2022] Open
Abstract
INTRODUCTION: The Kato-Katz technique is the standard diagnostic test for Schistosoma mansoni infection in rural areas. However, the utility of this method is severely limited by the day-to-day variability in host egg excretion in the stool. In high-transmission areas, the point-of-care circulating cathodic antigen (POC-CCA) urine assay has proven to be a reliable test. However, investigations of the reliability of the POC-CCA assay in low-transmission regions are under way. This study aimed to evaluate the sensitivity and specificity of the POC-CCA assay and the morbidity of schistosomiasis in a low-endemic area in Brazil. METHODS: Pains City is a low-transmission zone for schistosomiasis. A total of 300 subjects aged 7-76 years were randomly selected for the POC-CCA cassette test. For S. mansoni diagnosis, three stool samples on six slides were compared with one urine sample for each subject. The sensitivity and specificity in the absence of a gold standard were calculated using latent class analysis. Clinical examinations and abdominal ultrasounds were performed in 181 volunteers to evaluate morbidity associated with schistosomiasis. RESULTS: The sensitivity and specificity of the Kato-Katz technique were 25.6% and 94.6%, respectively. By contrast, the sensitivity and specificity of the POC-CCA assay were 68.1% and 72.8%, respectively. Hepatosplenic schistosomiasis was diagnosed in two patients (1.1%). CONCLUSIONS: Overall, the POC-CCA urine assay proved to be a useful test for diagnosing S. mansoni in a low-endemic area in Brazil. Severe clinical forms of schistosomiasis can be present even in such low-endemic areas.
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Affiliation(s)
- Fernanda Teixeira Ferreira
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Thiago André Fidelis
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Thiago Almeida Pereira
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.,Immunopathogenesis section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Alba Otoni
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.,Núcleo de Pesquisas em Epidemiologia e Saúde Coletiva, Universidade Federal de São João del-Rei , Divinópolis, MG, Brasil
| | - Leonardo Campos Queiroz
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Frederico Figueiredo Amâncio
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Carlos Maurício Antunes
- Instituto de Ensino e Pesquisa, Santa Casa de Misericórdia de Belo Horizonte, Belo Horizonte, MG, Brasil
| | - José Roberto Lambertucci
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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20
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Liu S, Zhou X, Piao X, Hou N, Shen Y, Zou Y, Li S, Cao J, Chen Q. Saposin-like Proteins, a Multigene Family of Schistosoma Species, are Biomarkers for the Immunodiagnosis of Schistosomiasis Japonica. J Infect Dis 2016; 214:1225-34. [PMID: 27190177 DOI: 10.1093/infdis/jiw188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/02/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND One major obstacle to schistosomiasis prevention and control is the lack of accurate and sensitive diagnostic approaches, which are essential for planning, targeting, and evaluating disease control efforts. METHODS Based on bioinformatics analysis, we identified a multigene family of saposin-like protein (SAPLP) in the schistosome genomes. Schistosoma japonicum SAPLPs (SjSAPLPs), including recently reported promising biomarker SjSP-13, were systematically and comparatively assessed as immunodiagnostic antigens for schistosomiasis japonica. RESULTS Two novel antigens (SjSAPLP4 and SjSAPLP5) could specifically react to serum samples from both S. japonicum-infected laboratory animals and patients. The sensitivities of SjSAPLP4, SjSAPLP5, and SjSP-13 for immunodiagnosis were 98% (95% confidence interval, 88.0%-99.9%), 96% (85.1%-99.3%), and 88% (75.0%-95.0%), respectively, and 100% (91.1%-100%) specificity was observed for the 3 antigens with enzyme-linked immunosorbent assay; there was no cross-reaction with clonorchiosis (0 of 19 patients), echinococcosis (0 of 20 patients), or trichinellosis (0 of 18 patients) for the 3 antigens. Antibodies to the 3 antigens could be detected in the serum samples of rabbits infected with 1000 cercariae as early as 3-4 weeks after infection. CONCLUSIONS These results suggest that SjSAPLP4 and SjSAPLP5 could serve as novel biomarkers for the immunodiagnosis of schistosomiasis japonica, which will further improve diagnostic sensitivity and specificity.
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Affiliation(s)
- Shuai Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Xiaosu Zhou
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Xianyu Piao
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Nan Hou
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Yujuan Shen
- National Institute of Parasitic Diseases, Laboratory of Parasite and Vector Biology, MOH, Chinese Center for Disease Control and Prevention, Shanghai
| | - Yang Zou
- Beijing Friendship Hospital, Capital Medical University, Beijing Tropical Medicine Research Institute
| | - Shanshan Li
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
| | - Jianping Cao
- National Institute of Parasitic Diseases, Laboratory of Parasite and Vector Biology, MOH, Chinese Center for Disease Control and Prevention, Shanghai
| | - Qijun Chen
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing Key Laboratory of Zoonosis, Shenyang Agriculture University, China
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21
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Danso-Appiah A, Minton J, Boamah D, Otchere J, Asmah RH, Rodgers M, Bosompem KM, Eusebi P, De Vlas SJ. Accuracy of point-of-care testing for circulatory cathodic antigen in the detection of schistosome infection: systematic review and meta-analysis. Bull World Health Organ 2016; 94:522-533A. [PMID: 27429491 PMCID: PMC4933137 DOI: 10.2471/blt.15.158741] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 12/19/2015] [Accepted: 01/26/2016] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE To assess the accuracy of point-of-care testing for circulatory cathodic antigen in the diagnosis of schistosome infection. METHODS We searched MEDLINE, EMBASE, LILACS and other bibliographic databases for studies published until 30 September 2015 that described circulatory cathodic antigen testing compared against one to three Kato-Katz tests per subject - for Schistosoma mansoni - or the filtration of one 10-ml urine sample per subject - for S. haematobium. We extracted the numbers of true positives, false positives, true negatives and false negatives for the antigen testing and performed meta-analyses using a bivariate hierarchical regression model. FINDINGS Twenty-six studies published between 1994 and 2014 met the inclusion criteria. In the detection of S. mansoni, a single antigen test gave a pooled sensitivity of 0.90 (95% confidence interval, CI: 0.84-0.94) and a pooled specificity of 0.56 (95% CI: 0.39-0.71; n = 7) when compared against a single Kato-Katz test. The corresponding values from comparisons with two to three Kato-Katz tests per subject were 0.85 (95% CI: 0.80-0.88) and 0.66 (95% CI: 0.53-0.76; n = 14), respectively. There appeared to be no advantage in using three antigen tests per subject instead of one. When compared against the results of urine filtration, antigen testing for S. haematobium showed poor sensitivity and poor specificity. The performance of antigen testing was better in areas of high endemicity than in settings with low endemicity. CONCLUSION Antigen testing may represent an effective tool for monitoring programmes for the control of S. mansoni.
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Affiliation(s)
- Anthony Danso-Appiah
- Department of Epidemiology and Disease Control, School of Public Health, University of Ghana, PO Box LG13, Legon, Ghana
| | - Jonathan Minton
- School of Social and Political Sciences, University of Glasgow, Glasgow, Scotland
| | - Daniel Boamah
- Department of Microbiology, Centre for Plant Medicine Research, Mampong, Ghana
| | - Joseph Otchere
- Department of Parasitology, University of Ghana, Legon, Ghana
| | - Richard H Asmah
- School of Biomedical and Allied Health Sciences, University of Ghana, Accra, Ghana
| | - Mark Rodgers
- Centre for Reviews and Dissemination, University of York, York, England
| | | | - Paolo Eusebi
- Health Planning Service, Regional Health Authority of Umbria, Perugia, Italy
| | - Sake J De Vlas
- Department of Public Health, Erasmus University Medical Centre Rotterdam, Rotterdam, Netherlands
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22
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Montresor A, Deol A, à Porta N, Lethanh N, Jankovic D. Markov Model Predicts Changes in STH Prevalence during Control Activities Even with a Reduced Amount of Baseline Information. PLoS Negl Trop Dis 2016; 10:e0004371. [PMID: 27035436 PMCID: PMC4817985 DOI: 10.1371/journal.pntd.0004371] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 12/17/2015] [Indexed: 11/25/2022] Open
Abstract
Background Estimating the reduction in levels of infection during implementation of soil-transmitted helminth (STH) control programmes is important to measure their performance and to plan interventions. Markov modelling techniques have been used with some success to predict changes in STH prevalence following treatment in Viet Nam. The model is stationary and to date, the prediction has been obtained by calculating the transition probabilities between the different classes of intensity following the first year of drug distribution and assuming that these remain constant in subsequent years. However, to run this model longitudinal parasitological data (including intensity of infection) are required for two consecutive years from at least 200 individuals. Since this amount of data is not often available from STH control programmes, the possible application of the model in control programme is limited. The present study aimed to address this issue by adapting the existing Markov model to allow its application when a more limited amount of data is available and to test the predictive capacities of these simplified models. Method We analysed data from field studies conducted with different combination of three parameters: (i) the frequency of drug administration; (ii) the drug distributed; and (iii) the target treatment population (entire population or school-aged children only). This analysis allowed us to define 10 sets of standard transition probabilities to be used to predict prevalence changes when only baseline data are available (simplified model 1). We also formulated three equations (one for each STH parasite) to calculate the predicted prevalence of the different classes of intensity from the total prevalence. These equations allowed us to design a simplified model (SM2) to obtain predictions when the classes of intensity at baseline were not known. To evaluate the performance of the simplified models, we collected data from the scientific literature on changes in STH prevalence during the implementation of 26 control programmes in 16 countries. Using the baseline data observed, we applied the simplified models and predicted the onward prevalence of STH infection at each time-point for which programme data were available. We then compared the output from the model with the observed data from the programme. Results The comparison between the model-predicted prevalence and the observed values demonstrated a good accuracy of the predictions. In 77% of cases the original model predicted a prevalence within five absolute percentage points from the observed figure, for the simplified model one in 69% of cases and for the simplified model two in 60% of cases. We consider that the STH Markov model described here could be an important tool for programme managers to monitor the progress of their control programmes and to select the appropriate intervention. We also developed, and made freely available online, a software tool to enable the use of the STH Markov model by personnel with limited knowledge of mathematical models. Several million children are periodically dewormed to prevent the impairments to health and the economy caused by soil-transmitted helminths in endemic communities. It is important that managers of STH control programmes be able to anticipate the impact of the control measures on the prevalence of the diseases for two main purposes:
to select the most appropriate intervention; and to be alerted in case of changes in prevalence that are less favourable than the expected values.
We therefore developed a model that predicts such changes, and also included modifications to enable its use in cases where a limited amount of data is available (SM1 and SM2). We retrospectively tested the performances of the model on 26 control programmes comparing the prevalence predicted by the model with those observed during programme implementation: in 77% of cases the prevalence predicted by the original model was within five percentage points of the observed values (69% in SM1 and 60% in SM2). We consider the performances of these models to be satisfactory. We designed a free online software to facilitate the use of these models by programme managers who may not be confident with modelling procedures.
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Affiliation(s)
- Antonio Montresor
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
- * E-mail:
| | - Arminder Deol
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Natacha à Porta
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Nam Lethanh
- Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Dina Jankovic
- Centre for Health Economics, University of York, York, United Kingdom
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23
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Kittur N, Castleman JD, Campbell CH, King CH, Colley DG. Comparison of Schistosoma mansoni Prevalence and Intensity of Infection, as Determined by the Circulating Cathodic Antigen Urine Assay or by the Kato-Katz Fecal Assay: A Systematic Review. Am J Trop Med Hyg 2016; 94:605-610. [PMID: 26755565 PMCID: PMC4775897 DOI: 10.4269/ajtmh.15-0725] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/11/2015] [Indexed: 12/18/2022] Open
Abstract
The relationship between results from Kato-Katz (KK) fecal microscopy and urine-based point-of-care circulating cathodic antigen (POC-CCA) assays for Schistosoma mansoni infection remains a critical issue. This systematic literature review of 25 published papers compares prevalence of S. mansoni infection by KK with that by the POC-CCA assay. Nineteen published studies met our inclusion criteria for data extraction and analysis. Above a prevalence of 50% by KK, KK and POC-CCA results yielded essentially the same prevalence. Below 50% prevalence by KK, the prevalence by the POC-CCA assay was between 1.5- and 6-fold higher and increased as prevalence by KK decreased. Five of nine publications met inclusion criteria for extractable data on intensity of S. mansoni infection by KK assay and visual band density using the POC-CCA assay. A clear positive relationship exists between intensity by the KK and POC-CCA assays. This systematic review indicates that below 50% prevalence, the POC-CCA assay is much more sensitive than the KK assay. However, the existing data are inadequate to precisely define the relationship between POC-CCA and KK at lower levels of KK prevalence. More studies directly comparing the two assays in low-prevalence areas are essential to inform decision-making by national schistosomiasis control programs.
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Affiliation(s)
| | | | | | | | - Daniel G. Colley
- *Address correspondence to Daniel G. Colley, Center for Tropical and Emerging Global Diseases, Room 330B Coverdell Center, 500 DW Brooks Drive, Athens, GA 30602. E-mail:
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Albonico M, Levecke B, LoVerde PT, Montresor A, Prichard R, Vercruysse J, Webster JP. Monitoring the efficacy of drugs for neglected tropical diseases controlled by preventive chemotherapy. J Glob Antimicrob Resist 2015; 3:229-236. [PMID: 27842865 DOI: 10.1016/j.jgar.2015.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 08/21/2015] [Indexed: 12/11/2022] Open
Abstract
In the last decade, pharmaceutical companies, governments and global health organisations under the leadership of the World Health Organization (WHO) have pledged large-scale donations of anthelmintic drugs, including ivermectin (IVM), praziquantel (PZQ), albendazole (ALB) and mebendazole (MEB). This worldwide scale-up in drug donations calls for strong monitoring systems to detect any changes in anthelmintic drug efficacy. This review reports on the outcome of the WHO Global Working Group on Monitoring of Neglected Tropical Diseases Drug Efficacy, which consists of three subgroups: (i) soil-transmitted helminthiases (ALB and MEB); (ii) onchocerciasis and lymphatic filariasis (IVM); and (iii) schistosomiasis (PZQ). Progress of ongoing work, challenges and research needs for each of the four main drugs used in helminthic preventive chemotherapy (PC) are reported, laying the ground for appropriate implementation of drug efficacy monitoring programmes under the co-ordination and guidelines of the WHO. Best practices for monitoring drug efficacy should be made available and capacity built as an integral part of neglected tropical disease (NTD) programme monitoring. Development of a disease-specific model to predict the impact of PC programmes, to detect outliers and to solicit responses is essential. Research studies on genetic polymorphisms in relation to low-efficacy phenotypes should be carried out to identify markers of putative resistance against all NTD drugs and ultimately to develop diagnostic assays. Development of combination and co-administration of NTD drugs as well as of new drug entities to boost the armamentarium of the few drugs available for NTD control and elimination should be pursued in parallel.
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Affiliation(s)
- M Albonico
- Fondazione Ivo de Carneri, via IV Marzo 14, 10122 Torino, Italy.
| | - B Levecke
- Laboratory of Parasitology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - P T LoVerde
- Departments of Biochemistry and Pathology, University of Texas Health Science Center, 7703 Floyd Curl Dr., MS7760, San Antonio, TX 78229-3900, USA
| | - A Montresor
- Department of Control of Neglected Tropical Diseases, World Health Organization, Avenue Appia 20, CH-1211 Geneva, Switzerland
| | - R Prichard
- Institute of Parasitology, McGill University, Macdonald Campus, 21 111 Lakeshore Road, St Anne-de-Bellevue, QC, Canada H9X 3V9
| | - J Vercruysse
- Laboratory of Parasitology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - J P Webster
- Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, Hawkshead Campus, North Mymms AL9 7TA, UK; Department of Infectious Disease Epidemiology, School of Public Health, St Mary's Hospital, Imperial College Faculty of Medicine, London W2 1PG, UK
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Sensitivity and Specificity of a Urine Circulating Anodic Antigen Test for the Diagnosis of Schistosoma haematobium in Low Endemic Settings. PLoS Negl Trop Dis 2015; 9:e0003752. [PMID: 25973845 PMCID: PMC4431728 DOI: 10.1371/journal.pntd.0003752] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/11/2015] [Indexed: 01/14/2023] Open
Abstract
Background Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are key goals of the World Health Organization for 2025. Conventional parasitological methods are insensitive for the detection of light-intensity infections. Techniques with high sensitivity and specificity are required for an accurate diagnosis in low-transmission settings and verification of elimination. We determined the accuracy of a urine-based up-converting phosphor-lateral flow circulating anodic antigen (UCP-LF CAA) assay for Schistosoma haematobium diagnosis in low-prevalence settings in Zanzibar, Tanzania. Methodology A total of 1,740 urine samples were collected in 2013 from children on Pemba Island, from schools where the S. haematobium prevalence was <2%, 2–5%, and 5–10%, based on a single urine filtration. On the day of collection, all samples were tested for microhematuria with reagent strips and for the presence of S. haematobium eggs with microscopy. Eight months later, 1.5 ml of urine from each of 1,200 samples stored at -20°C were analyzed by UCP-LF CAA assay, while urine filtration slides were subjected to quality control (QCUF). In the absence of a true ‘gold’ standard, the diagnostic performance was calculated using latent class analyses (LCA). Principal Findings The ‘empirical’ S. haematobium prevalence revealed by UCP-LF CAA, QCUF, and reagent strips was 14%, 5%, and 4%, respectively. LCA revealed a sensitivity of the UCP-LF CAA, QCUF, and reagent strips of 97% (95% confidence interval (CI): 91–100%), 86% (95% CI: 72–99%), and 67% (95% CI: 52–81%), respectively. Test specificities were consistently above 90%. Conclusions/Significance The UCP-LF CAA assay shows high sensitivity for the diagnosis of S. haematobium in low-endemicity settings. Empirically, it detects a considerably higher number of infections than microscopy. Hence, the UCP-LF CAA employed in combination with QCUF, is a promising tool for monitoring and surveillance of urogenital schistosomiasis in low-transmission settings targeted for elimination. The World Health Organization aspires to eliminate snail fever (schistosomiasis) as a public health problem and to interrupt the transmission of this disease in selected areas by 2025. Efforts to achieve these goals are currently being intensified. As a result, the prevalence and intensity of infection will decline in many parts of the world. To detect light-intensity infections, diagnostic tools with a high sensitivity and specificity are needed. We assessed the accuracy of a method that is able to diagnose schistosomiasis via the detection of circulating anodic antigen (CAA) in urine. We examined 1,200 urine samples from children living on Pemba Island, Tanzania, a low-endemic area targeted for schistosomiasis elimination. We found that the CAA-test had a considerably higher sensitivity than conventional urine filtration microscopy and reagent strips that are widely used in schistosomiasis control programs. The empirical prevalence of infection with the parasite Schistosoma haematobium determined by the CAA-test was up to 10 times higher than that obtained by urine filtration. Our results suggest that the CAA-test—in combination with urine filtration—is a promising approach for the diagnosis of S. haematobium in low-transmission settings that are targeted for elimination.
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Utzinger J, Becker SL, van Lieshout L, van Dam GJ, Knopp S. New diagnostic tools in schistosomiasis. Clin Microbiol Infect 2015; 21:529-42. [PMID: 25843503 DOI: 10.1016/j.cmi.2015.03.014] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/21/2015] [Accepted: 03/21/2015] [Indexed: 12/22/2022]
Abstract
Schistosomiasis is a water-based parasitic disease that affects over 250 million people. Control efforts have long been in vain, which is one reason why schistosomiasis is considered a neglected tropical disease. However, since the new millennium, interventions against schistosomiasis are escalating. The initial impetus stems from a 2001 World Health Assembly resolution, urging member states to scale-up deworming of school-aged children with the anthelminthic drug praziquantel. Because praziquantel is safe, efficacious and inexpensive when delivered through the school platform, diagnosis before drug intervention was deemed unnecessary and not cost-effective. Hence, there was little interest in research and development of novel diagnostic tools. With the recent publication of the World Health Organization (WHO) Roadmap to overcome the impact of neglected tropical diseases in 2020, we have entered a new era. Elimination of schistosomiasis has become the buzzword and this has important ramifications for diagnostic tools. Indeed, measuring progress towards the WHO Roadmap and whether local elimination has been achieved requires highly accurate diagnostic assays. Here, we introduce target product profiles for diagnostic tools that are required for different stages of a schistosomiasis control programme. We provide an update of the latest developments in schistosomiasis diagnosis, including microscopic techniques, rapid diagnostic tests for antigen detection, polymerase chain reaction (PCR) assays and proxy markers for morbidity assessments. Particular emphasis is placed on challenges and solutions for new technologies to enter clinical practice.
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Affiliation(s)
- J Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
| | - S L Becker
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Institute of Medical Microbiology and Hygiene, Saarland University Medical Centre, Homburg/Saar, Germany
| | - L van Lieshout
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - G J van Dam
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - S Knopp
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Department of Life Sciences, Natural History Museum, London, UK
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Mwinzi PNM, Kittur N, Ochola E, Cooper PJ, Campbell CH, King CH, Colley DG. Additional Evaluation of the Point-of-Contact Circulating Cathodic Antigen Assay for Schistosoma mansoni Infection. Front Public Health 2015; 3:48. [PMID: 25853117 PMCID: PMC4365547 DOI: 10.3389/fpubh.2015.00048] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 03/04/2015] [Indexed: 01/02/2023] Open
Abstract
Studies of the urine-based point-of-contact cathodic circulating antigen test (POC-CCA) in Schistosoma mansoni-endemic settings in Africa indicate it has good sensitivity in detecting infections, but in areas of low prevalence, the POC-CCA can be positive for persons who are egg-negative by Kato-Katz stool assays. We examined the POC-CCA assay for: (a) batch-to-batch stability; (b) intra-reader and inter-reader variability; (c) day-to-day variability compared to Kato-Katz stool assays, and (d) to see if praziquantel (PZQ) treatment converted Kato-Katz-negative/POC-CCA positive individuals to POC-CCA negativity. We found essentially no batch-to-batch variation, negligible intra-reader variability (2%), and substantial agreement for inter-reader reliability. Some day-to-day variation was observed over 5 days of urine collection, but less than the variation in Kato-Katz stool assays over 3 days. To evaluate the effect of treatment on Kato-Katz(-)/POC-CCA(+) children, 149 children in an area of 10-15% prevalence who were Kato-Katz(-) based on 3 stool samples but POC-CCA(+) were enrolled. Seven days after treatment (PZQ 40 mg/kg) samples were again collected and tested. Almost half (47%) POC-CCA positive children turned negative. Those still POC-CCA positive received a second treatment, and 34% of them turned POC-CCA negative upon this second treatment. Most who remained POC-CCA positive shifted each time to a "lesser" POC-CCA "level of positivity." The data suggest that most Kato-Katz-negative/POC-CCA positive individuals harbor low-intensity infections, and each treatment kills all or some of their adult worms. The data also suggest that when evaluated by a more sensitive assay, the effective cure rates for PZQ are significantly less than those inferred from fecal testing. These findings have public health significance for the mapping and monitoring of Schistosoma infections and in planning the transition from schistosomiasis morbidity control to elimination of transmission.
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Affiliation(s)
- Pauline N M Mwinzi
- Neglected Tropical Diseases Research Unit, Center for Global Health Research, Kenya Medical Research Institute , Kisumu , Kenya
| | - Nupur Kittur
- Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, GA , USA
| | - Elizabeth Ochola
- Neglected Tropical Diseases Research Unit, Center for Global Health Research, Kenya Medical Research Institute , Kisumu , Kenya
| | - Philip J Cooper
- Institute of Infection and Immunity, St George's University of London , London , UK ; Centro de Investigación en Enfermedades Infecciosas y Crónicas, Pontificia Universidad Católica del Ecuador , Quito , Ecuador
| | - Carl H Campbell
- Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, GA , USA
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine , Cleveland, OH , USA
| | - Daniel G Colley
- Center for Tropical and Emerging Global Diseases, University of Georgia , Athens, GA , USA ; Department of Microbiology, University of Georgia , Athens, GA , USA
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Modelling the effects of mass drug administration on the molecular epidemiology of schistosomes. ADVANCES IN PARASITOLOGY 2015; 87:293-327. [PMID: 25765198 DOI: 10.1016/bs.apar.2014.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
As national governments scale up mass drug administration (MDA) programs aimed to combat neglected tropical diseases (NTDs), novel selection pressures on these parasites increase. To understand how parasite populations are affected by MDA and how to maximize the success of control programmes, it is imperative for epidemiological, molecular and mathematical modelling approaches to be combined. Modelling of parasite population genetic and genomic structure, particularly of the NTDs, has been limited through the availability of only a few molecular markers to date. The landscape of infectious disease research is being dramatically reshaped by next-generation sequencing technologies and our understanding of how repeated selective pressures are shaping parasite populations is radically altering. Genomics can provide high-resolution data on parasite population structure, and identify how loci may contribute to key phenotypes such as virulence and/or drug resistance. We discuss the incorporation of genetic and genomic data, focussing on the recently sequenced Schistosoma spp., into novel mathematical transmission models to inform our understanding of the impact of MDA and other control methods. We summarize what is known to date, the models that exist and how population genetics has given us an understanding of the effects of MDA on the parasites. We consider how genetic and genomic data have the potential to shape future research, highlighting key areas where data are lacking, and how future molecular epidemiology knowledge can aid understanding of transmission dynamics and the effects of MDA, ultimately informing public health policy makers of the best interventions for NTDs.
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Sensitivity and specificity of multiple Kato-Katz thick smears and a circulating cathodic antigen test for Schistosoma mansoni diagnosis pre- and post-repeated-praziquantel treatment. PLoS Negl Trop Dis 2014; 8:e3139. [PMID: 25211217 PMCID: PMC4161328 DOI: 10.1371/journal.pntd.0003139] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 07/22/2014] [Indexed: 12/23/2022] Open
Abstract
Background Two Kato-Katz thick smears (Kato-Katzs) from a single stool are currently recommended for diagnosing Schistosoma mansoni infections to map areas for intervention. This ‘gold standard’ has low sensitivity at low infection intensities. The urine point-of-care circulating cathodic antigen test (POC-CCA) is potentially more sensitive but how accurately they detect S. mansoni after repeated praziquantel treatments, their suitability for measuring drug efficacy and their correlation with egg counts remain to be fully understood. We compared the accuracies of one to six Kato-Katzs and one POC-CCA for the diagnosis of S. mansoni in primary-school children who have received zero to ten praziquantel treatments. We determined the impact each diagnostic approach may have on monitoring and evaluation (M&E) and drug-efficacy findings. Method/Principle Findings In a high S. mansoni endemic area of Uganda, three days of consecutive stool samples were collected from primary school-aged children (six - 12 years) at five time-points in year one: baseline, one-week-post-, four-weeks-post-, six-months-post-, and six-months-one-week-post-praziquantel and three time-points in years two and three: pre-, one-week-post- and four-weeks-post-praziquantel-treatment/retreatment (n = 1065). Two Kato-Katzs were performed on each stool. In parallel, one urine sample was collected and a single POC-CCA evaluated per child at each time-point in year one (n = 367). At baseline, diagnosis by two Kato-Katzs (sensitivity = 98.6%) or one POC-CCA (sensitivity = 91.7%, specificity = 75.0%) accurately predicted S. mansoni infections. However, one year later, a minimum of three Kato-Katzs, and two years later, five Kato-Katzs were required for accurate diagnosis (sensitivity >90%) and drug-efficacy evaluation. The POC-CCA was as sensitive as six Kato-Katzs four-weeks-post and six-months-post-treatment, if trace readings were classified as positive. Conclusions/Significance Six Kato-Katzs (two/stool from three stools) and/or one POC-CCA are required for M&E or drug-efficacy studies. Although unable to measure egg reduction rates, one POC-CCA appears to be more sensitive than six Kato-Katzs at four-weeks-post-praziquantel (drug efficacy) and six-months-post-praziquantel (M&E). Schistosomiasis is a parasitic disease infecting over 200 million people. It remains a major public health concern despite treatment of over 120 million people in sub-Saharan Africa alone. Accurate diagnostic methods are essential for monitoring drug efficacy and long-term control program success. The World Health Organization recommends two Kato-Katz thick smears (Kato-Katzs) from a single stool for Schistosoma mansoni diagnosis to map prevalence and areas for control interventions. Although highly specific, Kato-Katzs are thought to be insensitive at low egg counts. The recently refined urine point-of-care circulating cathodic antigen test (POC-CCA) has been proposed as a diagnostic alternative for mapping areas for interventions, and potentially for assessing drug efficacy. Over three years we assessed the accuracy of six Kato-Katzs and a single POC-CCA in detecting infections in Ugandan primary-school children at 11 time points with repeated praziquantel treatments. Our results demonstrate that two Kato-Katzs accurately detect S. mansoni infection pre-treatment, but at least three days of two Kato-Katzs per stool or one POC-CCA are required for annual monitoring and treatment evaluation and/or drug-efficacy studies. One POC-CCA may be more sensitive in measuring S. mansoni prevalence than six Kato-Katzs, but its accuracies for rigorous intensity measures are still to be proven.
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