Novel genotypes and multilocus genotypes of Enterocytozoon bieneusi in pigs in northwestern China: A public health concern.

Enterocytozoon bieneusi, the most important and common microsporidian species, inhabits in most animals and humans causing diarrhea and systemic diseases. The objectives of the present study were to examine the prevalence and genetic variability of E. bieneusi in pigs in Shaanxi province, northwestern China. A total of 560 pig faecal samples were collected from five different farms in Shaanxi province and molecularly characterized using multilocus genotyping (MLST) technology. High E. bieneusi infection rate (78.9%) was observed in these samples. 12 known and 22 possible novel ITS genotypes were identified, with the novel SZZD1 as the predominant genotype distributed in all age groups and pig farms. 32 (including 11 known and 21 novel ones) of them belong to the zoonotic group 1. MLST analysis showed that 109 ITS positive samples formed 87 distinct multilocus genotypes (MLGs). An incomplete linkage disequilibrium (LD) and clonal genetic structure of E. bieneusi were found in pigs in Shaanxi province. These findings indicated the complex population structures of E. bieneusi in pigs in Shaanxi province and provided baseline data for better understanding of the epidemiological status of E. bieneusi in this province.