Lymphatic Filariasis (LF) is a highly disabiling disease that is endemic in 83 countries with over 1.3 billion people at risk of contracting it, yet most people know little about it.
LF is a devastating parasitic infection spread by mosquitoes. Caused by thread-like parasitic worms that damage the human lymphatic system - it is usually contracted in childhood, often before the age of five. One of the world's most disabling and disfiguring diseases, LF afflicts the poorest. The disease is estimated to infect over 120 million people, with more than 40 million incapacitated or disfigured with swelling of the limbs and breasts (lymphoedema) and genitals (hydrocele), or swollen limbs with dramatically thickened, hard, rough and fissured skin (elephantiasis). LF prevents afflicted individuals from experiencing a normal working and social life, furthering the cycle of poverty.
Worms lodge in the lymphatic system, the network of nodes and vessels that maintains the delicate fluid balance between the tissues and blood, and which is an essential component for the body's immune defence system. The worms live for an estimated 4-6 years, producing millions of immature microfilariae (tiny larvae) that circulate in the blood and are then picked up by mosquitoes.
How is LF contracted?
Filariasis is spread from an infected human, i.e. someone with worms in his/her bloodstream, to an uninfected human by mosquitoes. Adult worms live in an infected human's lymphatic vessels. The female worms release large numbers of very small worm larvae (called microfilaria), which circulate in an infected person's bloodstream. When a human is bitten by a mosquito, the mosquito ingests the larvae. The larvae develop in the mosquito into an infective stage and are then spread to other people via mosquito bites. After a bite, the larvae pass through the skin, travel to the lymphatic vessels and develop into adult worms.