is caused by the tubercle bacillus, Mycobacterium tuberculosis. It primarily affects the
lungs.There are two kinds of tuberculosis infection: latent and active. In latent TB, the TB bacteria remain in the body in an inactive state. They cause no symptoms and are not contagious, but they can become active. In active TB, the bacteria do symptoms and can be transmitted to others.
According to the World Health Organization (WHO), it’s one of the top 10 causes of death worldwide, killing 1.7 million people in 2016.