Genetic diversity and host specificity of Blastocystis in yaks in Xinjiang, northwest China.

Blastocystis is a common intestinal pathogen in human and animals. A total of 826 fecal samples were collected from six counties in Xinjiang Uygur Autonomous Region, China, and applied to PCR amplification based on the small subunit ribosomal RNA (SSU rRNA) gene of Blastocystis. The infection rate of Blastocystis in yaks was 75.5 % (624/826), with the different sampling sites varies from 54.2 % (156/288) in Hejing to 100 % (22/22) in Aketao (p < 0.01). About 20 % of the Blastocystis positive samples (n = 163) were selected from each sampling sites to sequenced. Eight subtypes (ST10, ST14, ST21, ST24, ST25, ST26, ST42 and ST44) were identified, with ST10 (n = 59) was the predominant subtype, followed by ST26 (n = 41), ST42 (n = 39), ST25 (n = 7), ST14 (n = 6), ST21 (n = 5), ST24 (n = 3), ST44 (n = 3). 22 known sequence types were identified from the 163 sequenced samples, indicating a marked high genetic diversity. These results indicating that the infection of Blastocystis was common in yaks in Xinjiang, and have host specificity of Blastocystis subtypes in the present study.