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.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Assessing factors influencing communities' acceptability of mass drug administration for the elimination of lymphatic filariasis in Guyana

BACKGROUND

Guyana is one of four countries in the Latin American Region where lymphatic filariasis (LF) remains endemic. In preparation for the introduction of a new triple drug therapy regimen (ivermectin, diethylcarbamazine, and albendazole (IDA)) in 2019, an acceptability study was embedded within sentinel site mapping in four regions to assess mass drug administration (MDA) coverage and compliance, acceptability, and perceptions about treatment and disease. The results from this survey would inform the rollout of IDA in Guyana in 2019.

METHODS

Data collection for the study occurred in August 2019, using a validated questionnaire administered by trained enumerators. Across all regions, a total of 1,248 participants were sampled by the Filarial Mapping team. Four-hundred and fifty-one participants aged over 18 years were randomly selected for participation in an expanded acceptability questionnaire. All data were captured in Secure Data Kit (SDK).

RESULTS

Acceptability was measured using a mean acceptability score. Unadjusted mean scores ranged from 24.6 to 29.3, with 22.5 as the threshold of acceptability. Regional variation occurred across many indicators of interest: self-rated understanding about LF, mechanisms of LF transmission, LF drug safety and history of treatment during MDA. Region IV (Georgetown) recorded higher knowledge about LF, but lower compliance and acceptability. Number of pills was not perceived as a concern.

CONCLUSION

Acceptability of MDA was good across all four regions under study. Results from this study set a baseline level for key indicators and acceptability, from which the acceptability of IDA can be measured. Regional variations across indicators suggest that localized approaches should be considered for social mobilization and MDA delivery to capture these contextual differences.

Eliminating onchocerciasis within the Meme River Basin of Cameroon: A social-ecological approach to understanding everyday realities and health systems

BACKGROUND

Onchocerciasis affects some of the world's most marginalized people, perpetuating poverty and inequalities. Mass Drug Administration (MDA) with Ivermectin has taken place within the Meme River basin region in Cameroon for over 15 years. Despite this, onchocerciasis is still prevalent in the region due to existing and emerging contextual challenges. Using a social-ecological approach we explore the everyday realities of communities, highlighting the challenges and potential solutions that could support Neglected Tropical Disease (NTD) programmes when transitioning from control to elimination of onchocerciasis in this highly endemic area and other similar communities.

METHODOLOGY/PRINCIPAL FINDING

In-depth interviews (71) with community members and Community Drug Distributors (CDDs) were conducted to understand current knowledge, attitudes, and behaviours in relation to transmission, prevention and treatment of onchocerciasis. Through application of the social-ecological model, four key themes were identified: 1. Contextual factors on health promotion interventions (Onchocerciasis history and understanding of the disease, prevention and mitigation strategies and MDA experience); 2. Social determinants (poverty and livelihoods, economic and social impacts on CDD volunteers and stigma); 3. Environmental determinants (exposure, housing, occupation and poverty); and 4. health seeking pathways and decision making for treatment (access, cost and preferable treatment routes). We discuss these core and cross cutting themes (gender differences and community participation/ownership) in relation to intersectoral collaboration, gender equity and health systems support, making recommendations for NTD programmes within the context of integrated and interdisciplinary approaches. These include the need for; intersectional and gender analysis at the local level, addressing environmental dimensions of onchocerciasis through integrated and regular health promotion, vector control strategies and access to safe water sources; reflection and action that embeds responses to social and economic barriers to MDA; integrated case detection and management that is responsive to onchocerciasis symptoms and related stigma and a fair and just support network for CDDs.

CONCLUSION/SIGNIFICANCE

NTD programmes need to respond to diverse community circumstances and behaviours. Communities are not a homogeneous risk group and treating them in this way will delay elimination. A deeper understanding of individual needs and their capacity to seek prevention and treatment must be considered if onchocerciasis is to be eliminated and the remaining impacts managed.

A multicenter, community-based, mixed methods assessment of the acceptability of a triple drug regimen for elimination of lymphatic filariasis

Background

Many countries will not reach elimination targets for lymphatic filariasis in 2020 using the two-drug treatment regimen (diethylcarbamazine citrate [DEC] and albendazole [DA]). A cluster-randomized, community-based safety study performed in Fiji, Haiti, India, Indonesia and Papua New Guinea tested the safety and efficacy of a new regimen of ivermectin, DEC and albendazole (IDA).

Methodology/Principal findings

To assess acceptability of IDA and DA, a mixed methods study was embedded within this community-based safety study. The study objective was to assess the acceptability of IDA versus DA. Community surveys were performed in each country with randomly selected participants (>14 years) from the safety study participant list in both DA and IDA arms. In depth interviews (IDI) and focus group discussions (FGD) assessed acceptability-related themes. In 1919 individuals, distribution of sex, microfilariae (Mf) presence and circulating filarial antigenemia (CFA), adverse events (AE) and age were similar across arms. A composite acceptability score summed the values from nine indicators (range 9–36). The median (22.5) score indicated threshold of acceptability. There was no difference in scores for IDA and DA regimens. Mean acceptability scores across both treatment arms were: Fiji 33.7 (95% CI: 33.1–34.3); Papua New Guinea 32.9 (95% CI: 31.9–33.8); Indonesia 30.6 (95% CI: 29.8–31.3); Haiti 28.6 (95% CI: 27.8–29.4); India 26.8 (95% CI: 25.6–28) (P<0.001). AE, Mf or CFA were not associated with acceptability. Qualitative research (27 FGD; 42 IDI) highlighted professionalism and appreciation for AE support. No major concerns were detected about number of tablets. Increased uptake of LF treatment by individuals who had never complied with MDA was observed.

Conclusions/Significance

IDA and DA regimens for LF elimination were highly and equally acceptable in individuals participating in the community-based safety study in Fiji, Haiti, India, Indonesia, and Papua New Guinea. Country variation in acceptability was significant. Acceptability of the professionalism of the treatment delivery was highlighted.

The acceptability of a new combination treatment regimen for lymphatic filariasis (ivermectin, plus DEC and albendazole, or IDA) was assessed as part of a larger community-based safety study in Fiji, Haiti, India, Indonesia and Papua New Guinea. To understand how trial participants and communities felt about the new treatment, a survey was carried out with people who had participated in the safety study receiving either the standard treatment [DEC plus albendazole (DA)] or the new treatment regimen (IDA). Focus group discussions and in-depth interviews were performed in the same communities. Results showed that there was no difference in acceptability between the DA and IDA. Adverse events and presence of filarial infection did not affect acceptability. The most important indicator associated with acceptability was country. All countries accepted the treatment regimens. Fiji had the highest acceptability scores, followed by Papua New Guinea, Indonesia, Haiti and India. Results from the qualitative research showed that study participants appreciated the professionalism of the drug delivery team and the support offered for the management of any adverse events.

An open label, block randomized, community study of the safety and efficacy of co-administered ivermectin, diethylcarbamazine plus albendazole vs. diethylcarbamazine plus albendazole for lymphatic filariasis in India

Background

Better drug regimens for mass drug administration (MDA) could accelerate the Global Programme to Eliminate Lymphatic Filariasis (LF). This community study was designed to compare the safety and efficacy of MDA with IDA (ivermectin, diethylcarbamazine and albendazole) or DA (diethylcarbamazine and albendazole) in India.

Methodology/Principal findings

This two-armed, open-labelled, block randomised, community study was conducted in LF endemic villages in Yadgir district, Karnataka, India. Consenting participants ≥5 years of age were tested for circulating filarial antigenemia (CFA) and microfilaremia (Mf) before treatment with a single oral dose of IDA or DA. Adverse events (AEs) were monitored actively for two days and passively for five more days. Persons with positive CFA or Mf tests at baseline were retested 12-months post-treatment to assess treatment efficacy.

Baseline CFA and Mf-rates were 26.4% and 6.9% in IDA and 24.5% and 6.4% in DA villages respectively. 4758 and 4160 participants received IDA and DA. Most AEs were mild after both treatments; fewer than 0.1% of participants experienced AEs with severity > grade 1. No serious AEs were observed. Fever, headache and dizziness were the most common AEs. AE rates were slightly higher after IDA than DA (8.3% vs. 6.4%, P<0.01). AEs were more frequent in females and Mf-positives after either treatment, but significantly more frequent after IDA (40.5% vs 20.2%, P < 0.001).

IDA was more effective for clearing Mf than DA (84% vs. 61.8%, P < 0.001). Geometric mean Mf counts per 60μl in retested Mf-positives decreased by 96.4% from 11.8 after IDA and by 90.0% from 9.5 after DA. Neither treatment was effective for clearing CFA.

Conclusions/Significance

IDA had an acceptable safety profile and was more effective for clearing Mf than DA. With adequate compliance and medical support to manage AEs, IDA has the potential to accelerate LF elimination in India.

Trial registration

Clinical Trial Registry of India (CTRI No/2016/10/007399)

Lymphatic filariasis (LF) is a major neglected tropical disease that is caused by filarial nematode worms. The strategies of the Global Programme to Eliminate Lymphatic Filariasis, launched in 2000, are mass drug administration (MDA) of antifilarial medications to kill the parasites and reduce transmission and morbidity management and disability prevention for those who are already affected by the disease. Recent clinical trials have shown that a single co-administered dose of ivermectin, diethylcarbamazine and albendazole (IDA) is more effective for clearing microfilariae (Mf) from the blood than the traditional two-drug regimen (DA). That is important, because blood Mf are essential for mosquitoes to transmit the parasite. As part of a large multicenter study, we assessed the safety of IDA and compared the efficacy of IDA and DA for clearing parasites from the blood. We treated almost 9,000 people in Wuchereria bancrofti endemic villages with either IDA or DA. Adverse events (AE) were monitored actively for two days and passively for another five days. AE rates were slightly higher after IDA than DA, but AEs were mild and self-limited. Infected persons, adults and females had higher AE rates in both treatment areas. We retested infected persons one year after treatment. IDA was significantly more effective for clearing Mf and reducing blood Mf counts than DA. Neither treatment was effective for clearing circulating filarial antigenemia. Our large study showed that IDA was well tolerated and more effective than DA. This new treatment has the potential to hasten LF elimination in India and many other countries.

A community survey of coverage and adverse events following country-wide triple-drug mass drug administration for lymphatic filariasis elimination, Samoa 2018

The Global Programme to Eliminate Lymphatic Filariasis has made considerable progress but is experiencing challenges in meeting targets in some countries. Recent World Health Organization guidelines have recommended two rounds of triple-drug therapy with ivermectin, diethylcarbamazine (DEC), and albendazole (IDA), in areas where mass drug administration (MDA) results with two drugs (DEC and albendazole) have been suboptimal, as is the case in Samoa. In August 2018, Samoa was the first country in the world to implement countrywide triple-drug MDA. This paper aims to describe Samoa’s experience with program coverage and adverse events (AEs) in the first round of triple-drug MDA. We conducted a large cross-sectional community survey to assess MDA awareness, reach, compliance, coverage and AEs in September/October 2018, 7–11 weeks after the first round of triple-drug MDA. In our sample of 4420 people aged ≥2 years (2.2% of the population), age-adjusted estimates indicated that 89.0% of the eligible population were offered MDA, 83.9% of the eligible population took MDA (program coverage), and 80.2% of the total population took MDA (epidemiological coverage). Overall, 83.8% (2986/3563) reported that they did not feel unwell at all after taking MDA. Mild AEs (feeling unwell but able to do normal everyday things) were reported by 13.3% (476/3563) and moderate or severe AEs (feeling unwell and being unable to do normal everyday activities such as going to work or school) by 2.9% (103/3563) of participants. This study following the 2018 triple-drug MDA in Samoa demonstrated a high reported program awareness and reach of 90.8% and 89.0%, respectively. Age-adjusted program coverage of 83.9% of the total population showed that MDA was well accepted and well tolerated by the community.

Lymphatic filariasis is a disease caused by worms and transmitted between humans by mosquitoes. A global program underway aims to eliminate lymphatic filariasis as a public health problem by distributing two deworming drugs to the whole population once a year for at least five years. In some countries, including Samoa, this strategy has not been sufficient to eliminate transmission. A new drug has been added, and in 2018, Samoa was the first country in the world to distribute country-wide triple-drug mass drug administration (MDA) using ivermectin, diethylcarbamazine, and albendazole. This study reports on the coverage achieved (percentage of people who reported taking the drugs) and adverse events after taking the drugs. The study was a large community survey of over 4000 people, done 7–11 weeks after the distribution of the first round of triple-drug MDA. We found that the program reached and offered MDA to approximately 90% of the whole population, and approximately 80% of the whole population swallowed the drugs. We also collected data on whether people felt unwell after taking the pills, and found that 84% of people taking the pills did not feel unwell at all, while 13% reported feeling unwell afterwards but were able to do normal everyday activities, and 3% reported that they had felt unwell and that it stopped them doing normal everyday activities, such as going to school or work.

Risk factors associated with failing pre-transmission assessment surveys (pre-TAS) in lymphatic filariasis elimination programs: Results of a multi-country analysis

Achieving elimination of lymphatic filariasis (LF) as a public health problem requires a minimum of five effective rounds of mass drug administration (MDA) and demonstrating low prevalence in subsequent assessments. The first assessments recommended by the World Health Organization (WHO) are sentinel and spot-check sites—referred to as pre-transmission assessment surveys (pre-TAS)—in each implementation unit after MDA. If pre-TAS shows that prevalence in each site has been lowered to less than 1% microfilaremia or less than 2% antigenemia, the implementation unit conducts a TAS to determine whether MDA can be stopped. Failure to pass pre-TAS means that further rounds of MDA are required. This study aims to understand factors influencing pre-TAS results using existing programmatic data from 554 implementation units, of which 74 (13%) failed, in 13 countries. Secondary data analysis was completed using existing data from Bangladesh, Benin, Burkina Faso, Cameroon, Ghana, Haiti, Indonesia, Mali, Nepal, Niger, Sierra Leone, Tanzania, and Uganda. Additional covariate data were obtained from spatial raster data sets. Bivariate analysis and multilinear regression were performed to establish potential relationships between variables and the pre-TAS result. Higher baseline prevalence and lower elevation were significant in the regression model. Variables statistically significantly associated with failure (p-value ≤0.05) in the bivariate analyses included baseline prevalence at or above 5% or 10%, use of Filariasis Test Strips (FTS), primary vector of Culex, treatment with diethylcarbamazine-albendazole, higher elevation, higher population density, higher enhanced vegetation index (EVI), higher annual rainfall, and 6 or more rounds of MDA. This paper reports for the first time factors associated with pre-TAS results from a multi-country analysis. This information can help countries more effectively forecast program activities, such as the potential need for more rounds of MDA, and prioritize resources to ensure adequate coverage of all persons in areas at highest risk of failing pre-TAS.

Achieving elimination of lymphatic filariasis (LF) as a public health problem requires a minimum of five rounds of mass drug administration (MDA) and being able to demonstrate low prevalence in several subsequent assessments. LF elimination programs implement sentinel and spot-check site assessments, called pre-TAS, to determine whether districts are eligible to implement more rigorous population-based surveys to determine whether MDA can be stopped or if further rounds are required. Reasons for failing pre-TAS are not well understood and have not previously been examined with data compiled from multiple countries. For this analysis, we analyzed data from routine USAID and WHO reports from Bangladesh, Benin, Burkina Faso, Cameroon, Ghana, Haiti, Indonesia, Mali, Nepal, Niger, Sierra Leone, Tanzania, and Uganda. In a model that included multiple variables, high baseline prevalence and lower elevation were significant. In models comparing only one variable to the outcome, the following were statistically significantly associated with failure: higher baseline prevalence at or above 5% or 10%, use of the FTS, primary vector of Culex, treatment with diethylcarbamazine-albendazole, lower elevation, higher population density, higher Enhanced Vegetation Index, higher annual rainfall, and six or more rounds of mass drug administration. These results can help national programs plan MDA more effectively, e.g., by focusing resources on areas with higher baseline prevalence and/or lower elevation.

The safety of combined triple drug therapy with ivermectin, diethylcarbamazine and albendazole in the neglected tropical diseases co-endemic setting of Fiji: A cluster randomised trial

Lymphatic filariasis has remained endemic in Fiji despite repeated mass drug administration using the well-established and safe combination of diethylcarbamazine and albendazole (DA) since 2002. In certain settings the addition of ivermectin to this combination (IDA) remains a safe strategy and is more efficacious. However, the safety has yet to be described in scabies and soil-transmitted helminth endemic settings like Fiji. Villages of Rotuma and Gau islands were randomised to either DA or IDA. Residents received weight-based treatment unblinded with standard exclusions. Participants were actively found and asked by a nurse about their health daily for the first two days and then asked to seek review for the next five days if unwell. Anyone with severe symptoms were reviewed by a doctor and any serious adverse event was reported to the Medical Monitor and Data Safety Monitoring Board. Of 3612 enrolled and eligible participants, 1216 were randomised to DA and 2396 to IDA. Age and sex in both groups were representative of the population. Over 99% (3598) of participants completed 7 days follow-up. Adverse events were reported by 600 participants (16.7%), distributed equally between treatment groups, with most graded as mild (93.2%). There were three serious adverse events, all judged not attributable to treatment by an independent medical monitor. Fatigue was the most common symptom reported by 8.5%, with headache, dizziness, nausea and arthralgia being the next four most common symptoms. Adverse events were more likely in participants with microfilaremia (43.2% versus 15.7%), but adverse event frequency was not related to the presence of scabies or soil-transmitted helminth infection. IDA has comparable safety to DA with the same frequency of adverse events experienced following community mass drug administration. The presence of co-endemic infections did not increase adverse events. IDA can be used in community programs where preventative chemotherapy is needed for control of lymphatic filariasis and other neglected tropical diseases.

Dosing pole recommendations for lymphatic filariasis elimination: A height-weight quantile regression modeling approach

BACKGROUND

The World Health Organization (WHO) currently recommends height or age-based dosing as alternatives to weight-based dosing for mass drug administration lymphatic filariasis (LF) elimination programs. The goals of our study were to compare these alternative dosing strategies to weight-based dosing and to develop and evaluate new height-based dosing pole scenarios.

METHODOLOGY/PRINCIPAL FINDINGS

Age, height and weight data were collected from >26,000 individuals in five countries during a cluster randomized LF clinical trial. Weight-based dosing for diethylcarbamazine (DEC; 6 mg/kg) and ivermectin (IVM; 200 ug/kg) with tablet numbers derived from a table of weight intervals was treated as the "gold standard" for this study. Following WHO recommended age-based dosing of DEC and height-based dosing of IVM would have resulted in 32% and 27% of individuals receiving treatment doses below those recommended by weight-based dosing for DEC and IVM, respectively. Underdosing would have been especially common in adult males, who tend to have the highest LF prevalence in many endemic areas. We used a 3-step modeling approach to develop and evaluate new dosing pole cutoffs. First, we analyzed the clinical trial data using quantile regression to predict weight from height. We then used weight predictions to develop new dosing pole cutoff values. Finally, we compared different dosing pole cutoffs and age and height-based WHO dosing recommendations to weight-based dosing. We considered hundreds of scenarios including country- and sex-specific dosing poles. A simple dosing pole with a 6-tablet maximum for both DEC and IVM reduced the underdosing rate by 30% and 21%, respectively, and was nearly as effective as more complex pole combinations for reducing underdosing.

CONCLUSIONS/SIGNIFICANCE

Using a novel modeling approach, we developed a simple dosing pole that would markedly reduce underdosing for DEC and IVM in MDA programs compared to current WHO recommended height or age-based dosing.

Pharmacokinetics, safety, and efficacy of a single co-administered dose of diethylcarbamazine, albendazole and ivermectin in adults with and without Wuchereria bancrofti infection in Côte d'Ivoire

Background

A single co-administered dose of ivermectin (IVM) plus diethylcarbamazine (DEC) plus albendazole (ALB), or triple-drug therapy, was recently found to be more effective for clearing microfilariae (Mf) than standard DEC plus ALB currently used for mass drug administration programs for lymphatic filariasis (LF) outside of sub-Saharan Africa. Triple-drug therapy has not been previously tested in LF-uninfected individuals from Africa. This study evaluated the pharmacokinetics (PK), safety, and efficacy of triple-drug therapy in people with and without Wuchereria bancrofti infection in West Africa.

Methods

In this open-label cohort study, treatment-naïve microfilaremic (>50 mf/mL, n = 32) and uninfected (circulating filarial antigen negative, n = 24) adults residing in Agboville district, Côte d’Ivoire, were treated with a single dose of IVM plus DEC plus ALB, and evaluated for adverse events (AEs) until 7 days post treatment. Drug levels were assessed by liquid chromatography and mass spectrometry. Persons responsible for assessing AEs were blinded to participants’ infection status.

Findings

There was no difference in AUC_0-inf or C_max between LF-infected and uninfected participants (P>0.05 for all comparisons). All subjects experienced mild AEs; 28% and 25% of infected and uninfected participants experienced grade 2 AEs, respectively. There were no severe or serious adverse events. Only fever (16 of 32 versus 4 of 24, P<0.001) and scrotal pain/swelling in males (6 of 20 versus 0 of 12, P = 0.025) were more frequent in infected than uninfected participants. All LF positive participants were amicrofilaremic at 7 days post-treatment and 27 of 31 (87%) remained amicrofilaremic 12 months after treatment.

Conclusions

Moderate to heavy W. bancrofti infection did not affect PK parameters for IVM, DEC or ALB following a single co-administered dose of these drugs compared to uninfected individuals. The drugs were well tolerated. This study confirmed the efficacy of the triple-drug therapy for clearing W. bancrofti Mf and has added important information to support the use of this regimen in LF elimination programs in areas of Africa without co-endemic onchocerciasis or loiasis.

Trial registration

ClinicalTrials.gov NCT02845713.

Lymphatic filariasis is a mosquito-borne infection that causes disability in the form of lymphedema, hydroceles, and elephantiasis. It has been targeted for global elimination based on mass drug administration in the total population at risk including many people uninfected with LF. Recently, a single co-administered dose of IVM + DEC + ALB has been shown to be much more effective than the standard treatment with DEC + ALB for sustained clearance of Mf for 3 years based on studies in Papua New Guinea. This study confirms the efficacy and safety of triple-drug therapy for clearing of Wuchereria bancrofti Mf in an African population. The presence of LF did not affect drug levels and the medicines were well tolerated, with 28% and 25% rate of moderate AEs in infected and uninfected individuals respectively, and no severe or serious AEs, supporting the use of triple-drug therapy for mass drug administration. This study shows for the first time that triple-drug therapy also has a potent macrofilaricidal effect, as determined by the reduction in circulating filarial antigen and inactivation of worm nests one year following treatment.

Systematic sampling of adults as a sensitive means of detecting persistence of lymphatic filariasis following mass drug administration in Sri Lanka

Background

Sri Lanka’s Anti-Filariasis Campaign conducted 5 annual rounds of mass drug administration (MDA) with diethylcarbamazine (DEC) plus albendazole to eliminate lymphatic filariasis (LF) in all endemic districts between 2002 and 2006. Post-MDA surveillance has consistently documented Wuchereria bancrofti microfilaremia (Mf) rates below 1% in all sentinel and spot check sites since that time, and all implementation units easily satisfied WHO’s target for school-based transmission assessment surveys (school-TAS) in 2013. However, more detailed studies have identified foci of persistent infection in the large coastal evaluation unit (EU) (population about 0.6 million) in Galle district. Therefore, the purpose of this study was to assess the sensitivity and feasibility of community-based TAS in adults (adult-TAS) and to compare results obtained by adult-TAS with prior school-TAS and molecular xenomonitoring (MX, molecular detection of filarial DNA in systematically sampled mosquitoes) results in this known problem area.

Methodology and principal findings

Two cluster surveys were performed in independent samples of 30 evaluation areas (EAs) in the coastal Galle EU in 2015. Each survey tested approximately 1,800 adults for circulating filarial antigenemia (CFA) with the Alere Filariasis Test Strip. The CFA prevalence for all persons tested (N = 3,612) was 1.8% (CI 1.4–2.2), and this was significantly higher than the CFA rate of 0.4% obtained by school-TAS in 2013. CFA prevalences in the two samples were similar [1.5% (CI 1.0–2.2), and 2.0% (CI 1.4–2.7)]. Antigenemia prevalence in sampled EUs was highly variable (range 0–11%), and it exceeded 5% in 6 EAs. The 30 EAs sampled in one of our adult-TAS surveys had recently been assessed for persistent filariasis by molecular xenomonitoring (MX). CFA prevalence in adults and filarial DNA prevalence in mosquitoes in these EAs were significantly correlated (r = 0.43; P = 0.02).

Conclusions

Community based adult-TAS provided a reproducible measure of persistent W. bancrofti infection in a large evaluation unit in Sri Lanka that has low-level persistence of LF following multiple rounds of MDA. In addition, adult-TAS and MX results illustrate the focality of persistent LF in this setting. Adult-TAS may be more sensitive than school-TAS for this purpose. Adult-TAS and MX are potential options for post-MDA and post-validation surveillance programs to identify problem areas that require mop-up activities. Adult-TAS should also be useful for remapping areas with uncertain LF endemicity for possible inclusion in national LF elimination programs.

Lymphatic filariasis (LF, also commonly known as “elephantiasis) is a leading cause of disability in the developing world. It is caused by parasitic worms that are transmitted by mosquitoes. The Sri Lankan Anti-Filariasis Campaign provided five annual rounds of MDA with diethylcarbamazine and albendazole in all infected areas between 2002 and 2006, and this reduced infection prevalence to very low levels in all sentinel and spot check sites. Sri Lanka conducted transmission assessment surveys (TAS, surveys for filarial antigenemia in primary school children) based on WHO guidelines in 2012–2013, and all evaluation units (EUs) in formerly endemic areas easily passed this test. However, other types of post-MDA surveys (antigenemia and microfilaremia assessments in communities, anti-filarial antibody assessment in primary grade school children and mosquito monitoring for filarial DNA) have shown evidence of persistent LF in Sri Lanka, with the strongest signals in a coastal EU in Galle district. Results from this study show that adult-TAS efficiently detected residual filarial infections in this EU that had passed school-TAS. Adult-TAS results were highly correlated with results from prior surveys that used molecular xenomonitoring (MX) to detect filarial parasite DNA in pools of mosquitoes collected in the same study areas. Thus adult-TAS and MX should be considered as an alternative surveillance approaches for verifying that LF has been eliminated following MDA and for identifying areas that require additional intervention.

A Trial of a Triple-Drug Treatment for Lymphatic Filariasis

BACKGROUND

The World Health Organization has targeted lymphatic filariasis for global elimination by 2020 with a strategy of mass drug administration. This trial tested whether a single dose of a three-drug regimen of ivermectin plus diethylcarbamazine plus albendazole results in a greater sustained clearance of microfilariae than a single dose of a two-drug regimen of diethylcarbamazine plus albendazole and is noninferior to the two-drug regimen administered once a year for 3 years.

METHODS

In a randomized, controlled trial involving adults from Papua New Guinea with Wuchereria bancrofti microfilaremia, we assigned 182 participants to receive a single dose of the three-drug regimen (60 participants), a single dose of the two-drug regimen (61 participants), or the two-drug regimen once a year for 3 years (61 participants). Clearance of microfilariae from the blood was measured at 12, 24, and 36 months after trial initiation.

RESULTS

The three-drug regimen cleared microfilaremia in 55 of 57 participants (96%) at 12 months, in 52 of 54 participants (96%) at 24 months, and in 55 of 57 participants (96%) at 36 months. A single dose of the two-drug regimen cleared microfilaremia in 18 of 56 participants (32%) at 12 months, in 31 of 55 participants (56%) at 24 months, and in 43 of 52 participants (83%) at 36 months (P=0.02 for the three-drug regimen vs. a single dose of the two-drug regimen at 36 months). The two-drug regimen administered once a year for 3 years cleared microfilaremia in 20 of 59 participants (34%) at 12 months, in 42 of 56 participants (75%) at 24 months, and in 51 of 52 participants (98%) at 36 months (P=0.004 for noninferiority of the three-drug regimen vs. the two-drug regimen administered once a year for 3 years at 36 months). Moderate adverse events were more common in the group that received the three-drug regimen than in the combined two-drug-regimen groups (27% vs. 5%, P<0.001). There were no serious adverse events.

CONCLUSIONS

The three-drug regimen induced clearance of microfilariae from the blood for 3 years in almost all participants who received the treatment and was superior to the two-drug regimen administered once and noninferior to the two-drug regimen administered once a year for 3 years. (Funded by the Bill and Melinda Gates Foundation; ClinicalTrials.gov number, NCT01975441 .).

A new diethylcarbamazine formulation (NANO-DEC) as a therapeutic tool for hepatic fibrosis

The aim of the present study was to assess if the uninterrupted and prolonged administration of nanoparticles containing diethylcarbamazine (NANO-DEC) would cause liver, kidney and heart toxicity and then analyze for the first time its action in model of liver fibrosis. Thus, NANO-DEC was administered in C57BL/6 mice daily for 48 days, and at the end the blood was collected for biochemical analyzes. In the long-term administration assay, the evaluation of serological parameters (CK-MB, creatinine, ALT, AST and urea) allowed the conclusion that NANO-DEC prolonged administration did not cause hepatic, renal and cardiac damage. For fibrosis assays, C57BL/6 mice were divided into six groups: 1) control (Cont); 2) carbon tetrachloride (CCl₄); 3) CCl₄ + DEC 25 mg/kg; 4) CCl₄ + DEC 50 mg/kg; 5) CCl₄ + NANO-DEC 5 mg/kg and 6) CCl₄ + NANO-DEC 12.5 mg/kg. Carbon tetrachloride induced hepatic fibrosis observed through increased inflammatory (TNF-α, IL-1β, COX-2, NO and iNOS) and fibrotic markers (TGF-β and TIMP-1), changes in the hepatic morphology, high presence of collagen fibers and elevated serum levels of AST, ALT and ALP. Treatment with NANO-DEC exhibited a superior anti-inflammatory and anti-fibrotic effects compared to the DEC traditional formulation, restoring liver morphology, reducing the content of collagen fibers and serological parameters, besides decreasing the expression of inflammatory and fibrotic markers. The present formulation of nanoencapsulated DEC is a well tolerated anti-inflammatory and anti-fibrotic drug and therefore could be a potential therapeutic tool for the treatment of chronic liver disorders.

Towards elimination of lymphatic filariasis in southeastern Madagascar: Successes and challenges for interrupting transmission

Introduction

A global strategy of mass drug administration (MDA) has greatly reduced the burden of lymphatic filariasis (LF) in endemic countries. In Madagascar, the National Programme to eliminate LF has scaled-up annual MDA of albendazole and diethylcarbamazine across the country in the last decade, but its impact on LF transmission has never been reported. The objective of this study was to evaluate progress towards LF elimination in southeastern Madagascar.

Methods

Three different surveys were carried out in parallel in four health districts of the Vatovavy Fitovinany region in 2016: i) a school-based transmission assessment survey (TAS) in the districts of Manakara Atsimo, Mananjary, and Vohipeno (following a successful pre-TAS in 2013); ii) a district-representative community prevalence survey in Ifanadiana district; and iii) a community prevalence survey in sentinel and spot-check sites of these four districts. LF infection was assessed using the Alere Filariasis Test Strips, which detect circulating filarial antigens (CFA) of adult worms. A brief knowledge, attitudes and practices questionnaire was included in the community surveys.

Principal findings

None of the 1,825 children sampled in the TAS, and only one in 1,306 children from sentinel and spot-check sites, tested positive to CFA. However, CFA prevalence rate in individuals older than 15 years was still high in two of these three districts, at 3.5 and 9.7% in Mananjary and Vohipeno, respectively. Overall CFA prevalence in sentinel and spot-check sites of these three districts was 2.80% (N = 2,707), but only two individuals had detectable levels of microfilaraemia (0.06%). Prevalence rate estimates for Ifanadiana were substantially higher in the district-representative survey (15.8%; N = 545) than in sentinel and spot-check sites (0.8%; N = 618). Only 51.2% of individuals surveyed in these four districts reported taking MDA in the last year, and 42.2% reported knowing about LF.

Conclusions

Although TAS results suggest that MDA can be stopped in three districts of southeastern Madagascar, the adult population still presents high CFA prevalence levels. This discordance raises important questions about the TAS procedures and the interpretation of their results.

Lymphatic filariasis is a neglected disease with chronic disabling consequences. Endemic countries have reduced lymphatic filariasis transmission through a strategy of annual rounds of mass drug administration (MDA), but the impact of such strategy has not yet been reported for Madagascar. In this study we conducted three different surveys and used rapid diagnostic tests to evaluate lymphatic filariasis transmission in four health districts of southeastern Madagascar. This included a school-based transmission assessment survey (TAS), the international gold standard to help national programmes confirm that they have interrupted lymphatic filariasis transmission, and two complementary community-based surveys. Our TAS results suggested that MDA could be stopped in three districts, confirming the consistent decline in lymphatic filariasis observed in recent years. However, the other two surveys revealed that the adult population still had high prevalence levels. This discordance raises questions about the TAS procedures and the interpretation of their results in contexts where, like in Madagascar, implementation of MDA is different for school age children than for the rest of the population.

Effectiveness of annual single doses of diethylcarbamazine citrate among bancroftian filariasis infected individuals in an endemic area under mass drug administration in Brazil

The Global Program to Eliminate Lymphatic Filariasis has achieved extraordinary success in reducing transmission and preventing morbidity through mass drug administration (MDA) to the population at-risk. Brazil is the only currently using diethylcarbamazine citrate (DEC) alone for MDA, so an assessment of its effectiveness is needed. We report the trends of filarial markers in a cohort of 175 individuals infected with Wuchereria bancrofti in areas that underwent MDA in the city of Olinda, Northeastern Brazil. The prospective study was conducted between 2007 and 2012 (corresponding to five annual MDA rounds). The quantification of microfilaraemia (QMFF) was assessed by filtration. Circulating filarial antigen (CFA) was detected through immunochromatographic point-of-care test (POCT-ICT) and Og4C3-ELISA whereas antifilarial antibody titres (IgG4) were assessed through Bm14 assay. The CFA and IgG4 titres were measured by Optical Density (OD). The main characteristics at baseline, MDA coverage and the trend of filarial infection markers during follow up were described. The trend of filarial markers in relation to time (years of MDA), sex and age were analysed through Generalized Estimating Equations (GEE) models. The models demonstrated a significant decrease in all markers during MDA. The probability of remaining positive by QMFF and POCT-ICT diminished 70% and 46%, respectively, after each MDA round. There was a significant annual drop in CFA (-0.290 OD) and IgG4 antibodies titres (-0.303 OD). This study provides evidence that MDA with DEC alone can be effective in the elimination of LF in Brazil.

Adverse events following single dose treatment of lymphatic filariasis: Observations from a review of the literature

Background

WHO’s Global Programme to Eliminate Lymphatic Filariasis (LF) uses mass drug administration (MDA) of anthelmintic medications to interrupt LF transmission in endemic areas. Recently, a single dose combination of ivermectin (IVM), diethylcarbamazine (DEC), and albendazole (ALB) was shown to be markedly more effective than the standard two-drug regimens (DEC or IVM, plus ALB) for achieving long-term clearance of microfilaremia.

Objective and methods

To provide context for the results of a large-scale, international safety trial of MDA using triple drug therapy, we searched Ovid Medline for studies published from 1985–2017 that reported adverse events (AEs) following treatment of LF with IVM, DEC, ALB, or any combination of these medications. Studies that reported AE rates by treatment group were included.

Findings

We reviewed 162 published manuscripts, 55 of which met inclusion criteria. Among these, 34 were clinic or hospital-based clinical trials, and 21 were community-based studies. Reported AE rates varied widely. The median AE rate following DEC or IVM treatment was greater than 60% among microfilaremic participants and less than 10% in persons without microfilaremia. The most common AEs reported were fever, headache, myalgia or arthralgia, fatigue, and malaise.

Interpretation

Mild to moderate systemic AEs related to death of microfilariae are common following LF treatment. Post-treatment AEs are transient and rarely severe or serious. Comparison of AE rates from different community studies is difficult due to inconsistent AE reporting, varied infection rates, and varied intensity of follow-up. A more uniform approach for assessing and reporting AEs in LF community treatment studies would be helpful.

WHO’s Global Programme to Eliminate Lymphatic Filariais (LF) supports annual mass drug administration to over 400 million people in LF-endemic areas each year. Two drug combinations (either DEC or ivermectin, given with albendazole) have been recommended in most endemic areas. With the exception of well-described serious adverse events (AEs) occurring in patients with high level loiasis, severe AEs due to these medications are extremely rare. Mild to moderate AEs, however, are common, particularly in patients with active filarial infection. In this manuscript we synthesize published data on AEs following single-dose treatment of LF with ivermectin, DEC, or albendazole. This provides a background against which to compare the safety of triple drug therapy (ivermectin, DEC, and albendazole) recently endorsed by WHO, and provides a useful context for evaluating safety of new treatments for LF. The compiled data illustrate that transient, mild to moderate AEs following single-dose LF treatment are common in microfilaremic patients and are much less common in amicrofilaremic patients. They also show that passive surveillance for post-treatment AEs underestimates AE incidence and suggest that adherence to common reporting standards would improve the usefulness of AE reporting in filariasis studies.

How elimination of lymphatic filariasis as a public health problem in the Kingdom of Cambodia was achieved

BACKGROUND

Endemicity of lymphatic filariasis (LF) in Cambodia was proven in 1956 when microfilariae were detected in mosquitos in the Kratié province. In 2001, an extensive study confirmed the presence of both Brugia malayi and Wuchereria bancrofti microfilariae. In 2003, the Ministry of Health established a national task force to develop policies and strategies for controlling and eliminating neglected tropical diseases (NTDs), with the goal of eliminating LF by 2015. This article summarizes the work accomplished to eliminate LF as a public health problem in Cambodia.

METHODS

The National Program to Eliminate Lymphatic Filariasis made excellent progress in the goal towards elimination due to strong collaboration between ministries, intensive supervision by national staff, and advocacy for mobilization of internal and external resources. Mass drug administration (MDA) with diethylcarbamazine citrate and albendazole was conducted in six implementation units, achieving > 70% epidemiological coverage for five consecutive rounds, from 2005 to 2009. In 2006, in 14 provinces, healthcare workers developed a line list of lymphedema and hydrocele patients, many of whom were > 40 years old and had been affected by LF for many years. The national program also trained healthcare workers and provincial and district staff in morbidity management and disability prevention, and designated health centers to provide care for lymphedema and acute attack. Two reference hospitals were designated to administer hydrocele surgery.

RESULTS

Effectiveness of MDA was proven with transmission assessment surveys. These found that less than 1% of school children had antigenemia in 2010, which fell to 0% in both 2013 and 2015. A separate survey in one province in 2015 using Brugia Rapid tests to test for LF antibody found one child positive among 1677 children. The list of chronic LF patients was most recently updated and confirmed in 2011-2012, with 32 lymphoedema patients and 17 hydrocele patients listed. All lymphedema patients had been trained on self-management and all hydrocele patients had been offered free surgery.

CONCLUSIONS

Due to the success of the MDA and the development of health center capacity for patient care, along with benefits gained from socioeconomic improvements and other interventions against vector-borne diseases and NTDs, Cambodia was validated by the World Health Organization as achieving LF elimination as a public health problem in 2016.

Reassessment of areas with persistent Lymphatic Filariasis nine years after cessation of mass drug administration in Sri Lanka

Background

Sri Lanka was one of the first countries to initiate a lymphatic filariasis (LF) elimination program based on WHO guidelines. The Anti-Filariasis Campaign provided 5 annual rounds of mass drug administration (MDA) with diethylcarbamazine plus albendazole in all 8 endemic districts from 2002–2006. Microfilaremia (Mf) prevalences have been consistently <1% in all sentinel and spot-check sites since 2006, and all evaluation units passed school-based transmission assessment surveys (TAS) in 2013. We previously reported results from comprehensive surveillance studies conducted in 2011–2013 that documented low-level persistence of Wuchereria bancrofti in 19 high risk areas in 8 endemic districts. We now present results from repeat surveys conducted 3 to 4 years later in 6 areas that had the strongest LF signals in the prior study.

Methodology and principal findings

The surveys assessed prevalence of filarial antigenemia (CFA) and Mf in communities, CFA and anti-filarial antibody in school children (ages 6–8), and filarial DNA in Culex mosquitoes (molecular xenomonitoring, MX). Three study areas had significantly improved infection parameters compared to the prior study, but three other areas had little change. MX was more sensitive for detecting W. bancrofti persistence, and it was a better predictor than other parameters. Adult males accounted for more than 80% of infections detected in the study.

Conclusions

These results suggest that W. bancrofti transmission was near the break point in some of the areas studied in 2011–13. LF is likely to decline to zero without further intervention in these areas, while other areas may require further intervention. Long term surveillance may be needed to verify W. bancrofti elimination in areas like Sri Lanka with efficient transmission by Culex. Test and treat or other programs targeting adult males plus bed net promotion may be more effective than MDA for clearing remaining hotspots of transmission in Sri Lanka.

Lymphatic Filariasis (LF, also known as “elephantiasis”) is a disabling and deforming tropical disease caused by parasitic worms that are transmitted by mosquitoes. The Sri Lankan Anti-Filariasis Campaign provided 5 annual rounds of mass drug administration (MDA) with diethylcarbamazine and albendazole between 2002 and 2006 in all endemic areas, and this reduced infection prevalence to very low levels. Post-MDA surveillance conducted by our group in 19 sentinel sites in 8 endemic districts in 2011–2013 revealed evidence of persistent LF infection in all study sites. The present paper reports results of repeat assessments conducted 3–4 years later in 6 areas with high signals in the prior study. LF parameters were significantly improved in 3 areas where LF appears to be on a glide path to elimination. However, LF infection parameters remained high in 3 areas, and further work will probably be required to interrupt transmission in these areas. Molecular xenomonitoring (to detect filarial DNA in mosquito vectors) was especially sensitive for detecting persistent LF in Sri Lanka, and this may also be true in other areas with Culex transmission. Our results suggest that test and treat or other programs targeting adult males plus expanded bed net use may be helpful for clearing up remaining LF hotspots.

Lymphatic pathology in asymptomatic and symptomatic children with Wuchereria bancrofti infection in children from Odisha, India and its reversal with DEC and albendazole treatment

Background

Once interruption of transmission of lymphatic filariasis is achieved, morbidity prevention and management becomes more important. A study in Brugia malayi filariasis from India has shown sub-clinical lymphatic pathology with potential reversibility. We studied a Wuchereria bancrofti infected population, the major contributor to LF globally.

Methods

Children aged 5–18 years from Odisha, India were screened for W. bancrofti infection and disease. 102 infected children, 50 with filarial disease and 52 without symptoms were investigated by lymphoscintigraphy and then randomized to receive a supervised single oral dose of DEC and albendazole which was repeated either annually or semi-annually. The lymphatic pathology was evaluated six monthly for two years.

Findings

Baseline lymphoscintigraphy showed abnormality in lower limb lymphatics in 80% of symptomatic (40/50) and 63·5% (33/52) of asymptomatic children. Progressive improvement in baseline pathology was seen in 70·8, 87·3, 98·6, and 98·6% of cases at 6, 12, 18, and 24 months follow up, while in 4·2, 22·5, 47·9 and 64·8%, pathology reverted to normal. This was independent of age (p = 0·27), symptomatic status (p = 0·57) and semi-annual/bi-annual dosing (p = 0·46). Six of eleven cases showed clinical reduction in lymphedema of legs.

Interpretation

A significant proportion of a young W. bancrofti infected population exhibited lymphatic pathology which was reversible with annual dosage of DEC and albendazole. This provides evidence for morbidity prevention & treatment of early lymphedema. It can also be used as a tool to improve community compliance during mass drug administration.

Trial registration

ClinicalTrials.gov No CTRI/2013/10/004121

Infection with lymphatic filarial parasites usually occurs early in childhood in endemic areas, but clinical signs appear much later. Reversal of lymphatic pathology has been shown with the much less common Brugia malayi infection using DEC and albendazole and there is scarce evidence whether the same occurs with bancroftian filariasis using the above drugs. We designed this study to look for prevalence of lymphatic pathology in children with and without clinical signs of infection and to observe the effect on the pre-treatment pathology using DEC and albendazole given once or twice a year. We have shown, using lymphoscintigraphy, that lymphatic vessel changes occur very early in infection, and treatment can reverse these changes, even when clinical symptoms are already apparent. This has important implications for lymphedema prevention, case management and for advocacy in the Lymphatic Filariasis Elimination Program. It also strengthens the previous evidence of benefit of treatment on early lymphedema management.

Detecting and confirming residual hotspots of lymphatic filariasis transmission in American Samoa 8 years after stopping mass drug administration

The Global Programme to Eliminate Lymphatic Filariasis (LF) aims to eliminate the disease as a public health problem by 2020 by conducting mass drug administration (MDA) and controlling morbidity. Once elimination targets have been reached, surveillance is critical for ensuring that programmatic gains are sustained, and challenges include timely identification of residual areas of transmission. WHO guidelines encourage cost-efficient surveillance, such as integration with other population-based surveys. In American Samoa, where LF is caused by Wuchereria bancrofti, and Aedes polynesiensis is the main vector, the LF elimination program has made significant progress. Seven rounds of MDA (albendazole and diethycarbamazine) were completed from 2000 to 2006, and Transmission Assessment Surveys were passed in 2010/2011 and 2015. However, a seroprevalence study using an adult serum bank collected in 2010 detected two potential residual foci of transmission, with Og4C3 antigen (Ag) prevalence of 30.8% and 15.6%. We conducted a follow up study in 2014 to verify if transmission was truly occurring by comparing seroprevalence between residents of suspected hotspots and residents of other villages. In adults from non-hotspot villages (N = 602), seroprevalence of Ag (ICT or Og4C3), Bm14 antibody (Ab) and Wb123 Ab were 1.2% (95% CI 0.6-2.6%), 9.6% (95% CI 7.5%-12.3%), and 10.5% (95% CI 7.6-14.3%), respectively. Comparatively, adult residents of Fagali'i (N = 38) had significantly higher seroprevalence of Ag (26.9%, 95% CI 17.3-39.4%), Bm14 Ab (43.4%, 95% CI 32.4-55.0%), and Wb123 Ab 55.2% (95% CI 39.6-69.8%). Adult residents of Ili'ili/Vaitogi/Futiga (N = 113) also had higher prevalence of Ag and Ab, but differences were not statistically significant. The presence of transmission was demonstrated by 1.1% Ag prevalence (95% CI 0.2% to 3.1%) in 283 children aged 7-13 years who lived in one of the suspected hotspots; and microfilaraemia in four individuals, all of whom lived in the suspected hotspots, including a 9 year old child. Our results provide field evidence that integrating LF surveillance with other surveys is effective and feasible for identifying potential hotspots, and conducting surveillance at worksites provides an efficient method of sampling large populations of adults.

Impact of mass drug administration for elimination of lymphatic filariasis in Nepal

Background

Lymphatic filariasis (LF) is a neglected tropical disease transmitted by mosquitoes. Nepal has implemented a national effort to eliminate LF by 2020 through mass drug administration (MDA) using diethylcarbamazine (DEC) and albendazole (ALB). We assessed the impact of MDAs on LF in selected districts of Nepal after the recommended six MDA rounds had been completed.

Methodology and principal findings

Baseline surveys were conducted in seven districts and mapping data were used as baseline in the other three districts before starting MDA in 2009. LF antigen (Ag) prevalence ranged from 1.06% to 20% among districts included in the baseline and mapping study. The number of people who received DEC and ALB were recorded during each MDA round and population-based cluster surveys were conducted at least once in each district during the life of the program. The reported MDA coverage in five districts was consistently at least 65%. Two districts achieved the targeted coverage in four out of five rounds and the rest three districts achieved the target only in the first round. A pre-transmission assessment survey (pre-TAS) was conducted in one sentinel site and at least one spot check site in each of the districts after five MDA rounds. In pre-TAS, all the sites of five districts (Pyuthan, Arghakhanchi, Kaski, Bhaktapur, and Kathmandu) and all but one spot check site of Lalitpur district had LF Ag < 2% (ranging from 0.0% to 1.99%). Transmission assessment survey (TAS) was conducted in six evaluation units (EUs) consisting of six districts qualified on pre-TAS. Though MDA coverage of 65% was not achieved in three districts (Kathmandu, Lalitpur and Bhaktapur), Nepal government in consultation with World Health Organization (WHO) decided to conduct TAS. All six EUs achieved the LF Ag threshold required to stop MDA in TAS, despite the low reported MDA coverage in those three districts.

Conclusions

Although Nepal has achieved significant progress towards LF elimination, five rounds of MDA were not sufficient to disrupt the transmission cycle in all districts, probably because of high baseline prevalence.

Lymphatic filariasis (LF) is a deforming and disabling infectious disease manifested in the form of elephantiasis and hydroceles. Based on mapping data, 61 out of 75 districts of Nepal were found to be endemic for LF and mass drug administration (MDA) of diethylcarbamazine and albendazole has been already started in 56 districts. The objective of MDA is to interrupt transmission of Wuchereria bancrofti in LF endemic districts. In 2015, ten districts had completed six MDA rounds. In this study we reported the impact of the national LF elimination effort in these ten districts of Nepal. The reported coverage rate in each MDA round was consistently above 65% in five districts. Compared to the baseline surveys, pre-transmission assessment surveys (pre-TAS) conducted after completion of five MDA rounds showed reductions in LF antigenemia (Ag) in most districts. Six out of ten districts (formed into six evaluation units) were eligible for TAS, which showed LF Ag below the cutoff point in all six EUs, suggesting successful interruption of LF transmission in six out of ten districts after six MDA rounds.

Reaching endpoints for lymphatic filariasis elimination- results from mass drug administration and nocturnal blood surveys, South Gujarat, India

BACKGROUND

Following the World Health Assembly resolution on Elimination of lymphatic filariasis (ELF) as a public health problem by the year 2020, a Global Program (GPELF) was launched in 1997 to help endemic countries to initiate national programs. The current strategy to interrupt transmission of LF, is administration of once-yearly, single-dose, two-drug regimen (Albendazole with Diethylcarbamazine (DEC) to be used in endemic areas with the goal of reaching 65% epidemiological coverage for 4-6 years. We report findings of independent assessment from year 2010 to 2015 for last six rounds, after initial five rounds of Mass Drug Administration (MDA) since 2005 for ELF in endemic area of Gujarat.

METHODS

Independent assessment of MDA was performed to find coverage and compliance indicators, reasons for non-coverage and non-compliance in five Implementation Units (IUs). Pre, during and post MDA evaluations were done in three phases. The impact of MDA was measured by microfilaraemia survey. A total of eight sites, four random and four fixed sentinel sites were selected to calculate microfilaria rate (MF) per IUs per year. In years 2010 to 2015, we report results from 125,936 nocturnal blood smears and 17551 population in 120 selected clusters. Four clusters were selected per year in each of the five IUs for assessment of MDA round.

RESULT

Post MDA survey showed drug coverage between 81%-88% and epidemiological coverage 77%-89% across years. Main reasons for non-coverage were drug administrator related (the team did not visit or missed people) while non-compliance was population related (fear of side effects, sickness, people forgot or absent). During MDA findings show that the directly observed consumption is considerably improved from 58% in 2010 to 82% in 2015. The knowledge about benefits of drug provided also increased from 59% to 90% over the years. The current MF rate is less than one in all IUs with an overall 68% percent decrease from baseline year 2005 to year 2015. The average MF rate of Gujarat is 0.44 for year 2015.

CONCLUSIONS

The findings show that achieving adequate epidemiological and drug coverage is possible by actual field level operation of the program in large endemic areas. The results and feedback from independent assessment, performed regularly, could guide the policymakers and program managers for mid-term corrections and to frame strategies to enhance program. Monitoring of coverage and impact indicator together informs decisions for reaching end-point of MDA. The impact indicator- microfilaria rate in all IUs of South Gujarat Region has reached and remained less than one percent signaling end-points of MDA. Post MDA stringent monitoring in form of TAS is recommended to keep vigil on maintenance of elimination achieved.

Community Rates of IgG4 Antibodies to Ascaris Haemoglobin Reflect Changes in Community Egg Loads Following Mass Drug Administration

Background

Conventional diagnostic methods for human ascariasis are based on the detection of Ascaris lumbricoides eggs in stool samples. However, studies of ascariasis in pigs have shown that the prevalence and the number of eggs detected in the stool do not correlate well with exposure of the herd to the parasite. On the other hand, an ELISA test measuring antibodies to Ascaris suum haemoglobin (AsHb) has been shown to be useful for estimating transmission intensity on pig farms. In this study, we further characterized the AsHb antigen and screened samples from a population-based study conducted in an area that is endemic for Ascaris lumbricoides in Indonesia to assess changes in AsHb antibody rates and levels in humans following mass drug administration (MDA).

Methodology/Principal findings

We developed and evaluated an ELISA to detect human IgG4 antibodies to AsHb. We tested 1066 plasma samples collected at different times from 599 subjects who lived in a village in rural Indonesia that was highly endemic for ascariasis. The community received 6 rounds of MDA for lymphatic filariasis with albendazole plus diethylcarbamazine between 2002 and 2007. While the AsHb antibody assay was not sensitive for detecting all individuals with Ascaris eggs in their stools, the percentage of seropositive individuals decreased rapidly following MDA. Reductions in antibody rates reflected decreased mean egg output per person both at the community level and in different age groups. Two years after the last round of MDA the community egg output and antibody prevalence rate were reduced by 81.6% and 78.9% respectively compared to baseline levels.

Conclusion/Significance

IgG4 antibody levels to AsHb appear to reflect recent exposure to Ascaris. The antibody prevalence rate may be a useful indicator for Ascaris transmission intensity in communities that can be used to assess the impact of control measures on the force of transmission.

Ascariasis is a neglected tropical disease caused by the intestinal nematode Ascaris lumbricoides that affects hundreds of millions of people in the developing world. Current methods for diagnosis of this infection are based on detecting eggs in the stool that are excreted by adult Ascaris worms. However, these methods have limited sensitivity for recent infections, and they do not detect infections with immature parasite stages that do not always result in the establishment of adult worms in the human intestine. We have previously shown that an assay for antibodies to Ascaris hemoglobin in pig serum is useful for assessing transmission of Ascaris infections on pig farms. In this study, we developed and evaluated a similar antibody assay that is based on the detection of human IgG4 antibodies to Ascaris haemoglobin (AsHb). Community antibody rates decreased rapidly following mass drug administration of the anthelmintic drug albendazole, and this decrease reflected reduced Ascaris egg excretion at the community level. This antibody test may be a useful tool for assessing the impact of control measures on the transmission of new Ascaris infections in endemic populations.

Maternal Infection Is a Risk Factor for Early Childhood Infection in Filariasis

Background

Global Program to Eliminate Lymphatic Filariasis (GPELF) launched by WHO aims to eliminate the disease by 2020. To achieve the goal annual mass drug administration (MDA) with diethylcarbamazine (DEC) plus albendazole (ABZ) has been introduced in all endemic countries. The current policy however excludes pregnant mothers and children below two years of age from MDA. Since pregnancy and early childhood are critical periods in determining the disease outcome in older age, the present study was undertaken to find out the influence of maternal filarial infection at the time of pregnancy on the susceptibility outcome of children born in a community after implementation of MDA for the first time.

Methodology and Principal Findings

The participants in this cohort consists of pregnant mothers and their subsequently born children living in eight adjacent villages endemic for filarial infections, in Khurda District, Odisha, India, where MDA has reduced microfilariae (Mf) rate from 12% to 0.34%. Infection status of mother and their children were assessed by detection of Mf as well as circulating filarial antigen (CFA) assay. The present study reveals a high rate of acquiring filarial infection by the children born to infected mother than uninfected mothers even though Mf rate has come down to < 1% after implementation of ten rounds of MDA.

Significance

To attain the target of eliminating lymphatic filariasis the current MDA programme should give emphasis on covering the women of child bearing age. Our study recommends incorporating supervised MDA to Adolescent Reproductive and Sexual Health Programme (ARSH) to make the adolescent girls free from infection by the time of pregnancy so as to achieve the goal.

Lymphatic filariasis, commonly known as elephantiasis, is a painful and profoundly disfiguring disease. A massive global effort has been undertaken to eliminate this disease by 2020 using annual mass drug administration (MDA). However the MDA excludes pregnant women and children below two years of age, which are the two critical periods thought to be playing a major role in determining the disease susceptibility in older age. We have been working on the impact of filarial infection at the time of pregnancy on neonates since 2009 in India. We have assessed the impact of maternal infection among a group of children from the time of their birth till they attain early childhood. We have observed that children born to mothers having filarial infection at the time of pregnancy were more prone to infection at early childhood than born to infection free mother in an area having very low infection rate after MDA. Our finding reveals that infection in mother at the time of pregnancy plays a crucial role in acquiring infection in children. Hence to achieve the goal of elimination of filariasis the women of child bearing age should be treated with antifilarials through MDA under supervision.

Enhanced efficacy of sequential administration of Albendazole for the clearance of Wuchereria bancrofti infection: Double blind RCT

Till today, there is no effective treatment protocol for the complete clearance of Wuchereria bancrofti (W.b) infection that causes secondary lymphoedema. In a double blind randomized control trial (RCT), 146 asymptomatic W. b infected individuals were randomly assigned to one of the four regimens for 12 days, DEC 300 mg + Doxycycline 100 mg coadministration or DEC 300 mg + Albendazole 400 mg co-administration or DEC 300 mg + Albendazole 400 mg sequential administration or control regimen DEC 300 mg and were followed up at 13, 26 and 52 weeks post-treatment for the clearance of infection. At intake, there was no significant variation in mf counts (F(3,137)=0.044; P=0.988) and antigen levels (F(3,137)=1.433; P=0.236) between the regimens. Primary outcome analysis showed that DEC + Albendazole sequential administration has an enhanced efficacy over DEC + Albendazole co-administration (80.6 Vs 64.7%), and this regimen is significantly different when compared to DEC + doxycycline co-administration and control (P<0.05), in clearing microfilaria in 13 weeks. Secondary outcome analysis showed that, all the trial regimens were comparable to control regimen in clearing antigen (F(3, 109)=0.405; P=0.750). Therefore, DEC + Albendazole sequential administration appears to be a better option for rapid clearance of W. b microfilariae in 13 weeks time. (Clinical trials.gov identifier - NCT02005653).

Solid lipid nanoparticles of diethylcarbamazine citrate for enhanced delivery to the lymphatics: in vitro and in vivo evaluation

OBJECTIVES

The major objective is to target diethylcarbamazine citrate (DEC) to the lymphatics and to increase its retention time. The effect of various excipients on the physicochemical characteristics of the nanoparticles was also studied.

MATERIALS AND METHODS

Solid lipid nanoparticles (SLNs) of DEC were prepared by ultrasonication by varying the concentrations of compritol 888 ATO, poloxamer 188 and soya lecithin. The SLNs were evaluated for size, shape, texture, surface charge, physical nature of the entrapped drug, entrapment efficiency and in vitro drug release. In vivo animal studies were carried out to estimate the pharmacokinetic parameters in blood and drug concentration in lymph after oral administration.

RESULTS

The size of the spherical particles was in the range of 27.25 ± 3.43 nm to 179 ± 3.08 nm and a maximum entrapment efficiency of 68.63 ± 1.53% was observed. In vitro release studies in pH 7.4 PBS displayed a rapid release and the maximum time taken for the complete drug to release was 150 min. In vivo studies indicated an enhancement in the amount of drug that reached lymphatics when administered via SLNs.

CONCLUSION

Targeting of DEC to the lymphatics is possible through SLNs and the retention time in the lymphatics can also be enhanced.

Coverage of, and compliance with, mass drug administration under the programme to eliminate lymphatic filariasis in India: a systematic review

India's mass drug administration (MDA) programme to eliminate lymphatic filariasis (PELF) covers all 250 endemic districts, but compliance with treatment is not adequate for the programme to succeed in eradicating this neglected tropical disease. The objective of our study was to systematically review published studies on the coverage of and compliance with MDA under the PELF in India. We searched several databases-PubMed/Medline, Google Scholar, CINAHL/EBSCO, Web of Knowledge (including Web of Science) and OVID-and by applying selection criteria identified a total of 36 papers to include in the review. Overall MDA coverage rates varied between 48.8% and 98.8%, while compliance rates ranged from 20.8% to 93.7%. The coverage-compliance gap is large in many MDA programmes. The effective level of compliance, ≥65%, was reported in only 10 of a total of 31 MDAs (5 of 20 MDAs in rural areas and 2 of 12 MDAs in urban areas). The review has identified a gap between coverage and compliance, and potentially correctable causes of this gap. These causes need to be addressed if the Indian programme is to advance towards elimination of lymphatic filariasis.

Impact of six rounds of mass drug administration on Brugian filariasis and soil-transmitted helminth infections in eastern Indonesia

BACKGROUND

The lymphatic filarial parasite Brugia timori occurs only in eastern Indonesia where it causes high morbidity. The absence of an animal reservoir, the inefficient transmission by Anopheles mosquitoes and the high sensitivity to DEC/albendazole treatment make this species a prime candidate for elimination by mass drug administration (MDA).

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated the effect of MDA using DEC and albendazole on B. timori and soil transmitted helminths (STH) in a cross-sectional study of a sentinel village on Alor Island annually over a period of 10 years. Pre-MDA the microfilaria (MF) prevalence was 26% and 80% of the residents had filaria-specific IgG4 antibodies. In 2010, 34 months after the 6(th) round of MDA, MF and antibody rates were only 0.17% and 6.4%, respectively. The MDA campaign had also a beneficial effect on STH. Baseline prevalence rates for Ascaris, hookworm and Trichuris were 34%, 28%, and 11%, respectively; these rates were reduced to 27%, 4%, and 2% one year after the 5(th) round of MDA. Unfortunately, STH rates rebounded 34 months after cessation of MDA and approached pre-MDA rates. However, the intensity of STH infection in 2009 was still reduced, and no heavy infections were detected.

CONCLUSIONS/SIGNIFICANCE

MDA with DEC/albendazole has had a major impact on B. timori MF and IgG4 antibody rates, providing a proof of principle that elimination is feasible. We also documented the value of annual DEC/albendazole as a mass de-worming intervention and the importance of continuing some form of STH control after cessation of MDA for filariasis.

Towards elimination of lymphatic filariasis: social mobilization issues and challenges in mass drug administration with anti-filarial drugs in Tamil Nadu, South India

India is a signatory to World Health Assembly resolution for elimination of lymphatic filariasis (LF) and National Health Policy has set the goal of LF elimination by 2015. Annual mass drug administration (MDA) is ongoing in endemic districts since 1996-97. Compliance rate is a crucial factor in achieving elimination and was assessed in three districts of Tamil Nadu for 10th and 11th treatment rounds (TRs). An in-depth study assessed the impact of social mobilization by drug distributors (DDs) in two areas from each of the three districts. Overall coverage and compliance for assessed TRs were 76.3 and 67.7% which is below the optimum level to achieve LF elimination. Modifiable determinants continue to be the reason for non-consumption even in the 11th TR and 20.8% were systematic non-compliers. In 76.4% of the cases, DDs failed to adhere to three mandatory visits as per the guidelines. Number of visits by DDs in relation to low and high MDA coverage areas showed a significant relationship (P ≤ 0.000). MDA is limited to drug distribution alone and efforts by DDs in preparing the community were inadequate. Probable means to meet the challenges in preparation of the community is discussed.

The prevalences ofWuchereria bancroftiantigenaemia in communities given six rounds of treatment with diethylcarbamazine, ivermectin or placebo tablets

The ICT filariasis card test was used to determine the prevalences of Wuchereria bancrofti antigenaemia among villagers in India. Prior to the tests, those living in the 15 study villages had been treated six times, in six rounds of mass treatment (with 54%-75% coverage) spread over 6 years, with single doses of diethylcarbamazine (five villages), ivermectin (five villages) or placebo (five villages). The corresponding overall prevalences (and ranges) of filarial antigenaemia were 20.2% (13.7%-28.6%), 22.6% (15.3%-34.3%) and 25.9% (22.6%-29.3%), respectively. The overall prevalence of antigenaemia in the villages where diethylcarbamazine (DEC) had been distributed (but not that in the 'ivermectin' villages) was significantly lower than that recorded in the 'placebo' villages (z =2.56; P <0.05). The prevalences of antigenaemia among the villagers aged 1-5 years (18.9%, 15.6% and 22.4% in the DEC, ivermectin and placebo villages, respectively) did not differ significantly with treatment (P >0.05). The results indicate that annual mass treatments based on DEC or ivermectin, with 54%-75% treatment coverage, may have only a limited effect on the prevalence of infection with adult W. bancrofti. The possible reasons for the antigenaemias observed are discussed.

Coverage and awareness of and compliance with mass drug administration for elimination of lymphatic filariasis in Burdwan District, West Bengal, India

India adopted WHO's strategy of repeated rounds of mass drug administration (MDA) with diethylcarbamazine to eliminate lymphatic filariasis. The present study attempted to assess the coverage and awareness of and compliance with MDA for elimination of lymphatic filariasis in Burdwan district of India, following MDA round in July 2010. A cross-sectional study was conducted among the four randomly-selected clusters in the district of Burdwan, West Bengal, India, covering 603 individuals from 154 households, using a predesigned pretested schedule. The drug distribution coverage, compliance, and effective coverage were 48.76%, 70.07%, and 34.16% respectively. Only 41.4% of the study population was aware of the MDA activity. This evaluation study noted that MDA is restricted to tablet distribution only. There is an urgent need to improve compliance with drug intake through strengthening of the awareness programme involving both government health workers and community volunteers.

Critical appraisal of mass DEC compliance in a district of west Bengal

A cross sectional study was carried out to assess drug compliance after Mass Drug Administration of DEC and the factors responsible for poor compliance among the population of Murshidabad district of West Bengal during Jan 2009. Total study unit were 120 families covering 3 villages and one municipality ward area (30 families from each area). As a part of Revised Filaria control strategy, MDA programme was implemented in Murshidabad district from 29th-31st December 2008. Result revealed that total covered population were 601, out of which 571 were eligible population for Mass drug administration (6 Pregnant women and <2 years age groups (24) were excluded). Drug distribution rate was 91.8%. Overall drug compliance was 42.3%. Total number of defaulters was 330 (57.7%). Non compliance was highest (75.5%) in urban area. Defaulters was more among male than female. Factors responsible for defaulters were no motivation (24.7%), drugs not supplied (22.5%), absence at home (13.5%), no faith (10.1%), fear of side effects (10.1%) and others (Forgotten, lack of prior IEC etc), illness, wrong information were 7.8%, 7.3%, 3.9% respectively. Majority has no side effects, only dizziness (3.3%), headache (1.7%), vomiting and others (4.1%) were experienced by the people after consumption of drugs. On an average 40% families were aware about ELF & transmission of disease. Only 43.7% of community members were informed about MDA by Health Workers prior to the implementation of MDA programme.

A study to compare the effect of adding 12 days DEC regimen to 6 years annual mass drug administration to eliminate microfilaraemia infection in the community in rural Kanpur, Uttar Pradesh, India

Lymphatic filariasis is a major public health problem of tropical countries. Although its elimination is planned as global effort using mass drug administration in affected communities but its impact has been influenced by MDA coverage across countries. The drug coverage is affected by fever as side effect and its continuation for over 6 years which affect the population participation. Therefore alternative approaches are needed which can show impact faster than standard MDA. Present research using additional 12 days dose of DEC to mf carriers, show that if drug coverage could be regular, sustainable impact could be created in 4 years.

Impact of insecticide treated mosquito nets and low dose monthly diethylcarbamazine on lymphatic filariasis infection between 1999 and 2004 in two endemic communities of north-eastern Tanzania

Lymphatic filariasis (LF) is among the poverty related neglected tropical diseases earmarked for elimination using mass drug administration (MDA) strategy. Additional use of insecticide treated mosquito nets (ITNs) might enhance elimination of LF infection. Between August 1998 and July 1999, all individuals aged 8 months from Magoda and Mpapayu villages in north-eastern Tanzania, were administered with monthly low dose diethylcarbamazine (DEC) at a dosage of 50mg in children aged < 15 years and 100mg in adults aged ≥ 15 years. ITNs were also distributed to Magoda in December 1998 and to Mpapayu in March 2001. The main objective of our study was to assess the impact of ITNs and low dose DEC on microfilaria (mf) prevalence and intensity and incidence of new mf infections. Four annual cross-sectional surveys were conducted between 1999 and 2004 in the two villages to screen for Wuchereria bancrofti microfilariae in individuals aged ≥ 1 year. Overall, 80% of the population in Magoda and 66% in Mpapayu were covered during these surveys. Results revealed a significant decrease in both mf prevalence and intensity in both villages. Furthermore, there was a steady decrease in mf incidence in Magoda; with 36.7 cases per 1000 person years in 2000 and 7.4 in 2004. In Mpapayu, the incidence initially increased from 20.8 cases in 2000 to 24.3 in 2001 and then decreased to 7.2 cases in 2004. Individuals using ITNs in Magoda had significantly lower risk of mf (OR=0.681; 95%CI: 0.496-0.934); and the risk of new infections was reduced by 58.8% (95%CI: 30.3-75.4). These results suggest that when MDA is complemented with ITNs there is high likelihood to half filariasis transmission within a shorter period than using chemotherapy alone.

Evaluation of effectiveness of diethylcarbamazine/albendazole combination in reduction of Wuchereria bancrofti infection using multiple infection parameters

OBJECTIVES

To evaluate the effect of multiple rounds of annual single dose of DEC (6 mg/kg) or albendazole (400mg) given alone or in combination on Wuchereria bancrofti microfilaraemia, anti-filarial IgG1 and IgG4 and antigenaemia.

METHODS

A total of 170 participants were randomly assigned to albendazole (n = 62), DEC (n = 54), and DEC plus albendazole (DEC/ALB) combination (n = 54). Blood samples were collected at pre-treatment in 1998, at 1 week and 6 months after the first treatment and thereafter before subsequent treatments in 1999 and 2000. Effects of treatment on W. bancrofti infection were determined by changes in levels of microfilaraemia, antifilarial antibodies and circulating filarial antigen.

RESULTS

Comparison of geometric mean microfilariae intensities between DEC/ALB combination and DEC or albendazole single therapy groups after two rounds of annual treatment and 24 months follow-up showed that combination therapy resulted in a greater reduction of microfilaraemia than single therapy with either albendazole (p < 0.001) or DEC alone (p = 0.146). The overall levels of anti-filarial antibodies decreased significantly (p = 0.028 for IgG1 and p < 0.043 for IgG4) in all treatment groups at 24 months follow-up. Additionally, overall reduction in geometric mean circulating filarial antigen levels at 24 months was 44%, 60% and 85% for albendazole, DEC and DEC/ALB groups, respectively.

CONCLUSIONS

These study findings suggest that albendazole improved efficacy of DEC and mass administration of a combination of the two drugs would therefore enhance the interruption of transmission of W. bancrofti in endemic areas. This information has important implications for the ongoing Global Program for Elimination of Lymphatic Filariasis.

Improving community participation to eliminate lymphatic filariasis in American Samoa

In 2000, the American Samoa Department of Health initiated a campaign of annual mass drug administration (MDA) with albendazole and diethylcarbamazine (DEC) to eliminate transmission of filariasis. Drug coverage was well below prescribed targets in the first three campaigns, ranging from 24 to 52% of the total population. Evaluation findings from a variety of formative research methods identified opportunities to improve MDA coverage and ensuing program modifications resulted in increased drug coverage of 65-71% in the following four annual distributions. Partnering with churches for drug distribution and using multiple media channels for health promotion led to sustained program improvements. With the increased emphasis on the use of mass distribution for delivery of drugs for a number of neglected tropical diseases, other programs may benefit from a similar approach.

Rural-urban population movement, community context and impact on DEC fortified salt program to eliminate lymphatic filariasis

Diethylcarbamazinecitrate (DEC) salt in conjunction with annual single-dose mass drug administration (MDA) with DEC tablets can be considered as potential option to hasten the process of Lymphatic Filariasis (LF) elimination. Consumption of DEC tablet/salt by at least 80% of the endemic population is crucial in achieving elimination in five years. This study examines the determinants of rural-urban population movement and its implication on DEC fortified salt program to control LF. Data was collected through questionnaire from 150 each movers and non-movers from 10 randomly selected villages and also using Key informant (KI) interviews in Villupuram district in Tamil Nadu. Households with at least one family member engaged in movement at any point of time in the previous year, range from 24 - 43% in different villages. Knowledge on cause, control, ongoing LF elimination programs and compliance with DEC tablets (28.7%) and salt (30%) were significantly higher (p < 0.05) among non-movers than movers (4.7% and 3.3% respectively). In order to achieve the goal of elimination of LF by 2020, measures need to be undertaken to ensure that the social mobilization activities and LF intervention programs need to cover the 24-43% of mobile population.

How endemic countries can accelerate lymphatic filariasis elimination? An analytical review to identify strategic and programmatic interventions

Lymphatic filariasis (LF) is endemic in 81 countries in the world, and a number of these countries have targeted for LF elimination. This review of literature and analysis was conducted to identify additional and sustainable strategies to accelerate LF elimination from endemic countries. This review noted that adverse events due to mass drug administration (MDA) of diethyl carbamazine (DEC) tablets, poor knowledge and information about LF amongst health workers & community members, and limited focus on information, education & communication (IEC) activities and interpersonal communication are the major barriers in LF elimination. The new approaches to increase compliance with DEC tablets (including exploring the possibility for DEC fortification of salt), targeted education programmes for physicians and health workers, and IEC material and inter personal communication to improve the knowledge of community are immediately required. There is a renewed and pressing need to conduct operational research, evolve sustainable and institutional mechanisms for education of physicians and health workers, ensure quality of trainings on MDA, strengthen IEC delivery mechanisms, implement internal and external monitoring of MDA activities, sufficient funding in timely manner, and to improve political and programmatic leadership. It is also time that lessons from other elimination programmes are utilized to accelerate targeted LF elimination from the endemic countries.

A single dose of doxycycline in combination with diethylcarbamazine for treatment of bancroftian filariasis

Standard treatment of lymphatic filariasis with diethylcarbamazine (DEC) is associated with systemic adverse reactions, thought to be due to the release of microfilariae material and Wolbachia endosymbiotic bacteria into the blood. Combination treatments with doxycycline for 3-8 weeks are more effective than standard treatment. However, long-term use of antibiotics may contribute to drug resistance and are not practical for use in remote areas. We assessed whether a single dose of doxycycline combined with the standard DEC regimen would reduce the incidence and severity of adverse reactions and increase the efficacy of standard treatment. Forty-four subjects from Tak Province were recruited into the randomized double-blind clinical trial study: 25 received DEC (300 mg) combined with a placebo, and 19 received DEC (300 mg) combined with doxycycline (200 mg). The incidences of adverse reactions to standard treatment were lower in the doxycycline group (45.5%) than in the placebo group (58.8%). Severe reactions occurred only in the placebo group (3 of 25 subjects). The severity of adverse reactions was significantly lower in the doxycycline group (mean score 0.45) than in the placebo group (mean score 1.17). The levels of IL-6 and Wolbachia DNA in the plasma were significantly lower in the doxycycline group. The filarial antigen levels were significantly lower in the doxycycline group at months 6 after treatment.

Increasing compliance with mass drug administration programs for lymphatic filariasis in India through education and lymphedema management programs

Background

Nearly 45% of people living at risk for lymphatic filariasis (LF) worldwide live in India. India has faced challenges obtaining the needed levels of compliance with its mass drug administration (MDA) program to interrupt LF transmission, which utilizes diethylcarbamazine (DEC) or DEC plus albendazole. Previously identified predictors of and barriers to compliance with the MDA program were used to refine a pre-MDA educational campaign. The objectives of this study were to assess the impact of these refinements and of a lymphedema morbidity management program on MDA compliance.

Methods/Principal Findings

A randomized, 30-cluster survey was performed in each of 3 areas: the community-based pre-MDA education plus community-based lymphedema management education (Com-MDA+LM) area, the community-based pre-MDA education (Com-MDA) area, and the Indian standard pre-MDA education (MDA-only) area. Compliance with the MDA program was 90.2% in Com-MDA+LM, 75.0% in Com-MDA, and 52.9% in the MDA-only areas (p<0.0001). Identified barriers to adherence included: 1) fear of side effects and 2) lack of recognition of one's personal benefit from adherence. Multivariable predictors of adherence amenable to educational intervention were: 1) knowing about the MDA in advance of its occurrence, 2) knowing everyone is at risk for LF, 3) knowing that the MDA was for LF, and 4) knowing at least one component of the lymphedema management techniques taught in the lymphedema management program.

Conclusions/Significance

This study confirmed previously identified predictors of and barriers to compliance with India's MDA program for LF. More importantly, it showed that targeting these predictors and barriers in a timely and clear pre-MDA educational campaign can increase compliance with MDA programs, and it demonstrated, for the first time, that lymphedema management programs may also increase compliance with MDA programs.

Global elimination of lymphatic filariasis requires giving drugs at least annually to populations who live at risk of becoming infected with the parasite. At least 80% of people at risk need to take the drugs annually for 5 or more years to stop transmission of the infection. People suffering from the long-term effects of infection, such as swollen legs, benefit from programs that teach self-care of their affected limbs. In this study, we assessed the impact of an educational campaign that, after addressing previously identified predictors of compliance, significantly improved drug compliance. The specific factors improving compliance included knowing about the drug distribution in advance, knowing that everyone is at risk for acquiring the infection, knowing that the drug distribution was for lymphatic filariasis prevention, and knowing at least one component of leg care. We also found that areas with programs to assist people with swollen legs had greater increases in compliance. This research provides evidence that program evaluation can be used to improve drug compliance. In addition, our work shows for the first time that programs to benefit people with swollen legs caused by lymphatic filariasis also increase the participation of people without disease in drug treatment programs.

Role of community empowerment in the elimination of lymphatic filariasis in south India

The World Health Assembly in 1997 has targeted the elimination of lymphatic filariasis (LF) by 2020, and in India the goal has been set for the year 2015 by annual single dose mass drug administration (MDA). The role of community empowerment in enhancing the drug compliance and bringing out the function of various methods used to disseminate the information on MDA to the villagers is focused. A longitudinal survey was carried out in nine villages in Tirukoilur block of Villupuram district, Tamil Nadu for filarial infection variables like microfilaraemia, antigenaemia, transmission indices before and after each MDA, to determine the drug impact. Prior to each MDA, health education campaigns with different approaches were carried out with community as the leading player. These IEC approaches were assessed after 4 MDAs for its perception in the community. After four rounds of MDA, there was a significant decline in the filarial infection variables. The microfilaraemia and antigenaemia declined by 59% and 67% respectively. The transmission indices lowered by 89% and 94% (in resting and landing catch of mosquitoes respectively). The decline in these variables, with a drug consumption rate of >80% was achieved due to the effective IEC campaigns prior to each MDA. After 4 MDAs almost 97% of the respondents were aware of lymphatic filariasis. The KAP survey in the rural villages revealed that the dissemination of MDA message through autorickshaw was the most effective, followed by school students' rally. Empowerment of community through the members of women self help groups and school students were observed to be integral to mass drug administration campaigns for the enhancement of drug compliance, thus leading to LF elimination.

Effect of a single dose of diethylcarbamazine, albendazole or both on the clearance of Wuchereria bancrofti microfilariae and antigenaemia among microfilaria carriers: a randomized trial

BACKGROUND

Lymphatic filariasis is a major vector-borne parasitic disease. The global programme to eliminate lymphatic filariasis was launched in 1997 and currently over 570 million people are covered under it in 48 countries. Mass annual single-dose drug administration of diethylcarbamazine (DEC), co-administrated with albendazole for 5-6 years and mass distribution of diethylcarbamazine-fortified salt are the two strategies for elimination of filariasis.

METHODS

Asymptomatic volunteers residing in Puducherry, India were screened for microfilaria (mf) by examining nocturnal thick blood smears. Those testing positive were randomly assigned to receive a single dose of DEC (6 mg/kg body weight) or albendazole 400 mg or both. Participants were hospitalized for 5 days. Membrane filtration count was used to assess microfilaraemia and ELISA (Og4C3) assay to measure circulating filarial antigens (CFA). Measurements were done before treatment and at 1, 2 and 3 years post-treatment. Viability of the adult worms was assessed by looking for the filarial dance sign (FDS) using ultrasound examination of the scrotum in men with hydrocele.

RESULTS

Fifty-four microfilaraemic Individuals were studied. The mf prevalence started decreasing only by day 180 posttreatment in the DEC group but much earlier in the other two groups (day 30 in the albendazole and day 90 in the DEC with albendazole group). The decrease in mfwas marginal (17.6%, 26.3% and 27.8%, respectively) by the end of year 1 posttreatment, but significant (96.7%, 78.6% and 93.3%, respectively) by the end of year 2 post-treatment (p < 0.05). By the end of year 3, the level decreased to 80% in the DEC, 90% in the albendazole and to 100% in the DEC and albendazole groups. However, the mf intensity decreased significantly (by 39%; p < 0.05) by day 7 post-treatment in both the DEC and DEC with albendazole groups, but only by day 30 in the albendazole group. In all the drug groups, the prevalence as well as intensity of CFA returned to pretreatment levels by the end of year 3 post-treatment.

CONCLUSION

Annual single-dose administration of all the 3 drug regimens significantly reduced antigenaemia levels. There were no significant differences in the efficacy and overall pattern of CFA clearance between the 3 drug regimens.

Imported bancroftian filariasis: diethylcarbamazine response and benzimidazole susceptibility of Wuchereria bancrofti in dynamic cross-border migrant population targeted by the National Program to Eliminate Lymphatic Filariasis in South Thailand

The implementation on the Thailand-Myanmar border of annual mass drug administration (MDA) of a single 6 mg/kg dose of diethylcarbamazine (DEC) plus 400mg albendazole, part of the National Program to Eliminate Lymphatic Filariasis (PELF), has been challenging. In particular, chain migration of cross-border Myanmar workers at risk for nocturnally periodic Wuchereria bancrofti infection can lead to imported bancroftian filariasis (IBF) in Thailand. IBF is targeted for multiple-dose MDA with 300 mg DEC, in addition to what is recommended by the World Health Organization (WHO). The dynamic Myanmar migrants in Phang-nga, southern Thailand were sampled to test whether the responsible W. bancrofti has a genetic predisposition of benzimidazole exposure, and IBF exhibits DEC susceptibility. The long-term migrants had more access to DEC. IBF in W. bancrofti antigenemic (microfilaremic vs. amicrofilaremic) short-term migrants exhibited susceptibility to a 300-mg single-dose DEC treatment. During the course of a 3-month follow-up, antigenemia was significantly reduced, but microfilaremia was fluctuated. Surprisingly, a newly recognized Mansonella infection co-existing among W. bancrofti-affected Myanmar migrants elicited microfilaremia clearance within a month after treatment. As a result of the presence of genetically stable W. bancrofti beta-tubulin (Wbtubb) gene responsible for benzimidazole susceptibility, IBF did not possess a genetic predisposition for benzimidazole exposure. Point mutations at positions Phe167Tyr and Phe200Tyr were not detected by Wbtubb locus-specific nested PCR and sequencing. This study has the potential to help guide not only the Thai/Myanmar PELF surveillance and monitoring of mass treatment impacts on W. bancrofti, but also the other endemic countries allied with the Global Program to Eliminate Lymphatic Filariasis (GPELF).