Elimination Of Lymphatic Filariasis Research Articles

The burden of lymphatic filariasis and its control strategies in Sierra Leone: A literature review

Lymphatic filariasis (LF) poses a significant health burden in Sierra Leone, with considerable socio-economic implications. LF, caused by parasitic worms transmitted through mosquito bites, leads to lymphedema, elephantiasis, and hydrocele, severely affecting individuals’ quality of life. Sierra Leone, with its tropical climate and inadequate healthcare infrastructure, faces unique challenges in combating lymphatic filariasis. This review explores the epidemiological landscape of LF in Sierra Leone, highlighting endemic regions, its impact, and control strategies. In 2005, epidemiological coverage of high-dose medications, like ivermectin and albendazole, exceeded 65% annually across 12 districts in Sierra Leone. By 2013, eight districts were eligible for transmission assessment surveys (TAS). After three additional rounds of mass drug administration (MDA), four districts became eligible for pre-TAS assessments in 2017. Despite efforts to control LF through mass drug administration (MDA) programs, challenges such as low treatment coverage, logistical constraints, and community resistance persist. Moreover, the impact of the Ebola outbreak on healthcare delivery has further impeded LF control efforts. This literature review adds to our understanding of LF control in Sierra Leone, providing valuable insights into the epidemiology, impact, challenges, and potential strategies for enhancing LF elimination efforts. It contributes to the broader discourse on neglected tropical diseases and public health interventions, emphasizing the need for context-specific approaches and interdisciplinary collaboration to achieve sustained progress towards LF elimination and improves public health outcomes.

Subnational Projections of Lymphatic Filariasis Elimination Targets in Ethiopia to Support National Level Policy.

Lymphatic filariasis (LF) is a debilitating, poverty-promoting, neglected tropical disease (NTD) targeted for worldwide elimination as a public health problem (EPHP) by 2030. Evaluating progress towards this target for national programmes is challenging, due to differences in disease transmission and interventions at the subnational level. Mathematical models can help address these challenges by capturing spatial heterogeneities and evaluating progress towards LF elimination and how different interventions could be leveraged to achieve elimination by 2030. Here we used a novel approach to combine historical geo-spatial disease prevalence maps of LF in Ethiopia with 3 contemporary disease transmission models to project trends in infection under different intervention scenarios at subnational level. Our findings show that local context, particularly the coverage of interventions, is an important determinant for the success of control and elimination programmes. Furthermore, although current strategies seem sufficient to achieve LF elimination by 2030, some areas may benefit from the implementation of alternative strategies, such as using enhanced coverage or increased frequency, to accelerate progress towards the 2030 targets. The combination of geospatial disease prevalence maps of LF with transmission models and intervention histories enables the projection of trends in infection at the subnational level under different control scenarios in Ethiopia. This approach, which adapts transmission models to local settings, may be useful to inform the design of optimal interventions at the subnational level in other LF endemic regions.

How Does the Proportion of Never Treatment Influence the Success of Mass Drug Administration Programs for the Elimination of Lymphatic Filariasis?

Mass drug administration (MDA) is the cornerstone for the elimination of lymphatic filariasis (LF). The proportion of the population that is never treated (NT) is a crucial determinant of whether this goal is achieved within reasonable time frames. Using 2 individual-based stochastic LF transmission models, we assess the maximum permissible level of NT for which the 1% microfilaremia (mf) prevalence threshold can be achieved (with 90% probability) within 10 years under different scenarios of annual MDA coverage, drug combination and transmission setting. For Anopheles-transmission settings, we find that treating 80% of the eligible population annually with ivermectin + albendazole (IA) can achieve the 1% mf prevalence threshold within 10 years of annual treatment when baseline mf prevalence is 10%, as long as NT <10%. Higher proportions of NT are acceptable when more efficacious treatment regimens are used. For Culex-transmission settings with a low (5%) baseline mf prevalence and diethylcarbamazine + albendazole (DA) or ivermectin + diethylcarbamazine + albendazole (IDA) treatment, elimination can be reached if treatment coverage among eligibles is 80% or higher. For 10% baseline mf prevalence, the target can be achieved when the annual coverage is 80% and NT ≤15%. Higher infection prevalence or levels of NT would make achieving the target more difficult. The proportion of people never treated in MDA programmes for LF can strongly influence the achievement of elimination and the impact of NT is greater in high transmission areas. This study provides a starting point for further development of criteria for the evaluation of NT.

Factors associated with never treatment and acceptability of mass drug administration for the elimination of lymphatic filariasis in Guyana, 2021.

Guyana remains one of four countries in the Americas endemic for lymphatic filariasis (LF). Elimination of LF requires repeated annual mass drug administration (MDA) with sufficient levels of coverage for success. This study assesses the acceptability and never treatment of LF MDA using data from a routine assessment survey in 2021. A subset of individuals, over 20 years of age (n = 2498), were selected to receive an expanded questionnaire to examine factors associated with acceptability and never treatment. Assessed factors include respondent demographics, knowledge, risk perceptions of LF, and opinions on the MDA programme. The majority (73%) of those with scores above the acceptability threshold (score ≥22.5) reported participating in MDA two or more times. Factors strongly and positively associated with scoring above the acceptability threshold include beliefs in importance of participation in MDA for their community (aOR = 2.8, 95%CI (1.1-7.2)), perception of importance of LF treatment (6.9 (3.2-14.7)), receiving treatment in 2021 (2.9 (1.5-5.4)), and the number of self-reported times taking treatment for LF (2.2 (1.1-4.4)). Ten percent of respondents participated in the MDA for the first time in 2021, while 15% reported never treatment during any round of LF MDA. Three factors were statistically associated with participation in MDA across the two levels of the models (level 1: took LF treatment once versus never, and level 2: took LF treatment twice versus never) included: 1) scoring above the acceptability threshold (aOR = 6.2, 95%CI(3.8-10.0)), 2) self-reported importance of participation in MDA for their community (7.1 (2.9-17.8)), and 3) personal beliefs that they should take LF treatment even if they are not sick (2.6 (1.7-3.9)). As Guyana moves closer to LF elimination, these results provide further insight and understanding into programmatic results and could inform further action following MDA activities-particularly if an approach is needed to address never treatment during MDA.

Predictive Value of Microfilariae-Based Stop-MDA Thresholds After Triple Drug Therapy With IDA Against Lymphatic Filariasis in Treatment-Naive Indian Settings.

Mass drug administration (MDA) of antifilarial drugs is the main strategy for the elimination of lymphatic filariasis (LF). Recent clinical trials indicated that the triple-drug therapy with ivermectin, diethylcarbamazine, and albendazole (IDA) is much more effective against LF than the widely used two-drug combinations (albendazole plus either ivermectin or diethylcarbamazine). For IDA-based MDA, the stop-MDA decision is made based on microfilariae (mf) prevalence in adults. In this study, we assess how the probability of eventually reaching elimination of transmission depends on the critical threshold used in transmission assessment surveys (TAS-es) to define whether transmission was successfully suppressed and triple-drug MDA can be stopped. This analysis focuses on treatment-naive Indian settings. We do this for a range of epidemiological and programmatic contexts, using the established LYMFASIM model for transmission and control of LF. Based on our simulations, a single TAS, one year after the last MDA round, provides limited predictive value of having achieved suppressed transmission, while a higher MDA coverage increases elimination probability, thus leading to a higher predictive value. Every additional TAS, conditional on previous TAS-es being passed with the same threshold, further improves the predictive value for low values of stop-MDA thresholds. An mf prevalence threshold of 0.5% corresponding to TAS-3 results in ≥95% predictive value even when the MDA coverage is relatively low.

Reducing the Antigen Prevalence Target Threshold for Stopping and Restarting Mass Drug Administration for Lymphatic Filariasis Elimination: A Model-Based Cost-effectiveness Simulation in Tanzania, India and Haiti.

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) aims to reduce and maintain infection levels through mass drug administration (MDA), but there is evidence of ongoing transmission after MDA in areas where Culex mosquitoes are the main transmission vector, suggesting that a more stringent criterion is required for MDA decision making in these settings. We use a transmission model to investigate how a lower prevalence threshold (<1% antigenemia [Ag] prevalence compared with <2% Ag prevalence) for MDA decision making would affect the probability of local elimination, health outcomes, the number of MDA rounds, including restarts, and program costs associated with MDA and surveys across different scenarios. To determine the cost-effectiveness of switching to a lower threshold, we simulated 65% and 80% MDA coverage of the total population for different willingness to pay per disability-adjusted life-year averted for India ($446.07), Tanzania ($389.83), and Haiti ($219.84). Our results suggest that with a lower Ag threshold, there is a small proportion of simulations where extra rounds are required to reach the target, but this also reduces the need to restart MDA later in the program. For 80% coverage, the lower threshold is cost-effective across all baseline prevalences for India, Tanzania, and Haiti. For 65% MDA coverage, the lower threshold is not cost-effective due to additional MDA rounds, although it increases the probability of local elimination. Valuing the benefits of elimination to align with the GPELF goals, we find that a willingness to pay per capita government expenditure of approximately $1000-$4000 for 1% increase in the probability of local elimination would be required to make a lower threshold cost-effective. Lower Ag thresholds for stopping MDAs generally mean a higher probability of local elimination, reducing long-term costs and health impacts. However, they may also lead to an increased number of MDA rounds required to reach the lower threshold and, therefore, increased short-term costs. Collectively, our analyses highlight that lower target Ag thresholds have the potential to assist programs in achieving lymphatic filariasis goals.

Heterogeneity in elimination efforts could increase the risk of resurgence of lymphatic filariasis in Madagascar

BackgroundProgress in lymphatic filariasis (LF) elimination is spatially heterogeneous in many endemic countries, which may lead to resurgence in areas that have achieved elimination. Understanding the drivers and consequences of such heterogeneity could help inform strategies to reach global LF elimination goals by 2030. This study assesses whether differences in age-specific compliance with mass drug administration (MDA) could explain LF prevalence patterns in southeastern Madagascar and explores how spatial heterogeneity in prevalence and age-specific MDA compliance may affect the risk of LF resurgence after transmission interruption. MethodologyWe used LYMFASIM model with parameters in line with the context of southeastern Madagascar and explored a wide range of scenarios with different MDA compliance for adults and children (40–100%) to estimate the proportion of elimination, non-elimination and resurgence events associated with each scenario. Finally, we evaluated the risk of resurgence associated with different levels of migration (2–6%) from surrounding districts combined with varying levels of LF microfilaria (mf) prevalence (0–24%) during that same study period. ResultsDifferences in MDA compliance between adults and children better explained the observed heterogeneity in LF prevalence for these age groups than differences in exposure alone. The risk of resurgence associated with differences in MDA compliance scenarios ranged from 0 to 19% and was highest when compliance was high for children (e.g. 90%) and low for adults (e.g. 50%). The risk of resurgence associated with migration was generally higher, exceeding 60% risk for all the migration levels explored (2–6% per year) when mf prevalence in the source districts was between 9% and 20%. ConclusionGaps in the implementation of LF elimination programme can increase the risk of resurgence and undermine elimination efforts. In Madagascar, districts that have not attained elimination pose a significant risk for those that have achieved it. More research is needed to help guide LF elimination programme on the optimal strategies for surveillance and control that maximize the chances to sustain elimination and avoid resurgence.

Motivation-opportunity-ability-behaviour of community members and program implementers towards mass drug administration for lymphatic filariasis elimination in India: a systematic review and implementation priority.

Lymphatic filariasis (LF) is a significant public health issue in India. Despite 10-15 rounds of mass drug administration (MDA) in India, the global LF elimination target of 2030 appears challenging. To strengthen the program, community and provider perspectives on ways to bridge a gap in MDA are needed. Through the motivation-opportunity-ability-behaviour (MOAB) lens, we systematically reviewed the facilitators and barriers encountered in LF elimination in India. We followed Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. We searched PubMed, Embase, ProQuest and Google Scholar databases to explore factors related to MDA program implementation in India through 30 June 2021. We analysed the data using a thematic framework. We identified 576 studies; of these, 20 studies were included. This review revealed that the public health system for distributing MDA drugs in India created a better enabling environment, including zero out-of-pocket expenditure, door-step distribution of medicines and ample capacity-building training and follow-up. However, community members were unaware of the rationale for drug consumption, leading to a gap in drug distribution and consumption. Motivation is required among community members, which suggests capacity-building training for service providers to counsel the community.

Towards global elimination of lymphatic filariasis: a systematic review of the application of spatial epidemiological methods to enhance surveillance and support elimination programmes

BackgroundIn recent decades, spatial epidemiology has increasingly been used to study neglected tropical diseases (NTDs). Spatial methods are particularly relevant when transmission is strongly driven by sociodemographic and environmental factors,...

The effectiveness of albendazole against hookworm infections and the impact of bi-annual treatment on anaemia and body mass index of school children in the Kpandai district of northern Ghana.

The impact of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) (initiated in 2000 in Ghana and ran for 12 years) in mitigating soil-transmitted helminth (STH) infections in LF-endemic areas is unknown. During a 1-year hiatus which ensued between 2011 and 2012, a longitudinal study was conducted to determine GPELF effect on hookworm infections in selected communities involved in the programme since its inception, while measuring the effectiveness of biannual ALB treatments on schoolchildren living in such communities. A total of 399 school children aged 3 to 18 years were randomly selected from four communities in the Kpandai district of northern Ghana. Each presented a single stool sample at baseline, 21 days post-treatment, at the 3rd and 6th months, 21 days post-second intervention (i.e. following sample collection and treatment with ALB in the 6th month), and in the ninth month of the study period. Haemoglobin (hb) levels were also measured at all time points using finger prick blood samples and a URIT digital test kit. Each participant submitting a sample, was treated with a single-dose ALB (400mg) at baseline and in the sixth month. Stool samples were processed by preparing duplicate Kato-Katz slides per sample, and examined by microscopy. The Body Mass Index-for-age z-scores (BAZ) of participants were assessed following the determination of BMIs at each time point by measuring their height and weight with a stadiometer and weighing scale. Overall hookworm prevalences were 25.68% (95% CI = 20.51-31.75) at baseline, 11.18% (95% CI = 7.87-15.41) 21 days post-treatment, 11.78% (95% CI = 8.38-16.11) and 6.95% (95% CI = 4.41-10.43) in the 3rd and 6th months, 0.91% (95% CI = 0.19-2.65) 21 days post-second intervention, and 8.46% (95% CI = 5.62-12.23) in the ninth month. Observed overall faecal egg count reduction rates (ERRs) were 94.21% (95% CI = 81.50%- 100.00%) 21 days after baseline treatment, 97.70% (95% CI = 85.08-100.00) and 96.95% (95% CI = 84.18%- 100.00%) in the 3rd and 6th months, 99.98% (95% CI = 86.42%- 100.00%) 21 days post-second intervention, and 17.18% (95% CI = 14.07%- 20.67%) in the 9th month. Respective cure rates (CRs) were 62.35% (95% CI = 46.71-81.56%), 85.88% (95% CI = 67.32-100.00%), 87.06% (95% CI = 68.36%- 100.00%), 98.82% (95% CI = 78.83%- 100.00%), and 36.36% (95% CI = 9.91%- 93.11%). Additionally, increases in the percent frequency of 'normal hb' (p < 0.01) were observed across the study time points, whilst 'normal BAZ' cases remained high (from 94.87% to 98.87%) throughout the study period. These findings primarily indicate satisfactory effectiveness of ALB which may be maintainable in mass drug administration programmes by the modification of treatment strategies from annual to bi-annual regimes. This could minimize the likelihood of emerging poorly-responding hookworm phenotypes in Ghana. Additionally, a positive impact of bi-annual treatment on participant anaemia status is herein indicated with particular regard to the school children in our cohort.

Elimination of lymphatic filariasis as a public health problem in Malawi.

Lymphatic filariasis (LF) is a parasitic disease transmitted by mosquitoes, causing severe pain, disfiguring, and disabling clinical conditions such as lymphoedema and hydrocoele. LF is a global public health problem affecting 72 countries, primarily in Africa and Asia. Since 2000, the World Health Organization (WHO) has led the Global Programme to Eliminate Lymphatic Filariasis (GPELF) to support all endemic regions. This paper focuses on the achievements of the Malawi LF Elimination Programme between 2000 and 2020 to eliminate LF as a public health problem, making it the second sub-Saharan country to receive validation from the WHO. The Malawi LF Programme addressed the widespread prevalence of LF infection and disease across the country, using the recommended WHO GPELF strategies and operational research initiatives in collaboration with key national and international partners. First, to stop the spread of infection (i.e., interrupt transmission) and reduce the circulating filarial antigen prevalence from as high as 74.4% to below the critical threshold of 1-2% prevalence, mass drug administration (MDA) using a two-drug regime was implemented at high coverage rates (>65%) of the total population, with supplementary interventions from other programmes (e.g., malaria vector control). The decline in prevalence was monitored and confirmed over time using several impact assessment and post-treatment surveillance tools including the standard sentinel site, spot check, and transmission assessment surveys and alternative integrated, hotspot, and easy-access group surveys. Second, to alleviate suffering of the affected populations (i.e., control morbidity) the morbidity management and disability prevention (MMDP) package of care was implemented. Specifically, clinical case estimates were obtained via house-to-house patient searching activities; health personnel and patients were trained in self-care protocols for lymphoedema and/or referrals to hospitals for hydrocoele surgery; and the readiness and quality of treatment and services were assessed with new survey tools. Malawi's elimination of LF will ensure that future generations are not infected and suffer from the disfiguring and disabling disease. However, it will be critical that the Malawi LF Elimination programme remains vigilant, focussing on post-elimination surveillance and MMDP implementation and integration into routine health systems to support long-term sustainability and ongoing success. Lymphatic filariasis, also known as elephantiasis, is a disabling, disfiguring, and painful disease caused by a parasite that infected mosquitoes transmit to millions of people worldwide. Since 2000, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has supported endemic countries such as Malawi in south-eastern Africa, to eliminate the disease as a public health problem. The Malawi National LF Elimination Programme has worked tirelessly over the past two decades to implement the GPELF recommended strategies to interrupt the transmission with a two-drug regime, and to alleviate suffering in patients with lymphoedema and/or hydrocoele through morbidity management and disability prevention. Additionally, the LF Programme has collaborated with national and international stakeholders to implement a range of supplementary operational research projects to address outstanding knowledge gaps and programmatic barriers. In 2020, the World Health Organisation validated that Malawi had successfully eliminated LF as a public health problem, making it the second country in sub-Saharan Africa to achieve this, which is remarkable given that Malawi previously had very high infection rates. The LF Programme now remains vigilant, putting its efforts towards post-elimination surveillance and the continued implementation of care for patients with chronic conditions. Malawi's elimination of LF will ensure that future generations are not affected by this devastating disease.

Factors influencing implementation of mass drug administration for lymphatic filariasis elimination: a mixed-method study in Odisha, India.

Background: Lymphatic filariasis (LF) persists as a public health problem in India. Despite more than ten rounds of mass drug administration (MDA), LF continues to be endemic in the Dhenkanal district of Odisha. Hence, we assessed the coverage and compliance of the MDA program and explored the factors affecting it in the Dhenkanal district. Methods: An explanatory mixed-method study was conducted, wherein for the quantitative survey, 552 participants aged 2years and above were recruited following a multistage cluster random sampling during February 2022. In-depth interviews were conducted among purposively selected key stakeholders and program implementers. Descriptive statistics were used to report coverage and compliance, along with a 95% confidence interval. Qualitative data were analyzed using a thematic approach. Results: We observed coverage of 99.28% and compliance of 85.87% for MDA drugs. Supervised drug administration proved to be a major pillar in increasing compliance. There was difficulty in administering drugs in urban areas due to gated societies, the absence of individuals during the day, and the perspective toward healthcare providers. Participants reported a lack of confidence in drug distributors and a fear of side effects as major causes for non-compliance. Conclusion: There is a need to strengthen MDA, especially in urban areas. An urban-specific strategy, along with surveillance, behavioral change communication, and the involvement of multi-disciplinary teams, is required.

Postintervention Immunological and Entomological Survey of Lymphatic Filariasis in the City of Olinda, Brazil, 2015-2016.

Lymphatic filariasis (LF) is a leading cause of disability due to infectious disease worldwide. The Recife Metropolitan Region (RMR) is the only remaining focus of LF in Brazil, where the parasite Wuchereria bancrofti is transmitted solely by the mosquito Culex quinquefasciatus. This study reports the results of transmission assessment surveys and molecular xenomonitoring in the city of Olinda, RMR, after nearly 15 years (2015-2016) of interventions for LF elimination. Participants were screened for W. bancrofti antigen via immunochromatographic card tests (ICT) in: 1) door-to-door surveys conducted for all children aged 5-7 years from 4 out of 17 intervention areas treated with at least five annual doses of mass drug administration (MDA), and 2) a two-stage cluster sampling survey of residents aged 5 years and older in non-MDA areas. Mosquitoes were collected via handheld aspirators in four MDA areas, differentiated by species, sex, and physiological status, pooled into groups of up to 10 blood-fed, semigravid, and gravid mosquitoes, and screened for W. bancrofti infection by real-time quantitative polymerase chain reaction (RT-qPCR). All 1,170 children from MDA areas and the entire population sample of 990 residents in non-MDA areas were ICT negative. In MDA areas, a total of 3,152 female Cx. quinquefasciatus mosquitoes in 277 households (range, 0-296 mosquitoes per house) were collected via aspiration. RT-qPCR of 233 pools of mosquitos were negative for W. bancrofti RNA; an independent reference laboratory confirmed these results. These results provide evidence that LF transmission has been halted in this setting.

Detection of Wuchereria bancrofti DNA in wild caught vector and non-vector mosquitoes: implications for elimination of lymphatic filariasis.

Transmission Assessment Survey (TAS) is the WHO recommended method used for decision-making to stop or continue the MDA in lymphatic filariasis (LF) elimination programme. The WHO has also recommended Molecular Xenomonitoring (MX) of LF infection in vectors as an adjunct tool in settings under post-MDA or validation period. Screening of non-vectors by MX in post-MDA / validation settings could be useful to prevent a resurgence of LF infection, as there might be low abundance of vectors, especially in some seasons. In this study, we investigated the presence of LF infection in non-vectors in an area endemic for LF and has undergone many rounds of annual MDA with two drugs (Diethylcarbamazine and Albendazole, DA) and two rounds of triple drug regimens (Ivermectin + DA). Mosquitoes were collected from selected villages of Yadgir district in Karnataka state, India, during 2019. A total of 680 female mosquitoes were collected, identified morphologically by species and separated as pools. The female mosquitoes belonging to 3 species viz., Anopheles subpictus, Culex gelidus and Culex quinquefaciatus were separated, pooled, and the DNA extracted using less expensive method and followed by LDR based real-time PCR assay for detecting Wuchereria bancrofti infection in vector as well as non-vector mosquitoes. One pool out of 6 pools of An. subpictus, 2 pools out of 6 pools of Cx. gelidus, and 4 pools out of 8 pools of Cx. quinquefaciatus were found to be positive for W. bancrofti infection by RT-PCR. The infection rate in vectors and non-vectors was found to be 1.8% (95% CI: 0.5-4.2%) and 0.9% (95% CI:0.2-2.3%), respectively. Our study showed that non-vectors also harbour W. bancrofti, thus opening an opportunity of using these mosquitoes as surrogate vectors for assessing risk of transmission to humans in LF endemic and post MDA areas.

Comparing different lymphatic filariasis patient estimate approaches and results in Ethiopia

BackgroundThe World Health Organization (WHO) recommends that countries ensure morbidity management and disability prevention (MMDP) services are available to all lymphedema and hydrocele patients in lymphatic filariasis (LF)-endemic areas. The first step in ensuring the availability of MMDP services is to understand the number and distribution of people with lymphedema and hydrocele. We examined the burden of lymphoedema and hydrocoele using different patient estimation approaches employed in endemic districts of the Beneshangul-Gumuz and Tigray regions of Ethiopia.Methodology/principal findingsIn Approach I, trained health extension workers (HEWs) conducted the patient estimates during a door-to-door pre-mass drug administration (MDA) census. Validation of a sample of the data collected was integrated with a post-MDA coverage survey. In Approach II, trained HEWs conducted a stand-alone patient estimation, and clinical officers validated all suspected patients. In 15 districts, 753,557 individuals were surveyed. A total of 1,645 lymphedema (1:1.6 male-to-female ratio) and 517 hydrocele cases were identified. The prevalence of lymphedema and hydrocele was 40 per 10,000 in the adult population and 25 per 10,000 in the adult male population, with wide variation across districts. Validation in Approach I showed that 94% of the lymphedema cases and 77% of hydrocele cases were correctly identified by the HEWs, while 60% and 53% were correctly identified in Approach II.Conclusion/significancePatient estimation is important for planning, prioritization, targeting interventions, and monitoring progress in LF-endemic areas. Trained HEWs can correctly identify most cases using a standardized patient estimate job aid and questionnaire, even when cascade training is used. For the purposes of LF elimination, these results are sufficient and at a low cost per district. Ethiopia’s LF program could integrate patient estimations into MDA activities in the remaining LF-endemic districts with minimal cost and effort.

Assessment of microfilaremia in 'hotspots' of four lymphatic filariasis endemic districts of Nepal during post-MDA surveillance.

The lymphatic filariasis (LF) elimination program in all sixty-three endemic districts of Nepal was based on annual mass drug administration (MDA) using a combination of diethylcarbamazine (DEC) and albendazole for at least 5 years. The MDA program was started in the Parsa district of the Terai region and at least six rounds of MDA were completed between 2003 and 2017 in all filariasis endemic districts of Central Nepal. Transmission Assessment Survey (TAS) report indicated that circulating filarial antigen (CFA) prevalence was below the critical value i.e., ≤ 2% in selected LF endemic districts of Central Nepal. Based on the TAS report, antigen-positive cases were found clustered in the foci of those districts which were considered as "hotspots". Hence the present study was designed to assess microfilaremia in hotspots of four endemic districts of Central Nepal after the MDA program. The present study assessed microfilaremia in hotspots of four endemic districts i.e. Lalitpur and Dhading from the hilly region and Bara and Mahottari from the Terai region of Central Nepal. Night blood samples (n = 1722) were collected by finger prick method from the eligible sample population irrespective of age and sex. Community people's participation in the MDA program was ensured using a structured questionnaire and chronic clinical manifestation of LF was assessed using standard case definition. Two districts one each from the hilly region (Lalitpur district) and Terai region (Bara district) showed improved microfilaria (MF) prevalence i.e. below the critical level (<1%) while the other two districts are still over the critical level. There was a significantly high prevalence of MF in male (p = <0.05) and ≥41 years of age group (p = <0.05) community people in the hotspots of four endemic districts. People who participated in the previous rounds of the MDA program have significantly low MF prevalence. The upper confidence limit of MF prevalence in all hotspots of four districts was above the critical level (>1%). Chronic clinical manifestation of LF showed significant association with the older age group (≥41 years) but not with sex. The study revealed LF transmission improved in hotspots of two districts while continued in others but the risk of LF resurgence cannot be ignored since the upper confidence level of MF prevalence is over 1% in all the hotspots studied districts. High MF prevalence is well correlated with the number of MDA rounds but not with the MDA coverage. Community people involved in MDA drug uptake in any previous and last rounds have significantly less MF infection. Hence it is recommended that before deciding to stop the MDA rounds it is essential to conduct the MF survey at the hotspots of the sentinel sites.

Zambia: A Narrative Review of Success and Challenges in Lymphatic Filariasis Elimination.

The establishment of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) to stop the transmission of infection has significantly reduced the incidence of lymphatic filariasis, a debilitating mosquito-borne neglected tropical disease. The primary strategies that have been employed include mass drug administration (MDA) of anthelminthics and morbidity management and disability prevention (MMDP). While some countries have been able to reach elimination status in Africa, there is still active transmission of LF in Zambia. The nematode responsible for the disease is Wuchereria bancrofti, which is transmitted by Anopheles mosquitoes. To alleviate the suffering of those infected by the disease, the Zambian Ministry of Health launched a program to eliminate LF as a public health problem in 2003. This project reviewed the efforts to achieve the elimination of LF in Zambia, past and present government policies, and the anticipated challenges. MDAs have been conducted since 2014 and coverage has been between 87% and 92%. Zambia has now moved towards pre-transmission assessment surveys (PRETAS) and transmission assessment surveys (TAS). MMDP is a major priority and planned to be conducted between 2022 and 2026. COVID-19 presented a new challenge in the control of LF, while climate change, immigration, co-infections, and funding limitations will complicate further progress.

Surveillance and Selective Treatment of Brugia malayi Filariasis Eleven Years after Stopping Mass Drug Administration in Belitung District, Indonesia.

Brugia malayi is the major cause of lymphatic filariasis (LF) in Indonesia. Zoophilic B. malayi was endemic in Belitung district, and mass drug administration (MDA) with diethylcarbamazine (DEC) and albendazole ceased after five annual rounds in 2010. The district passed three transmission assessment surveys (TAS) between 2011 and 2016. As part of the post-TAS3 surveillance of the national LF elimination program, we collected night blood samples for microfilaria (Mf) detection from 1,911 subjects more than 5 years of age in seven villages. A B. malayi Mf prevalence ranging from 1.7% to 5.9% was detected in five villages. Only 2 (5%) of the total 40 Mf-positive subjects were adolescents aged 18 and 19 years old, and 38 (95%) Mf-positive subjects were 21 years and older. Microfilarial densities in infected individuals were mostly low, with 60% of the subjects having Mf densities between 16 and 160 Mf/mL. Triple-drug treatment with ivermectin, DEC, and albendazole (IDA) was given to 36 eligible Mf-positive subjects. Adverse events were mostly mild, and treatment was well tolerated. One year later, 35 of the treated Mf-positive subjects were reexamined, and 33 (94%) had cleared all Mf, while the anti-Bm14 antibody prevalence remained almost unchanged. Results indicate that in B. malayi-endemic areas, post-TAS3 surveillance for Mf in the community may be needed to detect a potential parasite reservoir in adults. Selective treatment with IDA is highly effective in clearing B. malayi Mf and should be used to increase the prospects for LF elimination if MDA is reintroduced.

Diverse Information Sources and The Community’s High Level of Knowledge About Lymphatic Filariasis in Air Salobar and Waihaong, Ambon City, Indonesia

Background: Mass Drug Administration (MDA) is a strategy to eliminate lymphatic filariasis (LF) in endemic areas. However, individuals' decision to take LF drugs in MDA is associated with their knowledge and awareness about LF. This study examined the association between the community’s level of knowledge and awareness about LF with the number of informant types and media types for LF information in Waihaong and Air Salobar Health Centers, Ambon City, Indonesia. Methodology: We used data from a household survey conducted in January 2019 involving 944 respondents aged 18-70 living in the study sites. Data analysis was performed using multivariable logistic regression. Results: We found that only 33.3% of respondents had a high level of knowledge and awareness about LF. An increased odds of having a high level of knowledge and awareness about LF was associated with respondents receiving information from more than one type of informant and one type of media (aOR=10.55, 95%CI: 2.35-47.37, p=0.002), and among female respondents (aOR=1.92, 95%CI: 1.25-2.94). Conclusions: These findings emphasize the importance of comprehensive health promotion strategies using different types of informants and media to enhance the community's knowledge and awareness about LF, which is important to support the elimination of LF in Ambon City, Indonesia.

Erratum: Coverage and compliance of mass drug administration (MDA) programme for elimination of lymphatic filariasis in an endemic district of eastern Uttar Pradesh, India

Erratum: Coverage and compliance of mass drug administration (MDA) programme for elimination of lymphatic filariasis in an endemic district of eastern Uttar Pradesh, India