Onchocerciasis, also known as river blindness, is a parasitic disease endemic in 30 African countries. Infection is caused by a parasitic worm transmitted through a black fly bite. These flies breed in waterways, increasing the risk for those living nearby, hence the common name of “river blindness”. Fear of contracting the diseases has led many people in developing countries to abandon fertile lands along rivers, which in turn has lasting, negative socio-economic effects.
The World Health Organization estimates that 90 million people worldwide are at risk of infection, the second leading cause of infectious blindness worldwide, after trachoma.
Onchocerciasis is also classified as a neglected tropical disease (NTD).
Onchocerciasis is an infection caused by a parasitic worm (Onchocerca volvulus) that is transmitted through a black fly bite. When the human body is infected, the female adult worm produces thousands of larvae (microfilariae). These microfilariae move through the skin and eye causing damages such as skin rashes, lesions, itching, skin depigmentation and in the most serious cases, permanent blindness.
The death of microfilariae is very toxic to the skin and eyes, and causes terrible itching of the skin and eye damage which, after many years of exposure, leads to irreversible blindness.
Onchocerciasis is diagnosed by a slit lamp examination of the eye and skin biopsies which can detect the parasite.
Onchocerciasis is treated with ivermectin, a drug that paralyzes and kills the microfilariae, relieving intense itching of the skin and stopping the progression to blindness. It also prevents adult worms from producing more microfilaria for a few months after treatment, thus reducing transmission. It only takes one dose each year for treatment to be effective. Merck has generously donated the drug since 1987, and works with Ministries of Health and their partners like OPC to distribute the drug to affected populations.
Francophone Africa is frequently overlooked by international development stakeholders when it comes to restoring sight and providing quality eye care. The Organization for the Prevention of Blindness (OPC) works with local governments, civil society organizations and communities to fight blindness, restore vision, encourage local ownership of eye health care systems and ensure human right to sight.