Schistosomiasis —from immunopathology to vaccines

AbstractSchistosomiasis (bilharzia) is a neglected tropical disease caused by trematode worms of the genusSchistosoma. The transmission cycle involves human (or other mammalian) water contact with surface water contaminated by faeces or urine, as well as specific freshwater snails acting as intermediate hosts. The main disease-causing species areS. haematobium,S. mansoni andS. japonicum. According to the World Health Organisation, over 250 million people are infected worldwide, leading to considerable morbidity and the estimated loss of 1.9 million disability-adjusted life years (DALYs), a likely underestimated figure. Schistosomiasis is characterised by focal epidemiology and an over-dispersed population distribution, with higher infection rates in children. Complex immune mechanisms lead to the slow acquisition of immune resistance, but innate factors also play a part. Acute schistosomiasis, a feverish syndrome, is most evident in travellers following a primary infection. Chronic schistosomiasis affects mainly individuals with long-standing infections residing in poor rural areas. Immunopathological reactions against schistosome eggs trapped in host tissues lead to inflammatory and obstructive disease in the urinary system (S. haematobium) or intestinal disease, hepatosplenic inflammation and liver fibrosis (S. mansoni andS. japonicum). An effective drug —praziquantel—is available for treatment but, despite intensive efforts, no schistosomiasis vaccines have yet been ac...
Source: Seminars in Immunopathology - Category: Pathology Source Type: research