Onchocerciasis, or river blindness, is a neglected tropical disease that can cause disfigurement and blindness. The parasitic worm responsible for the condition is spread from person to person through bites from infected blackflies, predominantly in remote agricultural areas with fast-moving rivers. While symptoms of the disease can be severe, the most serious cases are typically due to repeated infections over the course of several years. Onchocerciasis (River Blindness) What is onchocerciasis? Onchocerciasis, also known as river blindness, is a disease that affects the skin and eyes. It’s caused by the worm Onchocerca volvulus. Onchocerca volvulus is a parasite. It is transmitted to humans by the bite (blood meal) of the female blackfly (Simulium). This type of blackfly is found near rivers and streams. That’s where the name “river blindness” comes from. Although the majority of people infected reside in sub-Saharan Africa (for example, Nigeria), it also occurs in Centr