Widespread presence of human-pathogenic Enterocytozoon bieneusi genotype D in farmed foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in China: first identification and zoonotic concern.

Enterocytozoon bieneusi is a well-known causative agent of microsporidial infections in a variety of mammal hosts including humans in China, whereas there were no epidemiological data on wild animals bred in captivity, and the role of the neglected hosts in transmission of zoonotic microsporidiasis remains unknown. Herein, we investigated feces from 191 farmed foxes (Vulpes vulpes) and 162 farmed raccoon dogs (Nyctereutes procyonoides) for the prevalence and genotypic characteristics of E. bieneusi in Harbin City, northeast China. Polymerase chain reaction (PCR) targeting the internal transcribed spacer (ITS) of the rRNA gene enabled the identification of 53 (27.7%) and 17 (10.5%) positives from fox and raccoon dog specimens, respectively. There was only minor difference in prevalence between juvenile and adult foxes. Adult raccoon dogs have an infection rate significantly higher than juveniles. The most common human-pathogenic E. bieneusi, genotype D, is widespread among foxes and raccoon dogs of various ages by sequence analysis of the ITS locus. Genotypes CHN-DC1 and mixed CHN-DC1/WildBoar3 were detected in one adult raccoon dog each. Here is the first report describing the presence of zoonotic E. bieneusi genotypes in farmed foxes and raccoon dogs. The widespread existence of genotype D in surveyed animals is of great concern for public health.