Prevalence of Enterocytozoon bieneusi and genetic diversity of ITS genotypes in sheep and goats in China

- E. bieneusi isolates were identified and genotyped in sheep and goats.
- Infection rates of E. bieneusi were 22.5% for sheep and 21.8% for goats.
- Six known genotypes and eight novel genotypes were identified.
- High genetic diversity was observed due to 35 polymorphic sites of 14 genotypes.
- Zoonotic potential of E. bieneusi genotypes was assessed by phylogenetic analyses.

Enterocytozoon bieneusi is the most common microsporidia species, recognized in more than 90% cases of human microsporidiosis and has been found in a variety of animal hosts. To explore the prevalence of E. bieneusi in sheep and goats in China, genetic diversity and zoonotic potential of E. bieneusi, 193 fecal specimens from 138 sheep and 55 goats from eight farms in Heilongjiang Province, China were analyzed for the occurrence of E. bieneusi by PCR and sequencing of the single internal transcribed spacer (ITS) of the rRNA gene. The average prevalence of E. bieneusi was 22.3% (43/193), with 22.5% (31/138) for sheep versus 21.8% (12/55) for goats. Altogether 14 genotypes of E. bieneusi were identified, including six known genotypes-BEB6 (n = 15), Peru6 (8), D (n = 6), O (n = 3), EbpC (n = 2), and EbpA (n = 1)-and eight novel genotypes named COS-I to COS-VII and COG-I (one each). Six of the genotypes were previously detected in humans. In phylogenetic analysis, the five novel genotypes COG-I and CCOS-IV to COS-VII were clustered into group 1 with zoonotic potential. These results indicate that these animals may play a potential role in the transmission of E. bieneusi to humans.

Phylogenetic relationship of the genotypes of E. bieneusi identified in this study and known genotypes previously published in GenBank as inferred by a neighbor-joining analysis of ITS sequences based on genetic distances calculated by the Kimura 2-parameter model. The numbers on the branches are percent bootstrapping values from 1000 replicates. Each sequence is identified by its accession number, host origin, and genotype designation. The group terminology for the clusters is based on the work of Zhao et al. (2014b). Genotypes with black square and black circles are novel and known genotypes identified in this study, respectively. 61