Lymphatic Filariasis

2020 Target: Global elimination by 2020

Clinical Background: Lymphatic filariasis, also known as elephantiasis or LF, is a mosquito-borne worm disease usually acquired in childhood that manifests clinically in late childhood and early adulthood. When the worms grow large enough, they block the lymphatic system, potentially leading to lymph fluid buildup that causes radical and disfiguring swelling of limbs and genitals known as elephantiasis.

Epidemiology: Approximately 120 million people have lymphatic filariasis, with 1.3 billion at risk. LF is concentrated in Southeast Asia and Africa with a significant burden in Brazil.

Burden: There is widespread social and economic discrimination against those who suffer from elephantiasis, resulting in an estimated $1.3 billion in lost productivity annually.

Treatment/Prevention Strategy: There are three drugs currently in use as a preventative tool or for treatment of LF: albendazole (donated by GlaxoSmithKline), ivermectin (Mectizan, donated by MSD) and DEC (to be donated Eisai beginning in 2014). Albendazole is administered in combination with either ivermectin or DEC through mass drug administration (MDA) programs to prevent people from acquiring LF. Each of these treatments targets the immature form of the worm, and must be given annually to prevent ongoing transmission until the adult worm dies naturally. Regions with high co-endemic levels of LF and Loa loa disease cannot use current treatments due to the potential for adverse effects. Elimination efforts would be helped if a drug to kill the adult form of the worm was developed, which would alleviate the need to annually treat people for LF. Treatment options for Loa loa areas would also greatly help in achieving the 2020 elimination target.

Key Organizations: The Global Alliance for the Elimination of Lymphatic Filariasis (GAELF) is a public–private partnership tasked with leading control efforts. The World Bank, WHO, MSD and GlaxoSmithKline are among the many partners involved in this effort. The Mectizan Donation Program started by MSD has worked in conjunction with GlaxoSmithKline through the program to deliver ivermectin and albendazole in areas in Africa where onchocerciasis and lymphatic filariasis overlap. Several companies are working on a variety of strategies, including working with DNDi, to develop new drugs to treat the adult form of the worms, and on the AWOL project, to develop drugs that target bacteria that live inside the worms.

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