Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 11 1 2016 03 14 52 64 Hossein GALAVANI Department of Parasitology and Mycology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran Saber GHOLIZADEH Social Determinants of Health Research Center, Urmia University of Medical Sciences, Urmia, Iran AND Medical Entomology Department, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran Khosrow HAZRATI TAPPEH Department of Parasitology and Mycology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran AND Cellular and Molecular Research Center, Urmia University of Medical Sciences, Urmia, Iran 2016 03 14 2016 03 14 Background: Fascioliasis, caused by Fasciola hepatica and F. gigantica, has medical and economic importance in the world. Molecular approaches comparing tradi­tional methods using for identification and characterization of Fasciola spp. are precise and reliable. The aims of current study were molecular characterization of Fasciola spp. in West Azerbaijan Province, Iran and then comparative analysis of them using GenBank sequences. Methods: A total number of 580 isolates were collected from different hosts in five cities of West Azerbaijan Province, in 2014 from 90 slaughtered cattle (n=50) and sheep (n=40). After morphological identification and DNA extraction, de­signing specific primer were used to amplification of ITS1, 5.8s and ITS2 regions, 50 samples were conducted to sequence, randomly. Result: Using morphometric characters 99.14% and 0.86% of isolates identified as F. hepatica and F. gigantica, respectively. PCR amplification of 1081 bp fragment and sequencing result showed 100% similarity with F. hepatica in ITS1 (428 bp), 5.8s (158 bp), and ITS2 (366 bp) regions. Sequence comparison among current study sequences and GenBank data showed 98% identity with 11 nucleotide mismatches. However, in phylogenetic tree F. hepatica sequences of West Azerbai­jan Province, Iran, were in a close relationship with Iranian, Asian, and African isolates. Conclusions: Only F. hepatica species is distributed among sheep and cattle in West Azerbaijan Province Iran. However, 5 and 6 bp variation in ITS1 and ITS2 regions, respectively, is not enough to separate of Fasciola spp. Therefore, more studies are essential for designing new molecular markers to correct species iden­tification. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/810 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/810/653