Molecular Characterization of Blastocystis sp. in Camelus bactrianus in Northwestern China

Blastocystis sp. is an important zoonotic protist in humans and various animals with worldwide distribution. However, there have been no data on the occurrence of Blastocystis sp. in C. bactrianus, an important economic animal in northwestern China. In the present study, a PCR-sequencing tool based on the SSU rRNA gene was applied to investigate the prevalence and genetic diversity of Blastocystis sp. in 638 faecal samples from C. bactrianus in 21 sampling sites within three main breeding areas (Gansu, Inner Mongolia and Xinjiang) in northwestern China. The total prevalence of Blastocystis sp. was 21.8% (139/638) in C. bactrianus, with the infection rates of 29.5% (18/61), 50.0% (14/28) and 19.5% (107/549) for animals aged <2 years, 2-6 years and >6 years, respectively. Significant differences in prevalence were detected among C. bactrianus from three geographic areas (χ² = 19.972, df = 2, p < 0.001) and all sampling sites (χ² = 104.154, df = 20, p < 0.001). A total of 16 of 21 sampling sites were positive for Blastocystis sp., with the prevalence ranging from 7.7% to 70.6%. Sequence analysis of the SSU rRNA gene identified eight subtypes in C. bactrianus in the present study, including seven animal adapted subtypes (ST10, ST14, ST21, ST24, ST25, ST26 and ST30) and one potentially novel subtype, with ST10 being the dominant one. To the best of our knowledge, this study provides the first insight for the occurrence and genetic make-up of Blastocystis sp. in C. bactrianus and contributes to the understanding of the transmission of Blastocystis infection in C. bactrianus in China.