Yersinia enteritis.

Y. enterocolitica has been shown to be a fairly common human pathogen in many countries. The clinical picture produced by Y. enterocolitica infections is quite variable. An acute abdominal disease (acute gastroenteritis or colitis, or a pseudoappendicitis due to acute terminal ileitis) and, less commonly, erythema nodosum and arthritis are the most important manifestations of the disease. On radiologic examination mucosal lesions of the terminal ileum are found in most patients with gastrointestinal symptoms. The colon is less frequently involved. The most typical lesions consist of shallow, small, round ulcers characteristic of the disease. Microscopic examination may suggest yersiniosis but does not show pathogenic signs. Y. enterocolitica can be detected by stool cultures or by serologic examinations. The disease is usually mild. If specific therapy is indicated the disease usually responds well to antibiotic therapy.