Progress towards lymphatic filariasis elimination in Ghana from 2000-2016: Analysis of microfilaria prevalence data from 430 communities

Confirmatory mapping for lymphatic filariasis in districts previously considered nonendemic in Ghana

OBJECTIVES

Lymphatic filariasis (LF) elimination efforts in Ghana have been ongoing since 2001, achieving substantial progress through mass drug administration (MDA). However, despite significant advances, LF transmission persists in certain areas. Some districts previously classified as nonendemic have reported lymphedema and hydrocele cases, raising concerns about LF endemicity. To address these gaps, a confirmatory mapping survey was conducted to reassess LF prevalence in districts with uncertain morbidity.

METHODS

A cross-sectional survey using the WHO-approved LF confirmatory mapping tool was conducted in 38/261 districts Ghana. Schoolchildren aged 9-14 years were randomly selected using the TAS Survey Sample Builder tool. Circulating filarial antigen (CFA) levels were measured using the Filaria Test Strip (FTS). Districts were classified as endemic if more than three positive cases were identified out 480 sampled. Subdistrict-level community surveys were conducted to confirm findings.

RESULTS

A total of 18,459 children were tested across the selected districts. Positive antigen cases were detected in 17 districts, with two districts (Nkoranza South and Wenchi Municipal) exceeding the critical threshold of three positive cases. Subdistrict surveys further confirmed high antigen prevalence of 1.68% (95% CI, 0.92-2.80; range: 1.00-5.00) and 4.73% (95% CI, 3.35-6.46; range: 0.96-14.29) in the Nkoranza South and Wenchi Municipal districts respectively.

CONCLUSION

The confirmatory mapping survey revealed ongoing LF transmission in two previously classified nonendemic districts. These districts were reclassified as endemic, requiring MDA. Treatment has therefore been initiated in the Nkoranza South and Wenchi Municipal districts. This study underscores the importance of reassessing endemicity and implementing targeted interventions in areas with uncertain LF transmission.

Lymphatic filariasis transmission 10 years after stopping mass drug administration in the Gomoa west district of Ghana

OBJECTIVES

A survey was conducted 10 years after stopping MDA in the Gomoa West District of Ghana to assess the Wuchereria bancrofti prevalence in both human and mosquito populations.

METHODS

In seven communities, infection in humans was assessed using the filariasis test strip (FTS). Mosquitoes were collected once a month over six months using pyrethrum spray catches (PSC). The mosquitoes were analyzed for W. bancrofti infections, using dissection followed by poolscreening PCR.

RESULTS

FTS results showed that 2/524 (0.38%; 95% CI, 0.0%-0.9%) individuals tested positive for antigen. Dissections revealed W. bancrofti infections in 5/107 Anopheles gambiae (4.7%: 95% CI, 2.2-8.5) from one community, with three mosquitoes harboring L3 larvae (2.8%: 95% CI, 0.9-7.5). PCR analysis of 683 mosquitoes in 57 pools revealed seven positive pools from two communities. The prevalence of infected mosquitoes by PCR for the district was 3.1% (95% CI, 0.5-24.0) for An. gambiae and 2.5% (95% CI, 0.4-23.5) for all Anopheles spp.

CONCLUSIONS

The infection rate in the Anopheles spp. exceeds the provisional 1% threshold suggested by WHO, indicating ongoing transmission risk ten years after stopping MDA. Further district-wide assessments are recommended to inform the scope of any interventions required in the Gomoa West district.

Ghana's path towards eliminating lymphatic filariasis

Lymphatic filariasis, also known as elephantiasis, is a debilitating parasitic disease that has been prevalent in various parts of the world, including China and Ghana. This paper explores the historical context of lymphatic filariasis in Ghana and China, as well as the fights towards eliminating the disease in both countries. The review also covered the strategies employed by the Chinese government to eliminate lymphatic filariasis and the key lessons that Ghana can learn from China's success. The discussion highlights the importance of political commitment, multisectoral collaboration, tailoring control strategies to local contexts, adopting a comprehensive approach, and emphasising health education and community mobilisation. By adopting these lessons and fostering a robust national strategy, engaging diverse stakeholders, and ensuring active community involvement, Ghana can work towards achieving lymphatic filariasis elimination, improving public health, and fostering sustainable development.

Modelling the cost of engage & treat and test & treat strategies towards the elimination of lymphatic filariasis in Ghana

BACKGROUND

Despite several years of LF-MDA implementation, Ghana still has some districts with mf prevalence >1%, partly due to poor treatment coverage levels resulting from non-participation in MDA. To address the challenges, we implemented Engage & Treat (E&T) and Test & Treat (T&T) strategies for individuals who miss or refuse MDA respectively, in a hotspot district, enabling us to reach many of those who seldom, or never, take part in MDA. This financial cost study was undertaken to analyse data on the LF-MDA, E&T and T&T implementation in 2021 and the financial cost to inform the rollout of the E&T and T&T as mop-up strategies in future LF-MDAs.

METHODS

This costing study analysed cost data from the 2021 LF-MDA implementation activities carried out by the Neglected Tropical Diseases (NTD) programme of the Ghana Health Service and the SENTINEL study, carried out in Ahanta West district for the two interventions (i.e., E&T and T&T). The 2021 Ghana Population and Housing Census data was used to estimate the LF-MDA-eligible population. The financial cost per person treated was estimated and these costs were applied to the projected population to obtain the financial cost for subsequent years.

RESULTS

Implementing MDA mop-up strategies either through the E&T or T&T to improve coverage comes at an additional cost to the elimination goals. For example, in 2024 the projected cost per person treated by the routine LF-MDA is estimated at US$0.83. The cost using the integrated LF-MDA and the E&T, T&T led by the NTD programme or T&T integrated into the health system was estimated at US$1.62, US$2.88, and US$2.33, respectively, for the same year. Despite the increased cost, the proposed combined LF-MDA and mop-up strategies will have a higher estimated population treated for 2024 (i.e., 1,392,211) compared to the routine LF-MDA approach (i.e., 988,470) for the same year.

CONCLUSION

Combining LF-MDA with E&T/T&T mop-up strategies, despite their high costs, may provide NTD Programmes with the options of improving treatment coverage and reaching the LF elimination target sooner, given that the routine LF-MDA alone approach has been implemented for many years with some districts yet to reach the elimination targets.

An Ensemble Framework for Projecting the Impact of Lymphatic Filariasis Interventions Across Sub-Saharan Africa at a Fine Spatial Scale

BACKGROUND

Lymphatic filariasis (LF) is a neglected tropical disease targeted for elimination as a public health problem by 2030. Although mass treatments have led to huge reductions in LF prevalence, some countries or regions may find it difficult to achieve elimination by 2030 owing to various factors, including local differences in transmission. Subnational projections of intervention impact are a useful tool in understanding these dynamics, but correctly characterizing their uncertainty is challenging.

METHODS

We developed a computationally feasible framework for providing subnational projections for LF across 44 sub-Saharan African countries using ensemble models, guided by historical control data, to allow assessment of the role of subnational heterogeneities in global goal achievement. Projected scenarios include ongoing annual treatment from 2018 to 2030, enhanced coverage, and biannual treatment.

RESULTS

Our projections suggest that progress is likely to continue well. However, highly endemic locations currently deploying strategies with the lower World Health Organization recommended coverage (65%) and frequency (annual) are expected to have slow decreases in prevalence. Increasing intervention frequency or coverage can accelerate progress by up to 5 or 6 years, respectively.

CONCLUSIONS

While projections based on baseline data have limitations, our methodological advancements provide assessments of potential bottlenecks for the global goals for LF arising from subnational heterogeneities. In particular, areas with high baseline prevalence may face challenges in achieving the 2030 goals, extending the "tail" of interventions. Enhancing intervention frequency and/or coverage will accelerate progress. Our approach facilitates preimplementation assessments of the impact of local interventions and is applicable to other regions and neglected tropical diseases.

Knowledge and perceptions of lymphatic filariasis patients in selected hotspot endemic communities in southern Ghana

Lymphatic filariasis (LF) is a mosquito-borne neglected tropical disease that is one of the leading global causes of permanent disability. To date, LF interventions have been largely biomedical, focusing on drug treatments to disrupt parasite transmission and manage disease morbidity. Although important, these Mass Drug Administration (MDA) programs neglect the significance of socio-economic burden to the health of LF patients, which are compounded by social stigmatization, discrimination and associated depressive illnesses. The MDA program also typically fails to engage with local community beliefs and perceptions of LF, which may differ markedly from biomedical explanations and may have fueled non-compliance to treatments which is one of the major challenges of the Mass Drug Administration program. LF is not only a biomedical issue but also a social issue and LF interventions need to understand people's world views and the contexts through which they interpret bodily maladies. Hence, an effective LF intervention must bring together both the biomedical and the social components. The goal of this exploratory study was to assist in refining a large qualitative study (currently underway) that seeks to integrate culturally appropriate LF interventions into current LF control programs in Ghana. In this paper, we discuss the findings of a pre-intervention, exploratory study aimed at gaining a baseline grasp of a local culturally informed understanding of lymphatic filariasis and the knowledge gaps looking at three endemic Ghanaian communities in the Ahanta West District. A structured questionnaire was employed to assess the wellbeing, social inclusion, and cultural understanding of LF with a geographic focus within LF-endemic areas in Ghana. Interestingly, 45.8% of the 72 participants reported to have received information about LF from health care providers and the MDA program but only 5 out of the 72 (6.9%) respondents believed that LF was transmitted by mosquitos. This baseline study revealed several alternative interpretations and misconceptions about the disease, as well as the social and economic impacts, and importantly, the need to integrate qualitative research to develop culturally appropriate interventions and increase engagement with existing control programs.

Perceptions of the roles, impact, challenges and needs of community drug distributors in the control and elimination of neglected tropical diseases in difficult-to-access communities in Ghana

INTRODUCTION

The success of mass drug administration (MDA) campaigns to control and eliminate neglected tropical diseases (NTDs) in Ghana depends, to a large extent, on the essential role community drug distributors (CDDs) play. This study aimed to investigate community's perceptions of CDDs' roles, impact of CDDs' work, challenges faced by CDDs, and views on resources required to enhance CDDs' work to sustain MDA campaigns.

METHODS

A cross-sectional qualitative study employing the use of focus group discussions (FGDs) with community members and CDDs in selected NTD endemic communities together with individual interviews with district health officers (DHOs) was conducted. We interviewed 104 people aged 18 and over, purposively selected, through eight individual interviews, and 16 focus group discussions.

RESULTS

Participants in the community FGDs noted that health education and the distribution of drugs were the main roles of CDDs. Participants also perceived that the work of CDDs had prevented the onset of NTDs, treated symptoms of NTDs, and generally reduced the incidence of infections. In the interviews with CDDs and DHOs, lack of cooperation/non-compliance by community members, demands by community members, lack of working resources and low financial motivation were mentioned as the main challenges to the work of CDDs. Moreover, the provision of logistics and financial motivation for CDDs were identified as factors that will enhance their work.

CONCLUSIONS

Incorporating more attractive schemes will incentivise CDDs to improve output. Addressing the challenges highlighted is an important step for the work of CDDS to be effective in controlling NTDs in difficult-to-access communities in Ghana.

Perceptions of the roles, impact, challenges and needs of community drug distributors in the control and elimination of neglected tropical diseases in difficult-to-access communities in Ghana

The success of mass drug administration (MDA) campaigns to control and eliminate neglected tropical diseases (NTDs) in Ghana depends, to a large extent, on the essential role community drug distributors (CDDs) play. This study aimed to investigate community's perceptions of CDDs' roles, impact of CDDs' work, challenges faced by CDDs and views on resources required to enhance CDDs' work to sustain MDA campaigns. Methods : A cross-sectional qualitative study employing the use of focus group discussions (FGDs) with community members and CDDs in selected NTD endemic communities together with individual interviews with district health officers (DHOs)was conducted. We interviewed 104 people aged 18 and over, purposively selected, through eight individual interviews, and 16 focus group discussions. Results : Participants in the community FGDs noted that health education and distribution of drugs were the main roles of CDDs. Participants also perceived that the work of CDDs had prevented the onset of NTDs, treated symptoms of NTDs and generally reduced the incidence of infections. In the interviews with CDDs and DHOs, lack of cooperation/non-compliance by community members, demands by community members, lack of working resources and low financial motivation were mentioned as the main challenges to the work of CDDs. Moreover, provision of logistics and financial motivation for CDDs were identified as factors that will enhance their work. Conclusions : Incorporating more attractive schemes shall incentivise CDDs to improve output. Addressing the challenges highlighted is an important step for the work of CDDS to be effective in controlling NTDs in difficult-to-access communities in Ghana.

Criteria for selecting sentinel unit locations in a surveillance system for vector-borne disease: A decision tool

Objectives

With vector-borne diseases emerging across the globe, precipitated by climate change and other anthropogenic changes, it is critical for public health authorities to have well-designed surveillance strategies in place. Sentinel surveillance has been proposed as a cost-effective approach to surveillance in this context. However, spatial design of sentinel surveillance system has important impacts on surveillance outcomes, and careful selection of sentinel unit locations is therefore an essential component of planning.

Methods

A review of the available literature, based on the realist approach, was used to identify key decision issues for sentinel surveillance planning. Outcomes of the review were used to develop a decision tool, which was subsequently validated by experts in the field.

Results

The resulting decision tool provides a list of criteria which can be used to select sentinel unit locations. We illustrate its application using the case example of designing a national sentinel surveillance system for Lyme disease in Canada.

Conclusions

The decision tool provides researchers and public health authorities with a systematic, evidence-based approach for planning the spatial design of sentinel surveillance systems, taking into account the aims of the surveillance system and disease and/or context-specific considerations.

Semiannual Treatment of Albendazole Alone is Efficacious for Treatment of Lymphatic Filariasis: A Randomized Open-label Trial in Cote d'Ivoire

BACKGROUND

Ivermectin (IVM) plus albendazole (ALB), or IA, is widely used in mass drug administration (MDA) programs that aim to eliminate lymphatic filariasis (LF) in Africa. However, IVM can cause severe adverse events in persons with heavy Loa loa infections that are common in Central Africa. ALB is safe in loiasis, but more information is needed on its efficacy for LF. This study compared the efficacy and safety of 3 years of semiannual treatment with ALB to annual IA in persons with bancroftian filariasis.

METHODS

Adults with Wuchereria bancrofti microfilaremia (Mf) were randomized to receive either 3 annual doses of IA (N = 52), 6 semiannual doses of ALB 400 mg (N = 45), or 6 semiannual doses of ALB 800 mg (N = 47). The primary outcome is amicrofilaremia at 36 months.

RESULTS

IA was more effective for completely clearing Mf than ALB 400mg or ALB 800mg (79%, 95% confidence interval [CI]: 67-91; vs 48%, 95% CI: 32-66 and 57%, 95% CI: 41-73, respectively). Mean percentage reductions in Mf counts at 36 months relative to baseline tended to be greater after IA (98%, 95% CI: 88-100) than after ALB 400 mg (88%, 95% CI: 78-98) and ALB 800 mg (89%, 95% CI: 79-99) (P = .07 and P = .06, respectively). Adult worm nest numbers (assessed by ultrasound) were reduced in all treatment groups. Treatments were well tolerated.

CONCLUSIONS

Repeated semiannual treatment with ALB is macrofilaricidal for W. bancrofti and leads to sustained reductions in Mf counts. This is a safe and effective regimen that could be used as MDA to eliminate LF in areas where ivermectin cannot be used.

CLINICAL TRIALS REGISTRATION

NCT02974049.

Mapping Spatial Variation and Impact of the National MDA Program on Lymphatic Filariasis Elimination in Ghana: An Initial Study

Lymphatic filariasis (LF) is a public health menace, especially in developing countries. A periodic review of mass drug administration (MDA) performance is critical to monitoring elimination progress. However, investigating the spatial pattern of LF with respect to MDA intervention is yet to be documented. This is essential to appreciating the transmission dynamics across LF-endemic communities and how it is spatially impacted by MDA programs. The aim of this study was to map and explore the spatial variation and hotspots of LF infection among endemic communities and evaluate the impact of the MDA intervention program on its spatial pattern in Ghana. Relative risks, clustering and clusters, prevalence odds ratios, and their confidence intervals were studied with community-level LF data prior to intervention and post intervention periods. The overall risk of LF infection was 0.12% and 0.02% before and after MDA, respectively, suggesting reduced transmission. Using empirical Bayesian smoothing to map the relative risk, a substantial variation in the spatial distribution of the relative risk of LF among endemic communities was observed. Most of the excess prevalence communities were unexpectedly visible even after years of MDA. The Empirical Bayesian Moran’s Index for global clustering showed a reduction in clustering of LF prevalence after MDA with IM = 0.455 and 0.119 for before and after MDA, respectively. Furthermore, examining risks associated with ecological zones, it was observed that the Guinea Savannah and the Transition Zone were the most vulnerable zones for LF infection with prevalence odds ratios 18.70- and 13.20-fold higher than in the reference Moist evergreen zone, respectively. We observed a drastic reduction in risk in the Wet evergreen zone after MDA, while the Guinea Savannah sustained high levels of risk even after MDA. These findings should prompt public health officials to adopt stratified cluster sampling in LF-endemic regions to monitor the rate and density of microfilaria.

Community views on mass drug administration for filariasis: a qualitative evidence synthesis

BACKGROUND

The World Health Organization (WHO) recommends mass drug administration (MDA), giving a drug at regular intervals to a whole population, as part of the strategy for several disease control programmes in low- and middle-income countries. MDA is currently WHO policy for areas endemic with lymphatic filariasis, which is a parasitic disease that can result in swollen limbs and disability. The success depends on communities adhering to the drugs given, and this will be influenced by the perception of the drug, the programme, and those delivering it.  OBJECTIVES: To synthesize qualitative research evidence about community experience with, and understanding and perception of, MDA programmes for lymphatic filariasis. To explore whether programme design and delivery influence the community experience identified in the analysis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and seven other databases up to 8 April 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

This review synthesized qualitative research and mixed-methods studies when it was possible to extract qualitative data. Eligible studies explored community experiences, perceptions, or attitudes towards MDA programmes for lymphatic filariasis in any country, conducted between 2000 and 2019.  DATA COLLECTION AND ANALYSIS: We extracted data on study design including: authors, aims, participants, methods, and qualitative data collection methods. We also described programme delivery factors including: country, urban or rural setting, endemicity, drug regimen, rounds of MDA received at the time of the study, who delivered the drugs, how the drugs were delivered, use of health education, and sensitization and adherence monitoring. We conducted a thematic analysis and developed codes inductively using ATLAS.ti software. We examined codes for underlying ideas, connections, and interpretations and, from this, generated analytical themes. We assessed the confidence in the findings using the GRADE-CERQual approach, and produced a conceptual model to display our findings.  MAIN RESULTS: From 902 results identified in the search, 29 studies met our inclusion criteria. The studies covered a broad range of countries in Africa, South-East Asia, and South America, and explored the views and experiences of community members and community drug distributors in low-income countries endemic for lymphatic filariasis. Four themes emerged. People weigh up benefits and harms before participating. People understand the potential benefits in terms of relief of suffering, stigma, and avoiding costs (high confidence); however, these theoretical benefits do not always mesh with their experiences (high confidence). In particular, adverse effects are frightening and unwelcome (high confidence); and these effects are amplified through rumour and social media (moderate confidence). Many people are suspicious of MDA programmes. When people lack a scientific explanation for the programme and their experiences of it, they often develop social explanations instead. These are largely shaped on the historical backdrop and level of trust people have in relevant authority figures (high confidence), although some have unwavering faith in their government and, by extension, the programme (moderate confidence). Programmes expect compliance, and this can become coercive and blaming. Health workers and community members stigmatize non-compliance, which can become coercive (moderate confidence), so communities may appear to comply publicly, but privately reject treatment (moderate confidence). Community distributors are often not respected or valued. They have little authority (moderate confidence), and the behaviour of some distributors damages the MDA programme's reputation (high confidence). Communities want information about programmes to help make decisions about participation, but drug distributors are not sufficiently informed, or skilled in this communication (high confidence). We intended to assess whether programme designs influenced communities' perceptions of the programme and decision to adhere but were unable to do so as few studies adequately reported the design and implementation of the local programme. We have moderate to high confidence in the evidence contributing to the review themes and subthemes.

AUTHORS' CONCLUSIONS

Adherence with MDA for filariasis is influenced by individual direct experience of benefit and harm; social influences in the community; political influences and their relationship to government; and historical influences. Fear of adverse effects was frequently described and this appears to be particularly important for communities. When views were negative, we were surprised by the strength of feeling expressed. Enthusiasm for these schemes as a strategy in global policy needs debate in the light of these findings.

Coverage Validation Survey for Lymphatic Filariasis Treatment in Itang Special District of Gambella Regional State of Ethiopia: A Cross-Sectional Study

Background

Lymphatic filariasis (LF) is one of the most debilitating and disfiguring diseases common in Ethiopia. In order to alleviate this problem Mass drug administration (MDA) has been given once a year for the public living in endemic sites. Despite this fact there might be a difference between reported coverage and the actual coverage on the ground due to various errors, so assessing the actual coverage through coverage validation survey appears imperative.

Objective

The aim of this survey was to assess the difference between the reported coverage and actual coverage of Ivermectin (IVM) and Albendazole (ALB) treatment given for Lymphatic Filariasis in Itang special district of Gambella regional state, Ethiopia.

Setting

The study was conducted in Itang special district of Gambella region, the district was purposively selected for lymphatic filariasis treatment coverage survey. Eligible individuals aged 5 and above were interviewed. Data about the children were collected from parents or guardians and analyzed using STATA.

Results

The survey showed that the coverage for LF treatment was 81.5%. From 825 individuals that reported that they were offered the treatment 823 (99.6%) swallowed the drug. The coverage in school age children (5-14) shows significant difference with treatment coverage in individuals aged 15 and above (p<0.001) in the last mass drug administration campaign. The main reason for not being offered preventive chemotherapy (PC) during the mass drug administration campaigns was missing class during the MDA (37.2%).

Conclusion

The treatment coverage is higher than the recommended coverage of 65% of the target population. The coverage in school age children (5-14) showed significant difference with treatment coverage in individuals aged 15 and above. Improving the coverage level beyond this can significantly contribute to the LF elimination goal.

Spatial variation in lymphatic filariasis risk factors of hotspot zones in Ghana

BACKGROUND

Lymphatic Filariasis (LF), a parasitic nematode infection, poses a huge economic burden to affected countries. LF endemicity is localized and its prevalence is spatially heterogeneous. In Ghana, there exists differences in LF prevalence and multiplicity of symptoms in the country's northern and southern parts. Species distribution models (SDMs) have been utilized to explore the suite of risk factors that influence the transmission of LF in these geographically distinct regions.

METHODS

Presence-absence records of microfilaria (mf) cases were stratified into northern and southern zones and used to run SDMs, while climate, socioeconomic, and land cover variables provided explanatory information. Generalized Linear Model (GLM), Generalized Boosted Model (GBM), Artificial Neural Network (ANN), Surface Range Envelope (SRE), Multivariate Adaptive Regression Splines (MARS), and Random Forests (RF) algorithms were run for both study zones and also for the entire country for comparison.

RESULTS

Best model quality was obtained with RF and GBM algorithms with the highest Area under the Curve (AUC) of 0.98 and 0.95, respectively. The models predicted high suitable environments for LF transmission in the short grass savanna (northern) and coastal (southern) areas of Ghana. Mainly, land cover and socioeconomic variables such as proximity to inland water bodies and population density uniquely influenced LF transmission in the south. At the same time, poor housing was a distinctive risk factor in the north. Precipitation, temperature, slope, and poverty were common risk factors but with subtle variations in response values, which were confirmed by the countrywide model.

CONCLUSIONS

This study has demonstrated that different variable combinations influence the occurrence of lymphatic filariasis in northern and southern Ghana. Thus, an understanding of the geographic distinctness in risk factors is required to inform on the development of area-specific transmission control systems towards LF elimination in Ghana and internationally.

Achievements and challenges of lymphatic filariasis elimination in Sierra Leone

BACKGROUND

Lymphatic filariasis (LF) is targeted for elimination in Sierra Leone. Epidemiological coverage of mass drug administration (MDA) with ivermectin and albendazole had been reported >65% in all 12 districts annually. Eight districts qualified to implement transmission assessment survey (TAS) in 2013 but were deferred until 2017 due to the Ebola outbreak (2014-2016). In 2017, four districts qualified for conducting a repeat pre-TAS after completing three more rounds of MDA and the final two districts were also eligible to implement a pre-TAS.

METHODOLOGY/PRINCIPAL FINDINGS

For TAS, eight districts were surveyed as four evaluation units (EU). A school-based survey was conducted in children aged 6-7 years from 30 clusters per EU. For pre-TAS, one sentinel and one spot check site per district (with 2 spot check sites in Bombali) were selected and 300-350 persons aged 5 years and above were selected. For both surveys, finger prick blood samples were tested using the Filariasis Test Strips (FTS). For TAS, 7,143 children aged 6-7 years were surveyed across four EUs, and positives were found in three EUs, all below the critical cut-off value for each EU. For the repeat pre-TAS/pre-TAS, 3,994 persons over five years of age were surveyed. The Western Area Urban had FTS prevalence of 0.7% in two sites and qualified for TAS, while other five districts had sites with antigenemia prevalence >2%: 9.1-25.9% in Bombali, 7.5-19.4% in Koinadugu, 6.1-2.9% in Kailahun, 1.3-2.3% in Kenema and 1.7% - 3.7% in Western Area Rural.

CONCLUSIONS/SIGNIFICANCE

Eight districts in Sierra Leone have successfully passed TAS1 and stopped MDA, with one more district qualified for conducting TAS1, a significant progress towards LF elimination. However, great challenges exist in eliminating LF from the whole country with repeated failure of pre-TAS in border districts. Effort needs to be intensified to achieve LF elimination.