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. |