Discussion

Schistosomiasis is a neglected tropical disease that affects hundreds of millions of the world's poorest people. The pathology of schistosomiasis stems from the fact that these parasites lay hundreds-to-thousands of eggs per day while living in the vasculature. Therefore, understanding the mechanisms that control the development and maintenance of the schistosome reproductive system could present new opportunities to limit the spread of the disease and blunt the pathology caused by the parasite. Interestingly, female schistosome sexual development depends of constant physical contact with a male worm. Although this phenomenon was described almost 100 years ago, there are few molecular insights into how this process is regulated. A major stumbling block for addressing this issue is that the reproductive system of female schistosomes degenerates within days of being removed from the host. Therefore, detailed studies of schistosome reproduction have not previously been possible using molecular approaches. To address this issue we have developed a novel media formulation that supports male-induced female sexual development and long-term egg production in vitro. Using this media we have discovered a role for a parasite-specific nuclear receptor that is essential for female reproductive development. We are exploring the model that this receptor is activated in females upon pairing with a male worm. We are hopeful the application this new media, together with modern approaches, will allow us to address how female schistosome reproductive development is controlled on a molecular level.