Molecular characterization and zoonotic potential of Enterocytozoon bieneusi in ruminants in northwest China.

This study was conducted to examine the molecular characteristics and assess the zoonotic potential of Enterocytozoon bieneusi in ruminants in northwest China. A total of 1581 fresh fecal samples were collected from eight categories of ruminants. The E. bieneusi was screened and genotyped via nested polymerase chain reaction (PCR) amplification targeting the internal transcribed spacer (ITS) of the small subunit rRNA (ssu rRNA) gene. The result indicated that the average infection rate of E. bieneusi in ruminants was 16.0% (253/1581), with infection rates of E. bieneusi in Mongolian sheep, Mongolian goats, Chifeng cattle, red deer, alpine musk deer, and blue sheep at 21.8% (169/777), 8.2% (46/561), 25.9% (28/108), 13.2% (5/38), 20.0% (4/20), and 6.3% (1/16), respectively. The infections of E. bieneusi varied by different categories. For the different age groups, the infection rates in lambs (29.3%, 108/369) and calves (57.1%, 8/14) were significantly higher than that in ewes (21.1%, 215/1020) and cows (21.3%, 20/94). For the molecular characterization, diverse E. bieneusi ITS genotypes were identified, with a total of 13 genotypes were observed, including 10 known genotypes (BEB6, COS-I, J, CHC8, I, CHG1, BEB4, CHG3, CHS7, and NCF2) and 3 novel genotypes (CNR1 to CNR3). Genotype BEB6 was predominant (59.7%, 151/253). Phylogenetic analysis revealed that most E. bieneusi ITS genotypes clustered into group 2 and only one (NCF2) genotype belonged to group 1. The zoonotic genotypes identified in ruminants in the present study indicated the zoonotic potential of E. bieneusi. In addition, simultaneous identification of genotypes, such as BEB6, COS-I, and BEB4, in the same eco-geographical system indicated some host multiplicity transmission potential of E. bieneusi.