Onchocerciasis (or river blindness) affects up to 37 million people worldwide and is most abundant in Africa. It is responsible for skin disease and blindness. It is caused by a large worm (known as Onchocerca volvulus) which is transmitted to humans via black flies which breed in rivers and streams – hence the name river blindness.
Symptoms occurs when worms die within the skin which results in inflammation of the skin. This can cause intense itching, dermatitis and depigmentation; this create conditions like lizard skin and leopard skin. If the larvae migrate to the eye their death results in inflammation leading ultimately to blindness.