Lymphatic filariasis in human is caused by the developing and adults forms of filarial parasites present in the lymphatic system.
Three parasites belonging to two genera are responsible: Wucheria bancrofti, Brugia malayi and Brugia timori.
The disease is variably characterized by acute lymphatic inflammation or chronic lymphatic obstruction associated with intermittent fevers or recurrent episodes of dyspnea and bronchospasm.
It is a progressive disease leading to non-pitting edema and brawny changes that may involve a whole limb. Overtime, there is progressive enlargement, coarsening and fissuring of the skin leading to the classical appearances of elephantiasis. The limbs or scrotum may become hugely swollen. Eventually, the adult worms will doe, but the lymphatic obstruction remains and tissue damage continues.