Clinical Manifestations of Mesoendemic Onchocerciasis in an Area with Multiple Filarial Species

Abstract

Background: The Imo River Basin, Nigeria is endemic for onchocerciasis, bancroftian filariasis, loaiasis and mansonellosis. This study was aimed at determining the clinical manifestations of onchocerciasis in this region.

Methods: A cross-sectional study was carried out in 2006 in Umuowaibu I and Ndiorji commu­nities in Okigwe Local Government Area of Imo State, Nigeria. Consenting individuals were ex­amined for various gradations of skin manifestations, subcutaneous nodules, and visual im­pair­ments by qualified medical doctors. Five categories of skin manifestations were observed, namely permanent itching, onchodermatitis, atrophy of skin, leopard skin, and sowda. A total of 1024 individuals were examined.

Results: The prevalence of the skin manifestations were permanent itching (2.5%), onchoder­ma­titis (3.9%), atrophy of the skin (5.8%), leopard skin (22.1%), and sowda (0.1%). The preva­lence of subcutaneous nodules was 25.3%, but 88.9% among the oldest age group, and mostly found in lower half of body. The majority of cases of visual acuity problems (6.8% overall prev­alence) were in the oldest age groups. Among those who were ≥ 20 years old, the prevalence of visual acuity problems was significantly higher in females than in males (χ²-test; P< 0.05). Only two of the examined persons were observed to be blind.

Conclusion: Clinical manifestations of onchocerciasis are perhaps more intense in the area prob­ably because of presence of endemic infections of other filarial species.