Occurrence and description of Clinostomum complanatum (Rudolphi, 1819) metacercariae in freshwater fishes from Gheshlagh basin, West of Iran

Clinostomum spp. have a long uncertain taxonomic history which also have attracted great attentions. This could be due to their zoonotic potential and the presence of yellow grubs in the fish as a second intermediate host. In the current study, a total of 3oo freshwater fish belonging to the nine species were collected from two stations in the Gheshlagh basin, Kurdistan Province. Four species including Alburnus mossulensis, Capoeta damascina, Garra rufa and Squalius cephalus were found to be infected with the metacercariae. The highest prevalence (4.1%) and mean abundance (0.31±0.37) were observed in C. damascina. The metacercariae were identified using molecular (Internal Transcribed Spacer (ITS)), SEM and morphological analysis as Clinostomum complanatum. The phylogenetic analysis of four sequences of ITS gene were conducted. The specimens were placed within a lineage of C. complanatum and formed a clade with other Clinostomum species in the Palearctic region. The current study revealed the C. damascina, G. rufa and A. mossulensis as new hosts for C. complanatum and first report of this metacercariae in the region. Furthermore, the present study demonstrate the first molecular and morphological data on C. complanatum of the Iranian freshwater fish.