Lymphatic filariasis, commonly known as elephantiasis, is a painful and profoundly disfiguring disease. While the infection is usually acquired in childhood, its visible manifestations occur later in life, causing temporary or permanent disability. In endemic countries, lymphatic filariasis has a major social and economic impact.
Most infected people are asymptomatic and will never develop clinical symptoms, despite the fact that the parasite damages the lymph system. A small percentage of persons will develop lymphedema. This is caused by improper functioning of the lymph system that results in fluid collection and swelling. This mostly affects the legs, but can also occur in the arms, breasts, and genitalia.
Globally, 1103 million people live in the countries where preventive treatment for lymphatic filariasis is required. WHO's African and South-East Asia regions harbour 94% of the population living in endemic areas, and 98% of the infected population. Of the total population requiring preventive chemotherapy for lymphatic filariasis, 632 million (57%) live in the South-East Asia Region (9 endemic countries) and 410 million (37%) live in the African Region (35 countries).