Evidence of in vitro germinal layer development in Echinococcus granulosus cysts.

In vitro protoscolices of Echinococcus granulosus grew in a vesicular direction. After 9 days the laminated layer was observed; it reached thicknesses up to 140 micron. By day 125 of culture, the cysts had reached sizes of up to 4.875 micron and a high percentage of cysts had been obtained (10.4%). The ultrastructure of these cysts was studied and the existence of a germinal layer was demonstrated.