Developmental gene expression profiles of the human pathogen Schistosoma japonicum

Gene expression profiles were linked to the major environmental settings through which the developmental stages of the fluke have to adapt during the course of its life cycle. Gene ontologies of the differentially expressed genes revealed a wide range of functions and processes. In addition, stage-specific, differentially expressed genes were identified that were involved in numerous biological pathways and functions including calcium signalling, sphingolipid metabolism and parasite defence.The findings provide a comprehensive database of gene expression in an important human pathogen, including transcriptional changes in genes involved in evasion of the host immune response, nutrient acquisition, energy production, calcium signalling, sphingolipid metabolism, egg production and tegumental function during development. This resource should help facilitate the identification and prioritization of new anti-schistosome drug and vaccine targets for the control of schistosomiasis.Schistosomiasis afflicts ~200 million people in 76 countries [1]. The disease is caused by infection with blood flukes of the genus Schistosoma and depending on the invading species, is characterised clinically by chronic hepatic and intestinal fibrosis, portal hypertension, anaemia and calcification of the urinary tract. The parasitic worms have a complex developmental cycle that involves infection of freshwater intermediate molluscan hosts and the blood stream of mammals (Figure 1). Schistosome infection results from direct contact with fresh water contaminated by free-swimming larval forms of the parasite known as cercariae. Cercariae penetrate human skin, shed their tails, releasing schistosomula which enter capillaries and lymphatic vessels en route to the lungs. After several days, the male and female juvenile worms migrate to the portal venous system, where they mature and unite. Adult worm pairs then migrate to the veins of the intestines, in the case of Schistosoma mansoni and S. japonic