Background

The Global Programme for the Elimination of Lymphatic Filariasis (GPELF) was established in early 2000. This followed World Health Assembly Resolution 50.29 (WHA 50.29) in 1997 calling on the member states of the World Health Organisation (WHO) to eliminate the disease as a public health problem. This landmark resolution followed the 1993 declaration by the International Task Force for Disease Eradication (ITFDE) that lymphatic filariasis (see Table 1) was one of the six eliminable diseases [1].

Table 1 Lymphatic Filariasis
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Figure 1
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The proportions of the total, global burden posed by lymphatic filariasis that occur in the areas covered by the World Health Organization's regional offices for the Americas (AMRO), Eastern Mediterranean (EMRO), Africa (AFRO), South-east Asia (SEARO) and the Western Pacific (WPRO). Burden was estimated as the number of disability-adjusted life-years (DALY) lost and is shown split, in the pie chart for each region, according to the type of mosquito responsible for transmitting the causative parasite. Reprinted with permission from Annals of Tropical Medicine and Parasitology, Vol. 96, Supplement No. 2, S3–S13 (2002).

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Intensive research over the last decade has shown the efficacy of new drug combinations [2], created simple diagnostic tools [3] (See additional file 3), improved knowledge of pathology [4, 5] (See additional file 4) and demonstrated that those with existing disability could have symptoms of lymphoedema and elephantiasis alleviated by community home-based care [6].

The WHA resolution also prompted two major pharmaceutical donors to provide free donations of albendazole globally (GlaxoSmithKline) and Mectizan® (ivermectin) (Merck and Co. Inc.), for countries where lymphatic filariasis and onchocerciasis (river blindness) are co-endemic, for as long as needed (Table 2) [7, 8]. These pledges represent the largest long-term donation to a global health care initiative and a commitment to provide quality drugs to stop transmission of a disease. However, both companies recognize that the provision of drugs alone is not enough to sustain programme activity and provide wider support to the programme.

Table 2 Lymphatic Filariasis as a unique and successful programme
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Discussion

The development of a new strategy – time limited (at least 5 years) – annual co-administration of two drugs and the creation of GPELF and the Global Alliance for the Elimination of Lymphatic Filariasis (GAELF) builds on successful lymphatic filariasis elimination programmes in several countries [7–9]. These countries in different endemic areas and epidemiological settings have convincingly demonstrated that transmission could be stopped permanently. China, Japan, Korea, Thailand and the Solomon Islands using different strategies have eliminated transmission; Sri Lanka has eliminated Brugian filariasis and smaller foci in Brazil, Malaysia, Costa Rica, Suriname and Trinidad and Tobago have been eliminated [10].

The establishment of a diverse partnership in 2000 to form GAELF and the endorsement of the WHO strategic plan created a momentum that has resulted in 34 countries establishing active programmes. The programme has expanded rapidly with the number of people treated annually rising from 2.9 million in 12 countries in 2000 to 28.89 million in 2001 and an estimated 60 million in 34 countries in 2002 [11]. This upscaling occurred as the safety and tolerability of the drug combinations was confirmed on an increasingly large scale, as the extent of the disease and its consequent disabling effects on poor people were recognised, and as the magnitude of the latent burden in children was appreciated at the same time that new diagnostic tests revealed that children acquire infection at an early age [12] (One study from Haiti found that by the age four more than 25% of children were already infected [13]). These findings were recognised by many endemic countries who considered that LF was a priority as a disease that could be eliminated as public health problem, thus improving productivity and well-being of affected communities through reducing costs to individuals, communities and under-resourced health systems and enhancing earning capacity through increased productivity in various sectors.

It has also become increasingly apparent that the two-drug intervention provides substantial collateral health benefits to afflicted communities and provides additional intervention platforms for health systems. The multiplicities of health benefits that derive from annual treatment are depicted in Table 3, whilst the opportunity for integration and synergy with other health programmes are shown in Table 4.

Table 3 The benefits of Lymphatic Filariasis elimination
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Table 4 Opportunities for integration and synergy with other programmes
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Lymphatic filariasis is one of the "neglected diseases"; however its elimination appears not only feasible if programmes are sustained over a 5-year time scale but the programme has unique characteristics which enable it to appeal to a wide constituency of donors (Tables 2 and 5). Lymphatic filariasis elimination can viably contribute to the achievement of the Millennium Development Goals (Table 5) and represents an, as yet, unheralded global health success story; early targets for expansion of the programme's treatment numbers have been achieved. Countries have become convinced of the benefits of the programme, an active non-restrictive alliance of committed partners has been created, and real progress in arresting transmission has been reported from countries which commenced treatment in 2000 and which have completed three or four rounds of mass drug administration (MDA) – Egypt, Samoa, Vanuatu, Tanzania and Zanzibar. All are recording significant declines in prevalence and intensity of microfilariaemia. Furthermore, those suffering from the disease also appear to benefit from the treatment itself – an unpredicted outcome – as the frequency of filarial fevers are markedly reduced, and more recently a study from Papua New Guinea has shown a decrease in the incidence of hydrocoele (swelling of the scrotal sac) following annual mass treatment over 4 years [14] (although the effects on leg lymphoedema are equivocal [15]). The momentum of this success must be sustained to bring hope to the 1+ billion people at risk and remove LF as an impediment to the productivity and well-being of poor people and free future generations from exclusion, stigma, dependency and pain [16].

Table 5 Lymphatic Filariasis elimination and the Millennium Development Goals
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Summary

Lymphatic filariasis elimination is an "easy-to-do" inexpensive health intervention that provides considerable "beyond filariasis" benefits (Tables 4 and 5), exemplifies partnership and is easily evaluated. The success in global health action documented here requires and deserves further support to bring to fruition elimination of lymphatic filariasis as a public health problem and health benefits to poor people. A future free of lymphatic filariasis will reduce poverty and bring better health to poor people, prevent disability, strengthen health systems and build partnerships.

If the international health community cannot deliver two safe efficacious drugs annually – which are largely free – which in addition to stopping transmission of lymphatic filariasis also bring profound additional health benefits, it is difficult to expect more complex interventions to succeed in controlling other infectious diseases.

The Global Alliance for the Elimination of Lymphatic Filariasis has the skills, commitment and partnerships to succeed, thereby preventing the next generation of children being infected and subsequently afflicted by this most stigmatising of diseases. There is, however, a need for significant new resources to be committed to achieve this goal.

Related websites

Global Alliance for the Elimination of Lymphatic Filariasis

http://www.filariasis.org/

GlaxoSmithKline: Lymphatic Filariasis Programme

http://www.gsk.com/filariasis/

Mectizan® Donation Program

http://mectizan.org/lymphatic_filariasis.asp

filariasis.net

http://www.filariasis.net/