Yersinia pseudotuberculosis infection has been reporte in the United States in six species of domestic mammal (cat, cow, goat, rabbit, sheep, and swine), five species of wild mammal including black-tailed jack rabbit (Lepus californicus), white-tailed antelope squirrel (Citellus lecurus), eastern cottontail (Sylvilagus floridanus), black-faced kangaroo (Macropus melanops), and albino fallow deer (Dama dama), and three birds (canary, dove, and pigeon). Also, epizootics in chinchilla caused by Yersinia enterocolitica have been recorded in the United States. The importance of intestinal carriers in fecal-oral spread of infection is emphasized in the epizootiology of yersiniosis (infection with Y. pseudotuberculosis or Y. enterocolitica). Wild birds and rodents appear to be significant reservoirs of Y. pseudotuberculosis, but birds have not been found infected with Y. enterocolitica.