Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis bacteria. The bacteria usually attack the lungs, but can also affect other parts of the body, including the kidney, spine, and brain. If not treated properly, TB can be fatal. TB is spread from person to person through the air when someone with active TB coughs or sneezes. People nearby breathe in the bacteria and become infected. However, not everyone infected with the bacteria becomes sick. Those who are infected with the bacteria but do not get sick have what is called latent TB infection. People who have latent TB do not feel sick, do not have any symptoms, and cannot spread TB to others. However, latent TB can turn into active TB. Symptoms include weakness, weight loss, fever, night sweats, chest pain, coughing, and coughing up blood. Active TB can be treated with medications, however, however there are drug-resistant strains. People with latent TB infection can take medicine so that they will not develop active TB disease.