Epidemiological Survey and Phylogenetic Characterization of Cysticercus tenuicollis Isolated from Tibetan Pigs in Tibet, China

Cysticercus tenuicollis, commonly known as "water bell," is a larva of Taenia hydatigena, which is the most significant parasite of pigs. However, until now very few information is available regarding the prevalence and genetic characterization of the Cysticercus tenuicollis in Tibetan pigs. Therefore, the aim of this study was to investigate the prevalence and phylogenetic analysis of Cysticercus tenuicollis in Tibetan pigs. For this purpose, the COX2 gene of Cysticercus tenuicollis was amplified and sequenced for the first time in Tibetan pigs. The overall prevalence of Cysticercus tenuicollis was 43.93% in Tibetan pigs, with further distribution of 42.86% in 2014 and 45.35% in 2015. In Tibetan male and female pigs, the prevalence of Cysticercus tenuicollis was 43.39% and 44.56%, respectively. The prevalence of Cysticercus tenuicollis in different growing stages (juveniles, subadults, and adults) varied from 30.20% to 63.79%. The phylogenetic analysis of the Cysticercus tenuicollis isolates showed very close resemblance to 16 reference strains, isolates from Gansu, Hunan, and Sichuan provinces of China. To the best of our knowledge, this is the first report on the prevalence and genetic characterization of Cysticercus tenuicollis derived from Tibetan pigs. The data of present study provides baseline information for controlling cysticerci infections in pigs in Tibetan Plateau, China.