Protoscolicidal effect of praziquantel--in-vitro and electron microscopical studies on Echinococcus granulosus.

Praziquantel was investigated in an in-vitro culture system of protoscoleces of Echinococcus granulosus (hydatid disease). Live protoscoleces were obtained from ovine pulmonary and hepatic cysts. As well as testing for serial viability, protoscoleces were examined by scanning and transmission electron microscopy. Praziquantel concentrations as low as 50 micrograms/l had a profound and rapid effect on the viability of protoscoleces. Electron microscopy of treated parasite demonstrated gross damage to the tegument. Praziquantel is a most effective and rapid scolicidal agent which may well be of clinical value.