Measles is mono-directional. Tuberculosis is different in that the timing is very different. After exposure, the infectious period could range from a few weeks to a few months to years. Host immune response does not eliminate the pathogen. TB replicates in the lungs.
Pulmonary damage is a requisite for infectious quality.
There is a case of a patient who had infectious TB for 41 years. TB is bi-directional. A gym teacher was a heavy smoker with a smoker's hack. This cough disguised the fact that he had tuberculosis. Centuries Tuberculosis in the 19th Century TB is steady, unlike cholera, which peaks.