High genotype diversity and zoonotic potential of Enterocytozoon bieneusi in yaks (Bos grunniens) from Ganzi Tibetan Autonomous Prefecture, Sichuan Province.

Enterocytozoon bieneusi is a common pathogen in humans and various animals, threatening the breeding industry and public health. However, there is limited information on the molecular characteristics of E. bieneusi in yaks, an economically important animal mainly domesticated in the Qinghai Tibet Plateau in China. In the present study, nested PCR targeting the ITS gene region was applied to investigate the positive rates and genetic diversity of E. bieneusi in 223 faecal samples of yaks from three locations in Ganzi Tibetan Autonomous Prefecture, Sichuan Province. The total positive rate of E. bieneusi was 23.8% (53/223). Significant differences in positive rates were identified among yaks from three locations (χ 2  = 8.535, p = 0.014) and four age groups (χ 2  = 17.259, p = 0.001), with the highest positive rates in yaks from Yajiang and aged < 6 months, respectively. Sequence analysis identified seven known (EbpC, LW1, LQ10, PigEBITS5, ESH-01, J and BEB4) and five novel (Ganzi1-5) ITS genotypes. Phylogenetic analysis showed eight genotypes (EbpC, LW1, LQ10, PigEBITS5, ESH-01, Ganzi1, Ganzi2 and Ganzi4) in group 1 and three genotypes (J, BEB4 and Ganzi3) in group 2, indicating high genotype diversity and zoonotic potential of E. bieneusi in yaks from Ganzi. Considering the increasing zoonotic genotypes in yaks in the present study compared with previous findings, interventions should be developed to reduce the potential transmission of E. bieneusi between humans and animals.