Mycobacterium avium ssp. paratuberculosis vs Crohn’s Disease

Crohn's disease (CD) is a chronic inflammatory bowel disease, with the potential to affect any segment of the gastrointestinal tract. Despite the great advances in recent decades, which provided a better understanding of the pathogenesis of the disease, it is yet to be completely elucidated. Presence of genetic factors, luminal factors such as microflora and factors related to the intestinal barrier and immunoregulation are pieces that interact with each other and with environmental factors. The possibility of an infectious etiology has always been widely discussed. In this context, Mycobacterium avium subspecies paratuberculosis (MAP) has attracted the interest of many researchers because of the similarity between paratuberculosis and CD. In 1913, two decades before the description of CD in 1932, T. K. Dalziel made associations between chronic cases of enteritis in humans and paratuberculosis in cattle (Behr and Kapur, 2008). Some genetic studies also support the role of MAP in CD and susceptibility genes have been identified, which encode proteins involved in the innate immunity defense against intracellular bacteria. However, no study is conclusive about a causal relationship. It is not possible to conclude that a single agent is solely responsible for the etiology of CD: a multifactorial cause is much more likely (Grant et al., 2001). Whereas the causal relationship has not been established, therapeutic implications require further studies. Results of these studies could help answer questions about the role of MAP in the etiology of CD.