All infectious diseases are prevalent in the population and require three basic components: the source of infection, the transmission route and the susceptible person, and tuberculosis is no exception. The source of infection is TB patients with TB bacilli in their sputum. The main transmission route is airborne, followed by dietary transmission and mother-to-child transmission. Tuberculosis is caused by the invasion of Mycobacterium tuberculosis into the body. However, not all TB patients can transmit their own TB bacilli to others, but only if they are able to expel the bacilli from their bodies. Therefore, only patients who excrete the bacillus from their bodies are likely to pass the bacillus into the air and infect people around them. Airborne transmission of tuberculosis can occur through droplet transmission and dust transmission. When a tuberculosis patient coughs, sneezes or speaks loudly, very small sputum containing bacteria is ejected from the patient’s mouth, and this very small sputum is called droplets. The droplets containing bacteria can stay in the air for a long time. At this time, if a healthy person is very close to the patient, it is possible to inhale the droplets containing bacteria into the lungs and be infected, this infection is called droplet infection. The more bacteria, the longer the contact time, the greater the danger. In addition, if the patient spits out the sputum containing bacteria on the ground, after the sputum dries, the tuberculosis bacilli will be attached to the dust, and when it is windy or when cleaning the ground, the dust containing bacteria will fly up. If you breathe it into your lungs, you may be infected, and this infection is called dust infection. However, it is not the main mode of transmission. Since the above infections occur through the respiratory tract, they are collectively referred to as respiratory infections.