THE EFFECTS OF ALBENDAZOLE AND ALBENDAZOLE SULFOXIDE COMBINATION-THERAPY ON ECHINOCOCCUS-GRANULOSUS IN-VITRO

Protoscoleces of Echinococcus granulosus were incubated in vitro with decreasing concentrations of either albendazole (ABZ) or albendazole s ulphoxide (ABZ.SO) (50, 10, 1 and 0.1 mu g ml(-1)), and in combination . Viability was assessed by the methylene blue exclusion test and esta blishment of infection in mice. Protoscolex ultrastructure was determi ned by means of transmission and scanning electron microscopy. ABZ and ABZ.SO, when used separately had protoscolicidal activity after a lon ger incubation period (30 days) than when used as combined compounds. When incubated in the presence of ABZ + ABZ.SO, protoscolex viability dropped rapidly. That is, protoscoleces were all nonviable at 12 days of exposure, with no cyst developing following their inoculation into mice. The ultrastructural changes induced by ABZ or ABZ.SO alone, were : (a) rostellar disorganization, (b) formation of numerous blebs on th e tegument, (c) loss of the microtriches, (d) increased vesiculation w ithin the tegumentary cytons together, (e) an increase in lipid deposi ts and (f) depletion of glycogen reserves. After incubation with combi ned ABZ and ABZ.SO the tegument contained numerous blebs which became detached, leaving debris only, some intact nuclei being discernible in the protoscolex parenchyma.