Positive TB is contagious. Positive TB refers to positive sputum bacteria. Sputum includes two types of tests: one is a positive sputum smear test for Mycobacterium antacidum; the other is a positive sputum culture for Mycobacterium tuberculosis. Both of these positive conditions indicate positive sputum bacteria, and TB is infectious and requires anti-tuberculosis treatment. Patients with TB who have sputum can cough, sneeze, laugh or talk and spread microscopic droplets of Mycobacterium tuberculosis into the air, where they can remain for several hours and can be infected when inhaled by others. It is important to keep a certain distance from people with tuberculosis and to wear a mask as an effective way to stop transmission. TB patients should also cover their mouths and noses when coughing or sneezing to avoid infecting others.