Johne's disease is a chronic disease in animals (especially cattle and other ruminants) that eventually causes persistent diarrhea and substantial weight loss. It is caused by Mycobacterium avium subspecies paratuberculosis, a bacteria often simply referred to by the initials "MAP."

Crohn's disease is a condition of humans that bears some similarities to Johne's disease. It is a chronic inflammatory bowel disease (IBD) that can result in persistent diarrhea, along with other clinical signs. Inflammatory bowel diseases are quite commonly diagnosed by physicians in the United States.

Researchers studying Crohn's disease (CD) have found a number of risk factors for the disease. Crohn's disease has been reported more commonly in urban than rural areas and appears to be more prevalent in developed than in lesser-developed countries. There is evidence that genetics, race/ethnicity, and immunity play a role in the development of this condition. However, there is no consensus about how to best prevent or treat this condition. (For more information, visit this Web site: www.ccfa.org/info/about/crohns)

Some doctors and researchers have examined the possible role of MAP in CD. Some evidence has suggested that patients with CD are more likely to have the MAP bacteria in their gut tissues than people without CD, although research has also found MAP in people without CD. There is also other evidence that supports the postulation that MAP might somehow be involved in the disease condition in at least some CD patients. However, there is a lot of controversy about the possible role and importance of MAP in Crohn's disease.

Further research is needed to more clearly define what role, if any, MAP might play in Crohn's disease. At this point, it appears that even if MAP is involved, other factors are as, or more, important in the development of CD.

For more information on this topic and other links, visit this Web site: www.johnes.org/zoonotic/index.html.