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

28 Oct 2008

Marcia Triunfol

Source: Plos Neglected Tropical Diseases (see original article)

Citation: Ottesen EA, Hooper PJ, Bradley M, Biswas G.The global programme to eliminate lymphatic filariasis: health impact after 8 years (2008). PLoS Negl Trop Dis; 2(10):e317.

What were the health benefits of a massive drug administration programme that provided 1.9 billion treatments to 570 million people in 48 endemic countries during a 7-year period? What additional benefits might this programme have had on society and people’s lives? How does one quantify the overall impact of such a programme? Based on the available data, one makes assumptions and projections.

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) has been described as the most successful public health programme ever conducted. It was created to address a specific resolution by the World Health Assembly and received essential contributions from two pharmaceutical companies, namely GlaxoSmithKline and Merck & Co, Inc, which provided drug donations. Countries included in the programme also made purchases of some of the drugs used.

The study by Ottesen and colleagues used several resources and data to establish what the situation would be like now if the programme had never existed. How many children would have been infected by LF, how many would be at risk, how many newborns would have died?

By examining sources like the Weekly Epidemiological Record (WER) and WHO Annual Reports corresponding to the 2000-2007 programme period, the authors established the number of endemic countries, and how many individuals and children were at risk. Population demographics in each of the countries were determined according to data provided by the Population Reference Bureau and the World Bank Health, Nutrition, and Population Statistics. Disability Adjusted Life Years (DALYs) was calculated based on data provided by the Global Bureau of Disease. Using these sources, the authors were able to make assumptions and estimate the overall impact of the programme.

The overall impact includes not only the direct health benefits that massive drug treatment may have had on treated individuals but also what the paper refers to as the ‘beyond LF benefits’. For instance, the authors were also interested in knowing the impact of the programme on parasites other than LF, as the same drugs used to treat LF may also be used to treat intestinal parasite infections. Therefore, two separate groups of impacts were identified. Group one includes the impact of the programme on LF-related benefits, which are those that are directly related to the programme and represent the direct and obvious benefits of not contracting or developing LF. Group two includes those secondary impacts such as the ones related to the benefits of not contracting parasitic infections.

In-group one, two main impacts were detected. They were described as Protecting newborns from LF infection and disease, and as Preventing the progression to overt disease in LF-endemic populations. In Protecting newborns from LF infection and disease, the authors estimated that the programme protected 6.6 million newborns. If not protected, these 6.6 million babies might have developed during their lives approximately 1.4 million cases of hydrocoele, more than 800,000 cases of lymphoedema and 4.4 million cases of subclinical disease. This also means that 6.0 million disability adjusted life years (DALYs) may have been prevented. In Preventing the progression to overt disease in LF-endemic populations, the authors estimated that the programme was able to prevent 9.5 million infected individuals from developing full LF. This can be translated into 26 million DALYs averted.

In group two, which identifies those benefits obtained that are beyond LF itself, the authors detected three different impacts. They are described as Preventing the consequences of intestinal parasite infections, which are further divided into the impacts on children and those on childbearing-age women, and Prevention of debilitating skin diseases.

In Preventing the consequences of intestinal parasite infections on children, the authors estimated that approximately 56.5 million children received treatment for parasite infections. The authors went even further in estimating that the absence of intestinal parasite infections may have represented a substantial gain in children extra weight and extra growth, as children receiving the treatment are expected to have had their appetite increased. Other secondary impacts such as better school attendance, improvement in cognitive tests and others alike are also mentioned in the study as potential additional benefits of the programme.

In Preventing the consequences of intestinal parasite infections in women-of-childbearing-age, the authors estimated that 44.5 million women benefited from the programme. Secondary benefits may also include an increase in infant birth-weights, whereas maternal mortality may have decreased.

In Prevention on debilitating skin diseases, an estimate was made that millions of treatments were given through the GPELF programme to individuals who had not received treatments through the APOC (African Programme for Onchocersiasis Control), as APOC was implemented only in communities in which the incidence of onchocerciasis exceeded 40%.

As in any study of its kind, there are limitations. For instance, all estimates are based on the assumption that treated individuals will not become re-infected, which is not necessarily true. The results presented are of course only estimates but, as such, they clearly show that the benefits the programme seems to have provided are indeed impressive.

2008 Ottesen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Source

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

Authors:
Ottesen EA, Hooper PJ, Bradley M, Biswas G

References:
PLoS Negl Trop Dis 2008: Vol. 2 no. 10, pp. e317

Abstract:
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.

PMID: 18841205
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