They are distinguished by their vector and by their posterior ends. There are various filariasis that are found around the world but are very uncommon.
Filariasis is transmitted from an infected human to a mosquito.
The parasite develops in a mosquito for one to three weeks. The female worm releases embryos that develop into motile larvae, microfilariae. Larvae then go through a biological development in the thoracic muscles of vector. Migrate to the proboscis of the mosquito to be released during feeding. The larvae are then transmitted to another human by the infected mosquito vector.