Schistosomiasis: Review of an immune complex disease

Abstract

BACKGROUND: Morbidity due to human schistosomiasis is associated with host immune responses which result in immune based inflammation, granuloma formation and fibrotic lesions.

MATERIALS AND METHODS: This is a review of the literature on the immunology of schistosomiasis and the description of the immunopathogenesis of the disease. Relevant articles were retrieved using electronic search and hand search of published literature.

RESULTS: Host responses which include immune based inflammation, granuloma formation and fibrotic lesions are aimed at destroying schistosome ova lodged in the liver, intestinal and bladder walls, and other tissues. At the site of the infection, ‘swimmers’ itch is due to physical damage to the skin by proteases and other toxic substances secreted by cercaria. During intestinal Schistosomiasis, the parasitic ova are lodged in the liver provoking fibrogenesis, while during urinary schistosomiasis pathology is attributed to the formation of granuloma along the urinary tract, there is fibrosis which lead to strictures, calcification and urodynamic abnormalities. The classic descriptions of schistosomiasis-related morbidity focus on pathologies unique to schistosome infection: periportal fibrosis for intestinal schistosomiasis and bladder deformity and hydronephrosis for urogenital schistosomiasis.

CONCLUSION: This review provides some useful information concerning some aspects of the relationships between Schistosoma species and the human host.