Occurrence, molecular characterization and predominant genotypes of Enterocytozoon bieneusi in dairy cattle in Henan and Ningxia, China

BACKGROUND: Enterocytozoon bieneusi is the most frequently diagnosed microsporidian species in humans and a wide range of animals. This study was conducted to assess the prevalence and molecular characteristics of E. bieneusi in dairy cattle in Henan Province of central China and the Ningxia Hui Autonomous Region of northwest China. FINDINGS: Of 879 fresh fecal specimens, 24.3 % (214/879) tested positive for E. bieneusi by nested polymerase chain reaction (PCR) based on the internal transcriber spacer (ITS) gene. The highest infection rate, 46.8 % (51/109, P < 0.0001), was observed in a group of dairy cattle with diarrhea, located in Ningxia. The age groups with higher infection rates were pre-weaned calves (29.3 %, 127/434, P < 0.0001) and post-weaned calves (23.9 %, 63/264, P = 0.006). Sequencing and phylogenetic analysis revealed 20 E. bieneusi ITS genotypes (15 known and five new), including members of Group 1 and Group 2. Genotypes I and J were detected in 64.5 % (138/214) of the E. bieneusi positive specimens. CONCLUSIONS: Genotypes I and J were the dominant genotypes in dairy cattle in the present study. The detection of zoonotic genotypes of E. bieneusi in dairy farms indicates that cattle may play an important role as a reservoir host for zoonotic infections.