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Rebollo MP, Onyeze AN, Tiendrebeogo A, Senkwe MN, Impouma B, Ogoussan K, Zouré HGM, Deribe K, Cano J, Kinvi EB, Majewski A, Ottesen EA, Lammie P. Baseline Mapping of Neglected Tropical Diseases in Africa: The Accelerated WHO/AFRO Mapping Project. Am J Trop Med Hyg 2021; 104:2298-2304. [PMID: 33901001 PMCID: PMC8176498 DOI: 10.4269/ajtmh.20-1538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/10/2021] [Indexed: 11/30/2022] Open
Abstract
Mapping is a prerequisite for effective implementation of interventions against neglected tropical diseases (NTDs). Before the accelerated World Health Organization (WHO)/Regional Office for Africa (AFRO) NTD Mapping Project was initiated in 2014, mapping efforts in many countries were frequently carried out in an ad hoc and nonstandardized fashion. In 2013, there were at least 2,200 different districts (of the 4,851 districts in the WHO African region) that still required mapping, and in many of these districts, more than one disease needed to be mapped. During its 3-year duration from January 2014 through the end of 2016, the project carried out mapping surveys for one or more NTDs in at least 2,500 districts in 37 African countries. At the end of 2016, most (90%) of the 4,851 districts had completed the WHO-required mapping surveys for the five targeted Preventive Chemotherapy (PC)-NTDs, and the impact of this accelerated WHO/AFRO NTD Mapping Project proved to be much greater than just the detailed mapping results themselves. Indeed, the AFRO Mapping Project dramatically energized and empowered national NTD programs, attracted donor support for expanding these programs, and developed both a robust NTD mapping database and data portal. By clarifying the prevalence and burden of NTDs, the project provided not only the metrics and technical framework for guiding and tracking program implementation and success but also the research opportunities for developing improved diagnostic and epidemiologic sampling tools for all 5 PC-NTDs—lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiasis, and trachoma.
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Affiliation(s)
- Maria P Rebollo
- 1Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | | | | | | | - Benido Impouma
- 3World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | | | - Honorat G M Zouré
- 1Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Kebede Deribe
- 6Brighton and Sussex Medical School, Brighton, United Kingdom
| | - Jorge Cano
- 1Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Ekoue Boniface Kinvi
- 1Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
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Deribe K, Bakajika DK, Zoure HMG, Gyapong JO, Molyneux DH, Rebollo MP. African regional progress and status of the programme to eliminate lymphatic filariasis: 2000-2020. Int Health 2020; 13:S22-S27. [PMID: 33349875 PMCID: PMC7753167 DOI: 10.1093/inthealth/ihaa058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/10/2020] [Accepted: 08/12/2020] [Indexed: 01/23/2023] Open
Abstract
To eliminate lymphatic filariasis (LF) by 2020, the World Health Organization (WHO) has launched a campaign against the disease. Since the launch in 2000, significant progress has been made to achieve this ambitious goal. In this article we review the progress and status of the LF programme in Africa through the WHO neglected tropical diseases preventive chemotherapy databank, the Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN) portal and other publications. In the African Region there are 35 countries endemic for LF. The Gambia was reclassified as not requiring preventive chemotherapy in 2015, while Togo and Malawi eliminated LF as a public health problem in 2017 and 2020, respectively. Cameroon discontinued mass drug administration (MDA) and transitioned to post-MDA surveillance to validate elimination. The trajectory of coverage continues to accelerate; treatment coverage increased from 0.1% in 2000 to 62.1% in 2018. Geographical coverage has also significantly increased, from 62.7% in 2015 to 78.5% in 2018. In 2019, 23 of 31 countries requiring MDA achieved 100% geographic coverage. Although much remains to be done, morbidity management and disability prevention services have steadily increased in recent years. Vector control interventions conducted by other programmes, particularly malaria vector control, have had a profound effect in stopping transmission in some endemic countries in the region. In conclusion, significant progress has been made in the LF programme in the region while we identify the key remaining challenges in achieving an Africa free of LF.
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Affiliation(s)
- Kebede Deribe
- Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Cité du Djoué, P.O. Box 06 Brazzaville, Republic of Congo
- Brighton and Sussex Centre for Global Health Research, Department of Global Health and Infection, Brighton and Sussex Medical School, Brighton, BN1 9PX, UK
| | - Didier K Bakajika
- Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Cité du Djoué, P.O. Box 06 Brazzaville, Republic of Congo
| | - Honorat Marie-Gustave Zoure
- Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Cité du Djoué, P.O. Box 06 Brazzaville, Republic of Congo
| | - John O Gyapong
- University of Health and Allied Sciences, PMB 31, Ho, Volta Region, Ghana
| | - David H Molyneux
- Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool L3 5QA, UK
| | - Maria P Rebollo
- Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Cité du Djoué, P.O. Box 06 Brazzaville, Republic of Congo
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Rebollo MP, Zoure H, Ogoussan K, Sodahlon Y, Ottesen EA, Cantey PT. Onchocerciasis: shifting the target from control to elimination requires a new first-step-elimination mapping. Int Health 2019; 10:i14-i19. [PMID: 29471341 PMCID: PMC5881272 DOI: 10.1093/inthealth/ihx052] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/11/2017] [Indexed: 11/13/2022] Open
Abstract
The meaning of 'mapping' in relation to onchocerciasis has changed at least three times over the past 50 years as the programmatic goals and the assessment tools have changed. With the current goal being global elimination of Onchocerca volvulus (OV), all areas where OV might currently be transmitted and where mass drug administration (MDA) with ivermectin treatment has not been delivered previously must now be identified by careful, detailed 'elimination mapping' as either OV endemic or not, so that appropriate programmatic targets can be established. New tools and strategies for such elimination mapping have become available, though ongoing studies must still be completed to define agreed upon optimal diagnostic evaluation units, sampling strategies and serologic tools. With detailed guidance and technical support from the World Health Organization and with implementation and financial support from their global partners, the OV-endemic countries of Africa can soon complete their elimination mapping and then continue with MDA programmes to progressively achieve the same success in OV elimination as that already achieved by the growing list of formerly OV-endemic countries in the Americas.
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Affiliation(s)
- Maria P Rebollo
- Expanded Special Project for Elimination of NTDs, Decatur, GA, USA
| | - Honorat Zoure
- Expanded Special Project for Elimination of NTDs, Decatur, GA, USA
| | - Kisito Ogoussan
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, Georgia, USA
| | - Yao Sodahlon
- Mectizan Donation Program, Task Force for Global Health, Decatur, Georgia, USA
| | - Eric A Ottesen
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, Georgia, USA
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Sime H, Gass KM, Mekasha S, Assefa A, Woyessa A, Shafi O, Meribo K, Kebede B, Ogoussan K, Pelletreau S, Bockarie MJ, Kebede A, Rebollo MP. Results of a confirmatory mapping tool for Lymphatic filariasis endemicity classification in areas where transmission was uncertain in Ethiopia. PLoS Negl Trop Dis 2018; 12:e0006325. [PMID: 29579038 PMCID: PMC5886699 DOI: 10.1371/journal.pntd.0006325] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 04/05/2018] [Accepted: 02/16/2018] [Indexed: 12/01/2022] Open
Abstract
Background The goal of the global lymphatic filariasis (LF) program is to eliminate the disease as a public health problem by the year 2020. The WHO mapping protocol that is used to identify endemic areas in need of mass drug administration (MDA) uses convenience-based sampling. This rapid mapping has allowed the global program to dramatically scale up treatment, but as the program approaches its elimination goal, it is important to ensure that all endemic areas have been identified and have received MDA. In low transmission settings, the WHO mapping protocol for LF mapping has several limitations. To correctly identify the LF endemicity of woredas, a new confirmatory mapping tool was developed to test older school children for circulating filarial antigen (CFA) in settings where it is uncertain. Ethiopia is the first country to implement this new tool. In this paper, we present the Ethiopian experience of implementing the new confirmatory mapping tool and discuss the implications of the results for the LF program in Ethiopia and globally. Methods Confirmatory LF mapping was conducted in 1,191 schools in 45 woredas, the implementation unit in Ethiopia, in the regions of Tigray, Amhara, Oromia, SNNP, Afar and Harari, where the results of previous mapping for LF using the current WHO protocol indicated that LF endemicity was uncertain. Within each woreda schools were selected using either cluster or systematic sampling. From selected schools, a total of 18,254 children were tested for circulating filarial antigen (CFA) using the immuno-chromatographic test (ICT). Results Of the 18,254 children in 45 woredas who participated in the survey, 28 (0.16%) in 9 woredas tested CFA positive. According to the confirmatory mapping threshold, which is ≥2% CFA in children 9–14 years of age, only 3 woredas out of the total 45 had more CFA positive results than the threshold and thus were confirmed to be endemic; the remaining 42 woredas were declared non-endemic. These results drastically decreased the estimated total population living in LF-endemic woredas in Ethiopia and in need of MDA by 49.1%, from 11,580,010 to 5,893,309. Conclusion This study demonstrated that the new confirmatory mapping tool for LF can benefit national LF programs by generating information that not only can confirm where LF is endemic, but also can save time and resources by preventing MDA where there is no evidence of ongoing LF transmission. Lymphatic filariasis (LF) is a mosquito-borne parasitic disease, caused by 3 nematode parasites, Wuchereria bancrofti, Brugia malayi and Brugia timori. The aim of the Global Program to Eliminate LF (GPELF) is to interrupt LF transmission through mass drug administration (MDA) by 2020 and to alleviate the suffering of affected people. Mapping is the first programmatic step to determining areas of LF endemicity and establishing a national program. Ethiopia was believed to be endemic for LF, but until recently the distribution of LF in the country was unknown. From 2008–2013, mapping for LF was conducted using the current WHO protocol, and 112 woredas were identified as endemic or possibly endemic. In 45 of these 112 woredas, only a single CFA positive result was found (<1% prevalence), which called into question the stutus of transmission and need for MDA. To help resolve this uncertainty, a new confirmatory mapping tool was designed and tested in Ethiopia. The new mapping tool was piloted in the 45 woredas with uncertain LF transmission from the 2008–2013 mapping (S1 Table). This mapping confirmed that only 3 of the 45 woredas were endemic, which decreased estimated total population at risk of LF and in need of MDA from 11,580,010 to 5,893,309.
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Affiliation(s)
- Heven Sime
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
- * E-mail:
| | - Katherine M. Gass
- The Task Force for Global Health, Atlanta Georgia, United States of America
| | - Sindew Mekasha
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Adugna Woyessa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Oumer Shafi
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Kadu Meribo
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Kisito Ogoussan
- The Task Force for Global Health, Atlanta Georgia, United States of America
| | - Sonia Pelletreau
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Moses J. Bockarie
- European & Developing Countries Clinical Trials Partnership (EDCTP), Cape Town, South Africa
| | - Amha Kebede
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Maria P. Rebollo
- The Task Force for Global Health, Atlanta Georgia, United States of America
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Cano J, Basáñez MG, O'Hanlon SJ, Tekle AH, Wanji S, Zouré HG, Rebollo MP, Pullan RL. Identifying co-endemic areas for major filarial infections in sub-Saharan Africa: seeking synergies and preventing severe adverse events during mass drug administration campaigns. Parasit Vectors 2018; 11:70. [PMID: 29382363 PMCID: PMC5791223 DOI: 10.1186/s13071-018-2655-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/16/2018] [Indexed: 02/06/2023] Open
Abstract
Background Onchocerciasis and lymphatic filariasis (LF) are major filarial infections targeted for elimination in most endemic sub-Saharan Africa (SSA) countries by 2020/2025. The current control strategies are built upon community-directed mass administration of ivermectin (CDTI) for onchocerciasis, and ivermectin plus albendazole for LF, with evidence pointing towards the potential for novel drug regimens. When distributing microfilaricides however, considerable care is needed to minimise the risk of severe adverse events (SAEs) in areas that are co-endemic for onchocerciasis or LF and loiasis. This work aims to combine previously published predictive risk maps for onchocerciasis, LF and loiasis to (i) explore the scale of spatial heterogeneity in co-distributions, (ii) delineate target populations for different treatment strategies, and (iii) quantify populations at risk of SAEs across the continent. Methods Geographical co-endemicity of filarial infections prior to the implementation of large-scale mass treatment interventions was analysed by combining a contemporary LF endemicity map with predictive prevalence maps of onchocerciasis and loiasis. Potential treatment strategies were geographically delineated according to the level of co-endemicity and estimated transmission intensity. Results In total, an estimated 251 million people live in areas of LF and/or onchocerciasis transmission in SSA, based on 2015 population estimates. Of these, 96 million live in areas co-endemic for both LF and onchocerciasis, providing opportunities for integrated control programmes, and 83 million live in LF-monoendemic areas potentially targetable for the novel ivermectin-diethylcarbamazine-albendazole (IDA) triple therapy. Only 4% of the at-risk population live in areas co-endemic with high loiasis transmission, representing up to 1.2 million individuals at high risk of experiencing SAEs if treated with ivermectin. In these areas, alternative treatment strategies should be explored, including biannual albendazole monotherapy for LF (1.4 million individuals) and ‘test-and-treat’ strategies (8.7 million individuals) for onchocerciasis. Conclusions These maps are intended to initiate discussion around the potential for tailored treatment strategies, and highlight populations at risk of SAEs. Further work is required to test and refine strategies in programmatic settings, providing the empirical evidence needed to guide efforts towards the 2020/2025 goals and beyond. Electronic supplementary material The online version of this article (10.1186/s13071-018-2655-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jorge Cano
- Department of Disease Control, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, UK
| | - Simon J O'Hanlon
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, UK
| | - Afework H Tekle
- Research Foundation in Tropical Medicine and the Environment, Buea, Cameroon
| | - Samuel Wanji
- Department of Biochemistry and Microbiology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Medicine and the Environment, Buea, Cameroon
| | - Honorat G Zouré
- Former African Programme for Onchocerciasis Control Programme, Ouagadougou, Burkina Faso
| | - Maria P Rebollo
- Expanded Special Programme for Elimination of Neglected Tropical Diseases (ESPEN), Brazzaville, Republic of Congo
| | - Rachel L Pullan
- Department of Disease Control, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Gass KM, Sime H, Mwingira UJ, Nshala A, Chikawe M, Pelletreau S, Barbre KA, Deming MS, Rebollo MP. The rationale and cost-effectiveness of a confirmatory mapping tool for lymphatic filariasis: Examples from Ethiopia and Tanzania. PLoS Negl Trop Dis 2017; 11:e0005944. [PMID: 28976981 PMCID: PMC5643143 DOI: 10.1371/journal.pntd.0005944] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 10/16/2017] [Accepted: 09/07/2017] [Indexed: 11/19/2022] Open
Abstract
Endemicity mapping is required to determining whether a district requires mass drug administration (MDA). Current guidelines for mapping LF require that two sites be selected per district and within each site a convenience sample of 100 adults be tested for antigenemia or microfilaremia. One or more confirmed positive tests in either site is interpreted as an indicator of potential transmission, prompting MDA at the district-level. While this mapping strategy has worked well in high-prevalence settings, imperfect diagnostics and the transmission potential of a single positive adult have raised concerns about the strategy’s use in low-prevalence settings. In response to these limitations, a statistically rigorous confirmatory mapping strategy was designed as a complement to the current strategy when LF endemicity is uncertain. Under the new strategy, schools are selected by either systematic or cluster sampling, depending on population size, and within each selected school, children 9–14 years are sampled systematically. All selected children are tested and the number of positive results is compared against a critical value to determine, with known probabilities of error, whether the average prevalence of LF infection is likely below a threshold of 2%. This confirmatory mapping strategy was applied to 45 districts in Ethiopia and 10 in Tanzania, where initial mapping results were considered uncertain. In 42 Ethiopian districts, and all 10 of the Tanzanian districts, the number of antigenemic children was below the critical cutoff, suggesting that these districts do not require MDA. Only three Ethiopian districts exceeded the critical cutoff of positive results. Whereas the current World Health Organization guidelines would have recommended MDA in all 55 districts, the present results suggest that only three of these districts requires MDA. By avoiding unnecessary MDA in 52 districts, the confirmatory mapping strategy is estimated to have saved a total of $9,293,219. Mapping is used by lymphatic filariasis (LF) elimination programs to determine if mass drug administration (MDA) is required. The current mapping approach, designed to be simple and practical, has worked well in high-prevalence settings but concerns about its reliability in low-prevalence settings have been raised. To address these concerns, a confirmatory mapping strategy was developed that utilizes probability-based sampling of school attending children to determine if the prevalence of LF antigenemia is below a 2% threshold. The confirmatory mapping strategy was implemented in 45 districts in Ethiopia and 10 in Tanzania where the need for MDA was uncertain. In 52 of the 55 districts, the number of LF antigen-positive children identified by the confirmatory mapping strategy was below the predetermined threshold and MDA was deemed unnecessary, while in three districts the number of positive children exceeded the threshold, suggesting that MDA is required. The use of this mapping strategy, to confirm whether MDA is required, is estimated to have saved the Ethiopian and Tanzanian programs $9,293,219 by avoiding unnecessary MDA in 52 districts.
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Affiliation(s)
- Katherine M. Gass
- Neglected Tropical Disease Support Center, Task Force for Global Health, Atlanta, United States of America
- * E-mail:
| | - Heven Sime
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Upendo J. Mwingira
- Neglected Tropical Disease Control Program, Ministry of Health and Social Welfare, Dar es Salaam, Tanzania
| | - Andreas Nshala
- Neglected Tropical Disease Control Program, Ministry of Health and Social Welfare, Dar es Salaam, Tanzania
- IMA World Health Tanzania, Dar es Salaam, Tanzania
| | - Maria Chikawe
- Neglected Tropical Disease Control Program, Ministry of Health and Social Welfare, Dar es Salaam, Tanzania
| | | | - Kira A. Barbre
- Neglected Tropical Disease Support Center, Task Force for Global Health, Atlanta, United States of America
| | - Michael S. Deming
- Consultant, Neglected Tropical Diseases Support Center, Task Force for Global Health, Atlanta, United States of America
| | - Maria P. Rebollo
- Neglected Tropical Disease Support Center, Task Force for Global Health, Atlanta, United States of America
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bockarie MJ, Rebollo MP. Reducing the population requiring interventions against lymphatic filariasis in Africa. Lancet Glob Health 2016; 4:e154-5. [PMID: 26874545 DOI: 10.1016/s2214-109x(15)00292-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 11/27/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Moses J Bockarie
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
| | - Maria P Rebollo
- Rey Juan Carlos University, Calle Tulipan, Mostoles, Madrid, Spain
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9
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P. Rebollo M, Sime H, Assefa A, Cano J, Deribe K, Gonzalez-Escalada A, Shafi O, Davey G, Brooker SJ, Kebede A, Bockarie MJ. Shrinking the Lymphatic Filariasis Map of Ethiopia: Reassessing the Population at Risk through Nationwide Mapping. PLoS Negl Trop Dis 2015; 9:e0004172. [PMID: 26539700 PMCID: PMC4634982 DOI: 10.1371/journal.pntd.0004172] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 09/27/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mapping of lymphatic filariasis (LF) is essential for the delineation of endemic implementation units and determining the population at risk that will be targeted for mass drug administration (MDA). Prior to the current study, only 116 of the 832 woredas (districts) in Ethiopia had been mapped for LF. The aim of this study was to perform a nationwide mapping exercise to determine the number of people that should be targeted for MDA in 2016 when national coverage was anticipated. METHODOLOGY/PRINCIPAL FINDING A two-stage cluster purposive sampling was used to conduct a community-based cross-sectional survey for an integrated mapping of LF and podoconiosis, in seven regional states and two city administrations. Two communities in each woreda were purposely selected using the World Health Organization (WHO) mapping strategy for LF based on sampling 100 individuals per community and two purposely selected communities per woreda. Overall, 130 166 people were examined in 1315 communities in 658 woredas. In total, 140 people were found to be positive for circulating LF antigen by immunochromatographic card test (ICT) in 89 communities. Based on WHO guidelines, 75 of the 658 woredas surveyed in the nine regions were found to be endemic for LF with a 2016 projected population of 9 267 410 residing in areas of active disease transmission. Combining these results with other data it is estimated that 11 580 010 people in 112 woredas will be exposed to infection in 2016. CONCLUSIONS We have conducted nationwide mapping of LF in Ethiopia and demonstrated that the number of people living in LF endemic areas is 60% lower than current estimates. We also showed that integrated mapping of multiple NTDs is feasible and cost effective and if properly planned, can be quickly achieved at national scale.
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Affiliation(s)
- Maria P. Rebollo
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Heven Sime
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Jorge Cano
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Kebede Deribe
- Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Oumer Shafi
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Gail Davey
- Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom
| | - Simon J. Brooker
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Amha Kebede
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Moses J. Bockarie
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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Moraga P, Cano J, Baggaley RF, Gyapong JO, Njenga SM, Nikolay B, Davies E, Rebollo MP, Pullan RL, Bockarie MJ, Hollingsworth TD, Gambhir M, Brooker SJ. Modelling the distribution and transmission intensity of lymphatic filariasis in sub-Saharan Africa prior to scaling up interventions: integrated use of geostatistical and mathematical modelling. Parasit Vectors 2015; 8:560. [PMID: 26496983 PMCID: PMC4620019 DOI: 10.1186/s13071-015-1166-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 10/14/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination. The ability to interrupt transmission is, partly, influenced by the underlying intensity of transmission and its geographical variation. This information can also help guide the design of targeted surveillance activities. The present study uses a combination of geostatistical and mathematical modelling to predict the prevalence and transmission intensity of LF prior to the implementation of large-scale control in sub-Saharan Africa. METHODS A systematic search of the literature was undertaken to identify surveys on the prevalence of Wuchereria bancrofti microfilaraemia (mf), based on blood smears, and on the prevalence of antigenaemia, based on the use of an immuno-chromatographic card test (ICT). Using a suite of environmental and demographic data, spatiotemporal multivariate models were fitted separately for mf prevalence and ICT-based prevalence within a Bayesian framework and used to make predictions for non-sampled areas. Maps of the dominant vector species of LF were also developed. The maps of predicted prevalence and vector distribution were linked to mathematical models of the transmission dynamics of LF to infer the intensity of transmission, quantified by the basic reproductive number (R0). RESULTS The literature search identified 1267 surveys that provide suitable data on the prevalence of mf and 2817 surveys that report the prevalence of antigenaemia. Distinct spatial predictions arose from the models for mf prevalence and ICT-based prevalence, with a wider geographical distribution when using ICT-based data. The vector distribution maps demonstrated the spatial variation of LF vector species. Mathematical modelling showed that the reproduction number (R0) estimates vary from 2.7 to 30, with large variations between and within regions. CONCLUSIONS LF transmission is highly heterogeneous, and the developed maps can help guide intervention, monitoring and surveillance strategies as countries progress towards LF elimination.
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Affiliation(s)
- Paula Moraga
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Rebecca F Baggaley
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.
| | - John O Gyapong
- School of Public Health, College of Health Sciences, University of Ghana, Legon, Accra, Ghana.
| | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Birgit Nikolay
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | | | - Maria P Rebollo
- NTD Support Center, Task Force for Global Health, Emory University, Atlanta, USA.
| | - Rachel L Pullan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Moses J Bockarie
- Department of Vector Biology, Liverpool School for Tropical Medicine, Liverpool, UK.
| | - T Déirdre Hollingsworth
- Warwick Infectious Disease Epidemiology Research, Warwick Mathematics Institute, University of Warwick, Coventry, UK. .,School of Life Sciences, University of Warwick, Coventry, UK.
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
| | - Simon J Brooker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
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de Souza DK, Ansumana R, Sessay S, Conteh A, Koudou B, Rebollo MP, Koroma J, Boakye DA, Bockarie MJ. The impact of residual infections on Anopheles-transmitted Wuchereria bancrofti after multiple rounds of mass drug administration. Parasit Vectors 2015; 8:488. [PMID: 26399968 PMCID: PMC4581406 DOI: 10.1186/s13071-015-1091-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many countries have made significant progress in the implementation of World Health Organization recommended preventive chemotherapy strategy, to eliminate lymphatic filariasis (LF). However, pertinent challenges such as the existence of areas of residual infections in disease endemic districts pose potential threats to the achievements made. Thus, this study was undertaken to assess the importance of these areas in implementation units (districts) where microfilaria (MF) positive individuals could not be found during the mid-term assessment after three rounds of mass drug administration. METHODS This study was undertaken in Bo and Pujehun, two LF endemic districts of Sierra Leone, with baseline MF prevalence of 2 % and 0 % respectively in sentinel sites for monitoring impact of the national programme. Study communities in the districts were purposefully selected and an assessment of LF infection prevalence was conducted together with entomological investigations undertaken to determine the existence of areas with residual MF that could enable transmission by local vectors. The transmission Assessment Survey (TAS) protocol described by WHO was applied in the two districts to determine infection of LF in 6-7 year old children who were born before MDA against LF started. RESULTS The results indicated the presence of MF infected children in Pujehun district. An. gambiae collected in the district were also positive for W. bancrofti, even though the prevalence of infection was below the threshold associated with active transmission. CONCLUSIONS Residual infection was detected after three rounds of MDA in Pujehun--a district of 0 % Mf prevalence at the sentinel site. Nevertheless, our results showed that the transmission was contained in a small area. With the scale up of vector control in Anopheles transmission zones, some areas of residual infection may not pose a serious threat for the resurgence of LF if the prevalence of infections observed during TAS are below the threshold required for active transmission of the parasite. However, robust surveillance strategies capable of detecting residual infections must be implemented, together with entomological assessments to determine if ongoing vector control activities, biting rates and infection rates of the vectors can support the transmission of the disease. Furthermore, in areas where mid-term assessments reveal MF prevalence below 1 % or 2 % antigen level, in Anopheles transmission areas with active and effective malaria vector control efforts, the minimum 5 rounds of MDA may not be required before implementing TAS. Thus, we propose a modification of the WHO recommendation for the timing of sentinel and spot-check site assessments in national programs.
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Affiliation(s)
- Dziedzom K de Souza
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Rashid Ansumana
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK. .,Mercy Hospital Research Laboratory, Bo, Sierra Leone.
| | | | - Abu Conteh
- Ministry of Health and Sanitation, Freetown, Sierra Leone.
| | - Benjamin Koudou
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK.
| | | | - Joseph Koroma
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
| | - Moses J Bockarie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK.
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12
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Deribe K, Cano J, Newport MJ, Golding N, Pullan RL, Sime H, Gebretsadik A, Assefa A, Kebede A, Hailu A, Rebollo MP, Shafi O, Bockarie MJ, Aseffa A, Hay SI, Reithinger R, Enquselassie F, Davey G, Brooker SJ. Mapping and Modelling the Geographical Distribution and Environmental Limits of Podoconiosis in Ethiopia. PLoS Negl Trop Dis 2015. [PMID: 26222887 PMCID: PMC4519246 DOI: 10.1371/journal.pntd.0003946] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Ethiopia is assumed to have the highest burden of podoconiosis globally, but the geographical distribution and environmental limits and correlates are yet to be fully investigated. In this paper we use data from a nationwide survey to address these issues. Methodology Our analyses are based on data arising from the integrated mapping of podoconiosis and lymphatic filariasis (LF) conducted in 2013, supplemented by data from an earlier mapping of LF in western Ethiopia in 2008–2010. The integrated mapping used woreda (district) health offices’ reports of podoconiosis and LF to guide selection of survey sites. A suite of environmental and climatic data and boosted regression tree (BRT) modelling was used to investigate environmental limits and predict the probability of podoconiosis occurrence. Principal Findings Data were available for 141,238 individuals from 1,442 communities in 775 districts from all nine regional states and two city administrations of Ethiopia. In 41.9% of surveyed districts no cases of podoconiosis were identified, with all districts in Affar, Dire Dawa, Somali and Gambella regional states lacking the disease. The disease was most common, with lymphoedema positivity rate exceeding 5%, in the central highlands of Ethiopia, in Amhara, Oromia and Southern Nations, Nationalities and Peoples regional states. BRT modelling indicated that the probability of podoconiosis occurrence increased with increasing altitude, precipitation and silt fraction of soil and decreased with population density and clay content. Based on the BRT model, we estimate that in 2010, 34.9 (95% confidence interval [CI]: 20.2–51.7) million people (i.e. 43.8%; 95% CI: 25.3–64.8% of Ethiopia’s national population) lived in areas environmentally suitable for the occurrence of podoconiosis. Conclusions Podoconiosis is more widespread in Ethiopia than previously estimated, but occurs in distinct geographical regions that are tied to identifiable environmental factors. The resultant maps can be used to guide programme planning and implementation and estimate disease burden in Ethiopia. This work provides a framework with which the geographical limits of podoconiosis could be delineated at a continental scale. Podoconiosis is a neglected tropical disease that results in swelling of the lower legs and feet. It is common among barefoot individuals with prolonged contact with irritant soils of volcanic origin. The disease causes significant social and economic burden. The disease can be prevented by consistent shoe wearing and regular foot hygiene. A pre-requisite for implementation of prevention and morbidity management is information on where the disease is endemic and the identification of priority areas. We undertook nationwide mapping of podoconiosis in Ethiopia covering 1442 communities in 775 districts all over Ethiopia. During the survey, individuals underwent a rapid-format antigen test for diagnosis of lymphatic filariasis and clinical history and physical examination for podoconiosis. A suite of environmental and climatic data and a method called boosted regression tree modelling was used to predict the occurrence of podoconiosis. Our survey results indicated that podoconiosis is more widespread in Ethiopia than previously estimated. The modelling indicated that the probability of podoconiosis occurrence increased with increasing altitude, precipitation and silt fraction of soil and decreased with more clay content and population density. The map showed that in 2010, 34.9 million people lived in areas environmentally suitable for the occurrence of podoconiosis in Ethiopia.
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Affiliation(s)
- Kebede Deribe
- Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
- * E-mail:
| | - Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Nick Golding
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Rachel L. Pullan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Heven Sime
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | | | - Amha Kebede
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Asrat Hailu
- School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
| | - Maria P. Rebollo
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Oumer Shafi
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Moses J. Bockarie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Abraham Aseffa
- Armauer Hansen Research Institute/ALERT, Addis Ababa, Ethiopia
| | - Simon I. Hay
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Institute of Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Richard Reithinger
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- RTI International, Washington, District of Columbia, United States of America
| | | | - Gail Davey
- Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom
| | - Simon J. Brooker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Cano J, Moraga P, Nikolay B, Rebollo MP, Okorie PN, Davies E, Njenga SM, Bockarie MJ, Brooker SJ. An investigation of the disparity in estimates of microfilaraemia and antigenaemia in lymphatic filariasis surveys. Trans R Soc Trop Med Hyg 2015; 109:529-31. [PMID: 26101292 PMCID: PMC4542699 DOI: 10.1093/trstmh/trv048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 06/05/2015] [Indexed: 11/25/2022] Open
Abstract
Background The diagnosis of lymphatic filariasis (LF) is based typically on either microfilaraemia as assessed by microscopy or filarial antigenaemia using an immuno-chromatographic test. While it is known that estimates of antigenaemia are generally higher than estimates of microfilaraemia, the extent of the difference is not known. Methods This paper presents the results of an extensive literature search for surveys that estimated both microfilaraemia and antigenaemia in order to better understand the disparity between the two measures. Results and Conclusions In some settings there was a very large disparity, up to 40–70%, between estimates of microfilaraemia and antigenaemia. Regression analysis was unable to identify any predictable relationship between the two measures. The implications of findings for risk mapping and surveillance of LF are discussed.
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Affiliation(s)
- Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Paula Moraga
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Birgit Nikolay
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Maria P Rebollo
- NTD Support Center, Task Force for Global Health, Decatur, Atlanta, USA
| | - Patricia N Okorie
- Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | | | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Moses J Bockarie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Simon J Brooker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
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Rebollo MP, Sambou SM, Thomas B, Biritwum NK, Jaye MC, Kelly-Hope L, Escalada AG, Molyneux DH, Bockarie MJ. Elimination of lymphatic filariasis in the Gambia. PLoS Negl Trop Dis 2015; 9:e0003642. [PMID: 25785587 PMCID: PMC4364952 DOI: 10.1371/journal.pntd.0003642] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 02/24/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The prevalence of Wuchereria bancrofti, which causes lymphatic filariasis (LF) in The Gambia was among the highest in Africa in the 1950s. However, surveys conducted in 1975 and 1976 revealed a dramatic decline in LF endemicity in the absence of mass drug administration (MDA). The decline in prevalence was partly attributed to a significant reduction in mosquito density through the widespread use of insecticidal nets. Based on findings elsewhere that vector control alone can interrupt LF, we asked the question in 2013 whether the rapid scale up in the use of insecticidal nets in The Gambia had interrupted LF transmission. METHODOLOGY/PRINCIPAL FINDING We present here the results of three independently designed filariasis surveys conducted over a period of 17 years (1997-2013), and involving over 6000 subjects in 21 districts across all administrative divisions in The Gambia. An immunochromatographic (ICT) test was used to detect W. bancrofti antigen during all three surveys. In 2001, tests performed on stored samples collected between 1997 and 2000, in three divisions, failed to show positive individuals from two divisions that were previously highly endemic for LF, suggesting a decline towards extinction in some areas. Results of the second survey conducted in 2003 showed that LF was no longer endemic in 16 of 21 districts surveyed. The 2013 survey used a WHO recommended LF transmission verification tool involving 3180 6-7 year-olds attending 60 schools across the country. We demonstrated that transmission of W. bancrofti has been interrupted in all 21 districts. CONCLUSIONS We conclude that LF transmission may have been interrupted in The Gambia through the extensive use of insecticidal nets for malaria control for decades. The growing evidence for the impact of malaria vector control activities on parasite transmission has been endorsed by WHO through a position statement in 2011 on integrated vector management to control malaria and LF.
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Affiliation(s)
- Maria P. Rebollo
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Brent Thomas
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | | | - Louise Kelly-Hope
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - David H. Molyneux
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Moses J. Bockarie
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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15
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Rebollo MP, Mohammed KA, Thomas B, Ame S, Ali SM, Cano J, Escalada AG, Bockarie MJ. Cessation of mass drug administration for lymphatic filariasis in Zanzibar in 2006: was transmission interrupted? PLoS Negl Trop Dis 2015; 9:e0003669. [PMID: 25816287 PMCID: PMC4376862 DOI: 10.1371/journal.pntd.0003669] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 03/03/2015] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is targeted for elimination through annual mass drug administration (MDA) for 4-6 years. In 2006, Zanzibar stopped MDA against LF after five rounds of MDA revealed no microfilaraemic individuals during surveys at selected sentinel sites. We asked the question if LF transmission was truly interrupted in 2006 when MDA was stopped. METHODOLOGY/PRINCIPAL FINDINGS In line with ongoing efforts to shrink the LF map, we performed the WHO recommended transmission assessment surveys (TAS) in January 2012 to verify the absence of LF transmission on the main Zanzibar islands of Unguja and Pemba. Altogether, 3275 children were tested on both islands and 89 were found to be CFA positive; 70 in Pemba and 19 in Unguja. The distribution of schools with positive children was heterogeneous with pronounced spatial variation on both islands. Based on the calculated TAS cut-offs of 18 and 20 CFA positive children for Pemba and Unguja respectively, we demonstrated that transmission was still ongoing in Pemba where the cut-off was exceeded. CONCLUSIONS Our findings indicated ongoing transmission of LF on Pemba in 2012. Moreover, we presented evidence from previous studies that LF transmission was also active on Unguja shortly after stopping MDA in 2006. Based on these observations the government of Zanzibar decided to resume MDA against LF on both islands in 2013.
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Affiliation(s)
- Maria P. Rebollo
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | | | - Brent Thomas
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Shaali Ame
- Public Health Laboratory-IdC, Chake-chake, Pemba, Zanzibar, Tanzania
| | | | - Jorge Cano
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Moses J. Bockarie
- Centre for Neglected Tropical Diseases, Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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16
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Deribe K, Brooker SJ, Pullan RL, Sime H, Gebretsadik A, Assefa A, Kebede A, Hailu A, Rebollo MP, Shafi O, Bockarie MJ, Aseffa A, Reithinger R, Cano J, Enquselassie F, Newport MJ, Davey G. Epidemiology and individual, household and geographical risk factors of podoconiosis in Ethiopia: results from the first nationwide mapping. Am J Trop Med Hyg 2014; 92:148-158. [PMID: 25404069 PMCID: PMC4288951 DOI: 10.4269/ajtmh.14-0446] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although podoconiosis is one of the major causes of tropical lymphoedema and is endemic in Ethiopia its epidemiology and risk factors are poorly understood. Individual-level data for 129,959 individuals from 1,315 communities in 659 woreda (districts) were collected for a nationwide integrated survey of lymphatic filariasis and podoconiosis. Blood samples were tested for circulating Wuchereria bancrofti antigen using immunochromatographic card tests. A clinical algorithm was used to reach a diagnosis of podoconiosis by excluding other potential causes of lymphoedema of the lower limb. Bayesian multilevel models were used to identify individual and environmental risk factors. Overall, 8,110 of 129,959 (6.2%, 95% confidence interval [CI] 6.1–6.4%) surveyed individuals were identified with lymphoedema of the lower limb, of whom 5,253 (4.0%, 95% CI 3.9–4.1%) were confirmed to be podoconiosis cases. In multivariable analysis, being female, older, unmarried, washing the feet less frequently than daily, and being semiskilled or unemployed were significantly associated with increased risk of podoconiosis. Attending formal education and living in a house with a covered floor were associated with decreased risk of podoconiosis. Podoconiosis exhibits marked geographical variation across Ethiopia, with variation in risk associated with variation in rainfall, enhanced vegetation index, and altitude.
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Affiliation(s)
- Kebede Deribe
- *Address correspondence to Kebede Deribe, Brighton & Sussex Medical School and School of Public Health, Addis Ababa University, P.O. Box 2082/1250, Addis Ababa, Ethiopia. E-mail:
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Cano J, Rebollo MP, Golding N, Pullan RL, Crellen T, Soler A, Kelly-Hope LA, Lindsay SW, Hay SI, Bockarie MJ, Brooker SJ. The global distribution and transmission limits of lymphatic filariasis: past and present. Parasit Vectors 2014; 7:466. [PMID: 25303991 PMCID: PMC4197264 DOI: 10.1186/s13071-014-0466-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/29/2014] [Indexed: 12/27/2022] Open
Abstract
Background Lymphatic filariasis (LF) is one of the neglected tropical diseases targeted for global elimination by 2020 and to guide elimination efforts countries have, in recent years, conducted extensive mapping surveys. Documenting the past and present distribution of LF and its environmental limits is important for a number of reasons. Here, we present an initiative to develop a global atlas of LF and present a new global map of the limits of LF transmission. Methods We undertook a systematic search and assembly of prevalence data worldwide and used a suite of environmental and climatic data and boosted regression trees (BRT) modelling to map the transmission limits of LF. Results Data were identified for 66 of the 72 countries currently endemic and for a further 17 countries where LF is no longer endemic. Our map highlights a restricted and highly heterogeneous distribution in sub-Saharan Africa, with transmission more widespread in West Africa compared to east, central and southern Africa where pockets of transmission occur. Contemporary transmission occurs across much of south and South-east Asia and the Pacific. Interestingly, the risk map reflects environmental conditions suitable for LF transmission across Central and South America, including the southern States of America, although active transmission is only known in a few isolated foci. In countries that have eliminated LF, our predictions of environmental suitability are consistent with historical distribution. Conclusions The global distribution of LF is highly heterogeneous and geographically targeted and sustained control will be required to achieve elimination. This first global map can help evaluate the progress of interventions and guide surveillance activities. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0466-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Maria P Rebollo
- NTD Support Center, Task Force for Global Health, Emory University, Atlanta, United States of America. .,Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Nick Golding
- Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK.
| | - Rachel L Pullan
- 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.
| | - Anna Soler
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Louise A Kelly-Hope
- Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Steve W Lindsay
- School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom.
| | - Simon I Hay
- Department of Zoology, Spatial Ecology and Epidemiology Group, Tinbergen Building, University of Oxford, South Parks Road, Oxford, UK.
| | - Moses J Bockarie
- Department of Parasitology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
| | - Simon J Brooker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
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Sime H, Deribe K, Assefa A, Newport MJ, Enquselassie F, Gebretsadik A, Kebede A, Hailu A, Shafi O, Aseffa A, Reithinger R, Brooker SJ, Pullan RL, Cano J, Meribo K, Pavluck A, Bockarie MJ, Rebollo MP, Davey G. Integrated mapping of lymphatic filariasis and podoconiosis: lessons learnt from Ethiopia. Parasit Vectors 2014; 7:397. [PMID: 25164687 PMCID: PMC4153915 DOI: 10.1186/1756-3305-7-397] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/20/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The World Health Organization (WHO), international donors and partners have emphasized the importance of integrated control of neglected tropical diseases (NTDs). Integrated mapping of NTDs is a first step for integrated planning of programmes, proper resource allocation and monitoring progress of control. Integrated mapping has several advantages over disease specific mapping by reducing costs and enabling co-endemic areas to be more precisely identified. We designed and conducted integrated mapping of lymphatic filariasis (LF) and podoconiosis in Ethiopia; here we present the methods, challenges and lessons learnt. METHODS Integrated mapping of 1315 communities across Ethiopia was accomplished within three months. Within these communities, 129,959 individuals provided blood samples that were tested for circulating Wuchereria bancrofti antigen using immunochromatographic card tests (ICT). Wb123 antibody tests were used to further establish exposure to LF in areas where at least one ICT positive individual was detected. A clinical algorithm was used to reliably diagnose podoconiosis by excluding other potential causes of lymphoedema of the lower limb. RESULTS A total of 8110 individuals with leg swelling were interviewed and underwent physical examination. Smartphones linked to a central database were used to collect data, which facilitated real-time data entry and reduced costs compared to traditional paper-based data collection approach; their inbuilt Geographic Positioning System (GPS) function enabled simultaneous capture of geographical coordinates. The integrated approach led to efficient use of resources and rapid mapping of an enormous geographical area and was well received by survey staff and collaborators. Mobile based technology can be used for such large scale studies in resource constrained settings such as Ethiopia, with minimal challenges. CONCLUSIONS This was the first integrated mapping of podoconiosis and LF globally. Integrated mapping of podoconiosis and LF is feasible and, if properly planned, can be quickly achieved at nationwide scale.
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Affiliation(s)
| | - Kebede Deribe
- Brighton and Sussex Medical School, Falmer, Brighton, United Kingdom.
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Dome M, Ansumana R, Covington AL, Rebollo MP, Sesay S, Jacobsen KH, de Souza DK, Koudou BG, Michael E, Bockarie MJ. Lymphedema in a 7-year-old boy infected with Wuchereria bancrofti in Sierra Leone: a case report. Acta Trop 2014; 134:13-6. [PMID: 24561072 DOI: 10.1016/j.actatropica.2014.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/02/2014] [Accepted: 02/10/2014] [Indexed: 11/17/2022]
Abstract
We present a case of congenital lymphedema in a 7-year-old boy in Sierra Leone with active filarial infection and penile edema. The genital edema with onset at 6 months of age may have been due to a congenital abnormality in lymphatic drainage. Other possible causes of childhood lymphedema, including Milroy's disease, are discussed.
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Affiliation(s)
- Mackenzie Dome
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Rashid Ansumana
- Mercy Hospital Research Laboratory, Bo, Sierra Leone; Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK.
| | | | - Maria P Rebollo
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Santigie Sesay
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Kathryn H Jacobsen
- Department of Global and Community Health, George Mason University, Fairfax, VA, USA
| | - Dziedzom K de Souza
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Benjamin G Koudou
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, USA
| | - Moses J Bockarie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
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Rebollo MP, Bockarie MJ. Toward the elimination of lymphatic filariasis by 2020: treatment update and impact assessment for the endgame. Expert Rev Anti Infect Ther 2014; 11:723-31. [PMID: 23879610 DOI: 10.1586/14787210.2013.811841] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lymphatic filariasis (LF) is an important public health problem endemic in 73 countries, where it is a major cause of acute and chronic morbidity and a significant impediment to socioeconomic development. It is targeted for elimination by 2020, through preventive chemotherapy using albendazole in combination with either ivermectin or diethylcarbamazine citrate. Preventive chemotherapy enables the regular and coordinated administration of safe, single-dose medications delivered through mass drug administration (MDA). Many countries are now scaling down MDA activities after achieving 100% geographic coverage and instituting monitoring and evaluation procedures to establish the impact of several consecutive rounds of MDA and determine if transmission has been interrupted. At the same time, countries yet to initiate MDA for elimination of LF will adopt improved mapping and coverage assessment protocols to accelerate the efforts for achieving global elimination by 2020. This review provides an update on treatment for LF and describes the current global status of the elimination efforts, transmission control processes and strategies for measuring impact and continuing surveillance after MDA has ceased.
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Affiliation(s)
- Maria P Rebollo
- Center for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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de Souza DK, Sesay S, Moore MG, Ansumana R, Narh CA, Kollie K, Rebollo MP, Koudou BG, Koroma JB, Bolay FK, Boakye DA, Bockarie MJ. No evidence for lymphatic filariasis transmission in big cities affected by conflict related rural-urban migration in Sierra Leone and Liberia. PLoS Negl Trop Dis 2014; 8:e2700. [PMID: 24516686 PMCID: PMC3916318 DOI: 10.1371/journal.pntd.0002700] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 01/04/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In West Africa, the principal vectors of lymphatic filariasis (LF) are Anopheles species with Culex species playing only a minor role in transmission, if any. Being a predominantly rural disease, the question remains whether conflict-related migration of rural populations into urban areas would be sufficient for active transmission of the parasite. METHODOLOGY/PRINCIPAL FINDINGS We examined LF transmission in urban areas in post-conflict Sierra Leone and Liberia that experienced significant rural-urban migration. Mosquitoes from Freetown and Monrovia, were analyzed for infection with Wuchereria bancrofti. We also undertook a transmission assessment survey (TAS) in Bo and Pujehun districts in Sierra Leone. The majority of the mosquitoes collected were Culex species, while Anopheles species were present in low numbers. The mosquitoes were analyzed in pools, with a maximum of 20 mosquitoes per pool. In both countries, a total of 1731 An. gambiae and 14342 Culex were analyzed for W. bancrofti, using the PCR. Two pools of Culex mosquitoes and 1 pool of An. gambiae were found infected from one community in Freetown. Pool screening analysis indicated a maximum likelihood of infection of 0.004 (95% CI of 0.00012-0.021) and 0.015 (95% CI of 0.0018-0.052) for the An. gambiae and Culex respectively. The results indicate that An. gambiae is present in low numbers, with a microfilaria prevalence breaking threshold value not sufficient to maintain transmission. The results of the TAS in Bo and Pujehun also indicated an antigen prevalence of 0.19% and 0.67% in children, respectively. This is well below the recommended 2% level for stopping MDA in Anopheles transmission areas, according to WHO guidelines. CONCLUSIONS We found no evidence for active transmission of LF in cities, where internally displaced persons from rural areas lived for many years during the more than 10 years conflict in Sierra Leone and Liberia.
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Affiliation(s)
- Dziedzom K. de Souza
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Santigie Sesay
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Rashid Ansumana
- Mercy Hospital Research Laboratory, Bo, Sierra Leone
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Charles A. Narh
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Karsor Kollie
- Ministry of Health and Social Welfare, Monrovia, Liberia
| | - Maria P. Rebollo
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Benjamin G. Koudou
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Joseph B. Koroma
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Fatorma K. Bolay
- Liberian Institute for Biomedical Research, Charlesville, Liberia
| | - Daniel A. Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Moses J. Bockarie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
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Gunawardena S, Gunawardena NK, Kahathuduwa G, Karunaweera ND, de Silva NR, Ranasinghe UB, Samarasekara SD, Nagodavithana KC, Rao RU, Rebollo MP, Weil GJ. Integrated school-based surveillance for soil-transmitted helminth infections and lymphatic filariasis in Gampaha district, Sri Lanka. Am J Trop Med Hyg 2014; 90:661-6. [PMID: 24493672 DOI: 10.4269/ajtmh.13-0641] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We explored the practicality of integrating surveillance for soil-transmitted helminthiasis (STH, assessed by Kato-Katz) with transmission assessment surveys for lymphatic filariasis (LF) in two evaluation units (EUs) in Gampaha district, Sri Lanka (population 2.3 million). The surveys were performed 6 years after five annual rounds of mass drug administration with diethylcarbamazine and albendazole. Each transmission assessment survey tested children (N = 1,462 inland EU; 1,642 coastal EU) sampled from 30 primary schools. Low filarial antigenemia rates (0% and 0.1% for the inland and coastal EUs) suggest that LF transmission is very low in this district. The STH rates and stool sample participation rates were 0.8% and 61% (inland) and 2.8% and 58% (coastal). Most STH detected were low or moderate intensity Trichuris trichiura infections. The added cost of including STH testing was ∼$5,000 per EU. These results suggest that it is feasible to integrate school-based surveillance for STH and LF.
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Affiliation(s)
- Sharmini Gunawardena
- Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka; Department of Parasitology, Faculty of Medicine, University of Kelaniya, Sri Lanka; Anti Filariasis Campaign, Ministry of Health, Sri Lanka; Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, St. Louis, Missouri; Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, United Kingdom
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