An experimental animal model of Yersinia-induced arthritis was successfully developed in mice using Yersinia enterocolitica WA. In order for the Yersinia to induce arthritis the strain had to be cured of plasmid. The arthritis-susceptible mouse strains were DBA/2 and BDF1. C57B1/6, Balb/c, CBA and DBA/1 were arthritis-resistant. Both the dose of bacteria and the route of administration were critical.