“Crohn’s disease” – regional ileitis. With L. Ginzburg and G. D. Oppenheimer.

"Some of Crohn's initial research into the causes of the Crohn's disease was centered around his personal convictionthat it was caused by the same pathogen, a bacterium called Mycobacterium paratuberculosis (MAP), responsible for the similar condition that afflicts cattle called Johne's disease. However, he was unable to isolate the pathogen—most likely because M. paratuberculosis sheds its cellular wall in humans and takes the form of a spheroplast, making it virtually undetectable under an optical microscope. This theory has resurfaced in recent years and has been lent more credence with the arrival of more sophisticated methods of identifying MAP bacteria" (Wikpedia article on Burill Crohn, accessed 1-2020).

"While the causes of Crohn's disease are unknown, it is believed to be due to a combination of environmental, immune, and bacterial factors in genetically susceptible individuals.^[6][7][8][2] It results in a chronic inflammatory disorder, in which the body's immune system attacks the gastrointestinal tract, possibly targeting microbial antigens.^[7][9] While Crohn's is an immune-related disease, it does not appear to be an autoimmune disease (in that the immune system is not being triggered by the body itself).^[10] The exact underlying immune problem is not clear; however, it may be an immunodeficiency state.^[9][11][12] About half of the overall risk is related to genetics with more than 70 genes having been found to be involved.^[1][13] Tobacco smokers are twice as likely to develop Crohn's disease as nonsmokers.^[3] It also often begins after gastroenteritis.^[1] Diagnosis is based on a number of findings including biopsy and appearance of the bowel wall, medical imaging and description of the disease.^[1] Other conditions that can present similarly include irritable bowel syndrome and Behçet's disease.^[1] "(Wikipedia article on Crohn's disease, accessed 1-2020).