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Kostandova N, Mutembo S, Prosperi C, Mwansa FD, Nakazwe C, Namukoko H, Nachinga B, Chongwe G, Chilumba I, Matakala KH, Musukwa G, Hamahuwa M, Mufwambi W, Matoba J, Situtu K, Mutale I, Kong AC, Simulundu E, Ndubani P, Hasan AZ, Truelove SA, Winter AK, Carcelen AC, Lau B, Moss WJ, Wesolowski A. Who is missed in a community-based survey: Assessment and implications of biases due to incomplete sampling frame in a community-based serosurvey, Choma and Ndola Districts, Zambia, 2022. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0003072. [PMID: 38683820 PMCID: PMC11057754 DOI: 10.1371/journal.pgph.0003072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 03/10/2024] [Indexed: 05/02/2024]
Abstract
Community-based serological studies are increasingly relied upon to measure disease burden, identify population immunity gaps, and guide control and elimination strategies; however, there is little understanding of the potential for and impact of sampling biases on outcomes of interest. As part of efforts to quantify measles immunity gaps in Zambia, a community-based serological survey using stratified multi-stage cluster sampling approach was conducted in Ndola and Choma districts in May-June 2022, enrolling 1245 individuals. We carried out a follow-up study among individuals missed from the sampling frame of the serosurvey in July-August 2022, enrolling 672 individuals. We assessed the potential for and impact of biases in the community-based serosurvey by i) estimating differences in characteristics of households and individuals included and excluded (77% vs 23% of households) from the sampling frame of the serosurvey and ii) evaluating the magnitude these differences make on healthcare-seeking behavior, vaccination coverage, and measles seroprevalence. We found that missed households were 20% smaller and 25% less likely to have children. Missed individuals resided in less wealthy households, had different distributions of sex and occupation, and were more likely to seek care at health facilities. Despite these differences, simulating a survey in which missed households were included in the sampling frame resulted in less than a 5% estimated bias in these outcomes. Although community-based studies are upheld as the gold standard study design in assessing immunity gaps and underlying community health characteristics, these findings underscore the fact that sampling biases can impact the results of even well-conducted community-based surveys. Results from these studies should be interpreted in the context of the study methodology and challenges faced during implementation, which include shortcomings in establishing accurate and up-to-date sampling frames. Failure to account for these shortcomings may result in biased estimates and detrimental effects on decision-making.
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Affiliation(s)
- Natalya Kostandova
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Simon Mutembo
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Christine Prosperi
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Francis Dien Mwansa
- Department of Immunizations, Ministry of Health, Government of the Republic of Zambia, Lusaka, Zambia
| | - Chola Nakazwe
- Information, Research and Dissemination, Zambia Statistics Agency, Lusaka, Zambia
| | - Harriet Namukoko
- Population and Social Statistics, Zambia Statistics Agency, Lusaka, Zambia
| | - Bertha Nachinga
- Information, Research and Dissemination, Zambia Statistics Agency, Lusaka, Zambia
| | | | - Innocent Chilumba
- Biomedial Sciences Department, Tropical Diseases Research Centre, Ndola, Zambia
| | | | | | - Mutinta Hamahuwa
- Clinical Research Laboratory Department, Macha Research Trust, Macha, Zambia
| | - Webster Mufwambi
- Administration, Tropical Diseases Research Centre, Ndola, Zambia
| | - Japhet Matoba
- Molecular Biology Department, Macha Research Trust, Macha, Zambia
| | - Kenny Situtu
- Tropical Diseases Research Centre, Ndola, Zambia
| | - Irene Mutale
- Tropical Diseases Research Centre, Ndola, Zambia
| | - Alex C. Kong
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | | | | | - Alvira Z. Hasan
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Shaun A. Truelove
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Amy K. Winter
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Epidemiology and Biostatistics, University of Georgia, Athens, Georgia, United States of America
| | - Andrea C. Carcelen
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Bryan Lau
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of International Health, International Vaccine Access Center, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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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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3
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Fornace KM, Fronterrè C, Fleming FM, Simpson H, Zoure H, Rebollo M, Mwinzi P, Vounatsou P, Pullan RL. Evaluating survey designs for targeting preventive chemotherapy against Schistosoma haematobium and Schistosoma mansoni across sub-Saharan Africa: a geostatistical analysis and modelling study. Parasit Vectors 2020; 13:555. [PMID: 33203463 PMCID: PMC7672864 DOI: 10.1186/s13071-020-04413-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/21/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Schistosomiasis control programmes primarily use school-based surveys to identify areas for mass drug administration of preventive chemotherapy. However, as the spatial distribution of schistosomiasis can be highly focal, transmission may not be detected by surveys implemented at districts or larger spatial units. Improved mapping strategies are required to accurately and cost-effectively target preventive chemotherapy to remaining foci across all possible spatial distributions of schistosomiasis. METHODS Here, we use geostatistical models to quantify the spatial heterogeneity of Schistosoma haematobium and S. mansoni across sub-Saharan Africa using the most comprehensive dataset available on school-based surveys. Applying this information to parameterise simulations, we assess the accuracy and cost of targeting alternative implementation unit sizes across the range of plausible schistosomiasis distributions. We evaluate the consequences of decisions based on survey designs implemented at district and subdistrict levels sampling different numbers of schools. Cost data were obtained from field surveys conducted across multiple countries and years, with cost effectiveness evaluated as the cost per correctly identified school. RESULTS Models identified marked differences in prevalence and spatial distributions between countries and species; however, results suggest implementing surveys at subdistrict level increase the accuracy of treatment classifications across most scenarios. While sampling intensively at the subdistrict level resulted in the highest classification accuracy, this sampling strategy resulted in the highest costs. Alternatively, sampling the same numbers of schools currently recommended at the district level but stratifying by subdistrict increased cost effectiveness. CONCLUSIONS This study provides a new tool to evaluate schistosomiasis survey designs across a range of transmission settings. Results highlight the importance of considering spatial structure when designing sampling strategies, illustrating that a substantial proportion of children may be undertreated even when an implementation unit is correctly classified. Control programmes need to weigh the increased accuracy of more detailed mapping strategies against the survey costs and treatment priorities.
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Affiliation(s)
- Kimberly M Fornace
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK.
| | - Claudio Fronterrè
- Centre for Health Informatics, Computing and Statistics (CHICAS), Lancaster University, Lancaster, UK
| | | | - Hope Simpson
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Honorat Zoure
- Expanded Special Project of the Elimination of Neglected Tropical Diseases (ESPEN), Africa Regional Office of the World Health Organisation, Brazzaville, Congo
| | - Maria Rebollo
- Expanded Special Project of the Elimination of Neglected Tropical Diseases (ESPEN), Africa Regional Office of the World Health Organisation, Brazzaville, Congo
| | - Pauline Mwinzi
- Expanded Special Project of the Elimination of Neglected Tropical Diseases (ESPEN), Africa Regional Office of the World Health Organisation, Brazzaville, Congo
| | | | - Rachel L Pullan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
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4
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Macleod CK, Bailey RL, Dejene M, Shafi O, Kebede B, Negussu N, Mpyet C, Olobio N, Alada J, Abdala M, Willis R, Hayes R, Solomon AW. Estimating the Intracluster Correlation Coefficient for the Clinical Sign "Trachomatous Inflammation-Follicular" in Population-Based Trachoma Prevalence Surveys: Results From a Meta-Regression Analysis of 261 Standardized Preintervention Surveys Carried Out in Ethiopia, Mozambique, and Nigeria. Am J Epidemiol 2020; 189:68-76. [PMID: 31509177 PMCID: PMC7119302 DOI: 10.1093/aje/kwz196] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 09/03/2019] [Indexed: 11/13/2022] Open
Abstract
Sample sizes in cluster surveys must be greater than those in surveys using simple random sampling in order to obtain similarly precise prevalence estimates, because results from subjects examined in the same cluster cannot be assumed to be independent. Therefore, a crucial aspect of cluster sampling is estimation of the intracluster correlation coefficient (ρ): the degree of relatedness of outcomes in a given cluster, defined as the proportion of total variance accounted for by between-cluster variation. In infectious disease epidemiology, this coefficient is related to transmission patterns and the natural history of infection; its value also depends on particulars of survey design. Estimation of ρ is often difficult due to the lack of comparable survey data with which to calculate summary estimates. Here we use a parametric bootstrap model to estimate ρ for the ocular clinical sign “trachomatous inflammation—follicular” (TF) among children aged 1–9 years within population-based trachoma prevalence surveys. We present results from a meta-regression analysis of data from 261 such surveys completed using standardized methods in Ethiopia, Mozambique, and Nigeria in 2012–2015. Consistent with the underlying theory, we found that ρ increased with increasing overall TF prevalence and smaller numbers of children examined per cluster. Estimates of ρ for TF were independently higher in Ethiopia than in the other countries.
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Affiliation(s)
- Colin K Macleod
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin L Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael Dejene
- Michael Dejene Public Health Consultancy Services, Addis Ababa, Ethiopia
| | - Oumer Shafi
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | | | - Caleb Mpyet
- Department of Ophthalmology, Queen Mamohato Memorial Hospital, Maseru, Lesotho
- Sightsavers, Kaduna, Nigeria
- Kilimanjaro Centre for Community Ophthalmology International, Division of Ophthalmology, Groote Schuur Hospital, Cape Town, South Africa
| | - Nicholas Olobio
- National Trachoma Control Program, Department of Public Health, Federal Ministry of Health, Abuja, Nigeria
| | - Joel Alada
- Department of Ophthalmology, Queen Mamohato Memorial Hospital, Maseru, Lesotho
| | - Mariamo Abdala
- Ophthalmology Department, Ministry of Health, Maputo, Mozambique
| | | | - Richard Hayes
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Anthony W Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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5
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Khan AA, Florea VV, Hussain A, Jadoon Z, Boisson S, Willis R, Dejene M, Bakhtiari A, Mpyet C, Pavluck AL, Gillani M, Qureshi B, Solomon AW. Prevalence of Trachoma in Pakistan: Results of 42 Population-Based Prevalence Surveys from the Global Trachoma Mapping Project. Ophthalmic Epidemiol 2020; 27:155-164. [PMID: 31916887 PMCID: PMC7048080 DOI: 10.1080/09286586.2019.1708120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Purpose: Previous phases of trachoma mapping in Pakistan completed baseline surveys in 38 districts. To help guide national trachoma elimination planning, we set out to estimate trachoma prevalence in 43 suspected-endemic evaluation units (EUs) of 15 further districts. Methods: We planned a population-based trachoma prevalence survey in each EU. Two-stage cluster sampling was employed, using the systems and approaches of the Global Trachoma Mapping Project. In each EU, residents aged ≥1 year living in 30 households in each of 26 villages were invited to be examined by trained, certified trachoma graders. Questionnaires and direct observation were used to evaluate household-level access to water and sanitation. Results: One EU was not completed due to insecurity. Of the remaining 42, three EUs had trichiasis prevalence estimates in ≥15-year-olds ≥0.2%, and six (different) EUs had prevalence estimates of trachomatous inflammation—follicular (TF) in 1–9-year-olds ≥5%; each EU requires trichiasis and TF prevalence estimates below these thresholds to achieve elimination of trachoma as a public health problem. All six EUs with TF prevalences ≥5% were in Khyber Pakhtunkhwa Province. Household-level access to improved sanitation ranged by EU from 6% to 100%. Household-level access to an improved source of water for face and hand washing ranged by EU from 37% to 100%. Conclusion: Trachoma was a public health problem in 21% (9/42) of the EUs. Because the current outbreak of extremely drug-resistant typhoid in Pakistan limits domestic use of azithromycin mass drug administration, other interventions against active trachoma should be considered here.
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Affiliation(s)
- Asad Aslam Khan
- Ministry of National Health Services, Regulations and Coordination, Islamabad, Pakistan.,College of Ophthalmology and Allied Vision Sciences, King Edward Medical University, Lahore, Pakistan.,Mayo Hospital, Lahore, Pakistan
| | - Victor V Florea
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Arif Hussain
- College of Ophthalmology and Allied Vision Sciences, King Edward Medical University, Lahore, Pakistan
| | - Zahid Jadoon
- Pakistan Institute of Community Ophthalmology, Hayatabad Medical Complex, Peshawar, Pakistan
| | - Sophie Boisson
- Department of Public Health, The Environment and Social Determinants of Health, World Health Organization, Geneva, Switzerland
| | - Rebecca Willis
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA, USA
| | - Michael Dejene
- Michael Dejene Public Health Consultancy Services, Addis Ababa, Ethiopia
| | - Ana Bakhtiari
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA, USA
| | - Caleb Mpyet
- Department of Ophthalmology, University of Jos, Jos, Nigeria.,Sightsavers, Kaduna, Nigeria.,Kilimanjaro Centre for Community Ophthalmology International, Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
| | - Alexandre L Pavluck
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA, USA
| | | | - Babar Qureshi
- Neglected Tropical Diseases, CBM, Oakington, Cambridge, UK.,Eastern Mediterranean Region Alliance for Trachoma Control, Cairo, Egypt
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland.,Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK.,London Centre for Neglected Tropical Disease Research, London, UK
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Solomon AW, Willis R, Pavluck AL, Alemayehu W, Bakhtiari A, Bovill S, Chu BK, Courtright P, Dejene M, Downs P, Flueckiger RM, Haddad D, Hooper PJ, Kalua K, Kebede B, Kello AB, Macleod CK, McCullagh S, Millar T, Mpyet C, Ngondi J, Nwobi B, Olobio N, Onyebuchi U, Rotondo LA, Sarr B, Shafi O, Sokana O, West SK, Foster A, For The Global Trachoma Mapping Project. Quality Assurance and Quality Control in the Global Trachoma Mapping Project. Am J Trop Med Hyg 2019; 99:858-863. [PMID: 30039782 PMCID: PMC6159583 DOI: 10.4269/ajtmh.18-0082] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In collaboration with the health ministries that we serve and other partners, we set out to complete the multiple-country Global Trachoma Mapping Project. To maximize the accuracy and reliability of its outputs, we needed in-built, practical mechanisms for quality assurance and quality control. This article describes how those mechanisms were created and deployed. Using expert opinion, computer simulation, working groups, field trials, progressively accumulated in-project experience, and external evaluations, we developed 1) criteria for where and where not to undertake population-based prevalence surveys for trachoma; 2) three iterations of a standardized training and certification system for field teams; 3) a customized Android phone–based data collection app; 4) comprehensive support systems; and 5) a secure end-to-end pipeline for data upload, storage, cleaning by objective data managers, analysis, health ministry review and approval, and online display. We are now supporting peer-reviewed publication. Our experience shows that it is possible to quality control and quality assure prevalence surveys in such a way as to maximize comparability of prevalence estimates between countries and permit high-speed, high-fidelity data processing and storage, while protecting the interests of health ministries.
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Affiliation(s)
- Anthony W Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom.,London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | | | | | - Wondu Alemayehu
- Berhan Public Health and Eye Care Consultancy, Addis Adaba, Ethiopia.,The Fred Hollows Foundation Ethiopia, Addis Ababa, Ethiopia
| | | | - Sarah Bovill
- Sightsavers, Haywards Heath, West Sussex, United Kingdom
| | - Brian K Chu
- Task Force for Global Health, Decatur, Georgia
| | - Paul Courtright
- ilimanjaro Centre for Community Ophthalmology, Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
| | - Michael Dejene
- Michael Dejene Public Health Consultancy Services, Addis Ababa, Ethiopia
| | - Philip Downs
- Sightsavers, Haywards Heath, West Sussex, United Kingdom
| | | | - Danny Haddad
- Orbis International, New York, New York.,Emory Eye Center, Atlanta, Georgia
| | - P J Hooper
- Task Force for Global Health, Decatur, Georgia
| | - Khumbo Kalua
- Blantyre Institute for Community Outreach, Blantyre, Malawi
| | | | - Amir Bedri Kello
- Light for the World, Addis Ababa, Ethiopia.,ilimanjaro Centre for Community Ophthalmology, Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
| | | | | | - Tom Millar
- Sightsavers, Haywards Heath, West Sussex, United Kingdom
| | - Caleb Mpyet
- Department of Ophthalmology, Jos University, Jos, Nigeria.,Sightsavers Nigeria, Kaduna, Nigeria.,ilimanjaro Centre for Community Ophthalmology, Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
| | - Jeremiah Ngondi
- RTI International, Washington, District of Columbia.,The Carter Center, Atlanta, Georgia
| | - Benjamin Nwobi
- National Trachoma Control Program, Department of Public Health, Federal Ministry of Health, Abuja, Nigeria
| | - Nicholas Olobio
- National Trachoma Control Program, Department of Public Health, Federal Ministry of Health, Abuja, Nigeria
| | - Uwazoeke Onyebuchi
- National Trachoma Control Program, Department of Public Health, Federal Ministry of Health, Abuja, Nigeria
| | | | - Boubacar Sarr
- Ministère de la Santé et de la Prévention Médicale, Dakar, Senegal
| | - Oumer Shafi
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Oliver Sokana
- Eyecare Department, Ministry of Health, Honiara, Solomon Islands
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, The Wilmer Institute, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Allen Foster
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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7
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Missamou F, Marlhand H, Dzabatou-Babeaux ASP, Sendzi S, Bernasconi J, D'Souza S, Bakhtiari A, Millar T, Willis R, Bengraïne K, Resnikoff S, Solomon AW. A Population-Based Trachoma Prevalence Survey Covering Seven Districts of Sangha and Likouala Departments, Republic of the Congo. Ophthalmic Epidemiol 2019; 25:155-161. [PMID: 30806542 PMCID: PMC6444200 DOI: 10.1080/09286586.2018.1546878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
PURPOSE We set out to estimate the prevalence of trachoma and access to water and sanitation in seven suspected-trachoma-endemic districts of northern Congo, surveyed as a single evaluation unit. METHODS From a complete list of rural villages in the seven districts, we systematically selected 22 with probability proportional to village size. In selected villages, we included all households where there were fewer than 25 in total, or used compact segment sampling to select a group of approximately 20 households by random draw. In each selected household, all consenting residents aged ≥1 year were examined by Global Trachoma Mapping Project-certified trachoma graders, and data collected on household-level access to water and sanitation. RESULTS In November and December 2015, 466 households were visited in 22 villages, and 2081 (88%) of 2377 residents of those households were examined. No examined individual had trichiasis. The age-adjusted prevalence of the active trachoma sign trachomatous inflammation-follicular (TF) in 1-9-year-olds was 2.5% (95%CI 0.9-4.5%). Only 39% (95%CI 35-44%) of households had access to an improved source of drinking water. Only 10% (95%CI 7-13%) of households had access to an improved sanitation facility. CONCLUSION Trachoma is not a public health problem in this part of Congo. Access to water and sanitation is inadequate.
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Affiliation(s)
- François Missamou
- a Directorate-General for the Fight against Communicable Diseases and HIV/AIDS , Ministère de la Santé et de la Population , Brazzaville , Congo
| | - Hemilembolo Marlhand
- a Directorate-General for the Fight against Communicable Diseases and HIV/AIDS , Ministère de la Santé et de la Population , Brazzaville , Congo
| | - Angelie S Patrick Dzabatou-Babeaux
- a Directorate-General for the Fight against Communicable Diseases and HIV/AIDS , Ministère de la Santé et de la Population , Brazzaville , Congo
| | - Samuel Sendzi
- a Directorate-General for the Fight against Communicable Diseases and HIV/AIDS , Ministère de la Santé et de la Population , Brazzaville , Congo
| | | | | | | | | | | | - Karim Bengraïne
- b Organisation pour la prevention de la cécité , Paris , France
| | - Serge Resnikoff
- b Organisation pour la prevention de la cécité , Paris , France
| | - Anthony W Solomon
- e Clinical Research Department , London School of Hygiene & Tropical Medicine , London , UK.,f Department of Control of Neglected Tropical Diseases , World Health Organization , Geneva , Switzerland
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8
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Mwale C, Mumbi W, Funjika M, Sokesi T, Silumesii A, Mulenga M, Mutati G, Kwendakwema D, Chelu C, Adamu Y, Alemayehu W, Al-Khatib T, Bakhtiari A, Dejene M, Massae PA, Mpyet C, Nwosu C, Willis R, Courtright P, Solomon AW. Prevalence of Trachoma in 47 Administrative Districts of Zambia: Results of 32 Population-Based Prevalence Surveys. Ophthalmic Epidemiol 2019; 25:171-180. [PMID: 30806543 PMCID: PMC6444202 DOI: 10.1080/09286586.2018.1546880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Purpose: A number of previous administrative-district-level baseline trachoma prevalence estimates in Zambia required verification. We used methodologies and systems for trachoma surveys considered to represent international best practice in order to generate reliable estimates of the prevalence of trachoma. Methods: Between March 2016 and July 2017, we undertook 32 population-based prevalence surveys covering 47 administrative districts. In each of the 32 evaluation units (EUs), we selected 31 households in each of 24 clusters. In selected households, trained, certified graders examined all residents aged 1 year and above for evidence of trachomatous inflammation—follicular (TF) and trichiasis. In eyes that had trichiasis, the presence or absence of trachomatous scarring (TS) was recorded, and the subject was asked about previous trichiasis management recommendations from health workers. Results: Five EUs (encompassing seven administrative districts) had prevalence estimates of trichiasis+TS unknown to the health system in ≥15-year-olds of ≥0.2%, and require public-health-level implementation of trichiasis surgery services. Eleven EUs (encompassing 16 administrative districts) had TF prevalence estimates in 1–9-year-olds of ≥5%. Intervention with the A, F and E components of the SAFE strategy for trachoma elimination is required for nearly 1.5 million people. Conclusion: Trachoma is a public health problem in some parts of Zambia. The Ministry of Health will continue to partner with other stakeholders to implement the multi-sectoral SAFE strategy. Consideration should be given to re-surveying other suspected-endemic administrative districts in which surveys using older methodologies returned TF prevalence estimates ≥5%.
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Affiliation(s)
- Consity Mwale
- a Lusaka Provincial Health Office , Lusaka , Zambia.,b University Teaching Eye Hospital , Lusaka , Zambia
| | - Willard Mumbi
- c Ophthalmology Unit , Kabwe General Hospital , Kabwe , Zambia
| | - Misa Funjika
- d Ophthalmology Unit , Ndola Teaching Hospital , Ndola , Zambia
| | - Teddy Sokesi
- d Ophthalmology Unit , Ndola Teaching Hospital , Ndola , Zambia
| | | | - Muma Mulenga
- b University Teaching Eye Hospital , Lusaka , Zambia
| | - Grace Mutati
- b University Teaching Eye Hospital , Lusaka , Zambia
| | | | | | - Yilikal Adamu
- g Department of Ophthalmology, Faculty of Medicine , Addis Ababa University , Addis Ababa , Ethiopia
| | - Wondu Alemayehu
- h The Fred Hollows Foundation , Addis Ababa , Ethiopia.,i Berhan Public Health and Eye Care Consultancy , Addis Ababa , Ethiopia
| | - Tawfik Al-Khatib
- j Prevention of Blindness Program , Ministry of Public Health & Population , Sana'a , Yemen.,k Department of Ophthalmology, College of Medicine , University of Sana'a , Sana'a , Yemen.,l Eye Unit , Al-Thawra Hospital , Sana'a , Yemen
| | | | - Michael Dejene
- n Michael Dejene Public Health Consultancy Services , Addis Ababa , Ethiopia
| | | | - Caleb Mpyet
- p Department of Ophthalmology , University of Jos , Jos , Nigeria.,q Sightsavers , Kaduna , Nigeria.,r Kilimanjaro Centre for Community Ophthalmology International, Division of Ophthalmology , University of Cape Town , Cape Town , South Africa
| | | | | | - Paul Courtright
- r Kilimanjaro Centre for Community Ophthalmology International, Division of Ophthalmology , University of Cape Town , Cape Town , South Africa
| | - Anthony W Solomon
- s Clinical Research Department , London School of Hygiene & Tropical Medicine , London , UK.,t Department of Control of Neglected Tropical Diseases , World Health Organization , Geneva , Switzerland
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9
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Engelman D, Cantey PT, Marks M, Solomon AW, Chang AY, Chosidow O, Enbiale W, Engels D, Hay RJ, Hendrickx D, Hotez PJ, Kaldor JM, Kama M, Mackenzie CD, McCarthy JS, Martin DL, Mengistu B, Maurer T, Negussu N, Romani L, Sokana O, Whitfeld MJ, Fuller LC, Steer AC. The public health control of scabies: priorities for research and action. Lancet 2019; 394:81-92. [PMID: 31178154 PMCID: PMC11257500 DOI: 10.1016/s0140-6736(19)31136-5] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/14/2019] [Accepted: 04/25/2019] [Indexed: 12/16/2022]
Abstract
Scabies is a parasitic disease of the skin that disproportionately affects disadvantaged populations. The disease causes considerable morbidity and leads to severe bacterial infection and immune-mediated disease. Scientific advances from the past 5 years suggest that scabies is amenable to population-level control, particularly through mass drug administration. In recognition of these issues, WHO added scabies to the list of neglected tropical diseases in 2017. To develop a global control programme, key operational research questions must now be addressed. Standardised approaches to diagnosis and methods for mapping are required to further understand the burden of disease. The safety of treatments for young children, including with ivermectin and moxidectin, should be investigated. Studies are needed to inform optimum implementation of mass treatment, including the threshold for intervention, target, dosing, and frequency. Frameworks for surveillance, monitoring, and evaluation of control strategies are also necessary.
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Affiliation(s)
- Daniel Engelman
- Tropical Diseases Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia; Department of General Medicine, Royal Children's Hospital, Melbourne, VIC, Australia.
| | - Paul T Cantey
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Michael Marks
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Aileen Y Chang
- Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
| | - Olivier Chosidow
- Department of Dermatology, Hôpital Henri-Mondor, Assistance Publique Hôpitaux de Paris, Créteil, France; Université Paris-Est Créteil Val-de-Marne, Créteil, France
| | - Wendemagegn Enbiale
- Department of Dermatovenerology, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Dirk Engels
- Uniting to Combat Neglected Tropical Diseases, Switzerland
| | - Roderick J Hay
- Department of Dermatology, King's College London, London, UK
| | - David Hendrickx
- Telethon Kids Institute, University of Western Australia, Perth, WA, Australia
| | - Peter J Hotez
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
| | - John M Kaldor
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Mike Kama
- Ministry of Health and Medical Services, Suva, Fiji
| | | | - James S McCarthy
- QIMR Berghoefer Medical Research Institute, Brisbane, QLD, Australia
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Toby Maurer
- Department of Dermatology, University of California San Francisco, San Francisco, CA, USA
| | | | - Lucia Romani
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Oliver Sokana
- Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Margot J Whitfeld
- Department of Dermatology, St Vincent's Hospital, University of New South Wales, Sydney, NSW, Australia
| | - L Claire Fuller
- Chelsea and Westminster Healthcare National Health Service Foundation Trust, London, UK; International Foundation for Dermatology, London, UK
| | - Andrew C Steer
- Tropical Diseases Group, Murdoch Children's Research Institute, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia; Department of General Medicine, Royal Children's Hospital, Melbourne, VIC, Australia
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10
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Ali Thabit A, Al-Khatib T, Hail WHM, Al-Soofi A, Abdullah Thabit NA, Boather J, Abdullah A, Flueckiger RM, Pavluck AL, Willis R, Courtright P, Macleod CK, Solomon AW. Prevalence of trachoma in Yemen: results of population-based prevalence surveys of 42 evaluation units in nine governorates. Ophthalmic Epidemiol 2019; 25:62-69. [PMID: 30806535 PMCID: PMC6444195 DOI: 10.1080/09286586.2018.1441426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Purpose: In suspected trachoma-endemic areas of Yemen, we sought to determine the prevalence of the sign trachomatous inflammation—follicular (TF) in children aged 1–9 years, and the potential individual and household risk factors for TF in that age group. We also sought to determine the prevalence of trichiasis in adults aged ≥15 years. Methods: We conducted a cluster-sampled survey in each of 42 evaluation units (EUs) comprising 166 rural districts of nine Governorates (Adh Dhale’a, Al Hodeihah, Al Jawf, Hadramoot, Hajjah, Ibb, Lahj, Ma’rib, Taiz) using the Global Trachoma Mapping Project systems and methodologies. Fieldwork was undertaken from September 2013 to March 2015. Risk factors for TF in children aged 1–9 years were evaluated using multilevel random effects logistic regression. Results: The TF prevalence in children aged 1–9 years was ≥10% in two EUs (7 districts) and 5–9.9% in six EUs (24 districts). In adults aged ≥15 years, trichiasis prevalence was ≥0.2% in five EUs (19 districts). Being older (within the 1–9-year age bracket), being male, living in a household with higher numbers of children, and living in a household that reported the use of open defecation, were each independently associated with higher odds of TF. Conclusions: These surveys provided baseline data to enable planning for trachoma elimination. The World Health Organization Alliance for the Global Elimination of Trachoma by 2020 stands ready to assist Yemen once security considerations permit further surveys and implementation of control activities.
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Affiliation(s)
- Adnan Ali Thabit
- a Prevention of Blindness Program , Ministry of Public Health & Population , Sana'a , Yemen.,b Department of Ophthalmology, College of Medicine , University of Sana'a , Sana'a , Yemen.,c Eye Unit , Kuwait University Teaching Hospital , Sana'a , Yemen
| | - Tawfik Al-Khatib
- a Prevention of Blindness Program , Ministry of Public Health & Population , Sana'a , Yemen.,b Department of Ophthalmology, College of Medicine , University of Sana'a , Sana'a , Yemen.,d Eye Unit , Al-Thawra Hospital , Sana'a , Yemen
| | | | - Ahmed Al-Soofi
- e World Health Organization Country Office , Sana'a , Yemen
| | | | - Jamal Boather
- f Ministry of Public Health & Population , Sana'a , Yemen
| | | | | | | | | | - Paul Courtright
- h Kilimanjaro Centre for Community Ophthalmology, Division of Ophthalmology , University of Cape Town , Cape Town , South Africa
| | - Colin K Macleod
- i Clinical Research Department , London School of Hygiene & Tropical Medicine , London , UK
| | - Anthony W Solomon
- i Clinical Research Department , London School of Hygiene & Tropical Medicine , London , UK.,j London Centre for Neglected Tropical Diseases Research , London , UK.,k Department of Control of Neglected Tropical Diseases , World Health Organization , Geneva , Switzerland
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11
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Last A, Burr S, Alexander N, Harding-Esch E, Roberts CH, Nabicassa M, Cassama ETDS, Mabey D, Holland M, Bailey R. Spatial clustering of high load ocular Chlamydia trachomatis infection in trachoma: a cross-sectional population-based study. Pathog Dis 2018; 75:3791466. [PMID: 28472466 PMCID: PMC5808645 DOI: 10.1093/femspd/ftx050] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 05/02/2017] [Indexed: 11/12/2022] Open
Abstract
Chlamydia trachomatis (Ct) is the most common cause of bacterial sexually transmitted infection and infectious cause of blindness (trachoma) worldwide. Understanding the spatial distribution of Ct infection may enable us to identify populations at risk and improve our understanding of Ct transmission. In this study, we sought to investigate the spatial distribution of Ct infection and the clinical features associated with high Ct load in trachoma-endemic communities on the Bijagós Archipelago (Guinea Bissau). We collected 1507 conjunctival samples and corresponding detailed clinical data during a cross-sectional population-based geospatially representative trachoma survey. We used droplet digital PCR to estimate Ct load on conjunctival swabs. Geostatistical tools were used to investigate clustering of ocular Ct infections. Spatial clusters (independent of age and gender) of individuals with high Ct loads were identified using local indicators of spatial association. We did not detect clustering of individuals with low load infections. These data suggest that infections with high bacterial load may be important in Ct transmission. These geospatial tools may be useful in the study of ocular Ct transmission dynamics and as part of trachoma surveillance post-treatment, to identify clusters of infection and thresholds of Ct load that may be important foci of re-emergent infection in communities.
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Affiliation(s)
- Anna Last
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Sarah Burr
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia, PO Box 273 Banjul, Atlantic Boulevard, Fajara, The Gambia
| | - Neal Alexander
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Emma Harding-Esch
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Chrissy H Roberts
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Meno Nabicassa
- Programa Nacional de Saúde de Visão, Ministério de Saúde Publica, PO Box 50, Avenida de Unidade Africana, Bisssau, Guiné Bissau
| | | | - David Mabey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Martin Holland
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Robin Bailey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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12
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Elshafie BE, Osman KH, Macleod C, Hassan A, Bush S, Dejene M, Willis R, Chu B, Courtright P, Solomon AW. The Epidemiology of Trachoma in Darfur States and Khartoum State, Sudan: Results of 32 Population-Based Prevalence Surveys. Ophthalmic Epidemiol 2017; 23:381-391. [PMID: 27841721 PMCID: PMC5297557 DOI: 10.1080/09286586.2016.1243718] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Purpose: To complete the baseline trachoma map of Sudan by estimating the prevalence of trachoma and associated risk factors in the five Darfur States and Khartoum State. Methods: Using a standardized methodology developed for the Global Trachoma Mapping Project, we undertook a cross sectional, community-based survey in each of 32 evaluation units (EUs) covering all accessible districts. Results: We enumerated a total of 84,568 individuals, with 73,489 people (86.9%) examined from 20,242 households in 908 villages. The highest prevalence of trachomatous inflammation – follicular (TF) in children was found in El Fashir district (18.7%), and the lowest in El Malha district (0.0%). Five districts (El Fashir, Zalinji, Azoom, Maleet, and El Koma) were in the three EUs that had TF prevalences above the 10% threshold at which the World Health Organization recommends mass treatment with azithromycin, together with facial clean3liness and environmental improvement interventions, for at least 3 years. The highest trachomatous trichiasis prevalence in adults was found in the EU composed of Forbranga and Habillah (1.2%), and the lowest in the EU composed of As-salam and Belale districts in South Darfur (0.0%). TF in children was independently associated with younger age, unimproved sanitation in the household, having ≥5 children in the household, outside annual maximum temperatures <40°C, and living in an internally displaced persons camp. Conclusion: We found a high prevalence of trachoma in some areas of Darfur, but in general the prevalence throughout Darfur and Khartoum was low.
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Affiliation(s)
| | - Kamal Hashim Osman
- a National Program for Prevention of Blindness , Federal Ministry of Health , Khartoum , Sudan.,b Department of Ophthalmology , Al Neelain University , Khartoum , Sudan
| | - Colin Macleod
- c Clinical Research Department , London School of Hygiene & Tropical Medicine , London , UK.,d Sightsavers, Haywards Heath , UK
| | | | | | - Michael Dejene
- f Michael Dejene Public Health Consultancy Services , Addis Ababa , Ethiopia
| | | | - Brian Chu
- g Task Force for Global Health , Decatur , GA , USA
| | - Paul Courtright
- h KCCO International, Division of Ophthalmology , University of Cape Town , South Africa
| | - Anthony W Solomon
- c Clinical Research Department , London School of Hygiene & Tropical Medicine , London , UK.,i Department of Control of Neglected Tropical Diseases , World Health Organization , Geneva , Switzerland
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13
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Knowles SCL, Sturrock HJW, Turner H, Whitton JM, Gower CM, Jemu S, Phillips AE, Meite A, Thomas B, Kollie K, Thomas C, Rebollo MP, Styles B, Clements M, Fenwick A, Harrison WE, Fleming FM. Optimising cluster survey design for planning schistosomiasis preventive chemotherapy. PLoS Negl Trop Dis 2017; 11:e0005599. [PMID: 28552961 PMCID: PMC5464666 DOI: 10.1371/journal.pntd.0005599] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 06/08/2017] [Accepted: 04/26/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The cornerstone of current schistosomiasis control programmes is delivery of praziquantel to at-risk populations. Such preventive chemotherapy requires accurate information on the geographic distribution of infection, yet the performance of alternative survey designs for estimating prevalence and converting this into treatment decisions has not been thoroughly evaluated. METHODOLOGY/PRINCIPAL FINDINGS We used baseline schistosomiasis mapping surveys from three countries (Malawi, Côte d'Ivoire and Liberia) to generate spatially realistic gold standard datasets, against which we tested alternative two-stage cluster survey designs. We assessed how sampling different numbers of schools per district (2-20) and children per school (10-50) influences the accuracy of prevalence estimates and treatment class assignment, and we compared survey cost-efficiency using data from Malawi. Due to the focal nature of schistosomiasis, up to 53% simulated surveys involving 2-5 schools per district failed to detect schistosomiasis in low endemicity areas (1-10% prevalence). Increasing the number of schools surveyed per district improved treatment class assignment far more than increasing the number of children sampled per school. For Malawi, surveys of 15 schools per district and 20-30 children per school reliably detected endemic schistosomiasis and maximised cost-efficiency. In sensitivity analyses where treatment costs and the country considered were varied, optimal survey size was remarkably consistent, with cost-efficiency maximised at 15-20 schools per district. CONCLUSIONS/SIGNIFICANCE Among two-stage cluster surveys for schistosomiasis, our simulations indicated that surveying 15-20 schools per district and 20-30 children per school optimised cost-efficiency and minimised the risk of under-treatment, with surveys involving more schools of greater cost-efficiency as treatment costs rose.
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Affiliation(s)
- Sarah C. L. Knowles
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- * E-mail:
| | - Hugh J. W. Sturrock
- Global Health Group, University of California San Francisco, San Francisco, California, United States of America
| | - Hugo Turner
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
| | - Jane M. Whitton
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Charlotte M. Gower
- The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
| | - Samuel Jemu
- Ministry of Health, Capital City, Lilongwe 3, Malawi
| | - Anna E. Phillips
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Aboulaye Meite
- Ministry of Health and Social Welfare of Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Brent Thomas
- Fliarial Programme Support Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Karsor Kollie
- Neglected Tropical and Non Communicable Diseases Program, Ministry of Health and Social Welfare, Monrovia 10, Liberia
| | - Catherine Thomas
- Neglected Tropical and Non Communicable Diseases Program, Ministry of Health and Social Welfare, Monrovia 10, Liberia
| | - Maria P. Rebollo
- Fliarial Programme Support Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Ben Styles
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- National Foundation for Educational Research, Upton Park, Slough, United Kingdom
| | - Michelle Clements
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Wendy E. Harrison
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Fiona M. Fleming
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, Norfolk Place, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
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14
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Solomon AW, Pavluck AL, Courtright P, Aboe A, Adamu L, Alemayehu W, Alemu M, Alexander NDE, Kello AB, Bero B, Brooker SJ, Chu BK, Dejene M, Emerson PM, Flueckiger RM, Gadisa S, Gass K, Gebre T, Habtamu Z, Harvey E, Haslam D, King JD, Mesurier RL, Lewallen S, Lietman TM, MacArthur C, Mariotti SP, Massey A, Mathieu E, Mekasha A, Millar T, Mpyet C, Muñoz BE, Ngondi J, Ogden S, Pearce J, Sarah V, Sisay A, Smith JL, Taylor HR, Thomson J, West SK, Willis R, Bush S, Haddad D, Foster A. The Global Trachoma Mapping Project: Methodology of a 34-Country Population-Based Study. Ophthalmic Epidemiol 2016; 22:214-25. [PMID: 26158580 PMCID: PMC4687001 DOI: 10.3109/09286586.2015.1037401] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Purpose: To complete the baseline trachoma map worldwide by conducting population-based surveys in an estimated 1238 suspected endemic districts of 34 countries. Methods: A series of national and sub-national projects owned, managed and staffed by ministries of health, conduct house-to-house cluster random sample surveys in evaluation units, which generally correspond to “health district” size: populations of 100,000–250,000 people. In each evaluation unit, we invite all residents aged 1 year and older from h households in each of c clusters to be examined for clinical signs of trachoma, where h is the number of households that can be seen by 1 team in 1 day, and the product h × c is calculated to facilitate recruitment of 1019 children aged 1–9 years. In addition to individual-level demographic and clinical data, household-level water, sanitation and hygiene data are entered into the purpose-built LINKS application on Android smartphones, transmitted to the Cloud, and cleaned, analyzed and ministry-of-health-approved via a secure web-based portal. The main outcome measures are the evaluation unit-level prevalence of follicular trachoma in children aged 1–9 years, prevalence of trachomatous trichiasis in adults aged 15 + years, percentage of households using safe methods for disposal of human feces, and percentage of households with proximate access to water for personal hygiene purposes. Results: In the first year of fieldwork, 347 field teams commenced work in 21 projects in 7 countries. Conclusion: With an approach that is innovative in design and scale, we aim to complete baseline mapping of trachoma throughout the world in 2015.
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Affiliation(s)
- Anthony W Solomon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine , London , UK
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15
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Smith JL, Sturrock HJW, Assefa L, Nikolay B, Njenga SM, Kihara J, Mwandawiro CS, Brooker SJ. Factors associated with the performance and cost-effectiveness of using lymphatic filariasis transmission assessment surveys for monitoring soil-transmitted helminths: a case study in Kenya. Am J Trop Med Hyg 2015; 92:342-353. [PMID: 25487730 PMCID: PMC4347340 DOI: 10.4269/ajtmh.14-0435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/06/2014] [Indexed: 01/24/2023] Open
Abstract
Transmission assessment surveys (TAS) for lymphatic filariasis have been proposed as a platform to assess the impact of mass drug administration (MDA) on soil-transmitted helminths (STHs). This study used computer simulation and field data from pre- and post-MDA settings across Kenya to evaluate the performance and cost-effectiveness of the TAS design for STH assessment compared with alternative survey designs. Variations in the TAS design and different sample sizes and diagnostic methods were also evaluated. The district-level TAS design correctly classified more districts compared with standard STH designs in pre-MDA settings. Aggregating districts into larger evaluation units in a TAS design decreased performance, whereas age group sampled and sample size had minimal impact. The low diagnostic sensitivity of Kato-Katz and mini-FLOTAC methods was found to increase misclassification. We recommend using a district-level TAS among children 8-10 years of age to assess STH but suggest that key consideration is given to evaluation unit size.
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Affiliation(s)
- Jennifer L. Smith
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Global Health Group, University of California San Francisco, San Francisco, California; Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
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16
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Assefa LM, Crellen T, Kepha S, Kihara JH, Njenga SM, Pullan RL, Brooker SJ. Diagnostic accuracy and cost-effectiveness of alternative methods for detection of soil-transmitted helminths in a post-treatment setting in western Kenya. PLoS Negl Trop Dis 2014; 8:e2843. [PMID: 24810593 PMCID: PMC4014443 DOI: 10.1371/journal.pntd.0002843] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/22/2014] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES This study evaluates the diagnostic accuracy and cost-effectiveness of the Kato-Katz and Mini-FLOTAC methods for detection of soil-transmitted helminths (STH) in a post-treatment setting in western Kenya. A cost analysis also explores the cost implications of collecting samples during school surveys when compared to household surveys. METHODS Stool samples were collected from children (n = 652) attending 18 schools in Bungoma County and diagnosed by the Kato-Katz and Mini-FLOTAC coprological methods. Sensitivity and additional diagnostic performance measures were analyzed using Bayesian latent class modeling. Financial and economic costs were calculated for all survey and diagnostic activities, and cost per child tested, cost per case detected and cost per STH infection correctly classified were estimated. A sensitivity analysis was conducted to assess the impact of various survey parameters on cost estimates. RESULTS Both diagnostic methods exhibited comparable sensitivity for detection of any STH species over single and consecutive day sampling: 52.0% for single day Kato-Katz; 49.1% for single-day Mini-FLOTAC; 76.9% for consecutive day Kato-Katz; and 74.1% for consecutive day Mini-FLOTAC. Diagnostic performance did not differ significantly between methods for the different STH species. Use of Kato-Katz with school-based sampling was the lowest cost scenario for cost per child tested ($10.14) and cost per case correctly classified ($12.84). Cost per case detected was lowest for Kato-Katz used in community-based sampling ($128.24). Sensitivity analysis revealed the cost of case detection for any STH decreased non-linearly as prevalence rates increased and was influenced by the number of samples collected. CONCLUSIONS The Kato-Katz method was comparable in diagnostic sensitivity to the Mini-FLOTAC method, but afforded greater cost-effectiveness. Future work is required to evaluate the cost-effectiveness of STH surveillance in different settings.
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Affiliation(s)
- Liya M. Assefa
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Thomas Crellen
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Stella Kepha
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Jimmy H. Kihara
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Sammy M. Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Rachel L. Pullan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Simon J. Brooker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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