Parasitic flatworms of the genus Schistosoma cause disease when their eggs become trapped in host organs and elicit immune responses that result in tissue damage. A remarkable aspect of schistosome biology is that females remain reproductively mature only when paired with males in vivo. Galanti et al. show that failure to make eggs in the absence of males, or in vitro, is due to apoptosis within the vitellarium, a proliferative organ that produces vitelline cells, an essential component of the egg. Understanding schistosome reproduction may offer opportunities to prevent transmission and disease.

Image Credit: Sarah Galanti