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. Most people develop these clinical manifestations years after being infectedeople infected with adult worms can take a yearly dose of medicine, called diethylcarbamazine (DEC), that kills the microscopic worms circulating in the blood. While this drug does not kill all of the adult worms, it does prevent infected people from giving the disease to someone else.
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).