How is it Spread?
TB is spread when someone who has TB coughs, sneezes, laughs, sings or even talks loudly and contaminates the air with tiny droplets that contain live germs. If such droplets are then breathed in by someone else, that person becomes "infected". Tuberculosis is most commonly spread when people are together in small, enclosed spaces that have poor ventilation. The TB germs must be breathed in from the air; you cannot get TB by touching things like door knobs or sharing food and utensils.
Being "infected" does not mean that you have active TB. People may remain well for many years while the TB germs remain in an inactive state. Active TB disease usually develops over a period of several months or even years, often when the immune system is weakened (for example, the elderly or those with HIV). When TB is not active, it cannot be spread to others. The only way to know if you have become infected is to be tested.