| Fasciolosis is a worldwide disease of man and animals result in huge economic losses. The objective of this study was to characterize for the first time Fasciola gigantica in Iraq employing molecular approaches. In this work, 65 adult fasciola worms were isolated from sheep liver of different age and both sex during May-August 2017, in Kirkuk city, Iraq. Molecular analysis conducted on the internal transcribed spacer 1 to characterize the species of parasite depending on the sequence analysis. Results reveal that the isolated worms were Fasciola gigantica and they have a great similarity, up to 100%, compared with other global isolates. In addition, results documented a single nucleotide polymorphism, at the 276 th nucleotide of the studied fragment, and the isolates of our project highly related to various global isolates by using phylogenetic tree analysis. In conclusion,our isolates are faithfully analogous to global isolates with common SNP at 276 th nucleotide, and ITS1 gene considers a novel marker in identifying Fasciola gigantica and study the relation with other isolates.

This study was conducted to investigate the 18S rRNA gene of Fasciola gigantica obtained from the liver of cattle live in Aqrah city, Iraq. Fifty-nine Fasciola flukes were collected through routine investigation from livers of naturally infected local cattle (42 cows), from May to August 2017, at the central slaughterhouse of Aqrah city, Kurdistan region of Iraq, the flukes were washed by PBS and then fixed in ethanol. Genomic DNA was extracted, and a 560 bp fragment was amplified by PCR, subsequent by sequencing of PCR products. A remarkable result of this project was the deposition of our gene isolate in GenBank (Accession No. MG786553). However, it was confirmed by the sequence results that isolate species was F. gigantica, and interestingly our samples sequences have alignment match of 100% with many international isolates, without genetic mutations or variations. It is concluded that molecular study could be utilized for both diagnosis and differential diagnosis of parasites with huge precise. Also, an 18S rRNA gene is a perfect fragment for molecular study and phylogenetic analysis of F. gigantica, also our samples have 100% alignment match with universal isolates.