Cultivation of Schistosoma mansoni in vitro. II. production of infertile eggs by worm pairs cultured from cercariae.

Schistosoma mansoni grown from the cercarial stage in vitro produced infertile eggs in about 10% of the pairs studied. Cultured eggs were about half normal size, had a small and blunt lateral spine, and appeared to lack a germinal disc. The shell opposite the spine was typically thin and poorly formed. Eggs were often found in dyads. Vitelline conglomerates in long strands were sometimes deposited. Vitelline glands, ovaries, and testes were relatively poorly developed. Alterations of gas phase or addition of reducing agents, antioxidants, steroid hormones, specific adsorbents, or adult worm extracts did not improve the worms or augment egg production.