Tuberculosis is mainly caused by Mycobacterium tuberculosis and is a chronic infectious disease. Tuberculosis bacteria can theoretically invade all organs of the body and can be seen in basically all organs except for hair and nails, which are rare, but mainly involve the lungs. Common symptoms are coughing and sputum, which may be accompanied by blood in the sputum, low fever, night sweats, afternoon fever, chest pain, fatigue, weight loss, and difficulty in breathing, etc. When tuberculosis is suspected, you should go to the local designated medical institution for tuberculosis promptly. The source of TB infection is mainly sputum smear-positive TB patients, who spread droplets containing TB bacteria into the air mainly by coughing, sneezing or talking loudly. Healthy people who inhale aerosols or droplets containing tuberculosis bacteria may become infected, but the onset of infection is not necessarily influenced by the virulence of the tuberculosis bacteria and the body’s immunity. When the virulence of the tuberculosis bacillus is strong and the immunity of the body is low, tuberculosis is likely to occur.