By Professor Alan Fenwick of Imperial’s Schistosomiasis Control Initiative (SCI)
There are five neglected tropical diseases (NTDs) which are the scourge of Africa, the Indian sub-continent, the Far East and South America. Onchocerciasis is one of these 5 and until the late 20th century caused millions of people to gradually lose their sight and eventually go blind. The parasite is spread by infected Simulium blackflies which when they bite a human, transfer microscopic larvae to the human host, where they develop into adult worms and females produce millions of new larvae during their lifetime. It is these larvae that are the cause of irreversible blindness in as many as 25% of the adult population in several countries in Africa.