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Mutapi F, Garba A, Woolhouse M, Kazyoba P. Paediatric schistosomiasis: last mile preparations for deploying paediatric praziquantel. Trends Parasitol 2024; 40:687-695. [PMID: 39033047 DOI: 10.1016/j.pt.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/12/2024] [Accepted: 06/19/2024] [Indexed: 07/23/2024]
Abstract
Schistosomiasis is the second most important parasitic disease of public health importance in Africa, affecting over 50 million children aged <5 years old. Schistosomiasis control has focused on treating school-aged children (>6 years) and adults through mass drug administration (MDA). Following the recent development of a paediatric praziquantel (PZQ) formulation for children aged <5 years, there are now concerted efforts to determine optimal and effective ways to integrate treatment of these children into national schistosomiasis control programmes. In this opinion article we outline the pathway for successful drug access, delivery, and mainstreaming of the new formulation in endemic country health systems. Effective and sustained paediatric schistosomiasis treatment is an important target of the 2030 World Health Organization (WHO) neglected tropical diseases (NTDs) roadmap.
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Affiliation(s)
- Francisca Mutapi
- Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; Tackling Infections to Benefit Africa (TIBA) Partnership, TIBA Global Health Research Unit, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK.
| | - Amadou Garba
- Department of the Control of Neglected Tropical Diseases, World Health Organization, Geneva, 1211, Switzerland
| | - Mark Woolhouse
- Tackling Infections to Benefit Africa (TIBA) Partnership, TIBA Global Health Research Unit, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK; Usher Institute of Population Health Sciences and Informatics, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK
| | - Paul Kazyoba
- National Institute for Medical Research, 2448 Barack Obama Dr, Dar es Salaam, Tanzania; TIBA Partnership, NIMR, Tanzania, 2448 Barack Obama Dr, Dar es Salaam, Tanzania
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Kura K, Mutono N, Basáñez MG, Collyer BS, Coffeng LE, Thumbi SM, Anderson RM. How Does Treatment Coverage and Proportion Never Treated Influence the Success of Schistosoma mansoni Elimination as a Public Health Problem by 2030? Clin Infect Dis 2024; 78:S126-S130. [PMID: 38662698 PMCID: PMC11045018 DOI: 10.1093/cid/ciae074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND The 2030 target for schistosomiasis is elimination as a public health problem (EPHP), achieved when the prevalence of heavy-intensity infection among school-aged children (SAC) reduces to <1%. To achieve this, the new World Health Organization guidelines recommend a broader target of population to include pre-SAC and adults. However, the probability of achieving EPHP should be expected to depend on patterns in repeated uptake of mass drug administration by individuals. METHODS We employed 2 individual-based stochastic models to evaluate the impact of school-based and community-wide treatment and calculated the number of rounds required to achieve EPHP for Schistosoma mansoni by considering various levels of the population never treated (NT). We also considered 2 age-intensity profiles, corresponding to a low and high burden of infection in adults. RESULTS The number of rounds needed to achieve this target depends on the baseline prevalence and the coverage used. For low- and moderate-transmission areas, EPHP can be achieved within 7 years if NT ≤10% and NT <5%, respectively. In high-transmission areas, community-wide treatment with NT <1% is required to achieve EPHP. CONCLUSIONS The higher the intensity of transmission, and the lower the treatment coverage, the lower the acceptable value of NT becomes. Using more efficacious treatment regimens would permit NT values to be marginally higher. A balance between target treatment coverage and NT values may be an adequate treatment strategy depending on the epidemiological setting, but striving to increase coverage and/or minimize NT can shorten program duration.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
| | - Nyamai Mutono
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Kenya
- Paul G. Allen School for Global Health, Washington State University, Pullman
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
| | - Benjamin S Collyer
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
| | - Luc E Coffeng
- Department of Public Health, Erasmus University Medical Center, University Medical Center Rotterdam, The Netherlands
| | - S M Thumbi
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Kenya
- Paul G. Allen School for Global Health, Washington State University, Pullman
- Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
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Vaillant MT, Philippy F, Neven A, Barré J, Bulaev D, Olliaro PL, Utzinger J, Keiser J, Garba AT. Diagnostic tests for human Schistosoma mansoni and Schistosoma haematobium infection: a systematic review and meta-analysis. THE LANCET. MICROBE 2024; 5:e366-e378. [PMID: 38467130 PMCID: PMC10990967 DOI: 10.1016/s2666-5247(23)00377-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 10/22/2023] [Accepted: 11/16/2023] [Indexed: 03/13/2024]
Abstract
BACKGROUND Accurate diagnosis is pivotal for implementing strategies for surveillance, control, and elimination of schistosomiasis. Despite their low sensitivity in low-endemicity areas, microscopy-based urine filtration and the Kato-Katz technique are considered as reference diagnostic tests for Schistosoma haematobium and Schistosoma mansoni infections, respectively. We aimed to collate all available evidence on the accuracy of other proposed diagnostic techniques. METHODS In this systematic review and meta-analysis, we searched PubMed, Embase, the Cochrane Library, and LILACS for studies published from database inception to Dec 31, 2022, investigating the sensitivity and specificity of diagnostic tests for S haematobium and S mansoni infections against Kato-Katz thick smears or urine microscopy (reference tests) involving adults (aged ≥18 years), school-aged children (aged 7 to 18 years), or preschool-aged children (aged 1 month to 7 years). We extracted raw data on true positives, true negatives, false positives, and false negatives for the diagnostic tests and data on the number of participants, study authors, publication year, journal, study design, participants' age and sex, prevalence of Schistosoma infection, and treatment status. To account for imperfect reference tests, we used a hierarchical Bayesian latent class meta-analysis to model test accuracy. FINDINGS Overall, we included 121 studies, assessing 28 different diagnostic techniques. Most studies (103 [85%] of 121) were done in Africa, 14 (12%) in South America, one (1%) in Asia, and one (1%) in an unknown country. Compared with the reference test, Kato-Katz thick smears, circulating cathodic antigen urine cassette assay version 1 (CCA1, 36 test comparisons) had excellent sensitivity (95% [95% credible interval 88-99]) and reasonable specificity (74% [63-83]) for S mansoni. ELISA-based tests had a performance comparable to circulating cathodic antigen, but there were few available test comparisons. For S haematobium, proteinuria (42 test comparisons, sensitivity 73% [62-82]; specificity 94% [89-98]) and haematuria (75 test comparisons, sensitivity 85% [80-90]; specificity 96% [92-99]) reagent strips showed high specificity, with haematuria reagent strips having better sensitivity. Despite limited data, nucleic acid amplification tests (NAATs; eg, PCR or loop-mediated isothermal amplification [LAMP]) showed promising results with sensitivity estimates above 90%. We found an unclear risk of bias of about 70% in the use of the reference or index tests and of 50% in patient selection. All analyses showed substantial heterogeneity (I2>80%). INTERPRETATION Although NAATs and immunological diagnostics show promise, the limited information available precludes drawing definitive conclusions. Additional research on diagnostic accuracy and cost-effectiveness is needed before the replacement of conventional tests can be considered. FUNDING WHO and Luxembourg Institute of Health.
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Affiliation(s)
- Michel T Vaillant
- Competence Center for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Luxembourg.
| | - Fred Philippy
- Competence Center for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Luxembourg; Zortify, Luxembourg City, Luxembourg
| | - Anouk Neven
- Competence Center for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Jessica Barré
- Competence Center for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Luxembourg; Luxembourg National Office of Health, Luxembourg City, Luxembourg
| | - Dmitry Bulaev
- Competence Center for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Piero L Olliaro
- International Severe Acute Respiratory and Emerging Infection Consortium, Pandemic Sciences Institute, University of Oxford, Oxford, UK
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute and Medical Parasitology and Infection Biology Department, University of Basel, Basel, Switzerland
| | - Amadou T Garba
- Department of Control of Neglected Tropical Diseases, WHO, Geneva, Switzerland
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Rakotozandrindrainy R, Rakotoarivelo RA, Kislaya I, Marchese V, Rasamoelina T, Solonirina J, Ratiaharison EF, Razafindrakoto R, Razafindralava NM, Rakotozandrindrainy N, Radomanana M, Andrianarivelo MR, Klein P, Lorenz E, Jaeger A, Hoekstra PT, Corstjens PLAM, Schwarz NG, van Dam GJ, May J, Fusco D. Schistosome infection among pregnant women in the rural highlands of Madagascar: A cross-sectional study calling for public health interventions in vulnerable populations. PLoS Negl Trop Dis 2024; 18:e0011766. [PMID: 38626192 PMCID: PMC11051649 DOI: 10.1371/journal.pntd.0011766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 04/26/2024] [Accepted: 03/26/2024] [Indexed: 04/18/2024] Open
Abstract
INTRODUCTION Schistosomiasis is a parasitic infection highly prevalent in sub-Saharan Africa (SSA) with Madagascar being among the countries with highest burden of the disease worldwide. Despite WHO recommendations, suggesting treatment of pregnant women after the first trimester, this group is still excluded from Mass Drug Administration programs. Our study, had the objective to measure the prevalence of schistosome infection among pregnant women in Madagascar in order to inform public health policies for treatment in this vulnerable population. METHODS Women were recruited for this cross-sectional study between April 2019 and February 2020 when attending Antenatal Care Services (ANCs) at one of 42 included Primary Health Care Centers. The urine-based upconverting reporter particle, lateral flow (UCP-LF) test detecting circulating anodic antigen was used for the detection of schistosome infections. To identify factors associated with the prevalence of schistosome infection crude and adjusted prevalence ratios and 95% CIs were estimated using mixed-effect Poisson regression. RESULTS Among 4,448 participating women aged between 16 and 47 years, the majority (70.4%, 38 n = 3,133) resided in rural settings. Overall, the prevalence of schistosome infection was 55.9% (n = 2486, CI 95%: 53.3-58.5). A statistically significant association was found with age group (increased prevalence in 31-47 years old, compared to 16-20 years old (aPR = 1.15, CI 95%: 1.02-1.29) and with uptake of antimalaria preventive treatment (decreased prevalence, aPR = 0.85, CI 95%: 0.77-0.95). No other associations of any personal characteristics or contextual factors with schistosome infection were found in our multivariate regression analysis. DISCUSSION AND CONCLUSION The high prevalence of schistosome infection in pregnant women supports the consideration of preventive schistosomiasis treatment in ANCs of the Malagasy highlands. We strongly advocate for adapting schistosomiasis programs in highly endemic contexts. This, would contribute to both the WHO and SDGs agendas overall to improving the well-being of women and consequently breaking the vicious cycle of poverty perpetuated by schistosomiasis.
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Affiliation(s)
| | | | - Irina Kislaya
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
| | - Valentina Marchese
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
| | | | | | | | | | | | | | - Mickael Radomanana
- Infectious diseases service, University Hospital Tambohobe, Fianarantsoa, Madagascar
| | | | - Philipp Klein
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
| | - Eva Lorenz
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
| | - Anna Jaeger
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
| | | | | | - Norbert Georg Schwarz
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | | | - Jürgen May
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
| | - Daniela Fusco
- Department of Infectious Diseases Epidemiology, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Germany
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Wiegand RE, Odiere MR, Kinung’hi S, N'Goran EK, Mwinzi P, Secor WE. Age-group associations of schistosomiasis prevalence from trial data, Côte d'Ivoire, Kenya and the United Republic of Tanzania. Bull World Health Organ 2024; 102:265-275. [PMID: 38562204 PMCID: PMC10976868 DOI: 10.2471/blt.23.289843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/11/2023] [Accepted: 01/16/2024] [Indexed: 04/04/2024] Open
Abstract
Objective To determine if the prevalence of schistosomiasis in children aged 9-12 years is associated with the prevalence in 5-8-year-olds and adults after preventive chemotherapy in schools or the community. Methods We combined data from four community-randomized, preventive chemotherapy trials in treatment-naïve populations in Côte d'Ivoire, Kenya and the United Republic of Tanzania during 2010-2016 according to the number of praziquantel treatments and the delivery method. Schistosoma mansoni infection was sought on two slides prepared from each participant's first stool using the Kato-Katz technique. We assessed associations between S. mansoni prevalence in 9-12-year-olds and 5-8-year-olds and adults in the community before and after treatment using Bayesian regression models. Findings Stool samples from 47 985 5-8-year-olds, 81 077 9-12-year-olds and 20 492 adults were analysed. We found associations between the prevalence in 9-12-year-olds and that in 5-8-year-olds and adults after preventive treatment, even when only school-age children were treated. When the prevalence in 9-12-year-olds was under 10%, the prevalence in 5-8-year-olds was consistently under 10%. When the prevalence in 9-12-year-olds was under 50%, the prevalence in adults after two or four rounds of preventive chemotherapy was 10%-15% lower than before chemotherapy. Post-chemotherapy age-group associations were consistent with pre-chemotherapy associations in this analysis and previous studies. Conclusion The prevalence of S. mansoni infection in 9-12-year-olds was associated with the prevalence in other age groups and could be used to guide community treatment decisions.
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Affiliation(s)
- Ryan E Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS H24-5, Atlanta, Georgia, GA30329, United States of America
| | - Maurice R Odiere
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Safari Kinung’hi
- National Institute for Medical Research, Mwanza Centre, Mwanza, United Republic of Tanzania
| | | | - Pauline Mwinzi
- Expanded Special Programme for Elimination of Neglected Tropical Diseases, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road NE, MS H24-5, Atlanta, Georgia, GA30329, United States of America
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Kameni M, Musaigwa F, Kamguia LM, Kamdem SD, Mbanya G, Lamberton PHL, Komguep Nono J. Harnessing Schistosoma-associated metabolite changes in the human host to identify biomarkers of infection and morbidity: Where are we and what should we do next? PLoS Negl Trop Dis 2024; 18:e0012009. [PMID: 38512811 PMCID: PMC10956858 DOI: 10.1371/journal.pntd.0012009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024] Open
Abstract
Schistosomiasis is the second most widespread parasitic disease affecting humans. A key component of today's infection control measures is the diagnosis and monitoring of infection, informing individual- and community-level treatment. However, newly acquired infections and/or low parasite burden are still difficult to diagnose reliably. Furthermore, even though the pathological consequence of schistosome egg sequestration in host tissues is well described, the evidence linking egg burden to morbidity is increasingly challenged, making it inadequate for pathology monitoring. In the last decades, omics-based instruments and methods have been developed, adjusted, and applied in parasitic research. In particular, the profiling of the most reliable determinants of phenotypes, metabolites by metabolomics, emerged as a powerful boost in the understanding of basic interactions within the human host during infection. As such, the fine detection of host metabolites produced upon exposure to parasites such as Schistosoma spp. and the ensuing progression of the disease are believed to enable the identification of Schistosoma spp. potential biomarkers of infection and associated pathology. However, attempts to provide such a comprehensive understanding of the alterations of the human metabolome during schistosomiasis are rare, limited in their design when performed, and mostly inconclusive. In this review, we aimed to briefly summarize the most robust advances in knowledge on the changes in host metabolic profile during Schistosoma infections and provide recommendations for approaches to optimize the identification of metabolomic signatures of human schistosomiasis.
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Affiliation(s)
- Mireille Kameni
- Unit of Immunobiology and Helminth Infections, Laboratory of Molecular Biology and Biotechnology, Institute of Medical Research and Medicinal Plant Studies (IMPM), Ministry of Scientific Research and Innovation, Yaoundé, Cameroon
- Department of Microbiology and Parasitology, University of Bamenda, Bambili, North-West Region, Cameroon
| | - Fungai Musaigwa
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Leonel Meyo Kamguia
- Unit of Immunobiology and Helminth Infections, Laboratory of Molecular Biology and Biotechnology, Institute of Medical Research and Medicinal Plant Studies (IMPM), Ministry of Scientific Research and Innovation, Yaoundé, Cameroon
| | - Severin Donald Kamdem
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Gladice Mbanya
- Unit of Immunobiology and Helminth Infections, Laboratory of Molecular Biology and Biotechnology, Institute of Medical Research and Medicinal Plant Studies (IMPM), Ministry of Scientific Research and Innovation, Yaoundé, Cameroon
| | - Poppy H. L. Lamberton
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
| | - Justin Komguep Nono
- Unit of Immunobiology and Helminth Infections, Laboratory of Molecular Biology and Biotechnology, Institute of Medical Research and Medicinal Plant Studies (IMPM), Ministry of Scientific Research and Innovation, Yaoundé, Cameroon
- Division of Immunology, Health Science Faculty, University of Cape Town, Cape Town, South Africa
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Rotejanaprasert C, Chuaicharoen P, Prada JM, Thantithaveewat T, Adisakwattana P, Pan-ngum W. Evaluation of Kato-Katz and multiplex quantitative polymerase chain reaction performance for clinical helminth infections in Thailand using a latent class analysis. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220281. [PMID: 37598708 PMCID: PMC10440171 DOI: 10.1098/rstb.2022.0281] [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: 10/29/2022] [Accepted: 05/27/2023] [Indexed: 08/22/2023] Open
Abstract
Using an appropriate diagnostic tool is essential to soil-transmitted helminth control and elimination efforts. Kato-Katz (KK) is the most commonly used diagnostic, but recently other tools, such as real-time quantitative polymerase chain reaction (multiplex qPCR), are starting to be employed more. Here, we evaluated the performance of these two diagnostic tools for five helminth species in Thailand. In the absence of a gold standard, diagnostic performance can be evaluated using latent class analysis. Our results suggest that in moderate to high prevalence settings above 2% multiplex qPCR could be more sensitive than KK, this was particularly apparent for Opisthorchis viverrini in the northeastern provinces. However, for low prevalence, both diagnostics suffered from low sensitivity. Specificity of both diagnostics was estimated to be high (above 70%) across all settings. For some specific helminth infection such as O. viverrini, multiplex qPCR is still a preferable choice of diagnostic test. KK performed equally well in detecting Ascaris lumbricoides and Taenia solium when the prevalence is moderate to high (above 2%). Neither test performed well when the prevalence of infection is low (below 2%), and certainly in the case for hookworm and Trichuris trichiura. Combination of two or more diagnostic tests can improve the performance although the cost would be high. Development of new methods for helminth surveillance at the pre-elimination phase is therefore very important. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Chawarat Rotejanaprasert
- Department of Tropical Hygiene, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
| | | | - Joaquin M. Prada
- Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, UK
| | | | - Poom Adisakwattana
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wirichada Pan-ngum
- Department of Tropical Hygiene, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
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8
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Kabbas-Piñango E, Arinaitwe M, van Dam GJ, Moses A, Namukuta A, Nankasi AB, Mwima NK, Besigye F, Prada JM, Lamberton PHL. Reproducibility matters: intra- and inter-sample variation of the point-of-care circulating cathodic antigen test in two Schistosoma mansoni endemic areas in Uganda. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220275. [PMID: 37598698 PMCID: PMC10440168 DOI: 10.1098/rstb.2022.0275] [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: 02/02/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
Over 240 million people are infected with schistosomiasis. Detecting Schistosoma mansoni eggs in stool using Kato-Katz thick smears (Kato-Katzs) is highly specific but lacks sensitivity. The urine-based point-of-care circulating cathodic antigen test (POC-CCA) has higher sensitivity, but issues include specificity, discrepancy between batches and interpretation of trace results. A semi-quantitative G-score and latent class analyses making no assumptions about trace readings have helped address some of these issues. However, intra-sample and inter-sample variation remains unknown for POC-CCAs. We collected 3 days of stool and urine from 349 and 621 participants, from high- and moderate-endemicity areas, respectively. We performed duplicate Kato-Katzs and one POC-CCA per sample. In the high-endemicity community, we also performed three POC-CCA technical replicates on one urine sample per participant. Latent class analysis was performed to estimate the relative contribution of intra- (test technical reproducibility) and inter-sample (day-to-day) variation on sensitivity and specificity. Within-sample variation for Kato-Katzs was higher than between-sample, with the opposite true for POC-CCAs. A POC-CCA G3 threshold most accurately assesses individual infections. However, to reach the WHO target product profile of the required 95% specificity for prevalence and monitoring and evaluation, a threshold of G4 is needed, but at the cost of reducing sensitivity. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Elías Kabbas-Piñango
- School of Biodiversity, One Health & Veterinary Medicine, Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Moses Arinaitwe
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, 2333 ZA, The Netherlands
| | - Adriko Moses
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Annet Namukuta
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Andrina Barungi Nankasi
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Nicholas Khayinja Mwima
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Fred Besigye
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Joaquin M. Prada
- Department of Comparative Biomedical Sciences, Faculty of Health & Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Poppy H. L. Lamberton
- School of Biodiversity, One Health & Veterinary Medicine, Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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Phillips AE, Ower AK, Mekete K, Liyew EF, Maddren R, Mengistu B, Anjulo U, Chernet M, Dunn JC, Mohammed H, Belay H, Gidey B, Tasew G, Tadesse G, Salasibew M, Tollera G, Anderson R. Baseline soil-transmitted helminth and schistosome infection in the Geshiyaro project, Ethiopia: A unique transmission interruption project using biometric fingerprinting for longitudinal individual analysis. PLoS Negl Trop Dis 2023; 17:e0011589. [PMID: 37851666 PMCID: PMC10615263 DOI: 10.1371/journal.pntd.0011589] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/30/2023] [Accepted: 09/07/2023] [Indexed: 10/20/2023] Open
Abstract
BACKGROUND The Geshiyaro project aims to assess the feasibility of interrupting transmission of soil-transmitted helminths (STH) and schistosome (SCH) infection in the Wolaita zone of southern Ethiopia through high coverage community-wide mass drug administration (MDA), in combination with improved water, sanitation, and hygiene services and behaviour change communication delivered through the existing health care infrastructure. To accurately measure treatment coverage a population census was conducted enrolling individuals with biometric fingerprinting and barcoded ID cards. This paper details the baseline census and parasitology surveys conducted before the start of any interventions. METHODS The census was conducted in five of the 15 Wolaita districts between October 2018 and December 2019, enrolling all consenting participants from every household. Simultaneously, a cross-sectional parasitology survey was conducted in 130 out of 361 randomly selected communities from all 15 districts, with 100 individuals across all age groups (infant to adult) per community providing stool and urine for analysis by duplicate Kato-Katz and a point-of-care circulating cathodic antigen (POC-CCA) to test for Schistosoma mansoni and STH, and microhaematuria and urine filtration for Schistosoma haematobium. Of the 130 communities, 30 were randomly selected for annual, longitudinal parasitological monitoring, with 150 randomly selected individuals from infant to adult providing two days of stool and urine samples for analysis by the same diagnostic tests per community. RESULTS In total 97,919 households participated in the baseline census enrolling 466,071 individuals, with parasitological data obtained from 10,785 people. At baseline, 15.5% were infected with at least one STH species, with Ascaris lumbricoides (9.5%), followed by hookworm (7.2%) and Trichuris trichiura (1.8%). Substantial heterogeneity in STH prevalence was observed between communities ranging from 0% to 61% where most infections were low intensity. Schistosoma mansoni infection was the dominant schistosome infection (0.85% by Kato-Katz and 13.3% by POC-CCA trace negative and 21.5% trace positive), with few Schistosoma haematobium infections identified (2.77% haematuria positive and 0.13% positive by urine filtration). CONCLUSIONS While the national control program in Ethiopia has made good progress in reducing prevalence of STH and SCH in Wolaita since it was launched in 2015, there remain areas of persistent infection suggesting the existence of environmental or behavioural risk factors that contribute to ongoing transmission. This project aims to identify the most efficient intervention strategies to reduce community burden and reach interruption of transmission.
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Affiliation(s)
- Anna E. Phillips
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, St Mary’s Campus, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Alison K. Ower
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, St Mary’s Campus, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | | | | | - Rosie Maddren
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, St Mary’s Campus, London, United Kingdom
| | - Birhan Mengistu
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, St Mary’s Campus, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Ufaysa Anjulo
- Children’s Investment Fund Foundation, London, United Kingdom
| | - Melkie Chernet
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Julia C. Dunn
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, St Mary’s Campus, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | | | - Habtamu Belay
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Geremew Tasew
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | | | | | - Roy Anderson
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, St Mary’s Campus, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
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Reed AL, O'Ferrall AM, Kayuni SA, Baxter H, Stanton MC, Stothard JR, Jewell C. Modelling the age-prevalence relationship in schistosomiasis: A secondary data analysis of school-aged-children in Mangochi District, Lake Malawi. Parasite Epidemiol Control 2023; 22:e00303. [PMID: 37234267 PMCID: PMC10205779 DOI: 10.1016/j.parepi.2023.e00303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 04/26/2023] [Accepted: 05/02/2023] [Indexed: 05/27/2023] Open
Abstract
Schistosomiasis is an aquatic snail borne parasitic disease, with intestinal schistosomiasis (IS) and urogenital schistosomiasis (UGS) caused by Schistosoma mansoni and S. haematobium infections, respectively. School-aged-children (SAC) are a known vulnerable group and can also suffer from co-infections. Along the shoreline of Lake Malawi a newly emerging outbreak of IS is occurring with increasing UGS co-infection rates. Age-prevalence (co)infection profiles are not fully understood. To shed light on these (co)infection trends by Schistosoma species and by age of child, we conducted a secondary data analysis of primary epidemiological data collected from SAC in Mangochi District, Lake Malawi, as published previously. Available diagnostic data by child, were converted into binary response infection profiles for 520 children, aged 6-15, across 12 sampled schools. Generalised additive models were then fitted to mono- and dual-infections. These were used to identify consistent population trends, finding the prevalence of IS significantly increased [p = 8.45e-4] up to 11 years of age then decreasing thereafter. A similar age-prevalence association was observed for co-infection [p = 7.81e-3]. By contrast, no clear age-infection pattern for UGS was found [p = 0.114]. Peak prevalence of Schistosoma infection typically occurs around adolescence; however, in this newly established IS outbreak with rising prevalence of UGS co-infections, the peak appears to occur earlier, around the age of 11 years. As the outbreak of IS fulminates, further temporal analysis of the age-relationship with Schistosoma infection is justified. This should refer to age-prevalence models which could better reveal newly emerging transmission trends and Schistosoma species dynamics. Dynamical modelling of infections, alongside malacological niche mapping, should be considered to guide future primary data collection and intervention programmes.
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Affiliation(s)
- Amber L. Reed
- Lancaster Medical School, Lancaster University, Bailrigg House, Bailrigg, Lancaster LA1 4YE, UK
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke PI, Liverpool L3 5QA, UK
| | - Angus M. O'Ferrall
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke PI, Liverpool L3 5QA, UK
| | - Sekeleghe A. Kayuni
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke PI, Liverpool L3 5QA, UK
- MASM Medi Clinics Limited, Medical Aid Society of Malawi (MASM), P.O. Box 31659, Lilongwe 3. Malawi
| | - Hamish Baxter
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke PI, Liverpool L3 5QA, UK
| | - Michelle C. Stanton
- Vector Biology, Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool L3 5QA, UK
| | - J. Russell Stothard
- Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke PI, Liverpool L3 5QA, UK
| | - Christopher Jewell
- Mathematics and Statistics, Lancaster University, Bailrigg House, Bailrigg, Lancaster LA1 4YE, UK
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Colley DG, Ramzy RMR, Maganga J, Kinung'hi S, Odiere MR, Musuva RM, Campbell CH. The POC-CCA assay for detection of Schistosoma mansoni infection needs standardization in production and proper quality control to be reliable. Acta Trop 2023; 238:106795. [PMID: 36539024 DOI: 10.1016/j.actatropica.2022.106795] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/07/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022]
Affiliation(s)
- Daniel G Colley
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia; Department of Microbiology, University of Georgia, Athens, Georgia.
| | - Reda M R Ramzy
- National Nutrition Institute, General Organization for Teaching Hospitals and Institutes, Cairo, Egypt
| | - Jane Maganga
- National Institute for Medical Research (NIMR), Mwanza Centre, Mwanza, Tanzania
| | - Safari Kinung'hi
- National Institute for Medical Research (NIMR), Mwanza Centre, Mwanza, Tanzania
| | - Maurice R Odiere
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research (CGHR), Kisumu, Kenya
| | - Rosemary M Musuva
- Kenya Medical Research Institute (KEMRI), Centre for Global Health Research (CGHR), Kisumu, Kenya
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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12
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Limited efficacy of repeated praziquantel treatment in Schistosoma mansoni infections as revealed by highly accurate diagnostics, PCR and UCP-LF CAA (RePST trial). PLoS Negl Trop Dis 2022; 16:e0011008. [PMID: 36548444 PMCID: PMC9822103 DOI: 10.1371/journal.pntd.0011008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 01/06/2023] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Most studies assessing praziquantel (PZQ) efficacy have used relatively insensitive diagnostic methods, thereby overestimating cure rate (CR) and intensity reduction rate (IRR). To determine accurately PZQ efficacy, we employed more sensitive DNA and circulating antigen detection methods. METHODOLOGY A sub-analysis was performed based on a previously published trial conducted in children from Côte d'Ivoire with a confirmed Schistosoma mansoni infection, who were randomly assigned to a standard (single dose of PZQ) or intense treatment group (4 repeated doses of PZQ at 2-week intervals). CR and IRR were estimated based on PCR detecting DNA in a single stool sample and the up-converting particle lateral flow (UCP-LF) test detecting circulating anodic antigen (CAA) in a single urine sample, and compared with traditional Kato-Katz (KK) and point-of-care circulating cathodic antigen (POC-CCA). PRINCIPAL FINDINGS Individuals positive by all diagnostic methods (i.e., KK, POC-CCA, PCR, and UCP-LF CAA) at baseline were included in the statistical analysis (n = 125). PCR showed a CR of 45% (95% confidence interval (CI) 32-59%) in the standard and 78% (95% CI 66-87%) in the intense treatment group, which is lower compared to the KK results (64%, 95% CI 52-75%) and 88%, 95% CI 78-93%). UCP-LF CAA showed a significantly lower CR in both groups, 16% (95% CI 11-24%) and 18% (95% CI 12-26%), even lower than observed by POC-CCA (31%, 95% CI 17-35% and 36%, 95% CI 26-47%). A substantial reduction in DNA and CAA-levels was observed after the first treatment, with no further decrease after additional treatment and no significant difference in IRR between treatment groups. CONCLUSION/SIGNIFICANCE The efficacy of (repeated) PZQ treatment was overestimated when using egg-based diagnostics (i.e. KK and PCR). Quantitative worm-based diagnostics (i.e. POC-CCA and UCP-LF CAA) revealed that active Schistosoma infections are still present despite multiple treatments. These results stress the need for using accurate diagnostic tools to monitor different PZQ treatment strategies, in particular when moving toward elimination of schistosomiasis. CLINICAL TRIAL REGISTRATION www.clinicaltrials.gov, NCT02868385.
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Hoekstra PT, Madinga J, Lutumba P, van Grootveld R, Brienen EAT, Corstjens PLAM, van Dam GJ, Polman K, van Lieshout L. Diagnosis of Schistosomiasis without a Microscope: Evaluating Circulating Antigen (CCA, CAA) and DNA Detection Methods on Banked Samples of a Community-Based Survey from DR Congo. Trop Med Infect Dis 2022; 7:tropicalmed7100315. [PMID: 36288056 PMCID: PMC9608707 DOI: 10.3390/tropicalmed7100315] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
Detection of Schistosoma eggs in stool or urine is known for its low sensitivity in diagnosing light infections. Alternative diagnostics with better sensitivity while remaining highly specific, such as real-time PCR and circulating antigen detection, are progressively used as complementary diagnostic procedures but have not yet replaced microscopy. This study evaluates these alternative methods for the detection of Schistosoma infections in the absence of microscopy. Schistosomiasis presence was determined retrospectively in 314 banked stool and urine samples, available from a previous survey on the prevalence of taeniasis in a community in the Democratic Republic of the Congo, using real-time PCR, the point-of-care circulating cathodic antigen (POC-CCA) test, as well as the up-converting particle lateral flow circulating anodic antigen (UCP-LF CAA) test. Schistosoma DNA was present in urine (3%) and stool (28%) samples, while CCA (28%) and CAA (69%) were detected in urine. Further analysis of the generated data indicated stool-based PCR and the POC-CCA test to be suitable diagnostics for screening of S. mansoni infections, even in the absence of microscopy. A substantial proportion (60%) of the 215 CAA-positive cases showed low antigen concentrations, suggesting that even PCR and POC-CCA underestimated the “true” number of schistosome positives.
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Affiliation(s)
- Pytsje T. Hoekstra
- Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Correspondence:
| | - Joule Madinga
- Institute of Health and Society, Université Catholique de Louvain, 1348 Brussels, Belgium
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
| | - Pascal Lutumba
- Institut National de Recherche Biomédicale, Kinshasa 1197, Democratic Republic of the Congo
- Department of Tropical Medicine, University of Kinshasa, Kinshasa 7948, Democratic Republic of the Congo
| | - Rebecca van Grootveld
- Department of Clinical Microbiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Eric A. T. Brienen
- Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Paul L. A. M. Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Katja Polman
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
- Department of Health Sciences, VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
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Grolimund CM, Bärenbold O, Utzinger J, Keiser J, Vounatsou P. Modeling the effect of different drugs and treatment regimen for hookworm on cure and egg reduction rates taking into account diagnostic error. PLoS Negl Trop Dis 2022; 16:e0010810. [PMID: 36194622 PMCID: PMC9595538 DOI: 10.1371/journal.pntd.0010810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/25/2022] [Accepted: 09/12/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Hookworm infections, caused by Ancylostoma duodenale and Necator americanus, are of considerable public health importance. The World Health Organization recommends preventive chemotherapy as the key strategy for morbidity control. Meta-analyses have been conducted to estimate treatment efficacy of available drugs and drug combinations. However, in most studies, the relation between the diagnostic error and infection intensity have not been considered, resulting in an overestimation of cure rates (CRs). METHODOLOGY A Bayesian model was developed to compare the 'true' CR and egg reduction rate of different treatment regimens for hookworm infections taking into account the error of the recommended Kato-Katz thick smear diagnostic technique. It was fitted to the observed egg count data which was linked to the distribution of worms, considered the day-to-day variation of hookworm egg excretion and estimated the infection intensity-dependent sensitivity. The CR was obtained by defining the prevalence of infection at follow-up as the probability of having at least one fertilized female worm. The model was applied to individual-level egg count data available from 17 treatments and six clinical trials. PRINCIPAL FINDINGS Taking the diagnostic error into account resulted in considerably lower CRs than previously reported. Overall, of all treatments analyzed, mebendazole administered in six dosages of 100 mg each was the most efficacious treatment with a CR of 88% (95% Bayesian credible interval: 79-95%). Furthermore, diagnostic sensitivity varied with the infection intensity and sampling effort. For an infection intensity of 50 eggs per gram of stool, the sensitivity is close to 60%; for two Kato-Katz thick smears it increased to approximately 76%. CONCLUSIONS/SIGNIFICANCE Our model-based estimates provide the true efficacy of different treatment regimens against hookworm infection taking into account the diagnostic error of the Kato-Katz method. Estimates of the diagnostic sensitivity for different number of stool samples and thick smears are obtained. To accurately assess efficacy in clinical trials with the Kato-Katz method, at least two stool samples on consecutive days should be collected.
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Affiliation(s)
- Carla M. Grolimund
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Oliver Bärenbold
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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15
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Tupps C, Kargbo-Labour I, Paye J, Dhakal S, Hodges MH, Jones AH, Davlin S, Sonnie M, Manah S, Imtiaz R, Zhang Y. Community-wide prevalence and intensity of soil-transmitted helminthiasis and Schistosoma mansoni in two districts of Sierra Leone. PLoS Negl Trop Dis 2022; 16:e0010410. [PMID: 35594318 PMCID: PMC9162327 DOI: 10.1371/journal.pntd.0010410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 06/02/2022] [Accepted: 04/11/2022] [Indexed: 11/19/2022] Open
Abstract
In Sierra Leone, nationally powered school-based surveys have documented significant progress in the control of soil-transmitted helminthiasis (STH) and schistosomiasis. In order to assess the district-level prevalence and intensity of infection among key at-risk groups outside of school age children (SAC), we conducted a multi-stage, cluster-sample household survey in Bo and Kenema districts in May 2018. From both districts, we examined 1,282 pre-school age children (PSAC), 730 school age children (SAC), and 517 adults over 14 years (including 387 women of reproductive age, or WRA) for STH and Schistosoma mansoni infection using Kato Katz technique. In Bo, STH prevalence was 8.0% (95% Upper Confidence Limit 10.2%) in PSAC, 6.4% (95% Upper Confidence Limit 9.0%) in SAC, 14.1% (95% Upper Confidence Limit 17.4%) in all adults and 11.9% (95% Upper Confidence Limit 17.4%) in WRA. In Kenema, STH prevalence was 18.1% (95% Upper Confidence Limit 20.5%) in PSAC, 17.3% (95% Upper Confidence Limit 20.7%) in SAC, and 16.9% (95% Upper Confidence Limit 20.5%) in all adults and 16.9% (95% Upper Confidence Limit 22.6%) in WRA. Hookworm species were the most prevalent of STH in both districts overall. The overall prevalence of S. mansoni was <10% in Bo and <20% in Kenema, and was similar across age groups. No moderate or heavy intensity STH infections or heavy intensity S. mansoni infections, as per World Health Organization (WHO) classification, were detected in either district. Sanitation variables, such as toilet access and quality, were independently associated with STH and S. mansoni infection. In Kenema, STH prevalence in SAC was within the WHO-defined range for annual treatment, whereas a previous nationally-powered survey estimated it to lie within the range of treatment once per two years. By utilizing community-based sampling, we were able to assess prevalence among WRA and make recommendations based on current guidance from WHO. To continue toward elimination of STH and S. mansoni as a public health problem, resources should be mobilized to increase access to and uptake of improved sanitation at community and household levels.
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Affiliation(s)
- Cara Tupps
- Children Without Worms, The Task Force for Global Health, Atlanta, Georgia, United States of America
- * E-mail:
| | - Ibrahim Kargbo-Labour
- Neglected Tropical Diseases Program, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Jusufu Paye
- Helen Keller International, Freetown, Sierra Leone
| | - Sanjaya Dhakal
- Children Without Worms, The Task Force for Global Health, Atlanta, Georgia, United States of America
| | | | - Alexander H. Jones
- Children Without Worms, The Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Stacy Davlin
- Children Without Worms, The Task Force for Global Health, Atlanta, Georgia, United States of America
| | | | - Sallay Manah
- Children Without Worms, The Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Rubina Imtiaz
- Children Without Worms, The Task Force for Global Health, Atlanta, Georgia, United States of America
| | - Yaobi Zhang
- Helen Keller International, Regional Office for Africa, Dakar, Senegal
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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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Grolimund CM, Bärenbold O, Hatz CF, Vennervald BJ, Mayombana C, Mshinda H, Utzinger J, Vounatsou P. Infection intensity-dependent accuracy of reagent strip for the diagnosis of Schistosoma haematobium and estimation of treatment prevalence thresholds. PLoS Negl Trop Dis 2022; 16:e0010332. [PMID: 35468129 PMCID: PMC9071146 DOI: 10.1371/journal.pntd.0010332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 05/05/2022] [Accepted: 03/15/2022] [Indexed: 11/26/2022] Open
Abstract
Background Reagent strip to detect microhematuria as a proxy for Schistosoma haematobium infections has been considered an alternative to urine filtration for individual diagnosis and community-based estimates of treatment needs for preventive chemotherapy. However, the diagnostic accuracy of reagent strip needs further investigation, particularly at low infection intensity levels. Methods We used existing data from a study conducted in Tanzania that employed urine filtration and reagent strip testing for S. haematobium in two villages, including a baseline and six follow-up surveys after praziquantel treatment representing a wide range of infection prevalence. We developed a Bayesian model linking individual S. haematobium egg count data based on urine filtration to reagent strip binary test results available on multiple days and estimated the relation between infection intensity and sensitivity of reagent strip. Furthermore, we simulated data from 3,000 hypothetical populations with varying mean infection intensity to infer on the relation between prevalence observed by urine filtration and the interpretation of reagent strip readings. Principal findings Reagent strip showed excellent sensitivity even for single measurement reaching 100% at around 15 eggs of S. haematobium per 10 ml of urine when traces on reagent strip were considered positive. The corresponding specificity was 97%. When traces were considered negative, the diagnostic accuracy of the reagent strip was equivalent to urine filtration data obtained on a single day. A 10% and 50% urine filtration prevalence based on a single day sampling corresponds to 11.2% and 48.6% prevalence by reagent strip, respectively, when traces were considered negative, and 17.6% and 57.7%, respectively, when traces were considered positive. Conclusions/Significance Trace results should be included in reagent strip readings when high sensitivity is required, but excluded when high specificity is needed. The observed prevalence of reagent strip results, when traces are considered negative, is a good proxy for prevalence estimates of S. haematobium infection by urine filtration on a single day. Control of schistosomiasis, a parasitic worm infection affecting more than 200 million people worldwide, relies mainly on mass drug administration of praziquantel to school-age children as well as adults in areas where the disease is particularly rampant. The World Health Organization has set thresholds of observed prevalence that require intervention to reach the goal of eliminating schistosomiasis as a public health problem by 2025. Intervention thresholds are defined based on parasitologic methods, which is urine filtration for Schistosoma haematobium. There are alternative diagnostic methods to detect S. haematobium, such as the detection of blood in urine that is a common symptom of urogenital schistosomiasis. We determined the diagnostic sensitivity and specificity of a reagent strip to detect microhematuria using data from two villages in Tanzania at multiple time points (once before and several times after treatment with the deworming drug praziquantel) and translate the urine filtration intervention thresholds to reagent strip equivalents. We show that the reagent strip including trace results is almost perfectly sensitive for infections above 15 eggs of S. haematobium per 10 ml of urine and that a 10% observed prevalence by urine filtration corresponds to 17.6% observed prevalence by reagent strip including traces.
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Affiliation(s)
- Carla M. Grolimund
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Oliver Bärenbold
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Christoph F. Hatz
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Birgitte J. Vennervald
- Department of Veterinary and Animal Science, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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Clark J, Moses A, Nankasi A, Faust CL, Adriko M, Ajambo D, Besigye F, Atuhaire A, Wamboko A, Rowel C, Carruthers LV, Francoeur R, Tukahebwa EM, Lamberton PHL, Prada JM. Translating From Egg- to Antigen-Based Indicators for Schistosoma mansoni Elimination Targets: A Bayesian Latent Class Analysis Study. FRONTIERS IN TROPICAL DISEASES 2022; 3:825721. [PMID: 35784267 PMCID: PMC7612949 DOI: 10.3389/fitd.2022.825721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Schistosomiasis is a parasitic disease affecting over 240-million people. World Health Organization (WHO) targets for Schistosoma mansoni elimination are based on Kato-Katz egg counts, without translation to the widely used, urine-based, point-of-care circulating cathodic antigen diagnostic (POC-CCA). We aimed to standardize POC-CCA score interpretation and translate them to Kato-Katz-based standards, broadening diagnostic utility in progress towards elimination. A Bayesian latent-class model was fit to data from 210 school-aged-children over four timepoints pre- to six-months-post-treatment. We used 1) Kato-Katz and established POC-CCA scoring (Negative, Trace, +, ++ and +++), and 2) Kato-Katz and G-Scores (a new, alternative POC-CCA scoring (G1 to G10)). We established the functional relationship between Kato-Katz counts and POC-CCA scores, and the score-associated probability of true infection. This was combined with measures of sensitivity, specificity, and the area under the curve to determine the optimal POC-CCA scoring system and positivity threshold. A simulation parametrized with model estimates established antigen-based elimination targets. True infection was associated with POC-CCA scores of ≥ + or ≥G3. POC-CCA scores cannot predict Kato-Katz counts because low infection intensities saturate the POC-CCA cassettes. Post-treatment POC-CCA sensitivity/specificity fluctuations indicate a changing relationship between egg excretion and antigen levels (living worms). Elimination targets can be identified by the POC-CCA score distribution in a population. A population with ≤2% ++/+++, or ≤0.5% G7 and above, indicates achieving current WHO Kato-Katz-based elimination targets. Population-level POC-CCA scores can be used to access WHO elimination targets prior to treatment. Caution should be exercised on an individual level and following treatment, as POC-CCAs lack resolution to discern between WHO Kato-Katz-based moderate- and high-intensity-infection categories, with limited use in certain settings and evaluations.
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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
| | - Arinaitwe Moses
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Andrina Nankasi
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Christina L. Faust
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Moses Adriko
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Diana Ajambo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Fred Besigye
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Arron Atuhaire
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Aidah Wamboko
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Candia Rowel
- Vector Control Division, Ministry of Health, Kampala, 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 and Engineering, University of Chester, Chester, United Kingdom
| | | | - Poppy H. L. Lamberton
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Joaquin M. Prada
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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Kura K, Ayabina D, Hollingsworth TD, Anderson RM. Determining the optimal strategies to achieve elimination of transmission for Schistosoma mansoni. Parasit Vectors 2022; 15:55. [PMID: 35164842 PMCID: PMC8842958 DOI: 10.1186/s13071-022-05178-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/25/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In January 2021, the World Health Organization published the 2021-2030 roadmap for the control of neglected tropical diseases (NTDs). The goal for schistosomiasis is to achieve elimination as a public health problem (EPHP) and elimination of transmission (EOT) in 78 and 25 countries (by 2030), respectively. Mass drug administration (MDA) of praziquantel continues to be the main strategy for control and elimination. However, as there is limited availability of praziquantel, it is important to determine what volume of treatments are required, who should be targeted and how frequently treatment must be administered to eliminate either transmission or morbidity caused by infection in different endemic settings with varied transmission intensities. METHODS AND RESULTS: In this paper, we employ two individual-based stochastic models of schistosomiasis transmission developed independently by the Imperial College London (ICL) and University of Oxford (SCHISTOX) to determine the optimal treatment strategies to achieve EOT. We find that treating school-age children (SAC) only is not sufficient to achieve EOT within a feasible time frame, regardless of the transmission setting and observed age-intensity of infection profile. Both models show that community-wide treatment is necessary to interrupt transmission in all endemic settings with low, medium and high pristine transmission intensities. CONCLUSIONS The required MDA coverage level to achieve either transmission or morbidity elimination depends on the prevalence prior to the start of treatment and the burden of infection in adults. The higher the worm burden in adults, the higher the coverage levels required for this age category through community-wide treatment programmes. Therefore, it is important that intensity and prevalence data are collected in each age category, particularly from SAC and adults, so that the correct coverage level can be calculated and administered.
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Affiliation(s)
- Klodeta Kura
- grid.512598.2London Centre for Neglected Tropical Disease Research, London, UK ,grid.7445.20000 0001 2113 8111Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary’s Campus, Imperial College London, London, UK ,grid.14105.310000000122478951MRC Centre for Global Infectious Disease Analysis, London, UK
| | - Diepreye Ayabina
- grid.4991.50000 0004 1936 8948Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF UK
| | - T. Deirdre Hollingsworth
- grid.4991.50000 0004 1936 8948Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF UK
| | - Roy M. Anderson
- grid.512598.2London Centre for Neglected Tropical Disease Research, London, UK ,grid.7445.20000 0001 2113 8111Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary’s Campus, Imperial College London, London, UK ,grid.14105.310000000122478951MRC Centre for Global Infectious Disease Analysis, London, UK ,grid.35937.3b0000 0001 2270 9879The DeWorm3 Project, The Natural History Museum of London, London, UK
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Bassa FK, Eze IC, Assaré RK, Essé C, Koné S, Acka F, Laubhouet-Koffi V, Kouassi D, Bonfoh B, Utzinger J, N'Goran EK. Prevalence of Schistosoma mono- and co-infections with multiple common parasites and associated risk factors and morbidity profile among adults in the Taabo health and demographic surveillance system, South-Central Côte d'Ivoire. Infect Dis Poverty 2022; 11:3. [PMID: 34983662 PMCID: PMC8728899 DOI: 10.1186/s40249-021-00925-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022] Open
Abstract
Background Schistosomiasis remains an important public health problem, also among adults, and infected individuals not treated serve as a reservoir for continued transmission. Despite this fact, evidence on the epidemiology of schistosomiasis in adults in Côte d’Ivoire is scanty. This study aimed to determine the prevalence and risk factors of Schistosoma infection and co-infection with other helminth species and Plasmodium among adults in the Taabo region in the south-central part of Côte d’Ivoire. Methods A cross-sectional survey was carried out in April and May 2017 in the frame of the “Côte d’Ivoire Dual Burden of Disease Study” (CoDuBu). A total of 901 randomly selected individuals, aged 18–90 years, provided blood, stool and urine samples for the diagnosis of malaria and helminth infections. Stool samples were subjected to the Kato-Katz technique for detection of Schistosoma mansoni and soil-transmitted helminth eggs, while urine samples were examined for eggs of Schistosoma haematobium and circulating cathodic antigen of S. mansoni. Risk factors and morbidity profiles were assessed using health examination and questionnaires. Multinomial logistic regressions were employed to identify risk factors and morbidity patterns associated with S. mansoni mono- and co-infections. Results The prevalence of S. mansoni and S. haematobium was 23.2% and 1.0%, respectively. Most S. mansoni were mono-infections (81.3%). Independent determinants of S. mansoni infection were young age, low socioeconomic status (mono- and co-infection) and poor hygiene practices (co-infection) (P < 0.05). S. mansoni infection was independently associated with higher pain and symptom scores (mono-infection), poor self-rated health and low healthcare use (co-infection) (P < 0.05). Conclusions This study showed that adults represent a substantial reservoir of S. mansoni. To sustain schistosomiasis control and improve people’s wellbeing, it is important to expand preventive chemotherapy from school-aged children to adults, coupled with hygiene and health education.
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Affiliation(s)
- Fidèle K Bassa
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22, P.O. Box 582, Abidjan 22, Côte d'Ivoire.
| | - Ikenna C Eze
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.,University of Basel, 4003, Basel, Switzerland
| | - Rufin K Assaré
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22, P.O. Box 582, Abidjan 22, Côte d'Ivoire.,Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.,University of Basel, 4003, Basel, Switzerland.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01, P.O. Box 1303, Abidjan 01, Côte d'Ivoire
| | - Clémence Essé
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01, P.O. Box 1303, Abidjan 01, Côte d'Ivoire.,Institut d'Ethnosociologie, Université Félix Houphouët-Boigny, 01, P.O. Box 34,, Abidjan 01, Côte d'Ivoire
| | - Siaka Koné
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.,University of Basel, 4003, Basel, Switzerland.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01, P.O. Box 1303, Abidjan 01, Côte d'Ivoire
| | - Félix Acka
- Institut National de Santé Publique, 01, P.O. Box 47, Abidjan 01, Côte d'Ivoire
| | - Véronique Laubhouet-Koffi
- Ligue Ivoirienne Contre l'Hypertension Artérielle et les Maladies Cardiovasculaires, 17, P.O. Box 773, Abidjan 17, Côte d'Ivoire
| | - Dinard Kouassi
- Institut National de Santé Publique, 01, P.O. Box 47, Abidjan 01, Côte d'Ivoire
| | - Bassirou Bonfoh
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01, P.O. Box 1303, Abidjan 01, Côte d'Ivoire
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, 4002, Basel, Switzerland.,University of Basel, 4003, Basel, Switzerland
| | - Eliézer K N'Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22, P.O. Box 582, Abidjan 22, Côte d'Ivoire.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01, P.O. Box 1303, Abidjan 01, Côte d'Ivoire
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21
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Schistosoma mansoni infection risk for school-aged children clusters within households and is modified by distance to freshwater bodies. PLoS One 2021; 16:e0258915. [PMID: 34735487 PMCID: PMC8568121 DOI: 10.1371/journal.pone.0258915] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/07/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The interaction of socio-demographic and ecological factors with Schistosoma mansoni (S. mansoni) infection risk by age and the household clustering of infections between individuals are poorly understood. METHODS This study examined 1,832 individuals aged 5-90 years across 916 households in Mayuge District, Uganda. S. mansoni infection status and intensity were measured using Kato-Katz microscopy. Socio-demographic and ecological factors were examined as predictors of infection status and intensity using logistic and negative binomial regression models, respectively, with standard errors clustered by household. A subgroup analysis of children was conducted to examine the correlation of infection status between children and their caretakers. FINDINGS Infection varied within age groups based on the distance to Lake Victoria. Children aged 9-17 years and young adults aged 18-29 years who lived ≤0.50km from Lake Victoria were more likely to be infected compared to individuals of the same age who lived further away from the lake. Infections clustered within households. Children whose caretakers were heavily infected were 2.67 times more likely to be infected. CONCLUSION These findings demonstrate the focality of schistosome transmission and its dependence on socio-demographic, ecological and household factors. Future research should investigate the sampling of households within communities as a means of progressing towards precision mapping of S. mansoni infections.
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Demonstration of N, N-Dimethyldithiocarbamate as a Copper-Dependent Antibiotic against Multiple Upper Respiratory Tract Pathogens. Microbiol Spectr 2021; 9:e0077821. [PMID: 34468162 PMCID: PMC8557878 DOI: 10.1128/spectrum.00778-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Transition metals are necessary cofactors and structural elements in living systems. Exposure to high concentrations of biologically important transition metals, such as zinc and copper, results in cell toxicity. At the infection site, the immune system deploys metal sorbent proteins (e.g., lactoferrin and calprotectin) to starve pathogens of necessary metals (such as iron), while phagocytes expose engulfed pathogens to high levels of other metals, such as copper and zinc. The opportunistic pathogen Streptococcus pneumoniae (the pneumococcus) encounters macrophages during initial and protracted infections. The pneumococcus employs a copper export pathway, which improves colonization and persistent infection of the nasopharynx and the upper respiratory tract. Because copper is tightly regulated in the host, we instead sought to leverage the localized power of nutritional immunity by identifying small molecules with copper-dependent toxicity (CDT) through a targeted screen of compounds for antibiotic efficacy. We chose to include dithiocarbamates, based on the copper synergy observed in other organisms with 1-(diethylthiocarbamoyldisulfanyl)-N,N-diethyl-methanethioamide (tetraethylthiuram disulfide, disulfiram). We observed CDT of some dithiocarbamates in S. pneumoniae. Only N,N-dimethyldithiocarbamate (DMDC) was consistently toxic across a range of concentrations with copper both in vitro and in vivo against the pneumococcus. We also observed various degrees of CDT in vitro using DMDC in Staphylococcus aureus, Coccidioides posadasii, and Schistosoma mansoni. Collectively, we demonstrate that the compound DMDC is a potent bactericidal compound against S. pneumoniae with antimicrobial efficacy against bacterial and fungal pathogens. IMPORTANCE With the rise of antibiotic resistance, approaches that add new antimicrobials to the current repertoire are vital. Here, we investigate putative and known copper ionophores in an attempt to intoxicate bacteria and use ionophore/copper synergy, and we ultimately find success with N,N-dimethyldithiocarbamate (DMDC). We show that DMDC has in vitro efficacy in a copper-dependent manner and kills pathogens across three different kingdoms, Streptococcus pneumoniae, Coccidioides posadasii, and Schistosoma mansoni, and in vivo efficacy against S. pneumoniae. As such, dithiocarbamates represent a new potential class of antimicrobials and thus warrant further mechanistic investigation.
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N’Goran EK, Yalkinoglu Ö, Kourany-Lefoll E, Tappert A, Hayward B, Yin X, Bezuidenhout D, Huber E, Aka NAD, Ouattara M, Bagchus W. Efficacy and Safety of New Orodispersible Tablet Formulations of Praziquantel (Racemate and L-Praziquantel) in Schistosoma mansoni-Infected Preschool-Age Children and Infants: A Randomized Dose-Finding Phase 2 Study. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.679373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
IntroductionTwo novel formulations of praziquantel (PZQ) and Levo-(L-)PZQ (arpraziquantel) have been developed for the treatment of schistosomiasis in preschool-age children and infants.MethodsThis open-label, dose-finding Phase 2 study assessed the efficacy and safety of PZQ formulations in children and infants infected with Schisostoma mansoni in Côte d’Ivoire. In Part 1, 420 children aged 2.1–6.9 years (weight 10.0–29.9 kg) were enrolled and randomized to one of 7 treatment arms (n=60 per arm): commercially available racemate (rac)-PZQ at 3x20 mg/kg or 40 mg/kg (treatment arms 1 and 2); rac-PZQ orodispersible tablet (ODT) at 40 mg/kg or 60 mg/kg (treatment arms 3 and 4); or L-PZQ ODT at 30 mg/kg, 45 mg/kg, or 60 mg/kg (treatment arms 5, 6, and 7). The optimal formulation and dose identified (L-PZQ ODT 50 mg/kg) was used in Part 2, which enrolled 24 infants aged 6–24 months (weight 7.5–14.8 kg). Infants were treated in an age-staggered approach: age 13–24 months (treatment arm 8, n=20) and age 6–12 months (treatment arm 9, n=4). The primary endpoint was clinical cure rate (CR) demonstrated by the Kato–Katz method 14–21 days post-treatment. Secondary endpoints included CR by point-of-care circulating cathodic antigen, egg reduction rate (ERR), and adverse events (AEs).ResultsIn Part 1, CRs ≥70% were achieved in all treatment arms and were highest with L-PZQ ODT 60 mg/kg (89.7%), rac-PZQ 3x20 mg/kg (89.5%), and L-PZQ ODT 45 mg/kg (86.0%). In Part 2, CRs were >90%. All treatment arms had ERRs >95%. Treatment-related AEs were reported by 71 participants (16.0%) and were similar across treatment arms; most were mild and transient. The most common treatment-emergent AEs were laboratory abnormalities. No deaths or discontinuation due to treatment-emergent AEs were reported and no new safety concerns were identified.ConclusionNew rac-PZQ and L-PZQ ODT formulations used as single-dose therapy against S. mansoni demonstrated acceptable overall efficacy and safety in preschool-age children and infants, warranting further studies in this population.Clinical Trial RegistrationClinicalTrials.gov, identifier NCT02806232; Pan African Clinical Trials Registry, identifier PACTR201604001493593.
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Novel tools and strategies for breaking schistosomiasis transmission: study protocol for an intervention study. BMC Infect Dis 2021; 21:1024. [PMID: 34592960 PMCID: PMC8482678 DOI: 10.1186/s12879-021-06620-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Background Global elimination of schistosomiasis as a public health problem is set as target in the new World Health Organization’s Neglected Tropical Diseases Roadmap for 2030. Due to a long history of interventions, the Zanzibar islands of Tanzania have reached this goal since 2017. However, challenges occur on the last mile towards interruption of transmission. Our study will investigate new tools and strategies for breaking schistosomiasis transmission. Methods The study is designed as an intervention study, documented through repeated cross-sectional surveys (2020–2024). The primary endpoint will be the sensitivity of a surveillance-response approach to detect and react to outbreaks of urogenital schistosomiasis over three years of implementation. The surveys and multi-disciplinary interventions will be implemented in 20 communities in the north of Pemba island. In low-prevalence areas, surveillance-response will consist of active, passive and reactive case detection, treatment of positive individuals, and focal snail control. In hotspot areas, mass drug administration, snail control and behaviour change interventions will be implemented. Parasitological cross-sectional surveys in 20 communities and their main primary schools will serve to adapt the intervention approach annually and to monitor the performance of the surveillance-response approach and impact of interventions. Schistosoma haematobium infections will be diagnosed using reagent strips and urine filtration microscopy, and by exploring novel point-of-care diagnostic tests. Discussion Our study will shed light on the field applicability and performance of novel adaptive intervention strategies, and standard and new diagnostic tools for schistosomiasis elimination. The evidence and experiences generated by micro-mapping of S. haematobium infections at community level, micro-targeting of new adaptive intervention approaches, and application of novel diagnostic tools can guide future strategic plans for schistosomiasis elimination in Zanzibar and inform other countries aiming for interruption of transmission. Trial registration ISRCTN, ISCRCTN91431493. Registered 11 February 2020, https://www.isrctn.com/ISRCTN91431493
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Hoekstra PT, van Dam GJ, van Lieshout L. Context-Specific Procedures for the Diagnosis of Human Schistosomiasis – A Mini Review. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.722438] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Schistosomiasis is a parasitic disease caused by trematode blood flukes of the genus Schistosoma, affecting over 250 million people mainly in the tropics. Clinically, the disease can present itself with acute symptoms, a stage which is relatively more common in naive travellers originating from non-endemic regions. It can also develop into chronic disease, with the outcome depending on the Schistosoma species involved, the duration and intensity of infection and several host-related factors. A range of diagnostic tests is available to determine Schistosoma infection, including microscopy, antibody detection, antigen detection using the Point-Of-Care Circulating Cathodic Antigen (POC-CCA) test and the Up-Converting Particle Lateral Flow Circulating Anodic Antigen (UCP-LF CAA) test, as well as Nucleic Acid Amplification Tests (NAATs) such as real-time PCR. In this mini review, we discuss these different diagnostic procedures and explore their most appropriate use in context-specific settings. With regard to endemic settings, diagnostic approaches are described based on their suitability for individual diagnosis, monitoring control programs, determining elimination as a public health problem and eventual interruption of transmission. For non-endemic settings, we summarize the most suitable diagnostic approaches for imported cases, either acute or chronic. Additionally, diagnostic options for disease-specific clinical presentations such as genital schistosomiasis and neuro-schistosomiasis are included. Finally, the specific role of diagnostic tests within research settings is described, including a controlled human schistosomiasis infection model and several clinical studies. In conclusion, context-specific settings have different requirements for a diagnostic test, stressing the importance of a well-considered decision of the most suitable diagnostic procedure.
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Mewamba EM, Tiofack AAZ, Kamdem CN, Ngassam RIK, Mbagnia MCT, Nyangiri O, Noyes H, Womeni HM, Njiokou F, Simo G. Field assessment in Cameroon of a reader of POC-CCA lateral flow strips for the quantification of Schistosoma mansoni circulating cathodic antigen in urine. PLoS Negl Trop Dis 2021; 15:e0009569. [PMID: 34260610 PMCID: PMC8312929 DOI: 10.1371/journal.pntd.0009569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/26/2021] [Accepted: 06/16/2021] [Indexed: 11/23/2022] Open
Abstract
Background Determining Schistosoma mansoni infection rate and intensity is challenging due to the low sensitivity of the Kato-Katz (KK) test that underestimates the true disease prevalence. Circulating cathodic antigen (CCA) excreted in urine is constantly produced by adult worms and has been used as the basis of a simple, non-invasive point of care test (POC-CCA) for Schistosoma mansoni infections. Although the abundance of CCA in urine is proportional to worm burden, the POC-CCA test is marketed as a qualitative test, making it difficult to investigate the wide range of infection intensities. This study was designed to compare the prevalence and intensity of S. mansoni by KK and POC-CCA and quantify, on fresh and frozen (<-20°C) urine samples, CCA using the visual scores and the ESEquant LR3 reader. Methodology Stool and urine samples were collected from 759 school-aged children. The prevalence and intensity of S. mansoni were determined using KK and POC-CCA. The degree of the positivity of POC-CCA was estimated by quantifying CCA on fresh and frozen urine samples using visual scores and strip reader. The prevalence, the infection intensity as well the relative amounts of CCA were compared. Results The S. mansoni infection rates inferred from POC-CCA and KK were 40.7% and 9.4% respectively. Good correlations were observed between infection intensities recorded by; i) the reader and visual scoring system on fresh (Rho = 0.89) and frozen samples (Rho = 0.97), ii) the reader on fresh urine samples and KK (epg) (Rho = 0.44). Nevertheless, 238 POC-CCA positive children were negative for KK, and sixteen of them had high levels of CCA. The correlation between results from the reader on fresh and frozen samples was good (Rho = 0.85). On frozen samples, CCA was not detected in 55 samples that were positive in fresh urine samples. Conclusion This study confirmed the low sensitivity of KK and the high capacity of POC-CCA to provide reliable data on the prevalence and intensity of S. mansoni infections. The lateral flow reader enabled accurate quantification of CCA under field conditions on fresh and frozen urine samples with less time and effort than KK. Diagnosis of schistosomiasis has relied on the Kato-Katz technique which remains challenging due to its low sensitivity. To overcome this limitation, the Point-of-care-Circulating Cathodic Antigen (POC-CCA) test has been developed to detect CCA produced by adult living worm. However, this test is sold for qualitative use only because it is difficult to estimate the intensity of the positive band by eye. This study was designed with the aim of comparing the prevalence and intensity of S. mansoni infections by KK and POC-CCA and quantifying under field conditions on fresh and frozen (<-20°C) urine samples, CCA using the visual scores and the ESEquant LR3 reader. We conducted the KK and POC-CCA tests on stool and urine samples collected from SAC (5 to 4 years) in Makenene, Cameroon. Our results showed discrepancies between results from KK and POC-CCA test. The numerical values generated by the reader made it possible to avoid subjective visual interpretation of POC-CCA results. This study also identified children with high levels of CCA in their urine but without schistosome eggs in their stools. The good correlation observed between results obtained on fresh and frozen urine samples confirmed that POC-CCA test can be used on samples stored for one year at -20° C.
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Affiliation(s)
- Estelle Mezajou Mewamba
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Arnol Auvaker Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Cyrille Nguemnang Kamdem
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | | | - Mureille Carole Tchami Mbagnia
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Oscar Nyangiri
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Harry Noyes
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Hilaire Marcaire Womeni
- Unité de Recherche de Biochimie, des plantes Médicinales, des Sciences alimentaires et Nutrition, University of Dschang, Dschang, Cameroon
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
- Centre for Research in Infectious Diseases, Yaoundé, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
- * E-mail: ,
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Yin X, N’Goran EK, Ouattara M, Aka NAD, Diakité NR, Bassa FK, Kourany-Lefoll E, Tappert A, Yalkinoglu Ö, Huber E, Bezuidenhout D, Bagchus WM, Hayward B. Comparison of POC-CCA with Kato-Katz in Diagnosing Schistosoma mansoni Infection in a Pediatric L-Praziquantel Clinical Trial. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.686288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
IntroductionTraditionally Schistosoma mansoni infection is diagnosed by the Kato-Katz method. Thick smears from each stool sample are prepared on slides and eggs are counted microscopically. Commercially available point-of-care circulating cathodic antigen (POC-CCA) cassette tests detect schistosomiasis antigens from urine samples in 20 minutes. POC-CCA results are qualitative or semi-quantitative: signal intensity is an indicator of the amount of worm antigens in the sample. Both methods were used in a phase II trial investigating the efficacy and safety of new pediatric formulations of praziquantel (PZQ) among children ≤6 years (NCT02806232). This secondary analysis evaluated the consistency of results between the Kato-Katz and POC-CCA methods.MethodsPOC-CCA was used to pre-screen for S. mansoni infection. Children with positive results were tested by the Kato-Katz method, and those with positive Kato-Katz results (>1 egg/1 occurrence) were enrolled. Participants (N=444) were treated with different formulations and doses of PZQ. POC-CCA and Kato-Katz were performed at 2–3 weeks after treatment to evaluate drug efficacy. Cure rate (CR) was defined as the proportion of participants with a negative result per POC-CCA, or no eggs in the stool samples per Kato-Katz. Kappa statistic was used to assess the agreement on cure status, and Spearman correlation between POC-CCA positivity and Kato-Katz egg counts was evaluated. Sensitivity and specificity of POC-CCA were calculated using Kato-Katz as a reference standard.ResultsCR per POC-CCA, measured 2–3 weeks after treatment, was 52% [95% confidence interval (CI): 48%, 57%] across all treatment arms except in infants aged 3–12 months. CR per Kato-Katz was 83% (95% CI: 79%, 87%). Kappa statistic was 0.16 (95% CI: 0.09, 0.23), indicating that the agreement was slightly better than by chance. Relative to Kato-Katz, POC-CCA’s sensitivity to detect infection was 70% and specificity was 57%. Spearman correlation coefficient between POC-CCA positivity and Kato-Katz egg counts was 0.26 (95% CI: 0.17, 0.34).ConclusionPOC-CCA is sensitive and rapid for diagnosing S. mansoni infection, but its performance and consistency with Kato-Katz requires further investigation among young children.
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Mazigo HD, Fuss A, Mueller A. High Egg Reduction Rate but poor clearance of Circulating Cathodic Antigen three weeks after Praziquantel treatment among school children on Ijinga Island, north-western Tanzania. Acta Trop 2021; 218:105871. [PMID: 33647243 DOI: 10.1016/j.actatropica.2021.105871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 02/13/2021] [Accepted: 02/19/2021] [Indexed: 10/22/2022]
Abstract
Traditionally, efficacy of Praziquantel (PZQ) is monitored using Parasitological Cure Rates and Egg Reduction Rates applying Kato Katz (KK) technique. This parasitological technique has a number of limitations. Recently, the Point-of-Care Circulating Cathodic Antigen (POC-CCA) rapid test which is a highly sensitive technique, has emerged as a promising candidate to be used for evaluating the efficacy of PZQ. A prospective longitudinal study was conducted among 399 school children aged 7-17 years on Ijinga Island, north-western Tanzania. At baseline and three weeks after treatment, stool and urine samples were collected from participating school children and screened for S. mansoni infection using the KK technique as well as POC-CCA test. All S. mansoni infected children at baseline were treated with 40mg/kg of PZQ and followed up after three weeks. At baseline, the overall prevalence of S. mansoni infection was 56.6% (95%CI: 51.7-61.4) and 99.7% (95%CI: 98.2-99.9) (considering trace as positive) using KK technique and POC-CCA test, respectively. Three weeks after treatment, the prevalence of S. mansoni was 0.92% using the KK technique and 97.7% when applying the POC-CCA test. The parasitological cure rates based on KK technique and POC-CCA were 99.1% (95%CI: 97.5-99.8) and 2.3% (95%CI: 1.2-4.5). Egg Reduction Rate was 99.1%. Based on WHO guidelines using the KK technique, at three weeks point, the efficacy of PZQ is satisfactory. However, the assessment of the efficacy of PZQ using POC-CCA tests needs further evaluation.
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Graeff-Teixeira C, Favero V, Pascoal VF, de Souza RP, Rigo FDV, Agnese LHD, Bezerra FSM, Coelho PMZ, Enk MJ, Favre TC, Katz N, Oliveira RR, Dos Reis MG, Pieri OS. Low specificity of point-of-care circulating cathodic antigen (POCCCA) diagnostic test in a non-endemic area for schistosomiasis mansoni in Brazil. Acta Trop 2021; 217:105863. [PMID: 33587944 DOI: 10.1016/j.actatropica.2021.105863] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 02/01/2021] [Accepted: 02/08/2021] [Indexed: 02/08/2023]
Abstract
A point-of-care test for detecting schistosome circulating cathodic antigen in urine (POCCCA) has been proposed for mapping infection and defining prevalence thresholds for mass drug administration (MDA). However, there is increasing evidence that POCCCA may yield false-positive results, which requires rigorous specificity evaluation in non-endemic areas. POCCCA was applied in an area known to be free from infection and devoid of any condition for schistosomiasis transmission as part of a multicentre study to evaluate the performance of POCCCA in Brazil's low or potentially endemic settings. Besides POCCCA detection in urine, a search for eggs in stool was performed by Kato-Katz (KK) and Helmintex (HTX) methods. One-hundred-and-seventy-four participants returned urine samples, 140 of which delivered stool samples. All these were HTX-negative for Schistosoma mansoni, and all 118 tested with KK were negative for both S. mansoni and soil-transmitted helminths. POCCCA results from freshly collected urine yielded a specificity of 62.1% (95% CI: 53.6% - 70.2%), taking trace outcomes as positive according to the manufacturer's instructions. Retesting urine from the 140 HTX-negatives after one-year storage at -20 °C with two new POCCCA batches simultaneously yielded significantly different specificities (34.3%; 95%CI: 26.5% - 42.8% and 75.0%; 95% CI: 67.0% - 81.9%). These two batches had a weak agreement (Cohen's kappa: 0.56; 95%CI: 0.44-0.68) among the 174 urine samples retested. At present, POCCCA cannot be recommended either as a cut-off point for MDA or a reliable diagnostic tool for treatment of the infection carriers (selective chemotherapy) in low endemic areas and at final stages of transmission interruption. Manufacturers should be required to optimize production standardization and to assure quality and reproducibility of the test. Extended rigorous performance evaluations by different users from different regions are needed before POCCCA is widely recommended.
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Affiliation(s)
- Carlos Graeff-Teixeira
- Infectious Diseases Unit (NDI), Center for Health Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil; Research Group on Biomedical Parasitology, School of Sciences, Pontíficia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Vivian Favero
- Research Group on Biomedical Parasitology, School of Sciences, Pontíficia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Vanessa Fey Pascoal
- Research Group on Biomedical Parasitology, School of Sciences, Pontíficia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Renata Perotto de Souza
- Research Group on Biomedical Parasitology, School of Sciences, Pontíficia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - Francine de Vargas Rigo
- Research Group on Biomedical Parasitology, School of Sciences, Pontíficia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Luize Hoffmann Dall Agnese
- Research Group on Biomedical Parasitology, School of Sciences, Pontíficia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | | | | | - Tereza Cristina Favre
- Oswaldo Cruz Institute, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ, Brazil.
| | - Naftale Katz
- René Rachou Institute, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, MG, Brazil
| | | | - Mitermayer Galvão Dos Reis
- Gonçalo Muniz Institute, Fundação Oswaldo Cruz (FIOCRUZ), Salvador, BA, Brazil; Faculty of Medicine of Bahia, Federal University of Bahia, Salvador, BA, Brazil; Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, CT, United States of America.
| | - Otavio Sarmento Pieri
- Oswaldo Cruz Institute, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ, Brazil.
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Hoekstra PT, van Esbroeck M, de Dood CJ, Corstjens PL, Cnops L, van Zeijl-van der Ham CJ, Wammes LJ, van Dam GJ, Clerinx J, van Lieshout L. Early diagnosis and follow-up of acute schistosomiasis in a cluster of infected Belgian travellers by detection of antibodies and circulating anodic antigen (CAA): A diagnostic evaluation study. Travel Med Infect Dis 2021; 41:102053. [PMID: 33823289 DOI: 10.1016/j.tmaid.2021.102053] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND In order to evaluate the diagnostic value of schistosome circulating anodic antigen (CAA) detection, serum and urine CAA-levels were determined in a single cluster of 34 Belgian tourists at three timepoints within a period of 14 weeks following proven Schistosoma exposure in South Africa and compared with two in-house antibody assays. METHODS Samples were collected 4-5 and 7-8 weeks post-exposure and subsequently 5-6 weeks following praziquantel treatment. Schistosoma antibodies were detected by an adult worm antigen-immunofluorescence assay (AWA-IFA) and a soluble egg antigen-enzyme-linked immunosorbent assay (SEA-ELISA), while CAA concentrations were determined by the Up-Converting reporter Particle labelled Lateral Flow (UCP-LF) test. RESULTS Antibodies were detected in 25/34 (73%) travellers pre-treatment and in 27/34 (79%) post-treatment, with the AWA-IFA showing better performance than the SEA-ELISA. Pre-treatment, CAA was detected in 13/34 (38%) and 33/34 (97%) of the travellers in urine and serum, respectively. Post-treatment, all except one traveller became serum CAA negative. This in contrast to the detected antibodies, as well as the previously reported diagnostic results of this cluster. CONCLUSIONS The UCP-LF CAA serum assay has been demonstrated as the most sensitive method for the diagnosis of early Schistosoma infections and post-treatment monitoring in travellers.
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Affiliation(s)
- Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands.
| | - Marjan van Esbroeck
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Belgium
| | - Claudia J de Dood
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Paul Lam Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Lieselotte Cnops
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Belgium
| | | | - Linda J Wammes
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan Clerinx
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Belgium
| | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
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Bärenbold O, Garba A, Colley DG, Fleming FM, Assaré RK, Tukahebwa EM, Kebede B, Coulibaly JT, N’Goran EK, Tchuem Tchuenté LA, Mwinzi P, Utzinger J, Vounatsou P. Estimating true prevalence of Schistosoma mansoni from population summary measures based on the Kato-Katz diagnostic technique. PLoS Negl Trop Dis 2021; 15:e0009310. [PMID: 33819266 PMCID: PMC8062092 DOI: 10.1371/journal.pntd.0009310] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 04/22/2021] [Accepted: 03/16/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The prevalence of Schistosoma mansoni infection is usually assessed by the Kato-Katz diagnostic technique. However, Kato-Katz thick smears have low sensitivity, especially for light infections. Egg count models fitted on individual level data can adjust for the infection intensity-dependent sensitivity and estimate the 'true' prevalence in a population. However, application of these models is complex and there is a need for adjustments that can be done without modeling expertise. This study provides estimates of the 'true' S. mansoni prevalence from population summary measures of observed prevalence and infection intensity using extensive simulations parametrized with data from different settings in sub-Saharan Africa. METHODOLOGY An individual-level egg count model was applied to Kato-Katz data to determine the S. mansoni infection intensity-dependent sensitivity for various sampling schemes. Observations in populations with varying forces of transmission were simulated, using standard assumptions about the distribution of worms and their mating behavior. Summary measures such as the geometric mean infection, arithmetic mean infection, and the observed prevalence of the simulations were calculated, and parametric statistical models fitted to the summary measures for each sampling scheme. For validation, the simulation-based estimates are compared with an observational dataset not used to inform the simulation. PRINCIPAL FINDINGS Overall, the sensitivity of Kato-Katz in a population varies according to the mean infection intensity. Using a parametric model, which takes into account different sampling schemes varying from single Kato-Katz to triplicate slides over three days, both geometric and arithmetic mean infection intensities improve estimation of sensitivity. The relation between observed and 'true' prevalence is remarkably linear and triplicate slides per day on three consecutive days ensure close to perfect sensitivity. CONCLUSIONS/SIGNIFICANCE Estimation of 'true' S. mansoni prevalence is improved when taking into account geometric or arithmetic mean infection intensity in a population. We supply parametric functions and corresponding estimates of their parameters to calculate the 'true' prevalence for sampling schemes up to 3 days with triplicate Kato-Katz thick smears per day that allow estimation of the 'true' prevalence.
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Affiliation(s)
- Oliver Bärenbold
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Amadou Garba
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Daniel G. Colley
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Fiona M. Fleming
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Rufin K. Assaré
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | | | | | - Jean T. Coulibaly
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 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
| | - Louis-Albert Tchuem Tchuenté
- Laboratory of Parasitology and Ecology, University of Yaoundé I, Yaoundé, Cameroon
- Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon
| | - Pauline Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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32
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Bezerra DDF, Pinheiro MCC, Barbosa L, Viana AG, Fujiwara RT, Bezerra FSDM. Diagnostic comparison of stool exam and point-of-care circulating cathodic antigen (POC-CCA) test for schistosomiasis mansoni diagnosis in a high endemicity area in northeastern Brazil. Parasitology 2021; 148:420-426. [PMID: 33190646 PMCID: PMC11010182 DOI: 10.1017/s0031182020002164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 12/15/2022]
Abstract
This study aimed to evaluate the performance of the point-of-care circulating cathodic antigen (POC-CCA) test in a highly endemic area in Brazil, comparing it to the Kato-Katz (KK) technique for sensitivity, specificity and the intensity of the reaction of the test in relation to the parasitic load. The community in Sergipe, Brazil, participated in the study, providing three stool samples, one of urine (POC-CCA) and fingers tick blood sample was tested by enzyme-linked immunosorbent assay (ELISA). Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, kappa coefficient and Spearman's correlation were calculated for the POC-CCA test using the KK as the reference. The prevalence of schistosomiasis by KK testing was 48.82%; POC-CCA (t+) 66.14%; POC-CCA (t-) 45.24%. ELISA results showed 100% agreement in individuals with high and moderate eggs per gram (EPG). POC-CCA presented good diagnostic performance in individuals with medium and high EPG, but there were a high number of false negatives in individuals with low intensity infections. As observed, POC-CCA-filter test improves accuracy and sensitivity compared to a conventional test.
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Affiliation(s)
| | - Marta Cristhiany Cunha Pinheiro
- Laboratory of Parasitology and Mollusc Biology, Department of Clinical Analysis and Toxicology, Federal University of Ceará, Fortaleza, Brazil
| | - Luciene Barbosa
- Parasitology and Tropical Entomology Laboratory, Department of Morphology, Federal University of Sergipe, Aracajú, Brazil
| | | | - Ricardo Toshio Fujiwara
- Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Fernando Schemelzer de Moraes Bezerra
- Post-Graduate Program in Pathology, School of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Laboratory of Parasitology and Mollusc Biology, Department of Clinical Analysis and Toxicology, Federal University of Ceará, Fortaleza, Brazil
- Post-Graduate Program in Medical Sciences, School of Medicine, Federal University of Ceará, Fortaleza, Brazil
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Toor J, Rollinson D, Turner HC, Gouvras A, King CH, Medley GF, Hollingsworth TD, Anderson RM. Achieving Elimination as a Public Health Problem for Schistosoma mansoni and S. haematobium: When Is Community-Wide Treatment Required? J Infect Dis 2021; 221:S525-S530. [PMID: 31829414 PMCID: PMC7289541 DOI: 10.1093/infdis/jiz609] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The World Health Organization (WHO) has set elimination as a public health problem (EPHP) as a goal for schistosomiasis. As the WHO treatment guidelines for schistosomiasis are currently under revision, we investigate whether school-based or community-wide treatment strategies are required for achieving the EPHP goal. In low- to moderate-transmission settings with good school enrolment, we find that school-based treatment is sufficient for achieving EPHP. However, community-wide treatment is projected to be necessary in certain high-transmission settings as well as settings with low school enrolment. Hence, the optimal treatment strategy depends on setting-specific factors such as the species present, prevalence prior to treatment, and the age profile of infection.
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Affiliation(s)
- Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - David Rollinson
- Department of Life Sciences, Natural History Museum, London, UK.,Global Schistosomiasis Alliance, Department of Life Sciences, Natural History Museum, London, UK
| | - Hugo C Turner
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Anouk Gouvras
- Global Schistosomiasis Alliance, Department of Life Sciences, Natural History Museum, London, UK
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, USA
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, UK
| | - T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, UK.,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK.,The DeWorm3 Project, Natural History Museum, London, UK
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34
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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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Casacuberta-Partal M, Beenakker M, de Dood C, Hoekstra P, Kroon L, Kornelis D, Corstjens P, Hokke CH, van Dam G, Roestenberg M, van Lieshout L. Specificity of the Point-of-Care Urine Strip Test for Schistosoma Circulating Cathodic Antigen (POC-CCA) Tested in Non-Endemic Pregnant Women and Young Children. Am J Trop Med Hyg 2021; 104:1412-1417. [PMID: 33534739 DOI: 10.4269/ajtmh.20-1168] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/25/2020] [Indexed: 01/05/2023] Open
Abstract
The point-of-care urine based strip test for the detection of circulating cathodic antigen (POC-CCA) in schistosome infections is a frequently used tool for diagnosis and mapping of Schistosoma mansoni in school-aged children. Because of its ease of use, the test is increasingly applied to adults and preschool-aged children (PSAC), but its performance has not been specifically evaluated in these target groups. Recent observations have raised concerns about possible reduced specificity, in particular in pregnant women (PW) and PSAC. We thus explored specificity of the POC-CCA urine strip test (Rapid Medical Diagnostics, Pretoria, South Africa) in a non-endemic, nonexposed population of 47 healthy nonpregnant adults (NPAs), 52 PW, and 58 PSAC. A total of 157 urines were tested with POC-CCA, of which five (10.6%) NPAs, 17 (32.7%) PW, and 27 (46.5%) PSAC were positive. The highest scores were found in the youngest babies, with an infant of 9 months being the oldest positive case. On measuring pH, it appeared that all POC-CCA strongly positive urines were acidic (pH range 5-5.5), whereas addition of pH-neutral buffer to a subsample reversed the false positivity. We conclude that the POC-CCA test has reduced specificity in PW and infants younger than 9 months, but that the false positivity might be eliminated by modifications in the buffers used in the test.
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Affiliation(s)
| | - Margreet Beenakker
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Claudia de Dood
- 2Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Pytsje Hoekstra
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Lisa Kroon
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Dieuwke Kornelis
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Paul Corstjens
- 2Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Cornelis H Hokke
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Govert van Dam
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Meta Roestenberg
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands.,3Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Lisette van Lieshout
- 1Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
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36
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Colley DG, King CH, Kittur N, Ramzy RMR, Secor WE, Fredericks-James M, Ortu G, Clements MN, Ruberanziza E, Umulisa I, Wittmann U, Campbell CH. Evaluation, Validation, and Recognition of the Point-of-Care Circulating Cathodic Antigen, Urine-Based Assay for Mapping Schistosoma mansoni Infections. Am J Trop Med Hyg 2020; 103:42-49. [PMID: 32400347 PMCID: PMC7351311 DOI: 10.4269/ajtmh.19-0788] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Efforts to control Schistosoma mansoni infection depend on the ability of programs to effectively detect and quantify infection levels and adjust programmatic approaches based on these levels and program goals. One of the three major objectives of the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) has been to develop and/or evaluate tools that would assist Neglected Tropical Disease program managers in accomplishing this fundamental task. The advent of a widely available point-of-care (POC) assay to detect schistosome circulating cathodic antigen (CCA) in urine with a rapid diagnostic test (the POC-CCA) in 2008 led SCORE and others to conduct multiple evaluations of this assay, comparing it with the Kato–Katz (KK) stool microscopy assay—the standard used for more than 45 years. This article describes multiple SCORE-funded studies comparing the POC-CCA and KK assays, the pros and cons of these assays, the use of the POC-CCA assay for mapping of S. mansoni infections in areas across the spectrum of prevalence levels, and the validation and recognition that the POC-CCA, although not infallible, is a highly useful tool to detect low-intensity infections in low-to-moderate prevalence areas. Such an assay is critical, as control programs succeed in driving down prevalence and intensity and seek to either maintain control or move to elimination of transmission of S. mansoni.
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Affiliation(s)
- Daniel G Colley
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia.,Department of Microbiology, University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Reda M R Ramzy
- National Nutrition Institute, General Organization for Teaching Hospitals and Institutes, Cairo, Egypt
| | - William Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | | | - Michelle N Clements
- Medical Research Council, Clinical Research Trials Unit, University College London, London, United Kingdom.,Schistosomiasis Control Initiative, London, United Kingdom
| | - Eugene Ruberanziza
- Malaria and Other Parasitic Diseases Division, Neglected Tropical Diseases and Other Parasitic Diseases Unit, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda
| | - Irenee Umulisa
- African Leaders Malaria Alliance, Dar-es-Salam, Tanzania.,Malaria and Other Parasitic Diseases Division, Neglected Tropical Diseases and Other Parasitic Diseases Unit, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda
| | - Udo Wittmann
- Consult AG Statistical Services, Zurich, Switzerland.,Schistosomiasis Control Initiative, London, United Kingdom
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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37
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Colley DG, Jacobson JA, Binder S. Schistosomiasis Consortium for Operational Research and Evaluation (SCORE): Its Foundations, Development, and Evolution. Am J Trop Med Hyg 2020; 103:5-13. [PMID: 32400343 PMCID: PMC7351300 DOI: 10.4269/ajtmh.19-0785] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in late 2008 to conduct operational research that would inform practices related to the control and elimination of schistosomiasis. This article traces SCORE’s beginnings and underpinnings. These include an emphasis on openness and contributing to the development of a cohesive schistosomiasis control community, building linkages between researchers and national programs, and focusing on answering questions that will help Neglected Tropical Disease program managers to better control and eliminate schistosomiasis. It describes the development and implementation of SCORE’s multiple projects. SCORE began by drawing on advice from a broad range of experts by holding wide-ranging meetings that informed the priorities and protocols for SCORE research. SCORE’s major efforts included large, multicountry field studies comparing multiple strategies for mass drug administration with praziquantel, assessment of approaches to elimination, evaluation of a point-of-care assay for field mapping Schistosoma mansoni, and increasing the sensitivity of a laboratory-based diagnostic. SCORE also supported studies on morbidity due to schistosomiasis, quantification of vector snails and the detection of schistosome infections in snails, and changes in schistosome population genetics under praziquantel drug pressure. SCORE data and specimens are archived and will remain available for future research. Although much remains to be carried out, our hope is that through the already published articles and SCORE results described in this supplement, we will have provided a body of evidence to assist policy makers in the development of judicious guidelines for the control and elimination of schistosomiasis.
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Affiliation(s)
- Daniel G Colley
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia.,Department of Microbiology, University of Georgia, Athens, Georgia
| | | | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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38
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Colley DG, Fleming FM, Matendechero SH, Knopp S, Rollinson D, Utzinger J, Castleman JD, Kittur N, King CH, Campbell CH, Kabole FM, Kinung'hi S, Ramzy RMR, Binder S. Contributions of the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) to Schistosomiasis Control and Elimination: Key Findings and Messages for Future Goals, Thresholds, and Operational Research. Am J Trop Med Hyg 2020; 103:125-134. [PMID: 32400345 PMCID: PMC7351304 DOI: 10.4269/ajtmh.19-0787] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Herein, we summarize what we consider are major contributions resulting from the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) program, including its key findings and key messages from those findings. Briefly, SCORE's key findings are as follows: i) biennial mass drug administration (MDA) with praziquantel can control schistosomiasis to moderate levels of prevalence; ii) MDA alone will not achieve elimination; iii) to attain and sustain control throughout endemic areas, persistent hotspots need to be identified following a minimal number of years of annual MDA and controlled through adaptive strategies; iv) annual MDA is more effective than biennial MDA in high-prevalence areas; v) the current World Health Organization thresholds for decision-making based on the prevalence of heavy infections should be redefined; and vi) point-of-care circulating cathodic antigen urine assays are useful for Schistosoma mansoni mapping in low-to-moderate prevalence areas. The data and specimens collected and curated through SCORE efforts will continue to be critical resource for future research. Besides providing useful information for program managers and revision of guidelines for schistosomiasis control and elimination, SCORE research and outcomes have identified additional questions that need to be answered as the schistosomiasis community continues to implement effective, evidence-based programs. An overarching contribution of SCORE has been increased cohesiveness within the schistosomiasis field-oriented community, thereby fostering new and productive collaborations. Based on SCORE's findings and experiences, we propose new approaches, thresholds, targets, and goals for control and elimination of schistosomiasis, and recommend research and evaluation activities to achieve these targets and goals.
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Affiliation(s)
- Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Fiona M Fleming
- Department of Infectious Disease Epidemiology, Schistosomiasis Control Initiative, London, United Kingdom
| | - Sultani H Matendechero
- Division of Communicable Disease Prevention and Control, Neglected Tropical Diseases Unit, Ministry of Health, Nairobi, Kenya
| | - Stefanie Knopp
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, Natural History Museum, London, United Kingdom
| | - David Rollinson
- Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, Natural History Museum, London, United Kingdom
| | - Jürg Utzinger
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Jennifer D Castleman
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Fatma M Kabole
- Neglected Diseases Programme, Ministry of Health of Zanzibar, Zanzibar, United Republic of Tanzania
| | - Safari Kinung'hi
- National Institute for Medical Research (NIMR), Mwanza Centre, Mwanza, United Republic of Tanzania
| | - Reda M R Ramzy
- National Nutrition Institute, General Organization for Teaching Hospitals and Institutes, Cairo, Egypt
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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Hoekstra PT, Schwarz NG, Adegnika AA, Andrianarivelo MR, Corstjens PLAM, Rakotoarivelo RA, Rakotozandrindrainy R, Sicuri E, Kreidenweiss A, van Dam GJ. Fast and reliable easy-to-use diagnostics for eliminating bilharzia in young children and mothers: An introduction to the freeBILy project. Acta Trop 2020; 211:105631. [PMID: 32679109 DOI: 10.1016/j.actatropica.2020.105631] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/24/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023]
Abstract
Schistosoma antigen detection tests have a large potential for schistosomiasis control programs due to their ability to detect active and ongoing Schistosoma infections, their much higher sensitivity compared to microscopical methods, and the possibility to use non-invasive urine samples. Pregnant women and young children could especially benefit from affordable and easy-to-use antigen tests as inclusion of these vulnerable groups in mass drug administration campaigns will always require higher justification hurdles, especially in low to middle endemic regions with a higher proportion of individuals who are not infected and thus unnecessarily exposed to praziquantel. The overall objective of the 'fast and reliable easy-to-use diagnostics for eliminating bilharzia in young children and mothers' (freeBILy, www.freeBILy.eu) project is to thoroughly evaluate the point-of-care circulating cathodic antigen (POC-CCA) and the up-converting phosphor reporter particle, lateral flow circulating anodic antigen (UCP-LF CAA) urine strip tests to diagnose Schistosoma infections in pregnant women and young children and to assess their potential as a schistosomiasis control tool in test-and-treat strategies. The freeBILy project will generate valuable, evidence-based findings on improved tools and test-and-treat strategies to reduce the burden of schistosomiasis in pregnant women and young children.
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Affiliation(s)
- Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Norbert G Schwarz
- Bernhard-Nocht-Institut für Tropenmedizin, Hamburg, Germany; German Center for Infection Research, Germany
| | - Ayola A Adegnika
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands; German Center for Infection Research, Germany; Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Eberhard Karls Universität Tübingen, Tübingen, Germany
| | | | - Paul L A M Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | - Elisa Sicuri
- ISGlobal, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain; Health Economics Group, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK
| | - Andrea Kreidenweiss
- German Center for Infection Research, Germany; Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
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Kayuni SA, O'Ferrall AM, Baxter H, Hesketh J, Mainga B, Lally D, Al-Harbi MH, LaCourse EJ, Juziwelo L, Musaya J, Makaula P, Stothard JR. An outbreak of intestinal schistosomiasis, alongside increasing urogenital schistosomiasis prevalence, in primary school children on the shoreline of Lake Malawi, Mangochi District, Malawi. Infect Dis Poverty 2020; 9:121. [PMID: 32867849 PMCID: PMC7456765 DOI: 10.1186/s40249-020-00736-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/07/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Intestinal schistosomiasis was not considered endemic in Lake Malawi until November 2017 when populations of Biomphalaria pfeifferi were first reported; in May 2018, emergence of intestinal schistosomiasis was confirmed. This emergence was in spite of ongoing control of urogenital schistosomiasis by preventive chemotherapy. Our current study sought to ascertain whether intestinal schistosomiasis is transitioning from emergence to outbreak, to judge if stepped-up control interventions are needed. METHODS During late-May 2019, three cross-sectional surveys of primary school children for schistosomiasis were conducted using a combination of rapid diagnostic tests, parasitological examinations and applied morbidity-markers; 1) schistosomiasis dynamics were assessed at Samama (n = 80) and Mchoka (n = 80) schools, where Schistosoma mansoni was first reported, 2) occurrence of S. mansoni was investigated at two non-sampled schools, Mangochi Orphan Education and Training (MOET) (n = 60) and Koche (n = 60) schools, where B. pfeifferi was nearby, and 3) rapid mapping of schistosomiasis, and B. pfeifferi, conducted across a further 8 shoreline schools (n = 240). After data collection, univariate analyses and Chi-square testing were performed, followed by binary logistic regression using generalized linear models, to investigate epidemiological associations. RESULTS In total, 520 children from 12 lakeshore primary schools were examined, mean prevalence of S. mansoni by 'positive' urine circulating cathodic antigen (CCA)-dipsticks was 31.5% (95% confidence interval [CI]: 27.5-35.5). Upon comparisons of infection prevalence in May 2018, significant increases at Samama (relative risk [RR] = 1.7, 95% CI: 1.4-2.2) and Mchoka (RR = 2.7, 95% CI: 1.7-4.3) schools were observed. Intestinal schistosomiasis was confirmed at MOET (18.3%) and Koche (35.0%) schools, and in all rapid mapping schools, ranging from 10.0 to 56.7%. Several populations of B. pfeifferi were confirmed, with two new eastern shoreline locations noted. Mean prevalence of urogenital schistosomiasis was 24.0% (95% CI: 20.3-27.7). CONCLUSIONS We notify that intestinal schistosomiasis, once considered non-endemic in Lake Malawi, is now transitioning from emergence to outbreak. Once control interventions can resume after coronavirus disease 2019 (COVID-19) suspensions, we recommend stepped-up preventive chemotherapy, with increased community-access to treatments, alongside renewed efforts in appropriate environmental control.
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Affiliation(s)
- Sekeleghe A Kayuni
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK.,Medi Clinic Limited, Medical Aid Society of Malawi (MASM), 22 Lower Sclatter Road, P.O. Box 1254, Blantyre, Malawi
| | - Angus M O'Ferrall
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Hamish Baxter
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Josie Hesketh
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Bright Mainga
- Laboratory Department, Mangochi District Hospital, P.O. Box 42, Mangochi, Malawi
| | - David Lally
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Blantyre, Malawi
| | | | - E James LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Lazarus Juziwelo
- National Schistosomiasis and STH Control Programme, Ministry of Health, Lilongwe, Malawi
| | - Janelisa Musaya
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Blantyre, Malawi.,Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Peter Makaula
- Research for Health Environment and Development, P.O. Box 345, Mangochi, Malawi
| | - J Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK.
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Sassa M, Chadeka EA, Cheruiyot NB, Tanaka M, Moriyasu T, Kaneko S, Njenga SM, Cox SE, Hamano S. Prevalence and risk factors of Schistosoma mansoni infection among children under two years of age in Mbita, Western Kenya. PLoS Negl Trop Dis 2020; 14:e0008473. [PMID: 32841228 PMCID: PMC7447014 DOI: 10.1371/journal.pntd.0008473] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
Despite growing evidence that infants and very young children can be infected with schistosomes, the epidemiological features and risk factors are not well described in this age group. We aimed to assess the prevalence of S. mansoni infection in children under two years of age from a population with a known high burden of infection in school-aged children and adults and thus inform the need for interventions in this potentially vulnerable age group. In a cross-sectional study in Mbita Sub-county, along the east coast of Lake Victoria, Western Kenya, we enrolled 361 children aged 6-23 months. The prevalence of S. mansoni infection was detected using the Kato-Katz stool examination and a point-of-care test for urinary circulating cathodic antigen (POC-CCA) (Rapid Medical Diagnostics, Pretoria, South Africa). Three-hundred and five (305) children had complete data of whom 276 (90.5%, 95%CI: 86.6-93.5) children were positive for S. mansoni by the POC-CCA test, while 11 (3.6%, 95%CI: 1.8-6.4) were positive by the Kato-Katz method. All Kato-Katz positive cases were also positive by the POC-CCA test. In multivariable analysis, only geographical area, Rusinga West (AOR = 7.1, 95%CI: 1.4-35.2, P = 0.02), was associated with S. mansoni infection using Kato-Katz test. Independent associations for POC-CCA positivity included age, (12-17 months vs 6-11 months; AOR = 7.8, 95%CI: 1.8-32.6, P = 0.002) and breastfeeding in the previous 24 hours (AOR = 3.4, 95%CI: 1.3-9.0, P = 0.009). We found a potentially very high prevalence of S. mansoni infection among children under two years of age based on POC-CCA test results in Mbita Sub-county, Kenya, which if confirmed strongly supports the need to include infants in public health strategies providing universal prophylactic treatment in high burden settings. Further research is required to determine the accuracy of diagnostic tools to detect light infection among very young children and possible long-term health impacts.
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Affiliation(s)
- Miho Sassa
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Evans A. Chadeka
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Ngetich B. Cheruiyot
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Mio Tanaka
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Leading program, Program for Nuring Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Taeko Moriyasu
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Eco-Epidemiology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Satoshi Kaneko
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
- Department of Eco-Epidemiology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Sammy M. Njenga
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Sharon E. Cox
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
- Department of Global Health Development Policy Science, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail: (SEC); (SH)
| | - Shinjiro Hamano
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
- The Joint Usage/ Research Centre on Tropical Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
- Leading program, Program for Nuring Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- * E-mail: (SEC); (SH)
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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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Bergquist NR. Schistosomiasis Consortium for Operational Research and Evaluation: Mission Accomplished. Am J Trop Med Hyg 2020; 103:1-4. [PMID: 32400351 PMCID: PMC7351299 DOI: 10.4269/ajtmh.19-0838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 11/30/2022] Open
Abstract
The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), a program focusing on schistosomiasis control in sub-Saharan Africa between 2008 and 2019, investigated ways to improve coverage and efficacy of ongoing chemotherapy programs and concluded that because of continued transmission, mass distribution of praziquantel cannot eliminate the disease without complementary control activities. Schistosomiasis Consortium for Operational Research and Evaluation's activities comprised large-scale, multicountry field studies comparing various mass drug administration strategies and some specific research avenues, such as assessment of high-sensitivity diagnostics, identification of hotspots, quantification of the role of the snail host, predictive modeling, and changes in schistosome population genetics under drug pressure. The discoveries made and the insights gained regarding cost-effective strategies for delivering preventive chemotherapy should assist policy makers to develop guidelines for the control and ultimate elimination of schistosomiasis.
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Binder S, Campbell CH, Andros TS, Castleman JD, Kittur N, King CH, Colley DG. The Schistosomiasis Consortium for Operational Research and Evaluation 2008-2020: Approaches, Experiences, Lessons, and Recommendations. Am J Trop Med Hyg 2020; 103:114-124. [PMID: 32400350 PMCID: PMC7351309 DOI: 10.4269/ajtmh.19-0786] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
For the past 10 years, the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), funded by the Bill & Melinda Gates Foundation, has been supporting operational research to provide a stronger evidence base for controlling and moving toward elimination of schistosomiasis. The SCORE portfolio was developed and implemented with engagement from many stakeholders and sectors. Particular efforts were made to include endemic country neglected tropical disease program managers. Examples of the challenges we encountered include the need to balance rigor (e.g., conducting large cluster-randomized trials) with ensuring relevance to real-world settings, allowing for local contexts while standardizing key study aspects, adjusting to evolving technologies, and incorporating changing technologies into multiyear studies. The Schistosomiasis Consortium for Operational Research and Evaluation's findings and data and the collected specimens will continue to be useful in the years to come. Our experiences and lessons learned can benefit both program managers and researchers conducting similar work in the future.
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Affiliation(s)
- Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Tamara S Andros
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Jennifer D Castleman
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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Amoah AS, Hoekstra PT, Casacuberta-Partal M, Coffeng LE, Corstjens PLAM, Greco B, van Lieshout L, Lim MD, Markwalter CF, Odiere MR, Reinhard-Rupp J, Roestenberg M, Stothard R, Tchuem Tchuenté LA, de Vlas SJ, van Dam GJ. Sensitive diagnostic tools and targeted drug administration strategies are needed to eliminate schistosomiasis. THE LANCET. INFECTIOUS DISEASES 2020; 20:e165-e172. [PMID: 32595046 DOI: 10.1016/s1473-3099(20)30254-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/03/2020] [Accepted: 03/23/2020] [Indexed: 11/29/2022]
Abstract
Although preventive chemotherapy has been instrumental in reducing schistosomiasis incidence worldwide, serious challenges remain. These problems include the omission of certain groups from campaigns of mass drug administration, the existence of persistent disease hotspots, and the risk of recrudescent infections. Central to these challenges is the fact that the diagnostic tools currently used to establish the burden of infection are not sensitive enough, especially in low-endemic settings, which results in underestimation of the true prevalence of active Schistosoma spp infections. This central issue necessitates that the current schistosomiasis control strategies recommended by WHO are re-evaluated and, possibly, adapted. More targeted interventions and novel approaches have been used to estimate the prevalence of schistosomiasis, such as establishing infection burden by use of precision mapping, which provides high resolution spatial information that delineates variations in prevalence within a defined geographical area. Such information is instrumental in guiding targeted intervention campaigns. However, the need for highly accurate diagnostic tools in such strategies is a crucial factor that is often neglected. The availability of highly sensitive diagnostic tests also opens up the possibility of applying strategies of sample pooling to reduce the cost of control programmes. To interrupt the transmission of, and eventually eliminate, schistosomiasis, better local targeting of preventive chemotherapy, in combination with highly sensitive diagnostic tools, is crucial.
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Affiliation(s)
- Abena S Amoah
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK; Malawi Epidemiology and Intervention Research Unit, Chilumba, Malawi
| | - Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands.
| | | | - Luc E Coffeng
- Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Paul L A M Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Mark D Lim
- Global Health Division, The Bill & Melinda Gates Foundation, Seattle, WA, USA; Global Public Health Programs, American Society for Microbiology, Washington DC, USA
| | - Christine F Markwalter
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Maurice R Odiere
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | | | - Louis-Albert Tchuem Tchuenté
- Laboratory of Parasitology and Ecology, University of Yaoundé I, Yaoundé, Cameroon; Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon
| | - Sake J de Vlas
- Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
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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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Insights from quantitative and mathematical modelling on the proposed WHO 2030 goal for schistosomiasis. Gates Open Res 2019; 3:1517. [PMID: 31701091 DOI: 10.12688/gatesopenres.13052.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2019] [Indexed: 12/14/2022] Open
Abstract
Schistosomiasis remains one of the neglected tropical diseases (NTDs) impacting millions of people around the world. The World Health Organization (WHO) recently proposed a goal of elimination as a public health problem (EPHP) for schistosomiasis to be reached by 2030. Current WHO treatment guidelines for achieving EPHP focus on targeting school-aged children. The NTD Modelling Consortium has developed mathematical models to study schistosomiasis transmission dynamics and the impact of control measures. Our modelling insights on Schistosoma mansoni have shown that EPHP is likely to be attainable in low to moderate prevalence settings using the current guidelines. However, as prevalence rises within high prevalence settings, EPHP is less likely to be achieved unless both school-aged children and adults are treated (with coverage levels increasing with the adult burden of infection). We highlight the challenges that are faced by treatment programmes, such as non-adherence to treatment and resurgence, which can hinder progress towards achieving and maintaining EPHP. Additionally, even though EPHP may be reached, prevalence can still be high due to persisting infections. Therefore, without interruption of transmission, treatment will likely have to continue to maintain EPHP. Further modelling work is being carried out, including extending our results to S. haematobium. By providing these modelling insights, we aim to inform discussions on the goals and treatment guidelines for schistosomiasis.
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Insights from quantitative and mathematical modelling on the proposed WHO 2030 goal for schistosomiasis. Gates Open Res 2019; 3:1517. [PMID: 31701091 PMCID: PMC6820450 DOI: 10.12688/gatesopenres.13052.2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2019] [Indexed: 12/17/2022] Open
Abstract
Schistosomiasis remains one of the neglected tropical diseases (NTDs) impacting millions of people around the world. The World Health Organization (WHO) recently proposed a goal of elimination as a public health problem (EPHP) for schistosomiasis to be reached by 2030. Current WHO treatment guidelines for achieving EPHP focus on targeting school-aged children. The NTD Modelling Consortium has developed mathematical models to study schistosomiasis transmission dynamics and the impact of control measures. Our modelling insights on
Schistosoma mansoni have shown that EPHP is likely to be attainable in low to moderate prevalence settings using the current guidelines. However, as prevalence rises within high prevalence settings, EPHP is less likely to be achieved unless both school-aged children and adults are treated (with coverage levels increasing with the adult burden of infection). We highlight the challenges that are faced by treatment programmes, such as non-adherence to treatment and resurgence, which can hinder progress towards achieving and maintaining EPHP. Additionally, even though EPHP may be reached, prevalence can still be high due to persisting infections. Therefore, without interruption of transmission, treatment will likely have to continue to maintain EPHP. Further modelling work is being carried out, including extending our results to
S. haematobium. By providing these modelling insights, we aim to inform discussions on the goals and treatment guidelines for schistosomiasis.
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Mapping Schistosoma mansoni endemicity in Rwanda: a critical assessment of geographical disparities arising from circulating cathodic antigen versus Kato-Katz diagnostics. PLoS Negl Trop Dis 2019; 13:e0007723. [PMID: 31568504 PMCID: PMC6786642 DOI: 10.1371/journal.pntd.0007723] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/10/2019] [Accepted: 08/20/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Schistosomiasis is a neglected tropical disease caused by Schistosoma parasites. Intervention relies on identifying high-risk regions, yet rapid Schistosoma diagnostics (Kato-Katz stool assays (KK) and circulating cathodic antigen urine assays (CCA)) yield different prevalence estimates. We mapped S. mansoni prevalence and delineated at-risk regions using a survey of schoolchildren in Rwanda, where S. mansoni is an endemic parasite. We asked if different diagnostics resulted in disparities in projected infection risk. METHODS Infection data was obtained from a 2014 Rwandan school-based survey that used KK and CCA diagnostics. Across 386 schools screened by CCA (N = 19,217). To allow for uncertainty when interpreting ambiguous CCA trace readings, which accounted for 28.8% of total test results, we generated two presence-absence datasets: CCA trace as positive and CCA trace as negative. Samples (N = 9,175) from 185 schools were also screened by KK. We included land surface temperature (LST) and the Normalized Difference Vegetation and Normalized Difference Water Indices (NDVI, NDWI) as predictors in geostatistical regressions. FINDINGS Across 8,647 children tested by both methods, prevalence was 35.93% for CCA trace as positive, 7.21% for CCA trace as negative and 1.95% for KK. LST was identified as a risk factor using KK, whereas NDVI was a risk factor for CCA models. Models predicted high endemicity in Northern and Western regions of Rwanda, though the CCA trace as positive model identified additional high-risk areas that were overlooked by the other methods. Estimates of current burden for children at highest risk (boys aged 5-9 years) varied by an order of magnitude, with 671,856 boys projected to be infected by CCA trace as positive and only 60,453 projected by CCA trace as negative results. CONCLUSIONS Our findings show that people in Rwanda's Northern, Western and capital regions are at high risk of S. mansoni infection. However, variation in identification of environmental risk factors and delineation of at-risk regions using different diagnostics likely provides confusing messages to disease intervention managers. Further research and statistical analyses, such as latent class analysis, can be used to improve CCA result classification and assess its use in guiding treatment regimes.
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How can schistosome circulating antigen assays be best applied for diagnosing male genital schistosomiasis (MGS): an appraisal using exemplar MGS cases from a longitudinal cohort study among fishermen on the south shoreline of Lake Malawi. Parasitology 2019; 146:1785-1795. [PMID: 31452477 PMCID: PMC6939168 DOI: 10.1017/s0031182019000969] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We provide an update on diagnostic methods for the detection of urogenital schistosomiasis (UGS) in men and highlight that satisfactory urine-antigen diagnostics for UGS lag much behind that for intestinal schistosomiasis, where application of a urine-based point-of-care strip assay, the circulating cathodic antigen (CCA) test, is now advocated. Making specific reference to male genital schistosomiasis (MGS), we place greater emphasis on parasitological detection methods and clinical assessment of internal genitalia with ultrasonography. Unlike the advances made in defining a clinical standard protocol for female genital schistosomiasis, MGS remains inadequately defined. Whilst urine filtration with microscopic examination for ova of Schistosoma haematobium is a convenient but error-prone proxy of MGS, we describe a novel low-cost sampling and direct visualization method for the enumeration of ova in semen. Using exemplar clinical cases of MGS from our longitudinal cohort study among fishermen along the shoreline of Lake Malawi, the portfolio of diagnostic needs is appraised including: the use of symptomatology questionnaires, urine analysis (egg count and CCA measurement), semen analysis (egg count, circulating anodic antigen measurement and real-time polymerase chain reaction analysis) alongside clinical assessment with portable ultrasonography.
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