What is the difference between being infected with TB and having TB disease?
TB Infection (Latent TB) means that the bacteria are inside your body but they are not active. Typically, these people have strong immune systems and consequently, never have TB symptoms nor develop the disease. What’s more, they do not pass the disease on to other people. People with TB infection usually have positive skin test reactions and can develop the active disease at any point if they do not receive preventative therapy. TB Disease (Active TB) means that the bacteria are actively multiplying in your body and your immune system is immobilized to the disease. People with TB disease have symptoms and can pass the disease on to others. Consequently, TB disease must be treated, cured and of course prevented, when possible, as it can be fatal.
People infected with TB have inhaled the TB bacteria and will typically show a positive TB skin test; they cannot spread the infection to others and do not feel sick. Without treatment, only about 10% of people infected with TB will eventually progress to TB disease of the lungs, at which point they will be able to spread the infection to others and typically develop a bad cough lasting at least 3 weeks, chills, fever, night sweats and weight loss. With appropriate treatment, less than 1% of infected people progress to TB disease.
