Exogenous Reinfection in Tuberculosis

Tuberculosis, like all infectious diseases, involves exposure to a pathogen resulting in an asymptomatic period of incubation or latency that may progress to active disease. Unlike most other infectious diseases, tuberculosis involves a delay between infection and disease that is extremely variable, ranging from a few weeks to a lifetime. Therefore, the development of active tuberculosis in someone known to have been previously infected raises the question whether this represents a recrudescence of the initially infecting organism (endogenous reactivation) or a new strain of Mycobacterium tuberculosis (exogenous reinfection).For decades, this question has been central to a debate in which . . .