Prevalence and genotypic identification of Cryptosporidium spp. and Enterocytozoon bieneusi in captive Asiatic black bears (Ursus thibetanus) in Heilongjiang and Fujian provinces of China

BACKGROUND: Cryptosporidium and Enterocytozoon bieneusi are two important pathogens with zoonotic potential that cause enteric infections in a wide range of hosts, including humans. Both are transmitted from animals to humans by direct contact or through contaminated equipment. Bears are frequently found in Chinese zoos as ornamental animals as well as farmed as commercial animals, and are therefore in close contact with zoo- or farm-keepers, but the prevalence and zoonotic potential of Cryptosporidium and E. bieneusi in bears is poorly understood. In this study, we aimed to provide data on the occurrence and genetic diversity of Cryptosporidium and E. bieneusi in Asiatic black bears from Heilongjiang and Fujian, China. From May 2015 to December 2017, 218 fresh fecal specimens were collected from captive Asiatic black bears in Heilongjiang (n = 36) and Fujian (n = 182), China. Cryptosporidium and E. bieneusi were examined by PCR amplification of the partial small subunit of ribosomal DNA (SSU rDNA) and the internal transcribed spacer (ITS) region of rDNA, respectively. C. andersoni-positive isolates were subtyped through PCR analysis of the four minisatellite/microsatellite (MS1, MS2, MS3 and MS16) loci. RESULTS: The overall prevalence of Cryptosporidium and E. bieneusi were 2.4% (4/218) and 6.4% (14/218), respectively, with 2.8% (1/36) and 22.2% (8/36) in the Heilongjiang Province, and 1.6% (3/182) and 3.3% (6/182) in the Fujian Province. Sequence analysis confirmed the presence of Cryptosporidium species: C. andersoni (n = 3) and a genotype termed Cryptosporidium rat genotype IV (n = 1). All three identified C. andersoni belonged to the MLST subtype A4, A4, A4, A1. Two known E. bieneusi genotypes D (n = 4) and SC02 (n = 10) were identified, both of which belong to zoonotic Group 1. CONCLUSIONS: This is the first report of C. andersoni and Cryptosporidium rat genotype IV in bears. The discovery of the zoonotic potential of E. bieneusi genotype D in bears highlights its significant zoonotic potential and potential threat to human health.