Echinococcus granulosus: the influence of mebendazole therapy on the ultrastructural morphology of the germinal layer of hydatid cysts in humans and mice.

Upon ultrastructural examination it was found that prolonged mebendazole therapy of patients with hydatid disease often resulted in complete necrosis of the germinal layer of Echinococcus granulosus cysts. The affected cysts showed only remnants of degenerated germinal layer tissue including heterogeneous vesicular membranes, electron-dense amorphous structures, myeloid bodies, lipid globules, crystal-like precipitates and remnants derived from muscular tissue. Examination of the hydatid cysts of treated mice revealed the same time-related deteriorative effect of the anthelmintic as described previously for other cestode species. The advanced stage of degeneration of the germinal layer tissue observed in the murine cysts after treatment resembled the morphologic features present in the necrotic human cysts and gave additional information about the degeneration phenomenon.