The combination of praziquantel and albendazole (PZ + ABZ) used in the pres
ent study demonstrated an efficacy of 100% when used as chemoprophylactic t
reatment because no viable hydatid cysts developed after mice had been inje
cted with protoscolices. However. when the PZ + ABZ combination was used fo
r the treatment of 4-month secondary experimental hydatidosis. no significa
nt difference was found between the control and treated mice, although seve
re damage to the cyst ultrastructure of the treated mice was observed.