Abstract:

Monogeneans gill parasites of the diversified Dactylogyrus genus are host-specific to freshwater fish of the Cyprinidae family. Accurate detection of various Dactylogyrus species is very time-consuming and requires highly experienced personnel; to overcome this problem, the genomic DNA technology has been recently used to detect Dactylogyrus spp. In this study, 23 Cyprinus carpio and 19 Ctenopharyngodon idella isolates were collected from different farms and local markets of Ahvaz, southwest of Iran. The gill arches of each fish were carefully examined under a light microscope. Dactylogyrus species was identified morphologically. Identical species were kept in ethanol for molecular study. Molecular analysis was performed using amplification of the ITS-1 region of the ribosomal RNA gene of the parasite. Then, the amplified PCR products were sequenced. The aligned nucleotide sequences were analyzed to construct the phylogenetic tree of the identified species. The results revealed two lineages including D. extensus isolated from common carp and D. lamellatus taken from grass carp fish. Phylogenetic analysis showed that the detected D. extensus and D. lamellatus isolates from Khuzestan region were clustered with some Iranian (Guilan), Chinese and Czech isolates. Importing fingerlings from Guilan Province could lead to introducing monogenean infections to native cyprinid fish.

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