Enterocytozoon bieneusi in human and animals, focus on laboratory identification and molecular epidemiology

Human microsporidian infections have emerged following the onset of the AIDS pandemic. Microsporidia are unicellular eukaryotic parasites that form spores. They are an exceptionally diverse group of parasites that infect a wide range of eukaryotic cells in numerous invertebrate and vertebrate hosts. Of the 14 species newly described as pathogens in human, Enterocytozoon bieneusi, which causes gastrointestinal diseases, is the most common agent of human infections. In the past fifteen years, E. bieneusi was also identified in environmental sources, especially in surface water, as well as in wild, domestic and farm animals. These findings raised concerns for waterborne, foodborne and zoonotic transmission. Molecular analyses of the 243-bp internal Transcribed spacer-(ITS) of the rRNA gene have revealed a considerable genetic variation within E. bieneusi isolates of human and animal origins, supporting the potential for zoonotic transmission. The focus of this revue is to present and discuss recent advances in diagnosis and zoonotic potential of E. bieneusi infections.