Abstract:Objective: To understand the Escherichia. coli cause diarrhea mechanism of young raccoon dogs diarrheic, HPI pathogenicity island were detected to carry Yersinia enterocolitica. Methods: Pathogenicity islands gene irp2 and fyuA were detected by PCR amplification, and the virulence of E.coli strains was determined with mice by intraperitoneal injection. Results: E.coli strains were separated from organ and feces of diarrhea disease young raccoon dogs, which serotypes were O23 and O20. Two serotypes of E. coli were detected pathogenicity islands gene irp2 and fyuA, which further resulted in the occurrence of serious illness and death for experimental mice after intraperitoneal injection in virulence detection. Conclusion: young raccoon dogs diarrhea were caused E.coli strains carrying pathogenicity islands gene irp2 and fyuA of Yersinia enterocolitica HPI, which will bring putative threats to the health of young raccoon dogs.