Combined Effect of Flubendazole and Praziquantel on Echinococcus granulosus Protoscoleces and Microcysts

Background and objectives: Benzimidazoles such as albendazole are being used in some conditions to treat the hydatid disease, the common parasitic infections of humans and livestock that caused by Echinococcus granulosus. However, treatment with these drugs is not always with complete success. In this study we evaluate the in vitro efficacy of flubendazole (FLBZ) plus praziquantel (PZQ) against E. granulosus protoscoleces and microcysts.
Materials and methods: Viable and aseptically cultured protoscoleces were treated for 17 days with 5 µg/ml FLBZ, 1 µg/ml PZQ and a combination of both drugs. The viability of protoscoleces was assessed daily by microscopic observation and eosin test. Experiment was repeated three times and drug efficacies were presented as the mean value of protoscoleces viability rate. Developed microcysts from continues cultivation of protoscoleces were subjected to this treatment as same as protoscoleces, for 21 days. Structural changes of microcysts were visualized by inverted and transmission electron microscopy.
Results: The most protoscolicidal efficacy was significantly detected in the culture treated with the combination of FLBZ and PZQ, so that all protoscoleces were killed in the nine days post-treatment. Meanwhile, 21.7±9.5% and 30.8±5.3% of protoscoleces that incubated with the FLBZ or PZQ alone were still viable, respectively. Degenerative changes occurred in microcysts on four days of co-treatment with the drugs, while these occurred on six and eight days with FLBZ or PZQ alone, respectively.
Conclusion: This study indicates the favorable combined effect of the FLBZ and PZQ against E. granulosus protoscoleces and microcysts in vitro.

Keywords: Echinococcus granulosus, Protoscolex, Microcyst, Flubendazole, Praziquantel