Morphological and phylogenetic analysis of Raillietina spp. in indigenous chickens (Gallus gallus domesticus) in Bangladesh

Raillietina spp. (Cestoda: Davaineidae), the most common cestodes in indigenous chickens, cause a substantial production loss in poultry industry in Bangladesh. Here, we estimated the prevalence, confirmed the species and determined the genetic pattern of species of Raillietina using molecular tools. We collected and examined 375 chickens randomly from household of different villages of Mymensingh sadar and Gouripur upazila, Mymensingh district and adult parasites were isolated and identified. Genomic DNA was extracted from collected parasites, amplified ITS-2 and ND-1 genes, sequenced and analyzed. Out of 375 samples, 270 (72.0%) were found positive with Raillietina species and mean worm burden was 10.46 ± 0.56. Microscopically, three species of Raillietina, such as R. cesticillus (37.9%), R. echinobothrida (41.1%) and R. tetragona (52.8%) were detected on the basis of their morphological features. The total length, length and width of scolex, sucker and rostellum were also measured. Among different factors, age, farming nature and flock size of chickens were significantly (p < 0.05) influenced Raillietina infections. For further validation, the sequences of ITS-2 gene generated in this study were matched with reference sequences of R. cesticillus, R. echinobothrida and R. tetragona and found 99.63% − 100% similarity. The phylogenetic analyses of ITS-2 and ND-1 sequences were clustered together with the reference sequences of R. cesticillus, R. echinobothrida and R. tetragona confirming microscopic identification. This is the first confirmation of species of Raillietina along with the prevalence of the species, which will be helpful for the formulation of a control strategy and provide basic information for further molecular study.