Role of Echinococcus granulosus Mitochondrion Partial Gene Polymorphism in Responsiveness to Albendazole Treatment in Experimentally Infected Mice

Background and objective: Cystic echinococcosis which caused by the larval stage of the tapeworm Echinococcus granulosus is one of the important public health challenges worldwide. Various strains have been recorded. Available evidences revealed that pathogenesis of the disease has been associated with parasite genotype. The current study aimed to investigate role of mitochondrion partial genome polymorphisms, in responsiveness to albendazole treatment in murine model. Methods: Hydatid cysts were obtained from infected livers of sheep. Protoscoleces from each isolate were separated into two batches. First preserved in ethanol (70%) at -20 o C for molecular investigation. The second part was used for direct in vivo experiment. Genomic DNA was extracted and mitochondrion partial genome was amplified and sequenced. Fourteen groups of Mice (twelve mice each) were infected experimentally with protoscoleces from 14 hydatid cysts isolates. Responsiveness of each isolate to albendazole was assessed. Results: The sequencing profiles revealed no polymorphisms in 6 of the 14 studied isolates, while minor sequence polymorphisms, 0.33 %, that resulted in corresponding amino acid replacement, were observed in 3 of the isolates. Furthermore, remarkable DNA sequence polymorphisms were observed in 5 of the isolates, that caused affectable amino acid replacement in the suggested polypeptide sequences. Treatment efficacy of albendazole was positively correlated (r = 0.128) (P <0.001) with the polymorphism in E. granulosus mitochondrion partial genome. Conclusion: A polymorphic sequence profiles of E. granulosus mitochondrion partial genome can be used to detect the sensitivity of the causative strains to albendazole. However, further studies should be conducted to involve hydatid cyst isolates from other intermediate hosts, and to assess the effectiveness of other anthelmintic drugs against various strains of the tapeworm E. granulosus.