Discussion

The surfaces of parasites are diverse and they provide unique barriers that, among other functions, serve to help fend off attack from the host. At the same time, parasites can sense their external milieu and their surfaces are often sufficiently adapted to permit communication with the host. During its life cycle, the human parasite Schistosoma mansoni transits through various developmental stages that include cercariae that penetrate the skin, and schistosomules that mature into adult worms that pair and mature in the blood vessels. Here, activation of protein kinase-mediated cell signalling pathways within the parasite is considered as a molecular ‘signature’ for evaluating the extent to which human host molecules communicate with S. mansoni to ultimately affect parasite behaviour. By exploring the effects of host molecules as diverse as growth factors and neurotransmitters on selected protein kinase networks in cercariae, schistosomules and adult worms, it is now possible to develop paradigms whereby the schistosome parasite may be dependant on host-mediated molecular signalling events for its survival/development. Although only just ‘scratching the surface’, further elucidation of such host-parasite communication may be crucial to help develop strategies that target molecular pathways for schistosome control.