Enterocytozoon bieneusi Genotypes in Cattle on Farms Located within a Water Catchment Area.

Abstract

Enterocytozoon bieneusi is a microsporidian found in humans and other animals around the world. Investigations in some countries, such as the U.S., have indicated the importance of E.&#xa0;bieneusi as a zoonotic water- and food-borne pathogen. However, there is scant epidemiological information on E.&#xa0;bieneusi in animals in many countries including Australia. Here, we conducted the first molecular epidemiological study of E.&#xa0;bieneusi in farmed cattle in Victoria, Australia, to assess whether these bovids are carriers of "zoonotic" genotypes of E.&#xa0;bieneusi. A total of 471 individual faecal samples were collected from calves of <&#xa0;3&#xa0;mo and of 3-9&#xa0;mo of age. Genomic DNAs were extracted from individual faecal samples and then subjected to nested PCR-based sequencing of the internal transcribed spacer (ITS) of nuclear ribosomal DNA to identify E.&#xa0;bieneusi and define genotypes. Enterocytozoon bieneusi was detected in 49 of the 471 samples (10.4%). An analysis of ITS sequence data revealed three known genotypes (BEB4, I, and J) and three novel genotypes (designated TAR_fc1 to TAR_fc3). Phylogenetic analysis showed that genotypes BEB4, I, J, TAR_fc1, and TAR_fc2 clustered with genotypes identified previously in humans, indicating that cattle are carriers of E.&#xa0;bieneusi with zoonotic potential.