Occurrence and molecular characterization of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi from Tibetan sheep in Gansu, China

Abstract

Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are globally ubiquitous pathogens. However, little is known about the occurrence and distribution of Cryptosporidium spp., G. duodenalis, and E. bieneusi in Tibetan sheep. In the present study, fecal specimens of 177 Tibetan sheep were examined by nested PCR. 4.5% (n = 8), 1.7% (n = 3) and 34.5% (n = 61) of the Tibetan sheep were positive for Cryptosporidium spp., G. duodenalis, and E. bieneusi, respectively. Cryptosporidium ubiquitum was the only species found by small subunit (SSU) rRNA-based PCR, and subtyping of C. ubiquitum (n = 6) by 60-kDa glycoprotein (gp60) revealed that all positive isolates belonged to zoonotic XIIa subtype 2. Multilocus genotyping at the SSU rRNA and β-giardin (bg) genes suggested that three G. duodenalis positive specimens belonged to assemblage E. Sequences analysis of internal transcribed spacer (ITS) gene characterized four E. bieneusi genotypes which all belonged to Group 2, one novel CGS1 (n = 3), and three known: CM7 (n = 34), BEB6 (n = 22), and CHS3 (n = 2). We employed multilocus sequence typing (MLST) using three microsatellites (MS1, MS3 and MS7), one minisatellite (MS4), and sequence analysis of MLST yielded 3, 2, 2 and 2 genotypes at the MS1, MS3, MS4, and MS7 loci, respectively, forming 4 MLGs. Our findings elucidate the occurrence and distribution of three zoonotic pathogens in Tibetan sheep in China. More subsequent and detailed data are required to better understand the transmission of Cryptosporidium spp., G. duodenalis, and E. bieneusi in sheep.

Keywords: Cryptosporidium spp.; E. bieneusi; G. duodenalis; Tibetan sheep; Zoonotic.