Tuberculosis: TB disease and latent TB infection

Tuberculosis (TB) is primarily an airborne disease caused by the bacteria Mycobacterium tuberculosis, which are spread person-to-person through the air. This bacteria mainly affects the lungs, but may adversely affect other organs.

Individuals who are exposed to TB often do not feel sick or present any symptoms. These individuals are not contagious at this point, unless their infection persists into active TB disease. At this point the bacterium can be spread through microscopic droplets as the patient sneezes, coughs, talks, or otherwise projects contaminated sputum/saliva from their body. People nearby may breathe in these bacteria and become infected as the bacteria can stay in the air for several hours.

As a top infectious disease, current estimates are that TB infects nearly two billion people or about one-third of the world population. These infected, non-disease active people are considered latent TB cases. This means that people are infected with TB bacteria, but are not yet ill or active cases. Infected people have a lifetime risk of 10 percent to falling ill to TB.

According to the World Health Organization, in 2014 9.6 million people had developed active TB illness and 1.5 million died from the disease. During 2014, the CDC reported that 9,421 active TB cases were recorded within the United States. There were 108 cases of TB disease in Indiana in 2014.


  • TB is spread primarily through the air.
  • Bacteria is spread person-to-person in droplets as a TB sufferer sneezes, coughs, or talks.
  • Bacteria must be active in TB sufferers in order to spread.


  • Chronic or debilitating cough (that lasts 3 weeks or longer)
  • Pain in the chest
  • Coughing up bloody sputum (saliva)
  • Weight loss
  • Fever
  • Night sweats
  • Loss of appetite

Populations that are at the highest risk for TB include: children under five, people with an HIV infection, the immunocompromised, people who were recently exposed, and people with certain medical conditions. If you think you may have TB, see your health care provider for testing.



To prevent exposure to TB:

  • Limit contact with active TB patients.
  • Promptly detect active cases.
  • Seek proper treatment and patient care.
  • Maintain adequate ventilation in enclosed spaces.


Many strains of TB are classified as drug resistant and require special medications. Accounting for this, active TB patients often have to take a series of medications for numerous months to eradicate the infection and prevent reinfection. Treatment includes:

  • Regimental antibiotic drugs (for 6 months to 12 months)
  • Multi-drug-resistant (MDR) TB may require special TB drugs.
  • Completion of entire treatment cycle is vital to eradicate and prevent reinfection.

Indiana University response to TB

Due to the nature of the disease, active tuberculosis cases are taken very seriously at Indiana University. Cases are reported by law to the Indiana Department of Health. IDOH works with the university to control confirmed cases and to identify suspected cases.

Active tuberculosis cases and suspects are isolated until they are no longer infectious. They are excluded from campus and other congregate areas, which helps reduce the risk of transmission to others. Close contacts are identified and tested for tuberculosis. Additionally, other associated contacts, such as classmates and coworkers, are identified, contacted, and also offered testing.

Indiana University’s policy of the Management of Infectious and Communicable Disease (PS-EHS-03) is designed to minimize and control infectious diseases, like TB, on our campuses.

Additional resources