Background: Fascioliasis is a neglected zoonotic disease with worldwide distribution. Phylogenetic analysis of Fasciola species is critical because of their different epidemiology. Objectives: The current study aimed at identifying Fasciola spp. based on spermatogenesis and phylogenetic analysis of mitochondrial (ND1) gene. Methods: One hundred and fifty adults with fascioliasis were selected from the Eastern provinces of Iran, based on spermatogenetic ability, measurement criteria, and ITS (nuclear ribosomal DNA internal transcribed spacers) 1 gene restriction fragment length polymorphism (RFLP) pattern. Then, their genetic diversity indices and phylogenetic relationships were analyzed using mitochondrial DNA marker of Fasciola population spread in the East of Iran. Results: Aspermic F. gigantica was observed in the eastern part of Iran. Partial sequences of mtDNA showed new haplotypes in both species. Pairwise fixation index between different F. gigantica populations calculated from the nucleotide data set of ND1 gene were statistically significant and showed the genetic differences in pairwise population.
Conclusions:The results of the study showed that F. hepatica, lives in this region of Iran, had different genetic structures compared with the other Fasciola populations in the world. Fasciola gigantica present in the East of Iran had different genetic structures, compared with the other Fasciola population, based on genetic index.