[Crohn disease: uncertainty about the etiologic role of Mycobacterium paratuberculosis]

In recent years, attention and discussion have been devoted to the possible association of Mycobacterium paratuberculosis, agent of paratuberculosis in ruminants, with Crohn's disease. Both diseases, which affect young adults, are characterized by chronic granulomatous lesions, typically concentrated in the terminal ileum, and clinical signs of enteritis and weight loss. The etiology of Crohn's disease is unknown but genetic, environmental, immunological and microbiological influences, in various combinations, have been suggested. Human exposure to M. paratuberculosis may occur essentially from a fecal contamination (drinking water, milk...). This association between Crohn's disease and paratuberculosis has been shown but a causal relationship remains to be demonstrated.