General Information: This strain is a fully virulent serotype I strain isolated from a human patient. Environmental bacterium that causes gastrointestinal disease. Specific virulence factors are encoded within pathogenicity islands (PAIs) that are required for the invasive phenotype associated with Yersinia infections. One key virulence plasmid contained by the three human-specific pathogens is pCD1/pYv, which encodes a type III secretion system for the delivery of virulence proteins that contribute to internalization into the host cell. This organism was first isolated in 1883 by Malassez and Vignal and is termed pseudotuberculosis since it causes lesions in the lung that are similar to those observed during tuberculosis infection. It is ubiquitous in the environment and is a food and waterborne pathogen that affects animals as well as humans by causing gastroenteritis like Yersinia enterocolitica.