It is believed that an infectious agent is important in the development of Crohn's disease. The similarity of Crohn's disease to the animal form of ileitis, termed Johne's disease, supports the possibility that both disorders are caused by exposure to Mycobacterium avium paratuberculosis or MAP. Multiple investigators have demonstrated good clinical responses of patients with Crohn's disease to treatment with triple antibiotic therapy directed against mycobacterial infection.