Mass drug administration to eliminate lymphatic filariasis in India

Progress and impact of 20 years of a lymphatic filariasis elimination programme in South-East Asia

Background

The South-East Asia regional programme to eliminate lymphatic filariasis (LF) was launched in 2000. This study presents the progress and impact of the programme in the region.

Methods

Mass drug administration (MDA) and morbidity management data were accessed from the WHO preventive chemotherapy databank. The status of the programme in the nine South-East Asia countries was reviewed and progress was assessed. The impact of the programme on LF disease burden was estimated on the basis of the effectiveness of the MDA drugs against microfilaraemia and chronic disease.

Results

Under the MDA programme, 8.1 billion treatments were delivered in nine countries and 5.7 billion treatments were consumed by the target population during 2001–2018. Three of nine countries eliminated LF. Bangladesh is poised to reach its elimination goal by 2021. In the other five countries, 38–76% of intervention units completed intervention and surveillance is in progress. The MDA programme prevented or cured 74.9 million infections, equivalent to an 84.2% reduction. Close to 1 million lymphoedema patients and 0.5 million hydrocele patients were reported and are being provided with the minimum package of care.

Conclusions

The South-East Asia region's LF elimination programme reduced the burden of LF appreciably and is moving towards achieving the elimination goal in the next 8–10 y.

Economic evaluations of lymphatic filariasis interventions: a systematic review and research needs

In 2000, the World Health Organization established the Global Programme to Eliminate Lymphatic Filariasis (GPELF), with the goal of eliminating the disease as a public health problem by 2020. Since the start of the programme, a cumulative total of 6.2 billion treatments have been delivered to affected populations - with more than 556 million people treated in 2015 alone. In this paper, we perform a rigorous systematic review of the economic evaluations of lymphatic filariasis interventions have been conducted. We demonstrate that the standard interventions to control lymphatic filariasis are consistently found to be highly cost-effective. This finding has important implications for advocacy groups and potential funders. However, there are several important inconsistencies and research gaps that need to be addressed as we move forward towards the 2020 elimination goals. One of the most important identified research gaps was a lack of evaluation of new interventions specifically targeting areas co-endemic with onchocerciasis and Loa loa - which could become a major barrier to achieving elimination.

Can Lymphatic Filariasis Be Eliminated by 2020?

Interventions against neglected tropical diseases (NTD), including lymphatic filariasis (LF), scaled up dramatically after the signing of the London Declaration (LD) in 2012. LF is targeted for elimination by 2020, but some countries are considered not on track to meet the 2020 target using the recommended preventive chemotherapy and morbidity management strategies. In this Opinion article we review the prospects for achieving LF elimination by 2020 in the light of the renewed global action against NTDs and the global efforts to achieve the sustainable development goals (SDGs) by 2030. We conclude that LF can be eliminated by 2020 using cross-sectoral and integrated approaches because of the compound effect of the other SDG activities related to poverty reduction and water and sanitation.

Progress and impact of 13 years of the global programme to eliminate lymphatic filariasis on reducing the burden of filarial disease

BACKGROUND

A Global Programme to Eliminate Lymphatic Filariasis was launched in 2000, with mass drug administration (MDA) as the core strategy of the programme. After completing 13 years of operations through 2012 and with MDA in place in 55 of 73 endemic countries, the impact of the MDA programme on microfilaraemia, hydrocele and lymphedema is in need of being assessed.

METHODOLOGY/PRINCIPAL FINDINGS

During 2000-2012, the MDA programme made remarkable achievements - a total of 6.37 billion treatments were offered and an estimated 4.45 billion treatments were consumed by the population living in endemic areas. Using a model based on empirical observations of the effects of treatment on clinical manifestations, it is estimated that 96.71 million LF cases, including 79.20 million microfilaria carriers, 18.73 million hydrocele cases and a minimum of 5.49 million lymphedema cases have been prevented or cured during this period. Consequently, the global prevalence of LF is calculated to have fallen by 59%, from 3.55% to 1.47%. The fall was highest for microfilaraemia prevalence (68%), followed by 49% in hydrocele prevalence and 25% in lymphedema prevalence. It is estimated that, currently, i.e. after 13 years of the MDA programme, there are still an estimated 67.88 million LF cases that include 36.45 million microfilaria carriers, 19.43 million hydrocele cases and 16.68 million lymphedema cases.

CONCLUSIONS/SIGNIFICANCE

The MDA programme has resulted in significant reduction of the LF burden. Extension of MDA to all at-risk countries and to all regions within those countries where MDA has not yet reached 100% geographic coverage is imperative to further reduce the number of microfilaraemia and chronic disease cases and to reach the global target of interrupting transmission of LF by 2020.

Lymphatic filariasis elimination programme in Andaman and Nicobar Islands, India: drug coverage and compliance post eight rounds of MDA

Lymphatic filariasis (LF) is endemic in the Andaman and Nicobar islands, including the lone foci for a diurnally sub-periodic form of Wuchereria bancrofti in the Nancowry group of islands. A programme to eliminate LF was launched in 2004 by the Directorate of Health Services, Andaman and Nicobar Administration which involved a single annual mass drug administration (MDA) using diethylcarbamazine (DEC) with albendazole. So far, eight rounds of MDA have been implemented through the Public Health Care network. The pattern of antifilarial drug distribution and compliance achieved in the on-going LF elimination programme in these islands has been assessed. This is the first systematic effort undertaken in these remote islands to assess the coverage and compliance with the LF elimination programme. This study covered 900 households in each of the 3 districts. There were a largest number of side effects in the Nicobar district (6.4%). Non-consumption of drugs ranged from 18.6% (Nicobar) to 42% (North and Middle Andaman). A survey revealed that almost 95.3% of the respondents had heard about MDA from the drug distributors. Therefore, the distributors should be involved in programmes designed to educate the community at risk of acquiring filarial infection and the possible side effects of the drugs.

Enzyme-linked immunosorbent assay for the diagnosis of Wuchereria bancrofti infection using urine samples and its application in Bangladesh

In Sri Lanka, urine ELISA showed high sensitivity and specificity in detecting filaria-specific IgG4. It also produced much higher positive rates than antigen tests in prevalence studies with young children. In this study, we have confirmed the usefulness of urine ELISA in the field of Bangladesh. The ELISA detected 89 of 105 (85%) ICT antigen test positive subjects in endemic areas. With both ICT and microfilaria positives, the sensitivity was 97% (30/31). All of 104 ICT negative people in a non-endemic area were ELISA negative (100% specificity). In a prevalence study with 319 young children (5-10 years) from a low endemic area after five rounds of MDA, seven (2.2%) were detected by the present urine test, but only one (0.3%) by ICT (P=0.075). The satisfactorily high sensitivity, 100% specificity and effective case detection among young ages along with scope for analyzing the titers will indicate urine ELISA to be an effective tool in the post-MDA surveys to confirm elimination or to detect resurgence in Bangladesh.

Modeling the impact and costs of semiannual mass drug administration for accelerated elimination of lymphatic filariasis

The Global Program to Eliminate Lymphatic Filariasis (LF) has a target date of 2020. This program is progressing well in many countries. However, progress has been slow in some countries, and others have not yet started their mass drug administration (MDA) programs. Acceleration is needed. We studied how increasing MDA frequency from once to twice per year would affect program duration and costs by using computer simulation modeling and cost projections. We used the LYMFASIM simulation model to estimate how many annual or semiannual MDA rounds would be required to eliminate LF for Indian and West African scenarios with varied pre-control endemicity and coverage levels. Results were used to estimate total program costs assuming a target population of 100,000 eligibles, a 3% discount rate, and not counting the costs of donated drugs. A sensitivity analysis was done to investigate the robustness of these results with varied assumptions for key parameters. Model predictions suggested that semiannual MDA will require the same number of MDA rounds to achieve LF elimination as annual MDA in most scenarios. Thus semiannual MDA programs should achieve this goal in half of the time required for annual programs. Due to efficiency gains, total program costs for semiannual MDA programs are projected to be lower than those for annual MDA programs in most scenarios. A sensitivity analysis showed that this conclusion is robust. Semiannual MDA is likely to shorten the time and lower the cost required for LF elimination in countries where it can be implemented. This strategy may improve prospects for global elimination of LF by the target year 2020.

The Global Program to Eliminate Lymphatic Filariasis (LF) employs annual mass drug administration (MDA) of antifilarial drugs to reduce infection rates in populations and interrupt transmission. While this program is working well in many countries, progress has been slow in others, and some countries have not yet started MDA programs. We used computer simulation modeling and cost projections to study how increasing MDA frequency from once to twice per year would affect program duration and costs. Our results suggest that semiannual MDA is likely to reduce the time required to eliminate LF by 50% and reduce total program costs (excluding the cost of donated drugs) in most situations. For these and other reasons, we expect semiannual MDA to be superior to annual MDA in most endemic settings. Semiannual MDA should be considered as a means of accelerating LF elimination in areas where it can be implemented, because this may improve prospects for global elimination of LF by the target year 2020.

Lymphatic Filariasis in India : Problems, Challenges and New Initiatives

Filariasis is a major public health problem in India and inspite of existence of the National Filaria Control Programme since 1955, currently there may be up to 31 million microfilaraemics, 23 million cases of symptomatic filariasis, and about 473 million individuals potentially at risk of infection. Over the last 10 years advances have led to new diagnostic/ treatment tools and control strategies for filariasis. The new control strategy aims at transmission control through mass treatment and at disease control through individual patient management. As a signatory to 50(th) World Health Assembly resolution on global elimination of lymphatic filariasis in 1997, revised filariasis control program was launched in India in 13 districts in seven endemic states where mass drug administration was undertaken. Single dose mass administration annually in combination with other techniques has already eliminated lymphatic filariasis from Japan, Taiwan, South Korea and Solomon Islands and markedly reduced the transmission in China. Very high treatment coverage (probably > 85%) is required to achieve interruption of transmission and elimination in India. Hence, there is an urgent need for effective drug delivery strategies that are adapted to regional differences. This requires powerful advocacy tools and strategies as well as procedures for monitoring and evaluating the impact of elimination programme.

An evaluation of coverage and compliance of mass drug administration 2006 for elimination of lymphatic filariasis in endemic areas of gujarat

Background:

Mass drug administration (MDA) means once-in-a-year administration of diethyl carbamazine (DEC) tablet to all people (excluding children under 2 years, pregnant women and severely ill persons) in identified endemic areas. It aims at cessation of transmission of lymphatic filariasis.

Objective:

What has been the coverage and compliance of MDA in Gujarat during the campaign in December 2006?

Study Design:

Cross-sectional population based house-to-house visit.

Setting:

Urban and rural areas in Gujarat identified as endemic for filariasis where MDA 2006 was undertaken.

Study Variables:

Exploratory - Rural and urban districts; Outcome - coverage, compliance, actual coverage, side effects.

Analysis:

Percentage and proportions.

Results:

Twenty-six clusters, each comprising 32 households from six endemic districts, yielded an eligible population of 4164. The coverage rate was 85.2% with variation across different areas. The compliance with drug ingestion was 89% with a gap of 11% to be targeted by intensive IEC. The effective coverage (75.8%) was much below the target (85%). Side effects of DEC were minimum, transient and drug-specific. Overall coverage was marginally better in rural areas. The causes of poor coverage and compliance have been discussed and relevant suggestions have been made.

Filariasis: diagnosis and treatment

Filariasis is an infectious disease of the lymphatics and subcutaneous tissues caused by nematodes or filariae. Carried by mosquito vectors, this disease causes millions of people to suffer from lymphedema and elephantiasis, characteristics of filariasis infection. This disease can be diagnosed through the identification of microfilariae in blood or skin samples, antigen detection, radiographic imaging, or polymerase chain reaction. Mass drug administration by the World Health Organization has helped to diminish the incidence of filariasis. However, continued research on new drugs and vaccinations will be needed to control and reduce the microfilarial levels in the human population.

Predictors of compliance with a mass drug administration programme for lymphatic filariasis in Orissa State, India 2008

OBJECTIVES

To assess the performance of an educational campaign to increase adherence to a mass-administered DEC regimen against lymphatic filariasis (LF) in Orissa, and to identify factors that could enhance future campaigns.

METHOD

Randomized cluster survey, comparing areas that did and did not receive the educational campaign, using a household coverage survey and knowledge, attitudes and practices (KAP) survey.

RESULTS

LF MDA coverage for the entire population (n = 3449) was 56% (95% CI: 50.0-61.9). There was no statistical difference between the areas that did and did not receive the educational campaign. The most common barriers to adherence were fear of medication side effects (47.4%) and lack of recognition of one's risk for LF (15.8%). Modifiable, statistically significant, multivariable predictors of adherence were knowing that DEC prevents LF (aOR = 2.6, 95% CI: 1.4-5.1), knowing that mosquitoes transmit LF (aOR = 1.9, 95% CI: 1.1-3.2), and knowing both about the mass drug administration (MDA) in advance and that mosquitoes transmit LF (aOR = 5.4, 95% CI: 2.8-10.4).

CONCLUSIONS

India needs to increase compliance with MDA programmes to reach its goal of interrupting LF transmission. Promoting a simple public health message before MDA distribution, which takes into account barriers to and predictors of adherence, could raise compliance with the LF MDA programme.

The global programme to eliminate lymphatic filariasis: health impact after 8 years

BACKGROUND

In its first 8 years, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) achieved an unprecedentedly rapid scale-up: >1.9 billion treatments with anti-filarial drugs (albendazole, ivermectin, and diethylcarbamazine) were provided via yearly mass drug administration (MDA) to a minimum of 570 million individuals living in 48 of the 83 initially identified LF-endemic countries.

METHODOLOGY

To assess the health impact that this massive global effort has had, we analyzed the benefits accrued first from preventing or stopping the progression of LF disease, and then from the broader anti-parasite effects ('beyond-LF' benefits) attributable to the use of albendazole and ivermectin. Projections were based on demographic and disease prevalence data from publications of the Population Reference Bureau, The World Bank, and the World Health Organization.

RESULT

Between 2000 and 2007, the GPELF prevented LF disease in an estimated 6.6 million newborns who would otherwise have acquired LF, thus averting in their lifetimes nearly 1.4 million cases of hydrocele, 800,000 cases of lymphedema and 4.4 million cases of subclinical disease. Similarly, 9.5 million individuals--previously infected but without overt manifestations of disease--were protected from developing hydrocele (6.0 million) or lymphedema (3.5 million). These LF-related benefits, by themselves, translate into 32 million DALYs (Disability Adjusted Life Years) averted. Ancillary, 'beyond-LF' benefits from the >1.9 billion treatments delivered by the GPELF were also enormous, especially because of the >310 million treatments to the children and women of childbearing age who received albendazole with/without ivermectin (effectively treating intestinal helminths, onchocerciasis, lice, scabies, and other conditions). These benefits can be described but remain difficult to quantify, largely because of the poorly defined epidemiology of these latter infections.

CONCLUSION

The GPELF has earlier been described as a 'best buy' in global health; this present tally of attributable health benefits from its first 8 years strengthens this notion considerably.

Global eradication of lymphatic filariasis: the value of chronic disease control in parasite elimination programmes

The ultimate goal of the global programme against lymphatic filariasis is eradication through irrevocable cessation of transmission using 4 to 6 years of annual single dose mass drug administration. The costs of eradication, managerial impediments to executing national control programmes, and scientific uncertainty about transmission endpoints, are challenges to the success of this effort, especially in areas of high endemicity where financial resources are limited. We used a combined analysis of empirical community data describing the association between infection and chronic disease prevalence, mathematical modelling, and economic analyses to identify and evaluate the feasibility of setting an infection target level at which the chronic pathology attributable to lymphatic filariasis--lymphoedema of the extremities and hydroceles--becomes negligible in the face of continuing transmission as a first stage option in achieving the elimination of this parasitic disease. The results show that microfilaria prevalences below a threshold of 3.55% at a blood sampling volume of 1 ml could constitute readily achievable and sustainable targets to control lymphatic filarial disease. They also show that as a result of the high marginal cost of curing the last few individuals to achieve elimination, maximal benefits can occur at this threshold. Indeed, a key finding from our coupled economic and epidemiological analysis is that when initial uncertainty regarding eradication occurs and prospects for resolving this uncertainty over time exist, it is economically beneficial to adopt a flexible, sequential, eradication strategy based on controlling chronic disease initially.

Impact of 10 years of diethylcarbamazine and ivermectin mass administration on infection and transmission of lymphatic filariasis

The potential of repeated mass administration of diethylcarbamazine (DEC) and ivermectin to eliminate lymphatic filariasis has been examined in a study implemented in 10 villages with a population of 18415 in south India. During ten rounds of mass drug administration, 49-84% of the eligible population received treatment in different villages. Ten rounds of mass administration of DEC alone reduced the microfilaria (mf) prevalence and intensity by 93% and 97%, respectively, and the vector infection and infectivity rates by 91% and 89%, respectively. The corresponding figures with nine rounds of administration of ivermectin alone were 83%, 90%, 89% and 79%. Out of five villages in each treatment arm, the mf rate declined to <or=1% in four villages in the DEC arm and two villages in the ivermectin arm. No mosquitoes with infective-stage larvae were found in three of five villages in the DEC arm and two of five villages in the ivermectin arm. None of the children (n=130) were found to be positive for mf in either treatment arm. None of the 40 sampled children were found to be positive for circulating filarial antigenaemia in villages with lower endemicity in the DEC arm. The results suggest that ten rounds of DEC mass administration have the potential to interrupt transmission of infection in the majority of communities. The outcome was relatively less remarkable with ivermectin.

Factors influencing drug compliance in the mass drug administration programme against filariasis in the Western province of Sri Lanka

This descriptive, comparative, cross-sectional, randomized community-based study was done to determine factors influencing drug compliance in the mass drug administration (MDA) programme against filariasis in selected urban and rural populations within the Western province of Sri Lanka. The study population was selected using the cluster sampling method. Factors influencing drug compliance were determined by administration of an interviewer-based pre-tested questionnaire eliciting information regarding drug compliance, socio-economic status, educational background, knowledge, attitudes and practices with regard to the 2004 MDA. A total of 2319 people aged between 10 and 90 years (median 40) responded to the questionnaire. The belief that the MDA programme was beneficial was the most important factor affecting drug compliance, as revealed by multivariate analysis of the combined populations (P<0.001). This was so even in the urban population (P<0.001), while the belief regarding the severity (danger) of filariasis was important in the rural population (P=0.013), when the areas were considered individually. Therefore, it is essential for awareness programmes to highlight the dangers (complications) of the disease and to influence the community to perceive the benefits of a filariasis-free community as well as 'beyond filariasis' benefits of having albendazole given in combination in the MDA programme.

Controlling lymphatic filariasis and soil-transmitted helminthiasis together in South Asia: opportunities and challenges

Lymphatic filariasis (LF) and the major soil-transmitted helminth (STH) infections are co-endemic in many countries, particularly in Asia. Control strategies for both groups of infections have increasingly focused on the use of mass chemotherapy. With the use of albendazole, there is now a tool that is common to both. However, there are also important differences in their modes of transmission and epidemiology, and, as a result, in the overall control strategies. The Global Programme for the Elimination of Lymphatic Filariasis aims to eliminate LF through time-limited mass drug administration programmes. Control activities for STH are more diffuse, aiming to piggy-back de-worming onto existing services, such as school health activities; controlling morbidity, rather than eliminating infection, is the stated goal. In order to maximize health benefits to communities that are endemic for one or both of these infections, it is vitally important that policy makers and programme managers have a clear understanding of both commonalities and differences, and implement control strategies that allocate available resources in an optimal manner.

Global socioeconomic impact of cystic echinococcosis

Because the human and economic losses of cystic echinococcosis are substantial, global prevention and control measures should be increased.

Cystic echinococcosis (CE) is an emerging zoonotic parasitic disease throughout the world. Human incidence and livestock prevalence data of CE were gathered from published literature and the Office International des Epizooties databases. Disability-adjusted life years (DALYs) and monetary losses, resulting from human and livestock CE, were calculated from recorded human and livestock cases. Alternative values, assuming substantial underreporting, are also reported. When no underreporting is assumed, the estimated human burden of disease is 285,407 (95% confidence interval [CI], 218,515–366,133) DALYs or an annual loss of US $193,529,740 (95% CI, $171,567,331–$217,773,513). When underreporting is accounted for, this amount rises to 1,009,662 (95% CI, 862,119–1,175,654) DALYs or US $763,980,979 (95% CI, $676,048,731–$857,982,275). An annual livestock production loss of at least US $141,605,195 (95% CI, $101,011,553–$183,422,465) and possibly up to US $2,190,132,464 (95% CI, $1,572,373,055–$2,951,409,989) is also estimated. This initial valuation demonstrates the necessity for increased monitoring and global control of CE.

Priority setting and the 'neglected' tropical diseases

In this paper David Canning argues that interventions against 'neglected' tropical diseases should be thought of as investments in human capital and form an integral part of global poverty reduction. He argues that overall burden of disease should not be the criterion for priority setting; if the goal is to maximize health benefits from a fixed health budget then cost-effective interventions should be prioritized. Whilst many people find objectionable the assignment of a monetary value to health, a cost-benefit approach, combining health and economic benefits, would allow the health sector to present arguments to policy makers, based on the rate of return on investment. Since many health interventions in low-income countries have exceptionally high rankings in terms of cost-benefit ratios, this should result in large flows from other sectors to the health sector.