Last reviewed 01/2018

Onchocerciasis is a disease caused by the filarial nematode Onchocerca volvulus. It is transmitted by the blackfly genus Simulium. Species of which occur in Africa i.e. S. damnosum, S. naevi, and in Venezula i.e. S. metallicum.

Onchocerciasis is confined to West, East and Central Africa, Central South America and Southern Saudi Arabia.

The disease is characterised by genital elephantiasis, subcutaneous nodules and ocular lesions.