Could thymol have effectiveness on scolices and germinal layer of hydatid cysts?

Scolicidal solutions remain indispensable in the treatment of hydatid cyst disease. Properties of an ideal solution would be inexpensiveness and the promotion of a rapid and complete scolicidal effect with an absence of local and systemic side effects. From this point of view, no ideal solution and agents have been described yet. The aim of the present work was to determine the in vitro effect of high concentrations of thymol against protoscoleces, microcyst and cyst of Echinococcus granulosus and to evaluate its possible role as a scolicidal agent during surgery or PAIR. After short exposure times, a rapid effect was observed depending on the parasitic material. After 2 min of exposure to thymol, viability of protoscoleces was approximately 1.3% at a concentration of 250 μg/ml. The protoscolicidal effect is dose and time dependent. The results of the in vitro treatment with thymol were similar in both microcysts and secondary murine cysts. The employment of SEM and TEM allowed us to examine, at an ultrastructural level, the effects induced by thymol on E. granulosus protoscoleces, microcysts and murine cysts. In conclusion, the data obtained clearly demonstrated that thymol caused severe damages to the parasite even after short incubation times. This fact and the lack of toxicity at the evaluated concentrations, allow us to propose it as a possible scolicidal agent during hydatid cysts surgery and/or PAIR.