Pathogenesis of Crohn’s disease: Bug or no bug

The possibility of an infectious origin in inflammatory bowel disease (IBD) has been postulated since the first description of Crohn's disease (CD). Many observations implicate bacteria as a trigger for the development of CD: lesions occur in regions with higher bacterial concentrations; aphthous ulcers occur in Peyer's patches; inflammation resolves when the fecal stream is diverted and is reactivated following reinfusion of bowel contents;...