Prevalence and Molecular Characterization of Enterocytozoon bieneusi among Pigs in Chonburi Province, Eastern Thailand.

Enterocytozoon bieneusi is an organism that infects a wide variety of vertebrates, including humans. Pigs also harbor E. bieneusi, of which several genotypes have been recently detected in human feces. The aim of this study was to determine the prevalence of E. bieneusi infection among pigs raised in three smallholder farms and eight small large-scale farms in Chonburi Province, Eastern Thailand, using nested polymerase chain reaction of the internal transcribed spacer (ITS) of the small subunit of ribosomal RNA gene and to investigate genotypes of E. bieneusi isolates using nucleotide sequencing and phylogenetic tree analysis of the ITS region. Of 244 stool samples, E. bieneusi was detected in 14.8% (36/244). Two known zoonotic genotypes, that is, genotypes E (77.8%) and F (22.2%), were identified. Using phylogenetic tree analysis, these two genotypes were clustered in human pathogenic and zoonotic potential groups, designated as group 1. The high prevalence of zoonotic genotypes of E. bieneusi among pigs suggests that pig farming is one of the potential sources of human infection. This is the first report of E. bieneusi genotypes among pigs raised in pig farms in Eastern Thailand.