These worms are well-known for their longevity. S. mansoni has been known to live for years, even decades within their hosts. These worms live an average of 5-6 years, however there are reports of people becoming infected during childhood and not developing clinical symptoms until adolescence or adulthood.
Lead researcher Phillip Newmark wondered if maybe schistosomes were living so long because they also had stem cells that repaired damaged tissues to keep the worms young. Following up on his suspicions, he and his team began searching for these cells in schistosomes.
They used fluorescent tagging techniques to find actively dividing cells within the blood flukes, then they isolated the cells and studied them. Through their observations of these cells, they were able to determine that the cells divided to create two new cells: one that differentiated into another cell type (which varied) and one that was another stem cell. This is characteristic about what is already known of stem cells.
Here's a quote from Newmark about the research:
The cells we found in the schistosome look remarkably like planarian neoblasts. They aren’t associated with any one organ, but can give rise to multiple cell types. People often wonder why we study the ‘lowly’ planarian, but this work provides an example of how basic biology can lead you, in unanticipated and exciting ways, to findings that are directly relevant to important public health problems.
This paper isn't insinuating that these neoblast-like stem cells are the only reason that schistosomes can live for so long, it is merely demonstrating that having these cells plays a role in their longevity. With continued research, it is believed that new treatments for curing people of schistosome infections will be created that target these stem cells for more efficient killing of the parasite.
Isn't biology fascinating?! There's always something new to learn about things that we have spent decades and probably millions...maybe even billions...of dollars researching! Yay for a field that is ever-changing and oh-so-exciting! :D