Review: Oncocerciasis

Abstract

Oncocerciasis is a parasitic disease that primarily affects economically disadvantaged communities in Africa and Latin America. It results from infection with filarial nematode Oncocerca volvulus, transmitted to man through the bite of infected black fly of genius simulium. It is the second commonest infectious cause of blindness responsible for an estimated 340,000 cases of blindness and one million cases of visual impairment. The disease is endemic in 30 countries in Africa, six countries in Latin American and in Yemen. More than 85% of the world population is at risk of infection while 18 million are already suffering from the disease. Infection intensity and ocular morbidity including blindness is highest along fast flowing rivers where the vector breeds. Oncocercal blindness has serious social and economic impact. It strikes mainly at economically active adults at the prime of their life thereby leading to reduction in productivity, death and abandonment of fertile agricultural lands. The systemic and ocular manifestations of Oncocerciasis are discussed in this review in order to bring awareness of the importance of this disease in the epidemiology of blindness and visual impairment in South Sudan where it is endemic.