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Scarso S, Rakotoarivelo RA, Hey JC, Rasamoelina T, Razafindrakoto AR, Rasolojaona ZT, Razafindralava NM, Remkes A, Rakotozandrindrainy N, Rasoamanamihaja CF, Schwarz NG, May J, Rakotozandrindrainy R, Marchese V, Formenti F, Perandin F, Tamarozzi F, Mazzi C, Fusco D, Buonfrate D. Prevalence of Strongyloides stercoralis and other helminths in four districts of Madagascar. Trop Med Health 2024; 52:49. [PMID: 39075624 PMCID: PMC11285119 DOI: 10.1186/s41182-024-00619-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 07/18/2024] [Indexed: 07/31/2024] Open
Abstract
BACKGROUND Estimation of prevalence of Strongyloides stercoralis infection is required in endemic areas, in order to identify areas in need of control programmes. Data on prevalence of strongyloidiasis in Madagascar are scant. Aim of this work was to estimate prevalence of S. stercoralis in four districts of Madagascar. METHODS Fecal and serum samples collected in the context of a previous study on schistosomiasis were tested with S. stercoralis real-time PCR and serology, respectively. A multiplex real-time PCR for Ascaris lumbricoides, Ancylostoma duodenalis, Necator americanus, and Trichuris trichiura was done on fecal samples collected in the areas demonstrating higher prevalence of strongyloidiasis. Comparisons between proportions were made using Fisher exact test, with false discovery rate correction used for post-hoc comparisons. A multivariable Firth logistic regression model was used to assess potential risk factors for S. stercoralis infection. RESULTS Overall, 1775 serum samples were tested, of which 102 of 487 (20.9%) and 104 of 296 (35.2%) were serological-positive in Marovoay and in Vatomandry districts (both coastal areas), respectively, compared to 28 of 496 (5.6%) and 30 of 496 (6.1%) in Tsiroanomandidy and in Ambositra districts (both highlands), respectively (adj. p < 0.001). PCR for S. stercoralis was positive in 15 of 210 (7.1%) and in 11 of 296 (3.7%) samples from Marovoay from Vatomandry, respectively, while was negative for all samples tested in the other two districts. High prevalence of A. lumbricoides (45.9%), hookworm (44.6%) and T. trichiura (32.1%) was found in Vatomandry. In the multivariable analysis, strongyloidiasis was associated with hookworm infection. Hookworm infection was also associated with male sex and lower education level. CONCLUSIONS S. stercoralis prevalence proved higher in coastal areas compared to highlands. Different climatic conditions may explain this distribution, along with previous rounds of anthelminthics distributed in the country, which may have reduced the parasite load in the population. The high prevalence of the other soil-transmitted helminths (STH) in Vatomandry was unexpected, given the good coverage with benzimidazole in control campaigns. Further studies are needed to explore the risk factors for STH and S. stercoralis infections in Madagascar, in order to align with the WHO recommendations.
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Affiliation(s)
- Salvatore Scarso
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | | | - Jana Christina Hey
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | | | | | | | - Aaron Remkes
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | | | - Norbert Georg Schwarz
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
| | - Jürgen May
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | - Valentina Marchese
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Fabio Formenti
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Francesca Perandin
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Francesca Tamarozzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Cristina Mazzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Daniela Fusco
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Dora Buonfrate
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy.
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Puchner KP, Bottazzi ME, Periago V, Grobusch M, Maizels R, McCarthy J, Lee B, Gaspari E, Diemert D, Hotez P. Vaccine value profile for Hookworm. Vaccine 2024; 42:S25-S41. [PMID: 37863671 DOI: 10.1016/j.vaccine.2023.05.013] [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: 07/04/2022] [Revised: 04/24/2023] [Accepted: 05/03/2023] [Indexed: 10/22/2023]
Abstract
Hookworm, a parasitic infection, retains a considerable burden of disease, affecting the most underprivileged segments of the general population in endemic countries and remains one of the leading causes of mild to severe anemia in Low and Middle Income Countries (LMICs), particularly in pregnancy and children under 5. Despite repeated large scale Preventive Chemotherapy (PC) interventions since more than 3 decades, there is broad consensus among scholars that elimination targets set in the newly launched NTD roadmap will require additional tools and interventions. Development of a vaccine could constitute a promising expansion of the existing arsenal against hookworm. Therefore, we have evaluated the biological and implementation feasibility of the vaccine development as well as the added value of such a novel tool. Based on pipeline landscaping and the current knowledge on key biological aspects of the pathogen and its interactions with the host, we found biological feasibility of development of a hookworm vaccine to be moderate. Also, our analysis on manufacturing and regulatory issues as well as potential uptake yielded moderate implementation feasibility. Modelling studies suggest a that introduction of a vaccine in parallel with ongoing integrated interventions (PC, WASH, shoe campaigns), could substantially reduce burden of disease in a cost - saving mode. Finally a set of actions are recommended that might impact positively the likelihood of timely development and introduction of a hookworm vaccine.
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Affiliation(s)
| | - Maria Elena Bottazzi
- National School of Tropical Medicine, Baylor College of Medicine, Baylor, TX, USA
| | | | - Martin Grobusch
- Center of Tropical Medicine and Travel Medicine, Department of Infectious Diseases, Amsterdam University Medical Centers, Location AMC, Amsterdam Infection & Immunity, Amsterdam Public Health, University of Amsterdam, Amsterdam, The Netherlands
| | - Rick Maizels
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - James McCarthy
- The Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Bruce Lee
- Public Health Informatics, Computational, and Operations Research, Graduate School of Public Health and Health Policy, City University of New York, New York, NY, USA
| | - Erika Gaspari
- European & Developing Countries Clinical Trials Partnership (EDCTP), The Hague, The Netherlands
| | - David Diemert
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University Medical Center, Washington, DC, USA
| | - Peter Hotez
- National School of Tropical Medicine, Baylor College of Medicine, Baylor, TX, USA
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Smalley H, Keskinocak P, Swann J, Hanna C, Weiss A. Potential Impact of a Diagnostic Test for Detecting Prepatent Guinea Worm Infections in Dogs. Am J Trop Med Hyg 2024; 110:953-960. [PMID: 38579703 PMCID: PMC11066357 DOI: 10.4269/ajtmh.23-0534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/01/2023] [Indexed: 04/07/2024] Open
Abstract
Chad has seen a considerable reduction in cases of Guinea worm disease (or dracunculiasis) in domestic dogs in recent years. Tethering of dogs and application of Abate® larvicide to water sources appear to have contributed to this progress, but with 767 reported dog cases in 2021, accelerating elimination of the disease in Chad may require additional tools. We investigate the potential benefits of a hypothetical diagnostic test that could be capable of detecting prepatent infections in dogs. We adapt an agent-based simulation model for forecasting the impact of interventions on guinea worm disease in dogs to examine the interaction of multiple test factors including test accuracy, when the test can detect infection, dog selection, and dog-owner compliance with tethering recommendations. We find that a diagnostic test could be successful if used in conjunction with existing interventions, and elimination can be achieved within 2 years with 80% or higher test sensitivity, 90% or higher specificity, systematic testing of each dog twice per year, and more than 90% long-term tethering compliance when a dog tests positive or a worm is emerging. Because of the long incubation period of Guinea worm disease (10-14 months) and the fact that no treatment exists, the benefits of the test rely on the testing rollout and response of dog owners. If the test could estimate the timing of worm emergence, long-term tethering could be eliminated and infected dogs could be tethered only when the worms are expected, minimizing the related resources (human and financial) to support the intervention.
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Affiliation(s)
- Hannah Smalley
- H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Pinar Keskinocak
- H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Julie Swann
- H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, Georgia
- Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina
| | | | - Adam Weiss
- Guinea Worm Eradication Program, The Carter Center, Atlanta, Georgia
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Coffeng LE, Vlaminck J, Cools P, Denwood M, Albonico M, Ame SM, Ayana M, Dana D, Cringoli G, de Vlas SJ, Fenwick A, French M, Kazienga A, Keiser J, Knopp S, Leta G, Matoso LF, Maurelli MP, Montresor A, Mirams G, Mekonnen Z, Corrêa-Oliveira R, Pinto SA, Rinaldi L, Sayasone S, Steinmann P, Thomas E, Vercruysse J, Levecke B. A general framework to support cost-efficient fecal egg count methods and study design choices for large-scale STH deworming programs-monitoring of therapeutic drug efficacy as a case study. PLoS Negl Trop Dis 2023; 17:e0011071. [PMID: 37196017 PMCID: PMC10228800 DOI: 10.1371/journal.pntd.0011071] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 05/30/2023] [Accepted: 04/13/2023] [Indexed: 05/19/2023] Open
Abstract
BACKGROUND Soil-transmitted helminth (STH) control programs currently lack evidence-based recommendations for cost-efficient survey designs for monitoring and evaluation. Here, we present a framework to provide evidence-based recommendations, using a case study of therapeutic drug efficacy monitoring based on the examination of helminth eggs in stool. METHODS We performed an in-depth analysis of the operational costs to process one stool sample for three diagnostic methods (Kato-Katz, Mini-FLOTAC and FECPAKG2). Next, we performed simulations to determine the probability of detecting a truly reduced therapeutic efficacy for different scenarios of STH species (Ascaris lumbricoides, Trichuris trichiura and hookworms), pre-treatment infection levels, survey design (screen and select (SS); screen, select and retest (SSR) and no selection (NS)) and number of subjects enrolled (100-5,000). Finally, we integrated the outcome of the cost assessment into the simulation study to estimate the total survey costs and determined the most cost-efficient survey design. PRINCIPAL FINDINGS Kato-Katz allowed for both the highest sample throughput and the lowest cost per test, while FECPAKG2 required both the most laboratory time and was the most expensive. Counting of eggs accounted for 23% (FECPAKG2) or ≥80% (Kato-Katz and Mini-FLOTAC) of the total time-to-result. NS survey designs in combination with Kato-Katz were the most cost-efficient to assess therapeutic drug efficacy in all scenarios of STH species and endemicity. CONCLUSIONS/SIGNIFICANCE We confirm that Kato-Katz is the fecal egg counting method of choice for monitoring therapeutic drug efficacy, but that the survey design currently recommended by WHO (SS) should be updated. Our generic framework, which captures laboratory time and material costs, can be used to further support cost-efficient choices for other important surveys informing STH control programs. In addition, it can be used to explore the value of alternative diagnostic techniques, like automated egg counting, which may further reduce operational costs. TRIAL REGISTRATION ClinicalTrials.gov NCT03465488.
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Affiliation(s)
- Luc E. Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Johnny Vlaminck
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Piet Cools
- Department of Diagnostic Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | | | - Shaali M. Ame
- Laboratory Division, Public Health Laboratory-Ivo de Carneri, Chake Chake, United Republic of Tanzania
| | - Mio Ayana
- Department of Diagnostic Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Jimma University Institute of Health, Jimma University, Jimma, Ethiopia
| | - Daniel Dana
- Department of Diagnostic Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
- Jimma University Institute of Health, Jimma University, Jimma, Ethiopia
| | - Giuseppe Cringoli
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, St Mary’s Campus, Imperial College London, London, United Kingdom
| | - Michael French
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, St Mary’s Campus, Imperial College London, London, United Kingdom
- RTI International, Washington District of Columbia, United States of America
| | - Adama Kazienga
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Gemechu Leta
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Leonardo F. Matoso
- Laboratory of Molecular and Cellular Immunology, Research Center René Rachou—FIOCRUZ, Belo Horizonte, Brazil
- Nursing school, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Maria P. Maurelli
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Antonio Montresor
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | | | - Zeleke Mekonnen
- Jimma University Institute of Health, Jimma University, Jimma, Ethiopia
| | - Rodrigo Corrêa-Oliveira
- Laboratory of Molecular and Cellular Immunology, Research Center René Rachou—FIOCRUZ, Belo Horizonte, Brazil
| | - Simone A. Pinto
- Laboratory of Molecular and Cellular Immunology, Research Center René Rachou—FIOCRUZ, Belo Horizonte, Brazil
| | - Laura Rinaldi
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Somphou Sayasone
- Lao Tropical and Public Health Institute, Ministry of Health, Vientiane, Lao People’s Democratic Republic
| | - Peter Steinmann
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Jozef Vercruysse
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
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A review on innovative optical devices for the diagnosis of human soil-transmitted helminthiasis and schistosomiasis: from research and development to commercialization. Parasitology 2023; 150:137-149. [PMID: 36683384 PMCID: PMC10090604 DOI: 10.1017/s0031182022001664] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diagnosis of soil-transmitted helminth (STH) and schistosome infections relies largely on conventional microscopy which has limited sensitivity, requires highly trained personnel and is error-prone. Rapid advances in miniaturization of optical systems, sensors and processors have enhanced research and development of digital and automated microscopes suitable for the detection of these diseases in resource-limited settings. While some studies have reported proof-of-principle results, others have evaluated the performance of working prototypes in field settings. The extensive commercialization of these innovative devices has, however, not yet been achieved. This review provides an overview of recent publications (2010–2022) on innovative field applicable optical devices which can be used for the diagnosis of STH and schistosome infections. Using an adapted technology readiness level (TRL) scale taking into account the WHO target product profile (TPP) for these diseases, the developmental stages of the devices were ranked to determine the readiness for practical applications in field settings. From the reviewed 18 articles, 19 innovative optical devices were identified and ranked. Almost all of the devices (85%) were ranked with a TRL score below 8 indicating that, most of the devices are not ready for commercialization and field use. The potential limitations of these innovative devices were discussed. We believe that the outcome of this review can guide the end-to-end development of automated digital microscopes aligned with the WHO TPP for the diagnosis of STH and schistosome infections in resource-limited settings.
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Ward P, Broadfield LA, Dahlberg P, Leta G, Mekonnen Z, Nabatte B, Kabatereine N, Brooks A, Orrling KM, Gomes M, Van Hoecke S, Levecke B, Stuyver LJ. The development of an artificial intelligence-based digital pathology for neglected tropical diseases: A platform specific analysis of the World Health Organization diagnostic target product profile for soil-transmitted helminthiasis. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.990304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The World Health Organization (WHO) recently published target product profiles (TPPs) for neglected tropical diseases (NTDs) to inform and accelerate the development of diagnostics tools necessary to achieve targets in the decade ahead. These TPPs describe the minimal and ideal requirements for various diagnostic needs related to NTD specific use-cases. An early step towards the manufacture and implementation of new diagnostics is to critically review the TPPs and translate these into an initial design and ultimately into user requirement specifications (URS). Artificial intelligence-based digital pathology (AI-DP) may overcome critical shortcomings of current standards for most NTDs reliant on microscopy, such as poor reproducibility and error-prone manual read-out. Furthermore, a digitalised workflow can create opportunities to reduce operational costs via increased throughput and automated data capture, analysis, and reporting. Despite these promising benefits, a critical review of the NTD TPPs with consideration to an AI-DP diagnostic solution is lacking. We present a systematic analysis of one of the WHO TPPs with the aim to inform the development of a URS for an AI-DP solution for NTDs. As a case study we focused on monitoring and evaluation (M&E) of programs designed to control soil-transmitted helminths (STHs). To this end, we start by outlining a brief overview of diagnostic needs for STHs, after which we systematically analyse the recently published WHO TPPs, highlighting the technical considerations for an AI-DP diagnostic solution to meet the minimal requirements for this TPP. Finally, we further reflect on the feasibility of an AI-DP informing STH programs towards the WHO 2030 targets in due time.
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Roose S, Leta GT, Vlaminck J, Getachew B, Mekete K, Peelaers I, Geldhof P, Levecke B. Comparison of coproprevalence and seroprevalence to guide decision-making in national soil-transmitted helminthiasis control programs: Ethiopia as a case study. PLoS Negl Trop Dis 2022; 16:e0010824. [PMID: 36197895 PMCID: PMC9534397 DOI: 10.1371/journal.pntd.0010824] [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: 05/25/2022] [Accepted: 09/16/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND WHO recommends periodical assessment of the prevalence of any soil-transmitted helminth (STH) infections to adapt the frequency of mass drug administration targeting STHs. Today, detection of eggs in stool smears (Kato-Katz thick smear) remains the diagnostic standard. However, stool examination (coprology) has important operational drawbacks and impedes integrated surveys of multiple neglected tropical diseases. Therefore, the aim of the present study was to assess the potential of applying serology instead of coprology in STH control program decision-making. METHODOLOGY An antibody-ELISA based on extract of Ascaris lung stage larvae (AsLungL3-ELISA) was applied in ongoing monitoring activities of the Ethiopian national control program against schistosomiasis and soil-transmitted helminthiasis. Blood and stool samples were collected from over 6,700 students (median age: 11) from 63 schools in 33 woredas (districts) across the country. Stool samples of two consecutive days were analyzed applying duplicate Kato-Katz thick smear. PRINCIPAL FINDINGS On woreda level, qualitative (seroprevalence) and quantitative (mean optical density ratio) serology results were highly correlated, and hence seroprevalence was chosen as parameter. For 85% of the woredas, prevalence based on serology was higher than those based on coprology. The results suggested cross-reactivity of the AsLungL3-ELISA with Trichuris. When extrapolating the WHO coproprevalence thresholds, there was a moderate agreement (weighted κ = 0.43) in program decision-making. Using the same threshold values would predominantly lead to a higher frequency of drug administration. SIGNIFICANCE This is the first time that serology for soil-transmitted helminthiasis is applied on such large scale, thereby embedded in a control program context. The results underscore that serology holds promise as a tool to monitor STH control programs. Further research should focus on the optimization of the diagnostic assay and the refinement of serology-specific program decision-making thresholds.
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Affiliation(s)
- Sara Roose
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
- * E-mail: (SR); (BL)
| | - Gemechu Tadesse Leta
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Johnny Vlaminck
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Birhanu Getachew
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Kalkidan Mekete
- Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Iris Peelaers
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Peter Geldhof
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
- * E-mail: (SR); (BL)
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Kazienga A, Coffeng LE, de Vlas SJ, Levecke B. Two-stage lot quality assurance sampling framework for monitoring and evaluation of neglected tropical diseases, allowing for imperfect diagnostics and spatial heterogeneity. PLoS Negl Trop Dis 2022; 16:e0010353. [PMID: 35394996 PMCID: PMC9020685 DOI: 10.1371/journal.pntd.0010353] [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: 10/11/2021] [Revised: 04/20/2022] [Accepted: 03/28/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Monitoring and evaluation (M&E) is a key component of large-scale neglected tropical diseases (NTD) control programs. Diagnostic tests deployed in these M&E surveys are often imperfect, and it remains unclear how this affects the population-based program decision-making. METHODOLOGY We developed a 2-stage lot quality assurance sampling (LQAS) framework for decision-making that allows for both imperfect diagnostics and spatial heterogeneity of infections. We applied the framework to M&E of soil-transmitted helminth control programs as a case study. For this, we explored the impact of the diagnostic performance (sensitivity and specificity), spatial heterogeneity (intra-cluster correlation), and survey design on program decision-making around the prevalence decisions thresholds recommended by WHO (2%, 10%, 20% and 50%) and the associated total survey costs. PRINCIPAL FINDINGS The survey design currently recommended by WHO (5 clusters and 50 subjects per cluster) may lead to incorrect program decisions around the 2% and 10% prevalence thresholds, even when perfect diagnostic tests are deployed. To reduce the risk of incorrect decisions around the 2% prevalence threshold, including more clusters (≥10) and deploying highly specific diagnostic methods (≥98%) are the most-cost saving strategies when spatial heterogeneity is moderate-to-high (intra-cluster correlation >0.017). The higher cost and lower throughput of improved diagnostic tests are compensated by lower required sample sizes, though only when the cost per test is <6.50 US$ and sample throughput is ≥3 per hour. CONCLUSION/SIGNIFICANCE Our framework provides a means to assess and update M&E guidelines and guide product development choices for NTD. Using soil-transmitted helminths as a case study, we show that current M&E guidelines may severely fall short, particularly in low-endemic and post-control settings. Furthermore, specificity rather than sensitivity is a critical parameter to consider. When the geographical distribution of an NTD within a district is highly heterogeneous, sampling more clusters (≥10) may be required.
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Affiliation(s)
- Adama Kazienga
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - Luc E. Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
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