morphological and molecular discrimination of fasciola species isolated from domestic ruminants of urmia city, iran.

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 dra ii or ava ii 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.