Non-ocular clinical onchocerciasis in relation to skin microfilaria in the Taraba River Valley, Nigeria

Examination of 2,876 persons in fourteen communities was carried out for clinical onchocerciasis on the Taraba river valley, Nigeria, where parasitological findings indicate unusually high endemicity. Forty-five percent of the population had at least one type of skin lesion or the other, the commonest of which was pruritus. Thirty-two percent had nodules. Some of the nodules were located in unusual sites such as the mammae, anus. Nodule carriage and nodule-load as well as lymphatic enlargement were higher than those recorded elsewhere in Nigeria and tended to increase with increase in age. When subjected to regression analysis, the relationship between skin lesion, nodule carrier rate, nodule load, scrotal enlargement and microfilaria rate (mf) on one hand and microfilaria density (mfd) on the other showed a near-perfect correlation. The findings of this study suggest that certain clinical manifestations of onchocerciasis may be a reliable and more rapid alternative to the parasitological approach in the assessment of the prevalence and severity of the disease in communities with similar socioecological characteristics.