RESUMO
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.
RESUMO
Cysticercus tenuicollis is a larval stage of Taenia hydatigena resulting in cysticercosis, and responsible for enormous economic loses, especially in livestock production. Here, we planned to determine the prevalence and explore genetic variation of C. tenuicollis isolated from goats based on small subunit ribosomal RNA (rrnS) and cytochrome oxidase subunit 1 (cox1). To do this, samples were collected from different slaughter houses of municipal areas such as Bramhapalli slaughterhouse, Jubileeghat slaughterhouse and Mesuabazar slaughterhouse at Mymensingh sadar, and tentatively identified by morphological and morphometrical analysis. To study genetic variation, DNA was extracted from C. tenuicollis, and amplified rrnS and cox1 genes using specific primers, and were sequenced. Among 1372 examined animals, 177 (12.9%) were infected with C. tenuicollis. Cysts were recovered from peritoneum (7.9%), liver (4.4%) and urinary bladder (0.6%) of the infected animals. Females (18.9%) and adults (20.7%) were significantly more susceptible than male (8.8%) and young (9.3%), respectively. Genetic analysis defined 8 distinct rrnS genotypes and 9 unique cox1 haplotypes among 20 C. tenuicollis isolates. The nucleotide diversities were 0.00283 and 0.00434 for rrnS and cox1 genes, respectively. Neighbor joining (NJ) trees of rrnS and cox1 gene were constructed and the studied sequences were clustered with reference sequences of T. hydatigena with strong nodal support (100%). To compare Bangladeshi isolates, a median joining network was constructed with the population from other geographical regions and hosts. This led to a clustering pattern, but the clusters were not built with unique geographical regions or hosts. In conclusion, this is the first study that describes the genetic variation of T. hydatigena population and suggests the existence of host-specific variants. Therefore, it is fundamental to dispose infected viscera, restrict dog movement and proper management of slaughter house for the prevention and control of cysticercosis.
