Tuberculosis is only an infectious disease and is not inherited through DNA. If someone in the previous generation had TB disease and someone in the next generation or alternate generations gets it, this does not mean that it is hereditary, but only that the disease manifests itself after a certain period of time due to prolonged contact with the patient and being infected with large amounts of TB bacteria. TB infection and TB disease are two very different concepts. If a person is diagnosed with TB infection, it only means that the patient has TB bacteria in his body, but these bacteria have not caused lesions in tissues and organs; whereas if TB disease is diagnosed once, it means that the patient has developed lesions in his body. At the same time, being infected with TB bacilli does not necessarily mean that one will develop the disease; only a small percentage of the large number of people who are infected with TB bacilli will develop the disease.