About Tuberculosis (TB)

Tuberculosis, or more commonly known as TB, is caused by a bacterium called Mycobacterium tuberculosis. This bacterium typically attacks the lungs, but TB bacteria can also affect other parts of the body such as the brain, spine, and kidneys. Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection (LTBI) and TB disease.

Latent TB Infection (LTBI)

Latent tuberculosis infection (LTBI) is the presence of Mycobacterium tuberculosis (M. tuberculosis) in the body without signs and symptoms, or radiographic or bacteriologic evidence of tuberculosis (TB) disease. Persons with LTBI do not have active TB disease, but may develop it in the future, a process called TB reactivation.

Without treatment, about 1 in 10 people with LTBI will develop TB disease. About half of those who develop TB will do so within the first two years of infection.


The diagnosis of LTBI is based on a positive result of either a skin (tuberculosis skin test, TST) or blood (Interferon-gamma release assay, IGRA) test indicating an immune response to M.tuberculosis

Signs and Symptoms

  • People with LTBI are healthy and usually do not feel sick.
  • They typically have a positive skin test or blood test result
  • They typically have a negative (normal) chest x-ray
  • They cannot spread TB bacteria to others


It is important to provide preventative treatment to persons with LTBI to prevent the development of active disease. The CDC recommends one of the following 3 treatment regimens for LTBI.

  • Rifampin (RIF) daily for 4 months
  • Isoniazid (INH) daily or twice weekly for 9 months
  • Isoniazid (INH) and Rifapentine (RPT) once weekly for 3 months




TB Disease

How is it transmitted?

Tuberculosis is an airborne disease, spread through the air from person to person when someone who has contracted TB of the lungs or throat sneezes, coughs, speaks, or sings. People in close proximity to these particles in the air may breathe them in and also become infected.

TB CANNOT spread by:

  • shaking hands
  • sharing foods or drinks
  • bedding or toilet seats
  • sharing toothbrushes or other personal hygiene items
  • kissing or oral sexual contact

Signs and symptoms

Symptoms of TB include:

  • a strong, persistent cough lasting 3+ weeks
  • chest pains
  • coughing up blood or sputum
  • fatigue
  • weight loss
  • fever
  • weakness
  • night sweats & chills
  • loss of appetite


Those suffering from Tuberculosis can be treated by taking several drugs for the duration of 6 to 9 months. There are 10 drugs currently approved by the U.S. Food and Drug Administration (FDA) for treatment of TB.


In the Workplace:

Many healthcare settings have TB infection control plans that include early detection of infectious patients, precautions to avoid spread of airborne particles, and treatment of those people who have suspected or confirmed cases of TB.

While Traveling:

Travelers should avoid being in close proximity for a prolonged period of time with known TB positive patients. Particularly in crowded, enclosed environments such as hospitals, homeless shelters, prisons, or clinics.

Travelers who will be working in or spending much time in hospitals, clinics, or other health care settings where TB patients are likely to be in close contact, should refer to the facility’s infection control or occupational health regulations and consult with the experts on site to review environmental and administrative prevention procedures. Once those strategies are executed, additional precautions may include use of personal respiratory protective devices.

Travelers who anticipate potential, prolonged contact with those who have TB should receive a Tuberculin Skin Test (TST) or Interferon-Gamma Release Assay (IGRA) test before leaving the United States. If the test reaction is negative, they should have a repeat test 8 to 10 weeks once they’ve returned to the United States. Furthermore, yearly testing could be suggested for those who anticipate repeated or prolonged exposure or an extended stay over a period of years.

If you think you have TB or have been in close contact with someone who has confirmed TB disease, please contact Student Health Service 215-746-3535 and select the option to speak with a nurse.



Back to Disease Updates

(updated 9/20/2019)