Molecular characterization of Fasciola spp. from the endemic area of northern Iran based on nuclear ribosomal DNA sequences |
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| Authors: | Amor Nabil Halajian Ali Farjallah Sarra Merella Paolo Said Khaled Ben Slimane Badreddine |
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| Institution: | aUnité de Recherche: Génétique, Biodiversité et Valorisation des Bioressources UR/09-30, Institut Supérieur de Biotechnologie de Monastir, Tunisia;bDepartment of Parasitology, Science and Research Branch, Islamic Azad University, Tehran, Iran;cSezione di Parassitologia e Malattie Parassitarie Dipartimento di Biologia Animale, Università degli Studi di Sassari, Sardaigne, Italy;dInstitut Supérieur des Sciences et Technologies de l’Environnement de Borj Essedria, Tunisia |
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| Abstract: | Fasciolosis caused by Fasciola spp. (Platyhelminthes: Trematoda: Digenea) is considered as the most important helminth infection of ruminants in tropical countries, causing considerable socioeconomic problems. In the endemic regions of the North of Iran, Fasciola hepatica and Fasciola gigantica have been previously characterized on the basis of morphometric differences, but the use of molecular markers is necessary to distinguish exactly between species and intermediate forms. Samples from buffaloes and goats from different localities of northern Iran were identified morphologically and then genetically characterized by sequences of the first (ITS-1) and second (ITS-2) Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA (rDNA). Comparison of the ITS of the northern Iranian samples with sequences of Fasciola spp. from GenBank showed that the examined specimens had sequences identical to those of the most frequent haplotypes of F. hepatica (n = 25, 48.1%) and F. gigantica (n = 20, 38.45%), which differed from each other in different variable nucleotide positions of ITS region sequences, and their intermediate forms (n = 7, 13.45%), which had nucleotides overlapped between the two Fasciola species in all the positions. The ITS sequences from populations of Fasciola isolates in buffaloes and goats had experienced introgression/hybridization as previously reported in isolates from other ruminants and humans. Based on ITS-1 and ITS-2 sequences, flukes are scattered in pure F. hepatica, F. gigantica and intermediate Fasciola clades, revealing that multiple genotypes of Fasciola are able to infect goats and buffaloes in North of Iran. Furthermore, the phylogenetic trees based upon the ITS-1 and ITS-2 sequences showed a close relationship of the Iranian samples with isolates of F. hepatica and F. gigantica from different localities of Africa and Asia. In the present study, the intergenic transcribed spacers ITS-1 and ITS-2 showed to be reliable approaches for the genetic differentiation of Fasciola spp., providing bases for further studies on F. hepatica, F. gigantica and their intermediate forms in the endemic areas in Asia. |
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| Keywords: | Fasciola gigantica Fasciola hepatica Asia North of Iran ITS-1 ITS-2 ITS Genetic characterization Phylogenetic analysis |
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