Physicians of any specialty encounter the chronic course of yersiniasis, the clinical manifestations of which are polymorphic and similar to the symptoms of other diseases, including autoimmune ones. The long interval of an evolving pathological condition after the acute period of the disease leads to the fact that the clinical and laboratory manifestations of chronic yersiniasis are wrongly regarded as an independent nosological entities unassociated with the persistence of Yersinia. Dynamic blood tests for specific IgA to the Yersinia enterocolitica virulence factors that are an indirect sign of on-going pathogen persistence in the body are required to elaborate the tactics for the examination, treatment, and follow-up of patients.