After the first infection with Mycobacterium tuberculosis, the majority of people usually have no symptoms and do not develop tuberculosis. The following people are susceptible to tuberculosis: 1) people who have not been infected with Mycobacterium tuberculosis; 2) people who have been in close contact with patients with bacillary tuberculosis; 3) people with AIDS, diabetes, or long-term immunosuppressive drugs; 4) people with acromegaly and other obstructive respiratory diseases. TB is a chronic infectious disease, not a genetic disease, so TB is not hereditary; some families have several TB patients at the same time, mainly as a result of mutual transmission of infectious TB patients in the family, not heredity.