Filariasis comes from the threadlike worm filaria which is one to two centimeters or 45 - 50 centimeters long. The thin worm is carried by the Culex mosquito, a night-biting species.
As soon as the worm enters the body, it gives birth to embryos that scatter to blood vessels and the skin. The embryos are later picked up by a mosquito and mature in the insect's body. The mosquito then transfers the worms to humans, starting another cycle of infection.