Prevalence and Molecular Characterization of Cysticercus tenuicollis Cysts in Sheep Slaughtered in Palestine

Cysticercus tenuicollis is the metacestode of canine tapeworm Taenia hydatigena, which has been reported in domestic and wild ruminants. C. tenuicollis infection may constitute a health problem to domestic and wild ruminants and thus a source of economic loss in the meat industry. In Palestine, C.tenuicollis infection was not studied and its prevalence is unknown. Therefore, the aim of this study was to estimate the prevalence of C.tenuicollis infection among sheep and its molecular characteristics in Nablus, Northern part of the West Bank, Palestine. The study was performed from April to June 2014 and inspection carried out from 1489 sheep slaughtered at the municipal abattoir of Nablus, Northern part of the West Bank, Palestine. The overall prevalence of C. tenuicollis was 2.15%. The mean total length of large and small hooks was 38.78 mm and 23.42 mm, respectively. Using Ward's method, the length of the large and small hooks was weakly associated with the variability in mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. PCR amplification of small subunit ribosomal RNA (rrnS) and partial sequencing of mitochondrial (cox1) genes were performed for 20 isolates. Ten variable (polymorphic) sites were detected, including 7 singleton variable sites (SP) at positions 6, 72, 102, 141, 207, 231, 264 and 3 parsimony informative sites (PIP) at positions 51, 213 and 219. The average number of pairwise differences (π) of the cox1 sequences was 0.0045, suggesting that there was low genetic variation among these isolates. Neutrality tests (Tajima's D and Fu and Li's D) showed that the evolution of C. tenuicollis is evolving in a neutral mode. These findings would greatly help to implement control and preventive measures for C. tenuicollis in Palestine. Phylogenetic analysis computed by neighbor joining (NJ) from the partial cox1 gene nucleotide sequences revealed that C. tenuicollis isolates were composed of 9 haplotypes and distinguished from the other Taenia species, with the major haplotype comprising 11 out of 20 samples. Furthermore, the Phylogenetic analysis revealed that the Palestinian C.tenuicollis isolates were clustered in one clade, along with isolates from Iran, Turkey and Finland. These results confirm circulation of C. tenuicollis in different geographical regions.