Tuberculosis - Statistics & FactsTuberculosis, or TB, is an infectious disease that usually affects the lungs, but can potentially spread to other areas of the body, including the brain and spine. There are two types of TB, latent TB and active TB. With latent TB, bacteria remain in the body, but are inactive. People with latent TB show no symptoms and are not contagious, but there remains about a ten percent chance that the disease will become active. With active TB, the disease does cause symptoms and is contagious through the air. Common symptoms of TB include coughing, weight loss, fever, chest pain, fatigue, and night sweats.