Tuberculosis is not a viral infection, but a bacterial infection. The causative agent of tuberculosis is Mycobacterium tuberculosis, which can be spread through respiratory droplets. When a person with TB coughs, sneezes, talks, or laughs, droplets of Mycobacterium tuberculosis can be spread into the air, where they can live for several hours and be inhaled by others at risk of infection. Droplets of Mycobacterium tuberculosis can also adhere to dust and objects, and clothing and books can also be contaminated. A large number of germs can be found in the sputum of TB patients, and they can survive for 6-8 months in dry sputum. The main clinical symptoms of tuberculosis are fever, cough, chest tightness, chest pain, as well as weakness and night sweats.