Morphological and Molecular Discrimination of Fasciola Spe-cies Isolated From Domestic Ruminants of Urmia City, Iran

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 epidemiologi­cal characteristics. The current study was undertaken to discriminate Fasciola species in the domestic ruminants of Urmia city, Iran. 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 fragment length polymorphism (RFLP) analysis and sequenced for the phyloge­netic tree construction. Based on the morphometric examination, the flukes belonged to F. hepat­ica, F. gigantica and an intermediate Fasciola form. The PCR-RFLP analysis was able to differentiate F. hepatica from F. gigantica. While the phylogenetic reconstruc­tion justified, to some extent, the morphological diagnosis, it failed to segregate F. hepatica from F. gigantica identified in this and the previous studies. 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 manage­ment of their infection.