Molecular Characterization of Fasciola spp. from Some Parts of Iran

Identification of liver flukes, Fasciola hepatica, and Fasciola gigantica by morphometric parameters is not always reliable due to the overlapping measurements. This study aimed to characterize the liver flukes of animals from different parts of Iran by the genetic markers, ITS1, and COXI.

We collected flukes from infected livestock in six provinces of Iran from Sep to Nov 2016. The flukes were identified by amplification of a 680 bp sequence of ITS1 locus followed by a restriction fragment polymorphism (RFLP) assay. The genetic diversity among isolates was evaluated by amplification and sequencing of a 493 bp fragment of the COXI gene.

We obtained 38 specimens from Khuzestan, 22 from Tehran, 10 from Isfahan, 10 from Mazandaran, 4 from Kurdistan, and 3 from Ardabil provinces. PCR-RFLP analysis revealed two patterns, representing F. hepatica, and F. gigantica. Fifty specimens from cattle and sheep exhibited F. hepatica pattern and 37 from the cattle, sheep, buffalo, and goat that of F. gigantica. The phylogeny based on COXI revealed two distinct clades separating F. hepatica from F. gigantica. In our phylogeny, the Iranian F. gigantica isolates showed a distinct separation from the African flukes, while grouped with the East Asia specimens demonstrating a common ancestor. The F. hepatica isolates clustered with the flukes from different parts of the world, including East Asia, Europe, and South America.

The present study revealed a substantial genetic difference between F. gigantica populations of Asia and Africa, while F. hepatica isolates from different parts of the world shared high similarities.