A recent study challenged the earlier belief that tuberculous infection stays forever and that it could come back at any point and cause the disease again. Based on a review of clinical studies researchers from the Perelman School of Medicine at the University of Pennsylvania and colleagues show that people who test positive with immunologic TB skin or blood tests rarely develop TB. They suggest it's because the infecting organism Mycobacterium tuberculosis is likely dead wiped out naturally by people's immune systems. Despite that these people retain an immunological memory to the disease which the authors said likely explained why