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Boniface PK, Elizabeth FI. An Insight into the Discovery of Potent Antifilarial Leads Against Lymphatic Filariasis. Curr Drug Targets 2019; 21:657-680. [PMID: 31800381 DOI: 10.2174/1389450120666191204152415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 11/08/2019] [Accepted: 11/28/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVES Lymphatic filariasis is a neglected tropical disease caused by infection with filarial worms that are transmitted through mosquito bites. Globally, 120 million people are infected, with nearly 40 million people disfigured and disabled by complications such as severe swelling of the legs (elephantiasis) or scrotum (hydrocele). Current treatments (ivermectin, diethylcarbamazine) have limited effects on adult parasites and produce side effects; therefore, there is an urgent to search for new antifilarial agents. Numerous studies on the antifilarial activity of pure molecules have been reported accross the recent literature. The present study describes the current standings of potent antifilarial compounds against lymphatic filariasis. METHODS A literature search was conducted for naturally occurring and synthetic antifilarial compounds by referencing textbooks and scientific databases (SciFinder, PubMed, Science Direct, Wiley, ACS, SciELO, Google Scholar, and Springer, among others) from their inception until September 2019. RESULTS Numerous compounds have been reported to exhibit antifilarial acitivity in adult and microfilariae forms of the parasites responsible for lymphatic filariasis. In silico studies of active antifilarial compounds (ligands) showed molecular interactions over the protein targets (trehalose-6-phosphate phosphatase, thymidylate synthase, among others) of lymphatic filariasis, and supported the in vitro results. CONCLUSION With reference to in vitro antifilarial studies, there is evidence that natural and synthetic products can serve as basic scaffolds for the development of antifilarial agents. The optimization of the most potent antifilarial compounds can be further performed, followed by their in vivo studies.
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Affiliation(s)
- Pone Kamdem Boniface
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ferreira Igne Elizabeth
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
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Srividya A, Subramanian S, Jambulingam P, Vijayakumar B, Dinesh Raja J. Mapping and monitoring for a lymphatic filariasis elimination program: a systematic review. Res Rep Trop Med 2019; 10:43-90. [PMID: 31239804 PMCID: PMC6554002 DOI: 10.2147/rrtm.s134186] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 04/02/2019] [Indexed: 11/23/2022] Open
Abstract
Lymphatic filariasis (LF) is targeted for elimination by the year 2020. The Global Programme for Elimination of LF (GPELF) aims to achieve elimination by interrupting transmission through annual mass drug administration (MDA) of albendazole with ivermectin or diethylcarbamazine. The program has successfully eliminated the disease in 11 of the 72 endemic countries, putting in enormous efforts on systematic planning and implementation of the strategy. Mapping areas endemic for LF is a pre-requisite for implementing MDA, monitoring and evaluation are the components of programme implementation. This review was undertaken to assess how the mapping and impact monitoring activities have evolved to become more robust over the years and steered the LF elimination programme towards its goal. The findings showed that the WHO recommended mapping strategy aided 17 countries to delimit, plan and implement MDA in only those areas endemic for LF thereby saving resources. Availability of serological tools for detecting infection in humans (antigen/antibody assays) and molecular xenomonitoring (MX) in vectors greatly facilitated programme monitoring and evaluation in endemic countries. Results of this review are discussed on how these existing mapping and monitoring procedures can be used for re-mapping of unsurveyed and uncertain areas to ensure there is no resurgence during post-MDA surveillance. Further the appropriateness of the tests (Microfilaria (Mf)/antigenemia (Ag)/antibody(Ab) surveys in humans or MX of vectors for infection) used currently for post-MDA surveillance and their role in the development of a monitoring and evaluation strategy for the recently WHO recommended triple drug regimen in MDA for accelerated LF elimination are discussed.
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Affiliation(s)
- Adinarayanan Srividya
- Division of Epidemiology, Biostatistics and Operations Research, ICMR - Vector Control Research Centre, Puducherry, India
| | - Swaminathan Subramanian
- Division of Epidemiology, Biostatistics and Operations Research, ICMR - Vector Control Research Centre, Puducherry, India
| | - Purushothaman Jambulingam
- Division of Epidemiology, Biostatistics and Operations Research, ICMR - Vector Control Research Centre, Puducherry, India
| | - Balakrishnan Vijayakumar
- Division of Epidemiology, Biostatistics and Operations Research, ICMR - Vector Control Research Centre, Puducherry, India
| | - Jeyapal Dinesh Raja
- Division of Epidemiology, Biostatistics and Operations Research, ICMR - Vector Control Research Centre, Puducherry, India
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Minetti C, Tettevi EJ, Mechan F, Prada JM, Idun B, Biritwum NK, Osei-Atweneboana MY, Reimer LJ. Elimination within reach: A cross-sectional study highlighting the factors that contribute to persistent lymphatic filariasis in eight communities in rural Ghana. PLoS Negl Trop Dis 2019; 13:e0006994. [PMID: 30608931 PMCID: PMC6342320 DOI: 10.1371/journal.pntd.0006994] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 01/22/2019] [Accepted: 11/13/2018] [Indexed: 12/20/2022] Open
Abstract
Background Despite the progress achieved in scaling-up mass drug administration (MDA) for lymphatic filariasis (LF) in Ghana, communities with persistent LF still exist even after 10 years of community treatment. To understand the reasons for persistence, we conducted a study to assess the status of disease elimination and understand the adherence to interventions including MDA and insecticide treated nets. Methodology and principal findings We conducted a parasitological and epidemiological cross-sectional study in adults from eight villages still under MDA in the Northern Region savannah and the coastal Western Region of the country. Prevalence of filarial antigen ranged 0 to 32.4% and in five villages the prevalence of night blood microfilaria (mf) was above 1%, ranging from 0 to 5.7%. Median mf density was 67 mf/ml (range: 10–3,560). LF antigen positivity was positively associated with male sex but negatively associated with participating in MDA the previous year. Male sex was also associated with a decreased probability of participating in MDA. A stochastic model (TRANSFIL) was used to assess the expected microfilaria prevalence under different MDA coverage scenarios using historical data on one community in the Western Region. In this example, the model simulations suggested that the slow decline in mf prevalence is what we would expect given high baseline prevalence and a high correlation between MDA adherence from year to year, despite high MDA coverage. Conclusions There is a need for an integrated quantitative and qualitative research approach to identify the variations in prevalence, associated risk factors and intervention coverage and use levels between and within regions and districts. Such knowledge will help target resources and enhance surveillance to the communities most at risk and to reach the 2020 LF elimination goals in Ghana. Lymphatic filariasis (LF) is a mosquito-borne disease and a leading cause of disability and chronic morbidity worldwide. Despite the progress achieved so far in stopping LF transmission by treating the affected communities with specific drugs over several years, areas where lymphatic filariasis persists still exist. Understanding the reasons behind this is pivotal to both reach and sustain elimination. We investigated the factors associated with filariasis persistence in various communities still under drug treatment from two regions of Ghana. We reported high variability in disease burden, adherence to drug treatment and mosquito net use between regions and communities. LF infection was associated with men and not taking the drugs, and men were also less likely to take treatment. Using mathematical modelling, we showed that slight increases in treatment coverage will accelerate elimination. Our findings highlight the reasons for LF persistence and provide guidance on how to successfully achieve elimination by refining drug treatment distribution and mosquito control interventions more tailored to individuals and communities. We also demonstrated the value of using field-collected data in mathematical models to assess the current status of disease elimination and to identify the gaps in control interventions.
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Affiliation(s)
- Corrado Minetti
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Edward J. Tettevi
- Department of Environmental Biology and Health, Council for Scientific and Industrial Research Water Research Institute, Accra, Ghana
| | - Frank Mechan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Joaquín M. Prada
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Bright Idun
- Department of Environmental Biology and Health, Council for Scientific and Industrial Research Water Research Institute, Accra, Ghana
| | | | - Mike Yaw Osei-Atweneboana
- Department of Environmental Biology and Health, Council for Scientific and Industrial Research Water Research Institute, Accra, Ghana
| | - Lisa J. Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
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Jones C, Ngasala B, Derua YA, Tarimo D, Reimer L, Bockarie M, Malecela MN. Lymphatic filariasis transmission in Rufiji District, southeastern Tanzania: infection status of the human population and mosquito vectors after twelve rounds of mass drug administration. Parasit Vectors 2018; 11:588. [PMID: 30424781 PMCID: PMC6234578 DOI: 10.1186/s13071-018-3156-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 10/17/2018] [Indexed: 11/25/2022] Open
Abstract
Background Control of lymphatic filariasis (LF) in most of the sub-Saharan African countries is based on annual mass drug administration (MDA) using a combination of ivermectin and albendazole. Monitoring the impact of this intervention is crucial for measuring the success of the LF elimination programmes. This study assessed the status of LF infection in Rufiji district, southeastern Tanzania after twelve rounds of MDA. Methods Community members aged between 10 and 79 years were examined for Wuchereria bancrofti circulating filarial antigens (CFA) using immunochromatographic test cards (ICTs) and antigen-positive individuals were screened for microfilaraemia. All study participants were examined for clinical manifestation of LF and interviewed for drug uptake during MDA rounds. Filarial mosquito vectors were collected indoor and outdoor and examined for infection with W. bancrofti using a microscope and quantitative real-time polymerase chain reaction (qPCR) techniques. Results Out of 854 participants tested, nine (1.1%) were positive for CFA and one (0.1%) was found to be microfilaraemic. The prevalence of hydrocele and elephantiasis was 4.8% and 2.9%, respectively. Surveyed drug uptake rates were high, with 70.5% of the respondents reporting having swallowed the drugs in the 2014 MDA round (about seven months before this study). Further, 82.7% of the respondents reported having swallowed the drugs at least once since the inception of MDA programme in 2000. Of the 1054 filarial vectors caught indoors and dissected to detect W. bancrofti infection none was found to be infected. Moreover, analysis by qPCR of 1092 pools of gravid Culex quinquefasciatus collected outdoors resulted in an estimated infection rate of 0.1%. None of the filarial vectors tested with qPCR were found to be infective. Conclusion Analysis of indices of LF infection in the human population and filarial mosquito vectors indicated a substantial decline in the prevalence of LF and other transmission indices, suggesting that local transmission was extremely low if occurring at all in the study areas. We, therefore, recommend a formal transmission assessment survey (TAS) to be conducted in the study areas to make an informed decision on whether Rufiji District satisfied WHO criteria for stopping MDA.
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Affiliation(s)
- Clarer Jones
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, P. O. Box 65011, Dar es Salaam, Tanzania.
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, P. O. Box 65011, Dar es Salaam, Tanzania.,Department of Women's and Children's Health International Maternal and Child Health (IMCH), Uppsala Universitet, Uppsala, Sweden
| | - Yahya A Derua
- National Institute for Medical Research, P. O. Box 9653, Dar es Salaam, Tanzania
| | - Donath Tarimo
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, P. O. Box 65011, Dar es Salaam, Tanzania
| | - Lisa Reimer
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Moses Bockarie
- European and Development Countries Clinical Trials Partnership, Cape Town, South Africa
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Derua YA, Rumisha SF, Batengana BM, Max DA, Stanley G, Kisinza WN, Mboera LEG. Lymphatic filariasis transmission on Mafia Islands, Tanzania: Evidence from xenomonitoring in mosquito vectors. PLoS Negl Trop Dis 2017; 11:e0005938. [PMID: 28985217 PMCID: PMC5646871 DOI: 10.1371/journal.pntd.0005938] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 10/18/2017] [Accepted: 09/06/2017] [Indexed: 11/19/2022] Open
Abstract
Introduction Lymphatic filariasis (LF) is a chronic nematode infection transmitted by mosquitoes and in sub-Saharan Africa it is caused by Wuchereria bancrofti. The disease was targeted for global elimination by 2020 using repeated community-wide mass drug administration (MDA) distributed in endemic areas. However, recently, there has been a growing recognition of the potential role of including vector control as a supplement to MDA to achieve elimination goal. This study was carried out to determine mosquito abundance and transmission of bancroftian filariasis on Mafia Islands in Tanzania as a prerequisite for a search for appropriate vector control methods to complement the ongoing MDA campaign. Methods Mosquitoes were collected indoor and outdoor using Centre for Disease Control (CDC) light and gravid traps, respectively. Collected mosquitoes were identified based on their differential morphological features and Anopheles gambiae complex and An. funestus group were further identified to their respective sibling species by polymerase chain reaction (PCR). Filarial mosquito vectors were then examined for infection with Wuchereria bancrofti by microscopy and PCR technique. Results Overall, a total of 35,534 filarial mosquito vectors were collected, of which Anopheles gambiae complex, An. funestus group and Culex quinquefasciatus Say accounted for 1.3, 0.5 and 98.2%, respectively. Based on PCR identification, An. gambiae sensu stricto (s.s) and An. funestus s.s sibling species accounted for 88.3% and 99.1% of the identified members of the An. gambiae complex and An. funestus group, respectively. A total of 7,936 mosquitoes were examined for infection with W. bancrofti by microscopy. The infection and infectivity rates were 0.25% and 0.08%, respectively. Using pool screen PCR technique, analysis of 324 mosquito pools (each with 25 mosquitoes) resulted to an estimated infection rate of 1.7%. Conclusion The study has shown that Cx. quinquefasciatus is the dominant mosquito on Mafia Islands. By using mosquito infectivity as proxy to human infection, the study indicates that W. bancrofti transmission is still ongoing on Mafia Islands after more than a decade of control activities based on MDA. Lymphatic filariasis is a chronic human disease caused by parasitic worms and transmitted by mosquitoes. The disease is targeted for elimination by 2020 through the treatment of the entire population at risk in endemic areas using a mass drug administration (MDA) strategy. After several years of MDA, there is now growing interest in including vector control as a supplement to MDA to achieve elimination goal. This study was carried out to determine mosquito abundance and transmission of lymphatic filariasis on Mafia Islands in Tanzania after nine rounds of MDA. Mosquitoes were collected indoor and outdoor using Centre for Disease Control (CDC) light and gravid traps, respectively. Filarial mosquito vectors were examined for infection with Wuchereria bancrofti by microscopy and PCR technique. A total of 35,534 filarial mosquito vectors were collected, of which Anopheles gambiae complex, An. funestus group and Culex quinquefasciatus Say accounted for 1.3, 0.5 and 98.2%, respectively. Using PCR, An. gambiae sensu stricto (s.s) and An. funestus s.s sibling species accounted for 88.3% and 99.1% of the identified members of the An. gambiae complex and An. funestus group, respectively. A total of 7,936 mosquitoes were examined for infection with W. bancrofti by microscopy. The infection and infectivity rates were 0.25% and 0.08%, respectively. Using PCR technique, of 324 mosquito pools (each with 25 mosquitoes) tested, 115 were found to be infected with at least a larval stage of W. bancrofti. The study concludes that Cx. quinquefasciatus is the dominant mosquito on Mafia Islands and that W. bancrofti transmission is still ongoing on Mafia Islands after a decade of control activities based on MDA.
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Affiliation(s)
- Yahya A. Derua
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania
| | - Susan F. Rumisha
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - Bernard M. Batengana
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania
| | - Demetrius A. Max
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania
| | - Grades Stanley
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
| | - William N. Kisinza
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania
| | - Leonard E. G. Mboera
- National Institute for Medical Research, Headquarters, Dar es Salaam, Tanzania
- * E-mail:
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Jones C, Ngasalla B, Derua YA, Tarimo D, Malecela MN. Lymphatic filariasis elimination efforts in Rufiji, southeastern Tanzania: decline in circulating filarial antigen prevalence in young school children after twelve rounds of mass drug administration and utilization of long-lasting insecticide-treated nets. Int J Infect Dis 2017; 61:38-43. [PMID: 28527817 PMCID: PMC5521953 DOI: 10.1016/j.ijid.2017.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 05/09/2017] [Accepted: 05/11/2017] [Indexed: 11/24/2022] Open
Abstract
Interventions based on mass drug administration and insecticide-treated nets led to a marked decline in Wuchereria bancrofti circulating filarial antigen (CFA) in young school children. The official reported treatment coverage was relatively higher than the surveyed coverage. There has been an increase in ownership and utilization of insecticide-treated nets in the study areas.
Background Lymphatic filariasis (LF) is a parasitic infection transmitted by mosquito vectors, and in Sub-Saharan Africa it is caused by the nematode Wuchereria bancrofti. The disease has been targeted for global elimination with the annual mass drug administration (MDA) strategy. Vector control is known to play an important complementary role to MDA in reducing the transmission of LF. The effects of an MDA and insecticide-treated net intervention implemented in an endemic area of southeastern Tanzania are reported here. Methods A cross-sectional study assessing W. bancrofti circulating filarial antigen (CFA) was conducted in five primary schools in five different villages. Standard one pupils aged 6–9 years were screened for CFA using immunochromatographic test cards (ICT), with a total of 413 screened in 2012 and 659 in 2015. Just after CFA testing, the children were interviewed on their participation in the MDA campaign. Moreover, 246 heads of households in 2012 and 868 in 2015 were interviewed on their participation in MDA and utilization of long-lasting insecticide-treated nets (LLINs). Results The prevalence of CFA for the 413 children tested in 2012 was 14.3%, while it was 0.0% for the 659 children tested in 2015. The Tanzanian National Lymphatic Filariasis Elimination Programme reported annual treatment coverage for Rufiji District ranging from 54.3% to 94.0% during the years 2002–2014. The surveyed treatment was 51.6% in 2011 and 57.4% in 2014. With regard to LLINs, possession and utilization increased from 63.4% and 59.2%, respectively, in 2012, to 92.5% and 75.4%, respectively, in 2015. Conclusions The findings suggest that 12 rounds of MDA complemented with vector control through the use of insecticide-treated nets resulted in a marked reduction in W. bancrofti CFA in young school children.
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Affiliation(s)
- Clarer Jones
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, United Nations Road, PO Box 65001, Dar es Salaam, Tanzania.
| | - Billy Ngasalla
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, United Nations Road, PO Box 65001, Dar es Salaam, Tanzania.
| | - Yahya A Derua
- National Institute for Medical Research, PO Box 9653, Dar es Salaam, Tanzania.
| | - Donath Tarimo
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, United Nations Road, PO Box 65001, Dar es Salaam, Tanzania.
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van den Berg H, Kelly-Hope LA, Lindsay SW. Malaria and lymphatic filariasis: the case for integrated vector management. THE LANCET. INFECTIOUS DISEASES 2012; 13:89-94. [PMID: 23084831 DOI: 10.1016/s1473-3099(12)70148-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The global programmes to eliminate both malaria and lymphatic filariasis are facing operational and technical challenges. Available data show that the use of treated or untreated bednets and indoor residual spraying for malaria control concomitantly reduced filarial rates. In turn, mass drug administration campaigns against lymphatic filariasis can be combined with the distribution of insecticide-treated bednets. Combining these disease control efforts could lead to more efficient use of resources, more accurate attribution of effects, and more effective control of both diseases. Systematic integration requires coordination at all levels, mapping of coendemic areas, and comprehensive monitoring and evaluation.
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Affiliation(s)
- Henk van den Berg
- Laboratory of Entomology, Wageningen University, Wageningen, Netherlands.
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Ashton RA, Kyabayinze DJ, Opio T, Auma A, Edwards T, Matwale G, Onapa A, Brooker S, Kolaczinski JH. The impact of mass drug administration and long-lasting insecticidal net distribution on Wuchereria bancrofti infection in humans and mosquitoes: an observational study in northern Uganda. Parasit Vectors 2011; 4:134. [PMID: 21756371 PMCID: PMC3158553 DOI: 10.1186/1756-3305-4-134] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 07/15/2011] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) in Uganda is caused by Wuchereria bancrofti and transmitted by anopheline mosquitoes. The mainstay of elimination has been annual mass drug administration (MDA) with ivermectin and albendazole, targeted to endemic districts, but has been sporadic and incomplete in coverage. Vector control could potentially contribute to reducing W. bancrofti transmission, speeding up progress towards elimination. To establish whether the use of long-lasting insecticidal nets (LLINs) can contribute towards reducing transmission of W. bancrofti in a setting with ongoing MDA, a study was conducted in an area of Uganda highly endemic for both LF and malaria. Baseline parasitological and entomological assessments were conducted in 2007, followed by high-coverage LLIN distribution. Net use and entomological surveys were carried out after one year, and final parasitological and entomological evaluations were conducted in 2010. Three rounds of MDA had taken place before the study commenced, with a further three rounds completed during the course of the study. RESULTS In 2007, rapid mapping indicated 22.3% of schoolchildren were W. bancrofti antigen positive, and a baseline survey during the same year found age-adjusted microfilaraemia prevalence was 3.7% (95% confidence interval (CI): 2.6-5.3%). In 2010, age-adjusted microfilaraemia prevalence had fallen to 0.4%, while antigenaemia rates were 0.2% in children < 5 years and 6.0% in ≥ 5 years. In 2010, universal coverage of mosquito nets in a household was found to be protective against W. bancrofti antigen (odds ratio = 0.44, 95% CI: 0.22-0.89). Prevalence of W. bancrofti larvae in anopheline mosquitoes had decreased significantly between the 2007 and 2010 surveys, but there was an apparent increase in vector densities. CONCLUSION A marked reduction in W. bancrofti infection and infectivity in humans was observed in the study area, where both MDA and LLINs were used to reduce transmission. The extent to which LLINs contributed to this decline is equivocal, however. Further work investigating the impact of vector control on anopheline-transmitted LF in an endemic area not benefitting from MDA would be valuable to determine the effect of such interventions on their own.
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Affiliation(s)
- Ruth A Ashton
- Malaria Consortium Africa, Kampala, Uganda
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Tom Opio
- District Health Office, Dokolo, Uganda
| | - Anna Auma
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Tansy Edwards
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Gabriel Matwale
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - Simon Brooker
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Malaria Public Health & Epidemiology Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Jan H Kolaczinski
- Malaria Consortium Africa, Kampala, Uganda
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
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Bonfim C, Netto MJE, Pedroza D, Portugal JL, Medeiros Z. A socioenvironmental composite index as a tool for identifying urban areas at risk of lymphatic filariasis. Trop Med Int Health 2009; 14:877-84. [PMID: 19624474 DOI: 10.1111/j.1365-3156.2009.02317.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To describe the spatial distribution of lymphatic filariasis and its relationship with the socioenvironmental risk indicator, thus identifying priority localities for interventions in endemic urban areas. METHODS The study area was the municipality of Jaboatão dos Guararapes, State of Pernambuco, Brazil. The data sources were a parasitological survey and the 2000 demographic census. From these data, a socioenvironmental composite risk indicator was constructed using the 484 census tracts (CT) as the analysis units, based on the score-formation technique. Census tracts with higher indicator values presented higher risk of occurrences of filariasis. RESULTS Six thousand five hundred and seven households were surveyed and 23 673 individuals were examined, among whom 323 cases of microfilaremia were identified. The mean prevalence rate for the municipality was 1.4%. The indicator showed that 73% (237/323) of the cases of microfilaremia were in high-risk areas (third and fourth quartiles) with worse socioenvironmental conditions (RR = 4.86, CI = 3.09-7.73, P < 0.05). CONCLUSIONS The socioenvironmental composite risk indicator demonstrated sensitivity, since it was able to identify the localities with greater occurrence of infection. Because it can stratify spaces by using official and available data, it constitutes an important tool for use in the worldwide program for eliminating lymphatic filariasis.
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Affiliation(s)
- C Bonfim
- Fundação Joaquim Nabuco, Ministério da Educação, Recife, Brazil.
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