RESUMEN
BACKGROUND: Enterocytozoon bieneusi is the most common pathogen of 14 microsporidian species infecting humans worldwide. In China, E. bieneusi has been reported in some common livestock and environmental specimens. However, no information is available on occurrence of E. bieneusi in reindeers. The objective of the present study was to detect and genotype E. bieneusi in reindeers in China, and assess the zoonotic potential. FINDINGS: 125 fecal specimens were collected from wild reindeers in the northeast forest region of Great Hinggan Mountains of China. By PCR and sequencing of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene of E. bieneusi, an average infection rate of 16.8 % (21/125) was observed in reindeers. E. bieneusi was detected in two age groups: 7.7 % (3/39) in the youths (aged 1 to 2 years) and 22.2 % (18/81) in the adults (aged 3 to 8 years). Five genotypes were identified: one known genotype Peru6 (n = 6) and four novel genotypes named as CHN-RD1 (n = 12), and CHN-RD 2 to CHN-RD4 (one each). In phylogenetic analysis, all the novel genotypes together with known genotype Peru 6 were clustered into group 1. CONCLUSIONS: This is the first report of E. bieneusi infection in reindeers, expanding the host range of E. bieneusi. The fact of genotype Peru 6 previously reported in humans and the result of all the novel genotypes falling into zoonotic group 1 suggest the possibility of E. bieneusi transmitted from reindeers to humans.