Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 10 1 2015 03 15 46 55 EN Mohammad Yakhchali Dept. of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran. Reza Malekzadeh-Viayeh Lake Urmia Research Institute, Urmia University, Urmia, Iran. Abbas Imani-Baran Dept. of Pathobiology, Faculty of Veterinary Medicine, Tabriz University, Tabriz, Iran. Karim Mardani Dept. of Food Hygiene and Quality, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran. 2015 10 14   Background: The trematodes of the genus Fasciola (the liver flukes) are among the well-known instances of food-borne parasites worldwide. Differentiation of Fasciola species is important because of their different transmission and epidemio-logical characteristics. The current study was undertaken to discriminate Fasciola species in the domestic ruminants of Urmia city, Iran. Methods:Adult flukes were isolated from the naturally infected livers of the slaughtered water buffaloes and sheep. The flukes were initially identified based on morphological and morphometric parameters. A 618-bp-long fragment of the 28SrRNA gene of Fasciola was amplified by polymerase chain reaction (PCR). The amplified fragment was digested by DraII or AvaII enzymes for a restriction frag-ment length polymorphism (RFLP) analysis and sequenced for the phylogenetic tree construction. Results:Based on the morphometric examination, the flukes belonged to F. he-patica, F. gigantica and an intermediate Fasciola form. The PCR-RFLP analysis was able to differentiate F. hepatica from F. gigantica. While the phylogenetic reconstruc-tion justified, to some extent, the morphological diagnosis, it failed to segregate F. hepatica from F. gigantica identified in this and the previous studies. Conclusion:To resolve fully the problem of taxonomy and evolution in Fasciola species, employing a broad range of molecular and morphological approaches is necessary. This is crucial for epidemiological surveys and successful clinical man-agement of their infection. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/353 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/353/422