A review of recent advances in scientific knowledge of the symptomatology, pathology and pathogenesis of onchoceral infections.

In this review, the author discusses separately the cutaneous and the ocular aspects of the symptomatology, pathology and pathogenesis of onchocercal infections. Original results are also reported on dermal onchocerciasis.The less well known lesions are described in greater detail than the better-known. Among the former are the association of cutaneous tumours with dermal onchocerciasis, depigmentation of the skin, and the posterior ocular lesions. In dealing with the pathology of dermal onchocerciasis, the author demonstrates that the main effect of the death of the parasites is on the blood vessels, causing them to become atrophic so that the consequent anoxia gives rise to the better-known, more obvious changes of pachyderma.The relationship of allergic and nutritional factors with the different lesions is discussed. It is pointed out that the evidence connecting the symptomatology with allergy is not very conclusive while the evidence connecting nutritional factors with the ocular manifestations continues to mount.