Schistosomiasis is a parasitic disease caused by blood flukes (Phylum Platyhelminthes) of the genus Schistosoma. As many as 800 million people are affected in parts of South America, the Western Pacific and China with the majority (>95%) living in sub-Saharan Africa. Children as young as six months are infected with what can be a life-long affliction. In the severest of cases, damage to internal organs can kill. However, the disease is better known for its insidious ability to rob those who already live at or below subsistence of their physical and cognitive vitality. This translates to missed school days, decreased ability to work and lost potential regarding both personal and societal productivity. Often, schistosomiasis is just one of a number of overlapping parasitic diseases, including other worm infections, which when combined degrade the well-being of whole communities.
Although parasitic flatworms can display bewildering life-cycle complexity, schistosomes are relatively easy to keep in the lab requiring as hosts mice (or hamsters) and a robust fast-breeding snail vector – a fortunate situation given the importance of the global disease. This ease has not only facilitated a wealth of ‘classical’ life-history, biochemical, host-pathogen, and drug discovery studies, but also advances in ‘-omic’ applications over the last ten years with continually-improving annotations of genome, transcriptome and proteome data supported by interrogable databases. In turn, there has been a real effort in and measured success with a range of ‘post-genomic’ reverse genetic tools, typically involving both transient RNAi and transgenesis, but also viral-mediated germ line transgenesis. These developments are timely given the growing concern in the schistosome community at the precarious reliance on just one drug, praziquantel, to treat ‘continents of people’ and the consequent need to find new drug and vaccine targets, and diagnostic candidates. Nonetheless, a wish-list for a standardized schistosome ‘molecular tool kit’ would include such items as complete in vitro cultivation of the parasite without recourse to mammalian (or molluscan) hosts, targeted germ line integration and the generation of cell lines. On the flip side, an example of employing C. elegans as a functional screening tool for schistosome drug discovery is presented and this approach bodes well for future drug discovery efforts. Finally, a list of resources available to those potentially interested in working with schistosomes, even ‘on the side,’ is provided.
Articles submitted to the Worm Breeder's Gazette should not be cited in bibliographies. Material contained here should be treated as personal communication and cited as such only with the consent of the author.