Onchocerciasis is a serious neglected tropical disease caused by the filarial nematode Onchocerca volvulus, transmitted by black fly which leads to blindness and chronic disability with estimated infection rate of about 37 million people in tropical Africa and in isolated foci in Yemen and Latin America and have caused a debilitating eye and skin disease in more than 5million people with about 1.2 million visual impairment or blindness and half of this population residing in Nigeria. Background: Onchocerciasis or river blindness results from infestation by the nematode Onchocerca volvulus, characterized by eye affections and skin lesions with severe troublesome itching. It is a chronic, communicable, slowly progressive, parasitic disease which has being rated as the second-leading infectious cause of blindness worldwide annually. It is a neglected tropical disease of great public health concern which is transmitted by black fly with estimated infection rate of about 37 million people in tropical Africa and in isolated foci in Yemen and Latin America. It has caused a debilitating eye and skin disease in more than 5million people with about 1.2 million visual impairment or blindness and an estimate of over 85million people leaving in endemic areas with 99% of the cases resulting from Africa and half of this population residing in Nigeria. Also, estimate of about 120 million people are at a risk of contracting the disease due to the breeding habit of the vector. Methods: The databases Medline, WHO website, CDC website, PubMed, Web of Science World Factbook of Central Intelligence Agency, were searched for relevant studies published for the past five decades on onchocerciasis in Nigeria. Papers investigating it prevalence, clinical features, diagnosis, treatment, government policy, world health organisation policy and recent findings as well as further finding in Nigeria were included. Results: Extrapolation of data from the past five decades on onchocerciasis infection in Nigeria has shown that the rate of infection is significantly reduced in certain areas of the country due to repeated administration of Ivermectin. However, in most regions the infection rate still persist with a percentage of up-to 24 (75%), 45.2%, lizard skin and leopard skin were seen in 3.5% and 2.0% respectively, hanging groin 2.6% and scrotal enlargement at 8.6%, (Bakundi district of Taraba state with infection rate in excess of 30%), 54.2% (Ibarapa Local Government Area of Oyo state), 61% and 71% (Kuhe and Gube community of Benue state), 83% (Oria North Local Government Area of Edo state) and certain patients were blind due to onchocerciasis and were positive to onchocerciasis test. 79.5% in Oyo state (159 patients test positive for onchocerciasis out of 200 patients), 94.5 % in Kaduna state, (189 patients tested positive for onchocerciasis out of 200 patients). Conclusion: The results of this systematic review suggest that there have been a significant decrease in onchocerciasis infection in several regions of the country. However, the prevalence still persists mostly in river line area and regions which are inaccessible to the program as well as lack of orientation on the disease. Also, government policy on how often is Ivermectin made available to the people and making provision to reach these areas yet covered and the decreased in larvae control have also contributed to the high prevalence of the disease in Nigeria. This accounts for the reason why over 40% of the world prevalence rate is from Nigeria.
