Morphological and Molecular (28s rDNA) Characterization of Dicrocoelium dendriticum Isolates from Sheep, Goat and Cattle in Mazandaran Province, Iran

Background and Dicrocoeliasis is a prevalent parasite in ruminants caused by different species of Dicrocoelium spp. This parasite lives in bile duct and gallbladder of ruminants and accidentally in human. The economic significance of dicroceliasis is due to direct damage to the liver and, consequently, to the loss of significant amounts of protein. The present study aimed to investigate the morphometric and molecular (PCR and PCR-RFLP) parameters of Dicrocoelium species isolates from sheep, goat, and cattle in Mazandaran province, Iran during 2013-2015.
In this descriptive study, 50 trematodes isolated from livers of sheep (n= 20), goat (n= 20), and cattle (n= 10) were collected form abattoirs in Mazandaran province. Adult worms were studied by morphometric and molecular methods on 28s rDNA. The RFLP technique was used to identify the genus. Some samples were also sequenced.
All isolates of three hosts (sheep, goat, and cattle) showed significant differences in many morphological parameters. According to characterization of testicles that is a remarkable characteristic for differential diagnosis of Dicrocoelium species, they were in tandem position in all isolates. Moreover, no significant difference was observed in their size in different hosts. Four bands, including 116, 145, 393, and 409 bp were produced from PCR method after treatment by enzyme. In molecular technique, there were no any significant differences but in morphometric analysis, some differences were found.
The molecular and morphometric results indicated that D. dendriticum is the only species infecting sheep, goat, and cattle in Mazandaran province.