Molecular analysis of internal transcribed spacer 2 of Dicrocoelium dendriticum isolated from cattle, sheep, and goat in Iran

BACKGROUND: Dicrocoelium dendriticum is a broadly distributed zoonotic helminth, which is mainly reported from domesticated and wild ruminants. There is little data covering the molecular features of this trematode; therefore, current study aimed to molecularly analyze D. dendriticum in livestock. METHODS: Totally, 23 samples of D. dendriticum were collected from cattle, sheep, and goat from Ilam, Lorestan, and Khuzestan, three west and south-west provinces of Iran from February to August 2018. After genomic DNA extraction, the internal transcribed spacer (ITS) 2 fragment was amplified and sequenced in samples. To investigate genetic variations through the ITS 2 fragment of obtained D. dendriticum, phylogenetic tree and network analysis were employed. RESULTS: All 23 samples were successfully amplified and sequenced. Phylogenetic tree showed that our samples were clearly grouped in a clade together with reference sequences. There was no grouping based on either geographical regions or hosts. Network analysis confirmed the phylogenetic findings and showed the presence of nine distinct haplotypes, while our samples together most of sequences, which were previously submitted to the GenBank, were grouped in the Hap1. CONCLUSIONS: Our findings indicated that although ITS 2 fragment discriminate D. dendriticum, this fragment is not suitable to study intra-species genetic variations. Therefore, exploring and describing new genetic markers could be more appropriate to provide new data about the genetic distribution of this trematode.