Dipylidium caninum can be distinguished by a molecular assay, this method has been proven sensitive and specific in identifying cestode DNA (7) and is useful in biological studies and genetics in comparison with local or global previous studies (4). Numerous researchers have developed primers specific to various genes for D.caninum-PCR assay (12). Currently, this study examines primers for amplifying DC28SrRNA and mtDNA-genes with amplicon size 653 and 190 bp as PCR targets that didn't match cestode-infecting dogs, indicating great sensitivity of the PCR approach for parasite detection (4, 12).
Sequence analyses of 28sDC gene collected from all isolated cestode specimens from dogs' intestines and positively amplified using conventional PCR determined taxonomy status of D.caninum as first period in Iraq since other previous studies showed for many years that DNA sequence was possible to have very good technology to distinguish closed relation cestode species (16).
Nucleotide DC28SrRNA sequences, alignment-BLASTEn, and graphics analysis revealed similar sequences (mega-blast) found with NCBI database used BLASTn-program and revealed that alignment of 28S gene lies in Dipylidium species with equal to the total score and identity 99–100% as noted in NCBI database, which agrees with Beugnet et al. (4), and indicated that sequencing of gene was a great target for various isolates by molecularly identify (17).
Phylogeny of Iraqi D.caninum isolates in the current study had serial no MZ677330, OL460637, and OL413446 with similar sequences and shared 99.36% identity with South Africa accession no. MH045471 (7); Viet Nam accession no.ON248386 (unpublished), respectively. Iraqi isolates OL460638, and OL466918 were also closely related and shared 93% identity with USA D.caninum sequence isolates (AF023120.1 and MH182478.1) (18, 19). Besides, 93.5% identity with Iran D.caninum sequence isolates with accession no. MG774549.1 (20). Also, mtDNA gene with accession no. OR250020.1 have low genetic variation among all comparison-sequenced 98.91% identity with those of USA sequence with accession no. MG587892.1 (21); 99.46% of identities with D.caninum sequences in USA with accession no. OK523385.1 (19); and 99.36% of identities with D.caninum sequences in China with accession no. OP620562.1 (22).
Previous studies have shown a sequencing and then analysis of phylogeny trees are used to identify cestode species (23). According to some of them, diagnosing cestode species depending on morphological characteristics gives imprecise results for accurate detection because of an interplay of numerous morphological indicators among Dipylidium spp., such as cestode length and/or proglottid, segmentation, and other parameters, and researchers difficulties that facing during microscopic examination (24). The reason for this vibration indicates diversity in the environment, geographical regions of being near and/or from seaside and wet, animal abundance, and predisposing factors, especially with an intermediate host (25). Further research is needed an impact of Baghdad's population. Baghdad's rural regions had a higher risk of dipylidiasis infection because of huge numbers of shelter dogs living nearer domesticated animal management systems.