Molecular Characterization of Fasciola Samples Using Sequences of Second Internal Transcribed Spacer-rDNA in Different Geographical Localities of Sistan and Balouchestan Province, Iran

The Fasciola trematodes are the most common liver flukes, living in a range of animals with global distribution and resulting in profound economic loss and public health challenges. Previous studies have indicated that the sequences of the second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA) provide reliable genetic markers for molecular systemic studies of Fasciola. The objective of the present study was to characterize Fasciola samples from different geographical regions of Sistan and Balouchestan province using sequences of second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA). Twenty adult trematodes were collected from the livers of slaughtered infected cattle. Total genomic DNA was extracted and ITS-2 rDNA targets were amplified by polymerase chain reaction (PCR). All samples were sequenced and investigated using the ClustalW2 sequence alignment tool and MEGA software. The sequences of some Iranian and non-Iranian isolates were used for comparison, in order to evaluate the variation in sequence homology between geographically different trematode populations. The results of comparing the ITS-2 sequences with the BLAST GenBank database showed one type of sequence for F. hepatica and three different types of sequences for F. gigantica in the specimens. The present study demonstrated that Fasciola samples from cattle in two geographical locations in Sistan and Balouchestan province represented no genetic diversity in F. hepatica and high genetic variation in F. gigantica.