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Rajaonarifara E, Roche B, Chesnais CB, Rabenantoandro H, Evans M, Garchitorena A. Heterogeneity in elimination efforts could increase the risk of resurgence of lymphatic filariasis in Madagascar. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 120:105589. [PMID: 38548211 DOI: 10.1016/j.meegid.2024.105589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/02/2024]
Abstract
BACKGROUND Progress in lymphatic filariasis (LF) elimination is spatially heterogeneous in many endemic countries, which may lead to resurgence in areas that have achieved elimination. Understanding the drivers and consequences of such heterogeneity could help inform strategies to reach global LF elimination goals by 2030. This study assesses whether differences in age-specific compliance with mass drug administration (MDA) could explain LF prevalence patterns in southeastern Madagascar and explores how spatial heterogeneity in prevalence and age-specific MDA compliance may affect the risk of LF resurgence after transmission interruption. METHODOLOGY We used LYMFASIM model with parameters in line with the context of southeastern Madagascar and explored a wide range of scenarios with different MDA compliance for adults and children (40-100%) to estimate the proportion of elimination, non-elimination and resurgence events associated with each scenario. Finally, we evaluated the risk of resurgence associated with different levels of migration (2-6%) from surrounding districts combined with varying levels of LF microfilaria (mf) prevalence (0-24%) during that same study period. RESULTS Differences in MDA compliance between adults and children better explained the observed heterogeneity in LF prevalence for these age groups than differences in exposure alone. The risk of resurgence associated with differences in MDA compliance scenarios ranged from 0 to 19% and was highest when compliance was high for children (e.g. 90%) and low for adults (e.g. 50%). The risk of resurgence associated with migration was generally higher, exceeding 60% risk for all the migration levels explored (2-6% per year) when mf prevalence in the source districts was between 9% and 20%. CONCLUSION Gaps in the implementation of LF elimination programme can increase the risk of resurgence and undermine elimination efforts. In Madagascar, districts that have not attained elimination pose a significant risk for those that have achieved it. More research is needed to help guide LF elimination programme on the optimal strategies for surveillance and control that maximize the chances to sustain elimination and avoid resurgence.
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Affiliation(s)
- Elinambinina Rajaonarifara
- UMR 224 MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France; NGO Pivot, Ifanadiana, Madagascar; Sciences & Ingénierie, Sorbonne Université, Paris, France.
| | - Benjamin Roche
- UMR 224 MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | | | - Holivololona Rabenantoandro
- Service de Lutte contre les Maladies Epidémiques et Négligées - Ministère de la Santé Publique, Antananarivo, Madagascar
| | - Michelle Evans
- NGO Pivot, Ifanadiana, Madagascar; Departement of Global Health and Social Medicine, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | - Andres Garchitorena
- UMR 224 MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France; NGO Pivot, Ifanadiana, Madagascar
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Shaw C, McLure A, Graves PM, Lau CL, Glass K. Lymphatic filariasis endgame strategies: Using GEOFIL to model mass drug administration and targeted surveillance and treatment strategies in American Samoa. PLoS Negl Trop Dis 2023; 17:e0011347. [PMID: 37200375 DOI: 10.1371/journal.pntd.0011347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 05/31/2023] [Accepted: 04/29/2023] [Indexed: 05/20/2023] Open
Abstract
American Samoa underwent seven rounds of mass drug administration (MDA) for lymphatic filariasis (LF) from 2000-2006, but subsequent surveys found evidence of ongoing transmission. American Samoa has since undergone further rounds of MDA in 2018, 2019, and 2021; however, recent surveys indicate that transmission is still ongoing. GEOFIL, a spatially-explicit agent-based LF model, was used to compare the effectiveness of territory-wide triple-drug MDA (3D-MDA) with targeted surveillance and treatment strategies. Both approaches relied on treatment with ivermectin, diethylcarbamazine, and albendazole. We simulated three levels of whole population coverage for 3D-MDA: 65%, 73%, and 85%, while the targeted strategies relied on surveillance in schools, workplaces, and households, followed by targeted treatment. In the household-based strategies, we simulated 1-5 teams travelling village-to-village and offering antigen (Ag) testing to randomly selected households in each village. If an Ag-positive person was identified, treatment was offered to members of all households within 100m-1km of the positive case. All simulated interventions were finished by 2027 and their effectiveness was judged by their 'control probability'-the proportion of simulations in which microfilariae prevalence decreased between 2030 and 2035. Without future intervention, we predict Ag prevalence will rebound. With 3D-MDA, a 90% control probability required an estimated ≥ 4 further rounds with 65% coverage, ≥ 3 rounds with 73% coverage, or ≥ 2 rounds with 85% coverage. While household-based strategies were substantially more testing-intensive than 3D-MDA, they could offer comparable control probabilities with substantially fewer treatments; e.g. three teams aiming to test 50% of households and offering treatment to a 500m radius had approximately the same control probability as three rounds of 73% 3D-MDA, but used < 40% the number of treatments. School- and workplace-based interventions proved ineffective. Regardless of strategy, reducing Ag prevalence below the 1% target threshold recommended by the World Health Organization was a poor indicator of the interruption of LF transmission, highlighting the need to review blanket elimination targets.
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Affiliation(s)
- Callum Shaw
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia
| | - Angus McLure
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia
| | - Patricia M Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, Queensland, Australia
| | - Colleen L Lau
- School of Public Health, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia
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McLure A, Graves PM, Lau C, Shaw C, Glass K. Modelling lymphatic filariasis elimination in American Samoa: GEOFIL predicts need for new targets and six rounds of mass drug administration. Epidemics 2022; 40:100591. [DOI: 10.1016/j.epidem.2022.100591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 06/07/2022] [Accepted: 06/07/2022] [Indexed: 11/03/2022] Open
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Graves PM, Joseph H, Coutts SP, Mayfield HJ, Maiava F, Ah Leong-Lui TA, Tupuimatagi Toelupe P, Toeaso Iosia V, Loau S, Pemita P, Naseri T, Thomsen R, Berg Soto A, Burkot TR, Wood P, Melrose W, Aratchige P, Capuano C, Kim SH, Ozaki M, Yajima A, Lammie PJ, Ottesen E, Hansell L, Baghirov R, Lau CL, Ichimori K. Control and elimination of lymphatic filariasis in Oceania: Prevalence, geographical distribution, mass drug administration, and surveillance in Samoa, 1998-2017. ADVANCES IN PARASITOLOGY 2021; 114:27-73. [PMID: 34696844 DOI: 10.1016/bs.apar.2021.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Lymphatic filariasis (LF) is a major public health problem globally and in the Pacific Region. The Global Programme to Eliminate LF has made great progress but LF is persistent and resurgent in some Pacific countries and territories. Samoa remains endemic for LF despite elimination efforts through multiple two-drug mass drug administrations (MDA) since 1965, including renewed elimination efforts started in 1999 under the Pacific Programme for Elimination of LF (PacELF). Despite eight rounds of national and two rounds of subnational MDA under PacELF, Samoa failed transmission assessment surveys (TAS) in all three evaluation units in 2017. In 2018, Samoa was the first to distribute countrywide triple-drug MDA using ivermectin, diethylcarbamazine (DEC), and albendazole. This paper provides a review of MDAs and historical survey results from 1998 to 2017 in Samoa and highlights lessons learnt from LF elimination efforts, including challenges and potential ways to overcome them to successfully achieve elimination.
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Affiliation(s)
- Patricia M Graves
- College of Public Health, Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, and JCU WHO Collaborating Centre for Vector-Borne and Neglected Tropical Diseases, James Cook University, Cairns and Townsville, QLD, Australia.
| | - Hayley Joseph
- Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research and Department of Medical Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Shaun P Coutts
- Research School of Population Health, ANU College of Health and Medicine, The Australian National University, Canberra, ACT, Australia
| | - Helen J Mayfield
- School of Public Health, University of Queensland, Brisbane, QLD, Australia
| | | | | | | | | | - Siatua Loau
- Ministry of Health and Health Services, Apia, Samoa
| | - Paulo Pemita
- Ministry of Health and Health Services, Apia, Samoa
| | - Take Naseri
- Ministry of Health and Health Services, Apia, Samoa
| | | | - Alvaro Berg Soto
- College of Public Health, Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, and JCU WHO Collaborating Centre for Vector-Borne and Neglected Tropical Diseases, James Cook University, Cairns and Townsville, QLD, Australia
| | - Thomas R Burkot
- College of Public Health, Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, and JCU WHO Collaborating Centre for Vector-Borne and Neglected Tropical Diseases, James Cook University, Cairns and Townsville, QLD, Australia
| | - Peter Wood
- College of Public Health, Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, and JCU WHO Collaborating Centre for Vector-Borne and Neglected Tropical Diseases, James Cook University, Cairns and Townsville, QLD, Australia
| | - Wayne Melrose
- College of Public Health, Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, and JCU WHO Collaborating Centre for Vector-Borne and Neglected Tropical Diseases, James Cook University, Cairns and Townsville, QLD, Australia
| | | | | | - Sung Hye Kim
- WHO Division of Pacific Technical Support, Suva, Fiji
| | - Masayo Ozaki
- WHO Division of Pacific Technical Support, Suva, Fiji
| | - Aya Yajima
- WHO Regional Office for the Western Pacific, Manila, Philippines
| | | | - Eric Ottesen
- Task Force for Global Health, Atlanta, GA, United States
| | | | | | - Colleen L Lau
- Research School of Population Health, ANU College of Health and Medicine, The Australian National University, Canberra, ACT, Australia; School of Public Health, University of Queensland, Brisbane, QLD, Australia
| | - Kazuyo Ichimori
- College of Public Health, Medical and Veterinary Sciences, Australian Institute of Tropical Health and Medicine, and JCU WHO Collaborating Centre for Vector-Borne and Neglected Tropical Diseases, James Cook University, Cairns and Townsville, QLD, Australia
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Chakraborti S, Maiti A, Pramanik S, Sannigrahi S, Pilla F, Banerjee A, Das DN. Evaluating the plausible application of advanced machine learnings in exploring determinant factors of present pandemic: A case for continent specific COVID-19 analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:142723. [PMID: 33077215 PMCID: PMC7537593 DOI: 10.1016/j.scitotenv.2020.142723] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 05/21/2023]
Abstract
Coronavirus disease, a novel severe acute respiratory syndrome (SARS COVID-19), has become a global health concern due to its unpredictable nature and lack of adequate medicines. Machine Learning (ML) models could be effective in identifying the most critical factors which are responsible for the overall fatalities caused by COVID-19. The functional capabilities of ML models in epidemiological research, especially for COVID-19, are not substantially explored. To bridge this gap, this study has adopted two advanced ML models, viz. Random Forest (RF) and Gradient Boosted Machine (GBM), to perform the regression modelling and provide subsequent interpretation. Five successive steps were followed to carry out the analysis: (1) identification of relevant key explanatory variables; (2) application of data dimensionality reduction for eliminating redundant information; (3) utilizing ML models for measuring relative influence (RI) of the explanatory variables; (4) evaluating interconnections between and among the key explanatory variables and COVID-19 case and death counts; (5) time series analysis for examining the rate of incidences of COVID-19 cases and deaths. Among the explanatory variables considered in this study, air pollution, migration, economy, and demographic factor were found to be the most significant controlling factors. Since a very limited research is available to discuss the superiority of ML models for identifying the key determinants of COVID-19, this study could be a reference for future public health research. Additionally, all the models and data used in this study are open source and freely available, thereby, reproducibility and scientific replication will be achievable easily.
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Affiliation(s)
- Suman Chakraborti
- Center for the Study of Regional Development, Jawaharlal Nehru University, New Delhi, Delhi 110067, India.
| | - Arabinda Maiti
- Geography and Environment Management, Vidyasagar University, West Bengal, India.
| | - Suvamoy Pramanik
- Center for the Study of Regional Development, Jawaharlal Nehru University, New Delhi, Delhi 110067, India.
| | - Srikanta Sannigrahi
- School of Architecture, Planning and Environmental Policy, University College Dublin Richview, Clonskeagh, Dublin D14 E099, Ireland.
| | - Francesco Pilla
- School of Architecture, Planning and Environmental Policy, University College Dublin Richview, Clonskeagh, Dublin D14 E099, Ireland.
| | - Anushna Banerjee
- Center for the Study of Regional Development, Jawaharlal Nehru University, New Delhi, Delhi 110067, India
| | - Dipendra Nath Das
- Center for the Study of Regional Development, Jawaharlal Nehru University, New Delhi, Delhi 110067, India
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Potential strategies for strengthening surveillance of lymphatic filariasis in American Samoa after mass drug administration: Reducing 'number needed to test' by targeting older age groups, hotspots, and household members of infected persons. PLoS Negl Trop Dis 2020; 14:e0008916. [PMID: 33370264 PMCID: PMC7872281 DOI: 10.1371/journal.pntd.0008916] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 02/09/2021] [Accepted: 10/26/2020] [Indexed: 12/12/2022] Open
Abstract
Under the Global Programme to Eliminate Lymphatic Filariasis (LF), American Samoa conducted mass drug administration (MDA) from 2000-2006. Despite passing Transmission Assessment Surveys (TAS) in 2011/2012 and 2015, American Samoa failed TAS-3 in 2016, with antigen (Ag) prevalence of 0.7% (95%CI 0.3-1.8%) in 6-7 year-olds. A 2016 community survey (Ag prevalence 6.2% (95%CI 4.4-8.5%) in age ≥8 years) confirmed resurgence. Using data from the 2016 survey, this study aims to i) investigate antibody prevalence in TAS-3 and the community survey, ii) identify risk factors associated with being seropositive for Ag and anti-filarial antibodies, and iii) compare the efficiency of different sampling strategies for identifying seropositive persons in the post-MDA setting. Antibody prevalence in TAS-3 (n = 1143) were 1.6% for Bm14 (95%CI 0.9-2.9%), 7.9% for Wb123 (95%CI 6.4-9.6%), and 20.2% for Bm33 (95%CI 16.7-24.3%); and in the community survey (n = 2507), 13.9% for Bm14 (95%CI 11.2-17.2%), 27.9% for Wb123 (95%CI 24.6-31.4%), and 47.3% for Bm33 (95%CI 42.1-52.6%). Multivariable logistic regression was used to identify risk factors for being seropositive for Ag and antibodies. Higher Ag prevalence was found in males (adjusted odds ratio [aOR] 3.01), age ≥18 years (aOR 2.18), residents of Fagali'i (aOR 15.81), and outdoor workers (aOR 2.61). Ag prevalence was 20.7% (95%CI 9.7-53.5%) in households of Ag-positive children identified in TAS-3. We used NNTestav (average number needed to test to identify one positive) to compare the efficiency of the following strategies for identifying persons who were seropositive for Ag and each antibody: i) TAS of 6-7 year-old children, ii) population representative surveys of older age groups, and iii) targeted surveillance of subpopulations at higher risk of being seropositive (older ages, householders of Ag-positive TAS children, and known hotspots). For Ag, NNTestav ranged from 142.5 for TAS, to <5 for households of index children. NNTestav was lower in older ages, and highest for Ag, followed by Bm14, Wb123 and Bm33 antibodies. We propose a multi-stage surveillance strategy, starting with population-representative sampling (e.g. TAS or population representative survey of older ages), followed by strategies that target subpopulations and/or locations with low NNTestav. This approach could potentially improve the efficiency of identifying remaining infected persons and residual hotspots. Surveillance programs should also explore the utility of antibodies as indicators of transmission.
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Hedtke SM, Zendejas-Heredia PA, Graves PM, Sheridan S, Sheel M, Fuimaono SD, Lau CL, Grant WN. Genetic epidemiology of lymphatic filariasis in American Samoa after mass drug administration. Int J Parasitol 2020; 51:137-147. [PMID: 33166540 DOI: 10.1016/j.ijpara.2020.08.009] [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: 06/18/2020] [Revised: 08/05/2020] [Accepted: 08/09/2020] [Indexed: 11/18/2022]
Abstract
Over 892 million people in 48 countries are at risk of infection by nematodes that cause lymphatic filariasis. As part of the Global Programme to Eliminate Lymphatic Filariasis, mass drug administration is distributed to communities until surveillance indicates infection rates are below target prevalence thresholds. In some countries, including American Samoa, lymphatic filariasis transmission persists despite years of mass drug administration and/or has resurged after cessation. Nothing is known about the population genetics of Wuchereria bancrofti worms in Polynesia, or whether local transmission is persisting and/or increasing due to inadequate mass drug administration coverage, expansion from residual hotspots, reintroduction from elsewhere, or a combination. We extracted DNA from microfilariae on blood slides collected during prevalence surveys in 2014 and 2016, comprising 31 pools of five microfilariae from 22 persons living in eight villages. We sequenced 1104 bp across three mitochondrial markers (ND4, COI, CYTB). We quantified parasite genetic differentiation using variant calls and estimated haplotypes using principal components analysis, F-statistics, and haplotype networks. Of the variants called, all but eight were shared across the main island of Tutuila, and three of those were from a previously described hotspot village, Fagali'i. Genotypic data did not support population genetic structure among regions or villages in 2016, although differences were observed between worms collected in Fagali'i in 2014 and those from 2016. Because estimated haplotype frequency varied between villages, these statistics suggested genetic differentiation, but were not consistent among villages. Finally, haplotype networks demonstrated American Samoan sequence clusters were related to previously published sequences from Papua New Guinea. These are, to our knowledge, the first reports of W. bancrofti genetic variation in Polynesia. The resurgent parasites circulating on the main island of American Samoa represent a single population. This study is the first step towards investigating how parasite population structure might inform strategies to manage resurgence and elimination of lymphatic filariasis.
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Affiliation(s)
- Shannon M Hedtke
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia; Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria, Australia.
| | - Patsy A Zendejas-Heredia
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia
| | - Patricia M Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, Queensland, Australia
| | - Sarah Sheridan
- Department of Global Health, Research School of Population Health, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Meru Sheel
- National Centre for Epidemiology and Population Health, Research School of Population Health, The Australian National University, Acton, Australian Capital Territory, Australia
| | | | - Colleen L Lau
- Department of Global Health, Research School of Population Health, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Warwick N Grant
- Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, Victoria, Australia; Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, Victoria, Australia
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Burgert-Brucker CR, Zoerhoff KL, Headland M, Shoemaker EA, Stelmach R, Karim MJ, Batcho W, Bougouma C, Bougma R, Benjamin Didier B, Georges N, Marfo B, Lemoine JF, Pangaribuan HU, Wijayanti E, Coulibaly YI, Doumbia SS, Rimal P, Salissou AB, Bah Y, Mwingira U, Nshala A, Muheki E, Shott J, Yevstigneyeva V, Ndayishimye E, Baker M, Kraemer J, Brady M. Risk factors associated with failing pre-transmission assessment surveys (pre-TAS) in lymphatic filariasis elimination programs: Results of a multi-country analysis. PLoS Negl Trop Dis 2020; 14:e0008301. [PMID: 32479495 PMCID: PMC7289444 DOI: 10.1371/journal.pntd.0008301] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 06/11/2020] [Accepted: 04/16/2020] [Indexed: 11/20/2022] Open
Abstract
Achieving elimination of lymphatic filariasis (LF) as a public health problem requires a minimum of five effective rounds of mass drug administration (MDA) and demonstrating low prevalence in subsequent assessments. The first assessments recommended by the World Health Organization (WHO) are sentinel and spot-check sites—referred to as pre-transmission assessment surveys (pre-TAS)—in each implementation unit after MDA. If pre-TAS shows that prevalence in each site has been lowered to less than 1% microfilaremia or less than 2% antigenemia, the implementation unit conducts a TAS to determine whether MDA can be stopped. Failure to pass pre-TAS means that further rounds of MDA are required. This study aims to understand factors influencing pre-TAS results using existing programmatic data from 554 implementation units, of which 74 (13%) failed, in 13 countries. Secondary data analysis was completed using existing data from Bangladesh, Benin, Burkina Faso, Cameroon, Ghana, Haiti, Indonesia, Mali, Nepal, Niger, Sierra Leone, Tanzania, and Uganda. Additional covariate data were obtained from spatial raster data sets. Bivariate analysis and multilinear regression were performed to establish potential relationships between variables and the pre-TAS result. Higher baseline prevalence and lower elevation were significant in the regression model. Variables statistically significantly associated with failure (p-value ≤0.05) in the bivariate analyses included baseline prevalence at or above 5% or 10%, use of Filariasis Test Strips (FTS), primary vector of Culex, treatment with diethylcarbamazine-albendazole, higher elevation, higher population density, higher enhanced vegetation index (EVI), higher annual rainfall, and 6 or more rounds of MDA. This paper reports for the first time factors associated with pre-TAS results from a multi-country analysis. This information can help countries more effectively forecast program activities, such as the potential need for more rounds of MDA, and prioritize resources to ensure adequate coverage of all persons in areas at highest risk of failing pre-TAS. Achieving elimination of lymphatic filariasis (LF) as a public health problem requires a minimum of five rounds of mass drug administration (MDA) and being able to demonstrate low prevalence in several subsequent assessments. LF elimination programs implement sentinel and spot-check site assessments, called pre-TAS, to determine whether districts are eligible to implement more rigorous population-based surveys to determine whether MDA can be stopped or if further rounds are required. Reasons for failing pre-TAS are not well understood and have not previously been examined with data compiled from multiple countries. For this analysis, we analyzed data from routine USAID and WHO reports from Bangladesh, Benin, Burkina Faso, Cameroon, Ghana, Haiti, Indonesia, Mali, Nepal, Niger, Sierra Leone, Tanzania, and Uganda. In a model that included multiple variables, high baseline prevalence and lower elevation were significant. In models comparing only one variable to the outcome, the following were statistically significantly associated with failure: higher baseline prevalence at or above 5% or 10%, use of the FTS, primary vector of Culex, treatment with diethylcarbamazine-albendazole, lower elevation, higher population density, higher Enhanced Vegetation Index, higher annual rainfall, and six or more rounds of mass drug administration. These results can help national programs plan MDA more effectively, e.g., by focusing resources on areas with higher baseline prevalence and/or lower elevation.
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Affiliation(s)
| | - Kathryn L. Zoerhoff
- Global Health Division, RTI International, Washington, DC, United States of America
| | - Maureen Headland
- Global Health Division, RTI International, Washington, DC, United States of America
- Global Health, Population, and Nutrition, FHI 360, Washington, DC, United States of America
| | - Erica A. Shoemaker
- Global Health Division, RTI International, Washington, DC, United States of America
| | - Rachel Stelmach
- Global Health Division, RTI International, Washington, DC, United States of America
| | | | - Wilfrid Batcho
- National Control Program of Communicable Diseases, Ministry of Health, Cotonou, Benin
| | - Clarisse Bougouma
- Lymphatic Filariasis Elimination Program, Ministère de la Santé, Ouagadougou, Burkina Faso
| | - Roland Bougma
- Lymphatic Filariasis Elimination Program, Ministère de la Santé, Ouagadougou, Burkina Faso
| | - Biholong Benjamin Didier
- National Onchocerciasis and Lymphatic Filariasis Control Program, Ministry of Health, Yaounde, Cameroon
| | - Nko'Ayissi Georges
- National Onchocerciasis and Lymphatic Filariasis Control Program, Ministry of Health, Yaounde, Cameroon
| | - Benjamin Marfo
- Neglected Tropical Diseases Programme, Ghana Health Service, Accra, Ghana
| | | | | | - Eksi Wijayanti
- National Institute Health Research & Development, Ministry of Health, Jakarta, Indonesia
| | - Yaya Ibrahim Coulibaly
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Bamako, Mali
| | - Salif Seriba Doumbia
- Filariasis Unit, International Center of Excellence in Research, Faculty of Medicine and Odontostomatology, Bamako, Mali
| | - Pradip Rimal
- Epidemiology and Disease Control Division, Department of Health Service, Kathmandu, Nepal
| | | | - Yukaba Bah
- National Neglected Tropical Disease Program, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Upendo Mwingira
- Neglected Tropical Disease Control Programme, National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Andreas Nshala
- IMA World Health/Tanzania NTD Control Programme, Uppsala University, & TIBA Fellow, Dar es Salaam, Tanzania
| | - Edridah Muheki
- Programme to Eliminate Lymphatic Filariasis, Ministry of Health, Kampala, Uganda
| | - Joseph Shott
- Division of Neglected Tropical Diseases, Office of Infectious Diseases, Bureau for Global Health, USAID, Washington, DC, United States of America
| | - Violetta Yevstigneyeva
- Division of Neglected Tropical Diseases, Office of Infectious Diseases, Bureau for Global Health, USAID, Washington, DC, United States of America
| | - Egide Ndayishimye
- Global Health, Population, and Nutrition, FHI 360, Washington, DC, United States of America
| | - Margaret Baker
- Global Health Division, RTI International, Washington, DC, United States of America
| | - John Kraemer
- Global Health Division, RTI International, Washington, DC, United States of America
- Georgetown University, Washington, DC, United States of America
| | - Molly Brady
- Global Health Division, RTI International, Washington, DC, United States of America
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Yokoly FN, Zahouli JBZ, Méite A, Opoku M, Kouassi BL, de Souza DK, Bockarie M, Koudou BG. Low transmission of Wuchereria bancrofti in cross-border districts of Côte d'Ivoire: A great step towards lymphatic filariasis elimination in West Africa. PLoS One 2020; 15:e0231541. [PMID: 32282840 PMCID: PMC7153895 DOI: 10.1371/journal.pone.0231541] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/25/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is widely endemic in Côte d'Ivoire, and elimination as public health problem (EPHP) is based on annual mass drug administration (MDA) using ivermectin and albendazole. To guide EPHP efforts, we evaluated Wuchereria bancrofti infection indices among humans, and mosquito vectors after four rounds of MDA in four cross-border health districts of Côte d'Ivoire. METHODOLOGY We monitored people and mosquitoes for W. bancrofti infections in the cross-border health districts of Aboisso, Bloléquin, Odienné and Ouangolodougou, Côte d'Ivoire. W. bancrofti circulating filarial antigen (CFA) was identified using filariasis test strips, and antigen-positive individuals were screened for microfilaremia. Moreover, filarial mosquito vectors were sampled using window exit traps and pyrethrum sprays, and identified morphologically at species level. Anopheles gambiae s.l. and Culex quinquefasciatus females were analyzed for W. bancrofti infection using polymerase chain reaction (PCR) technique. PRINCIPAL FINDINGS Overall, we found a substantial decline in W. bancrofti infection indices after four rounds of MDA compared to pre-MDA baseline data. CFA prevalence fell from 3.38-5.50% during pre-MDA to 0.00-1.53% after MDA interventions. No subjects had detectable levels of CFA in Ouangolodougou. Moreover, post-MDA CFA prevalence was very low, and below the 1% elimination threshold in Aboisso (0.19%) and Odienné (0.49%). Conversely, CFA prevalence remained above 1% in Bloléquin (1.53%). W. bancrofti microfilariae (Mf) were not found in Aboisso, Bloléquin, and Ouangolodougou, except for Odienné with low prevalence (0.16%; n = 613) and microfilaremia of 32.0 Mf/mL. No An. gambiae s.l. and Cx. quinquefasciatus pools were infected with W. bancrofti in Bloléquin and Ouangolodougou, while they exhibited low infection rates in Aboisso (1% and 0.07%), and Odienné (0.08% and 0.08%), respectively. CONCLUSIONS In cross-border areas of Côte d'Ivoire, LF infection indices in humans and mosquito vectors substantially declined after four rounds of MDA. CFA prevalence fell under the World Health Organization (WHO)-established threshold (1%) in Aboisso, Ouangolodougou and Odienné. Moreover, W. bancrofti prevalence in mosquitoes was lower than WHO-established threshold (2%) in all areas. This might suggest the interruption of W. bancrofti transmission, and possible MDA cessation. However, a formal transmission assessment survey (TAS) and molecular xenomonitoring in mosquito vectors should be implemented before eventual MDA cessation. However, MDA should pursue in Bloléquin where W. bancrofti infection prevalence remained above 1%. Our results provided important ramifications for LF control efforts towards EPHP in Côte d'Ivoire.
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Affiliation(s)
- Firmain N. Yokoly
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Julien B. Z. Zahouli
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Centre d’Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, Bouaké, Côte d’Ivoire
| | - Aboulaye Méite
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Ministère de la Santé, Abidjan, Côte d’Ivoire
| | - Millicent Opoku
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
| | - Bernard L. Kouassi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Dziedzom K. de Souza
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Moses Bockarie
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Benjamin G. Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
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Graves PM, Sheridan S, Fuimaono S, Lau CL. Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014. Parasit Vectors 2020; 13:125. [PMID: 32164780 PMCID: PMC7068921 DOI: 10.1186/s13071-020-3996-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 02/26/2020] [Indexed: 01/21/2023] Open
Abstract
Background Prevalence of lymphatic filariasis (LF) antigen in American Samoa was 16.5% in 1999. Seven rounds of mass drug administration (MDA) programmes between 2000 and 2006 reduced antigen prevalence to 2.3%. The most efficient methods of surveillance after MDA are not clear, but testing specific at-risk groups such as adults may provide earlier warning of resurgence. The role of migration from LF endemic countries in maintaining transmission also needs investigation. Few studies have investigated knowledge about LF and how that relates to infection risk. This study aims to investigate associations between socio-demographics, population mobility, disease knowledge and LF infection risk. Methods In 2014, we surveyed 670 adults aged 16–68 years (62% female) at two worksites in American Samoa. Sera were tested for LF antigen and antibodies (Bm14 and Wb123) by rapid test and/or ELISA. Multivariate logistic regression was used to assess association between seromarkers and demographic factors, household socioeconomic status (SES), residence, travel history, and knowledge of LF. Results Overall, 1.8% of participants were positive for antigen, 11.8% for Bm14, 11.3% for Wb123 and 17.3% for at least one antibody. Recent travel outside American Samoa was not associated with positivity for any seromarker. Men had higher seroprevalence than women for all outcomes (any antibody: adjusted odds ratio (aOR) = 3.49 (95% CI: 2.21–5.49). Those aged over 35 years (compared to 15–24 years) had higher prevalence of Bm14 antibody (aOR = 3.75, 3.76 and 4.17 for ages 35–44, 45–54 and ≥ 55 years, respectively, P < 0.05). Lower SES was associated with seropositivity (antigen: aOR = 2.89, 95% CI: 1.09–7.69; either antibody: aOR = 1.51, 95% CI: 1.12–2.05). Those who knew that mosquitoes transmitted LF had lower Wb123 antibody prevalence (aOR = 0.55, 95% CI: 0.32–0.95). Conclusions Opportunistic sampling of adults at worksites provided an efficient and representative way to assess prevalence and risk factors for LF in American Samoa and in hindsight, foreshadowed the resurgence of transmission. Risk of LF infection, detected by one or more serological markers, was not related to recent travel history, but was strongly associated with male gender, older age, lower SES, and lack of knowledge about mosquito transmission. These results could guide future efforts to increase MDA participation.![]()
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Affiliation(s)
- Patricia M Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD, Australia. .,Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia.
| | - Sarah Sheridan
- Department of Global Health, Research School of Population Health, The Australian National University, Canberra, Australia
| | - Saipale Fuimaono
- Department of Public Health, American Samoa Department of Health, Pago Pago, American Samoa
| | - Colleen L Lau
- Department of Global Health, Research School of Population Health, The Australian National University, Canberra, Australia
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Hedtke SM, Kuesel AC, Crawford KE, Graves PM, Boussinesq M, Lau CL, Boakye DA, Grant WN. Genomic Epidemiology in Filarial Nematodes: Transforming the Basis for Elimination Program Decisions. Front Genet 2020; 10:1282. [PMID: 31998356 PMCID: PMC6964045 DOI: 10.3389/fgene.2019.01282] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 11/21/2019] [Indexed: 11/25/2022] Open
Abstract
Onchocerciasis and lymphatic filariasis are targeted for elimination, primarily using mass drug administration at the country and community levels. Elimination of transmission is the onchocerciasis target and global elimination as a public health problem is the end point for lymphatic filariasis. Where program duration, treatment coverage, and compliance are sufficiently high, elimination is achievable for both parasites within defined geographic areas. However, transmission has re-emerged after apparent elimination in some areas, and in others has continued despite years of mass drug treatment. A critical question is whether this re-emergence and/or persistence of transmission is due to persistence of local parasites-i.e., the result of insufficient duration or drug coverage, poor parasite response to the drugs, or inadequate methods of assessment and/or criteria for determining when to stop treatment-or due to re-introduction of parasites via human or vector movement from another endemic area. We review recent genetics-based research exploring these questions in Onchocerca volvulus, the filarial nematode that causes onchocerciasis, and Wuchereria bancrofti, the major pathogen for lymphatic filariasis. We focus in particular on the combination of genomic epidemiology and genome-wide associations to delineate transmission zones and distinguish between local and introduced parasites as the source of resurgence or continuing transmission, and to identify genetic markers associated with parasite response to chemotherapy. Our ultimate goal is to assist elimination efforts by developing easy-to-use tools that incorporate genetic information about transmission and drug response for more effective mass drug distribution, surveillance strategies, and decisions on when to stop interventions to improve sustainability of elimination.
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Affiliation(s)
- Shannon M. Hedtke
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia
| | - Annette C. Kuesel
- Unicef/UNDP/World Bank/World Health Organization Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Katie E. Crawford
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia
| | - Patricia M. Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD, Australia
| | - Michel Boussinesq
- Unité Mixte Internationale 233 "TransVIHMI", Institut de Recherche pour le Développement (IRD), INSERM U1175, University of Montpellier, Montpellier, France
| | - Colleen L. Lau
- Department of Global Health, Research School of Population Health, Australian National University, Acton, ACT, Australia
| | - Daniel A. Boakye
- Parasitology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Warwick N. Grant
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia
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The roadmap towards elimination of lymphatic filariasis by 2030: insights from quantitative and mathematical modelling. Gates Open Res 2019; 3:1538. [PMID: 31728440 PMCID: PMC6833911 DOI: 10.12688/gatesopenres.13065.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2019] [Indexed: 01/26/2023] Open
Abstract
The Global Programme to Eliminate Lymphatic Filariasis was launched in 2000 to eliminate lymphatic filariasis (LF) as a public health problem by 1) interrupting transmission through mass drug administration (MDA) and 2) offering basic care to those suffering from lymphoedema or hydrocele due to the infection. Although impressive progress has been made, the initial target year of 2020 will not be met everywhere. The World Health Organization recently proposed 2030 as the new target year for elimination of lymphatic filariasis (LF) as a public health problem. In this letter, LF modelers of the Neglected Tropical Diseases (NTDs) Modelling Consortium reflect on the proposed targets for 2030 from a quantitative perspective. While elimination as a public health problem seems technically and operationally feasible, it is uncertain whether this will eventually also lead to complete elimination of transmission. The risk of resurgence needs to be mitigated by strong surveillance after stopping interventions and sometimes perhaps additional interventions.
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Davis EL, Reimer LJ, Pellis L, Hollingsworth TD. Evaluating the Evidence for Lymphatic Filariasis Elimination. Trends Parasitol 2019; 35:860-869. [PMID: 31506245 PMCID: PMC7413036 DOI: 10.1016/j.pt.2019.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/19/2019] [Accepted: 08/19/2019] [Indexed: 12/01/2022]
Abstract
In the global drive for elimination of lymphatic filariasis (LF), 15 countries have achieved validation of elimination as a public health problem (EPHP). Recent empirical evidence has demonstrated that EPHP does not always lead to elimination of transmission (EOT). Here we show how the probability of elimination explicitly depends on key biological parameters, many of which have been poorly characterized, leading to a poor evidence base for the elimination threshold. As more countries progress towards EPHP it is essential that this process is well-informed, as prematurely halting treatment and surveillance programs could pose a serious threat to global progress. We highlight that refinement of the weak empirical evidence base is vital to understand drivers of elimination and inform long-term policy.
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Affiliation(s)
| | - Lisa J Reimer
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Lorenzo Pellis
- University of Manchester, Oxford Road, Manchester M13 9PL, UK
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