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

Background & Objective: Benzimidazoles such as albendazole are being used in some conditions to treat hydatid disease, the common parasitic infections of humans and livestock caused by Echinococcus granulosus. However, treatment with these drugs is not completely successful. In this study we evaluated the in vitro efficacy of flubendazole (FLBZ) and praziquantel (PZQ) against E. granulosus protoscoleces and microcysts. Materials & 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 were assessed daily by microscopic observation and eosin test. The experiment was repeated three times and drug efficacies were presented as the mean value of protoscoleces’ viability rate. Developed microcysts from the continued cultivation of protoscoleces were treated with the same doses of the drugs for a period of 21 days. The structural changes of the microcysts were visualized by inverted and transmission electron microscopy. Results: The most protoscolicidal efficacy was detected in the culture treated with the combination of FLBZ and PZQ, so that all protoscoleces were killed in nine days following the beginning of treatment. Meanwhile, 21.7±9.5% and 30.8±5.3% of protoscoleces that were incubated with the FLBZ or PZQ alone were still viable, respectively. Degenerative changes occurred in microcysts after four days of treatment with both drugs, while these changes occurred six and eight days later with FLBZ or PZQ alone, respectively. Conclusion: This study indicated the favorable combined effect of FLBZ and PZQ against E. granulosus protoscoleces and microcysts in vitro.