CULTIVATION OF SCHISTOSOMA-MANSONI INVITRO .3. IMPLANTATION OF CULTURED WORMS INTO MOUSE MESENTERIC VEINS

By injection into mice the potential for full development and oviposition of young schistosomules, juveniles and paired adults of S. mansoni, all grown in vitro from cercariae, was assessed. Schistosomules 2 h or 13 days old were injected into mice via the tail vein; older worms were implanted surgically into the ileocolic vein. Also implanted were previously ovigerous adult pairs that were perfused from mice and maintained in culture up to 53 days. Eventually, all were capable of producing viable eggs except the worm-pairs that had been grown to the adult stage in vitro; these failed to grow or develop further when implanted into mice. Pairs once mature in vivo could regain the capacity for oviposition even after prolonged maintenance in vitro but worms grown entirely in vitro to pairing may have missed some required stimulus which cannot be furnished later, even by an adequate animal host.