Filariasis refers to infection with nematodes (roundworms) of the family Filarioidea. There are three species of these thread-like filarial worms:
Wuchereria bancrofti: responsible for 90% of cases
Brugia malayi: causes most of the remainder of cases
Brugia timori: an uncommon cause
It can affect a number of organ systems of which the most recognized include:
lymphatic system: lymphatic filariasis
breast: filariasis of the breast
scrotum: scrotal filariasis