Q. What is tuberculosis?

Tuberculosis is an infectious bacterial disease caused by Mycobacterium tuberculosis, which is transmitted among humans through the respiratory route and most commonly affect the lungs but can damage any organ.1

Q. What are the organs most affected by tuberculosis?

Tuberculosis (TB) is a human disease caused by Mycobacterium tuberculosis. It mainly affects the lungs, making the pulmonary disease the most common presentation. Other commonly affected organ systems include the gastrointestinal (GI) system, the lymphoreticular system, the skin, the central nervous system, the musculoskeletal system, the reproductive system, and the liver.2

Q. What Are the Symptoms of TB?

Symptoms of active TB include a cough that lasts more than three weeks, loss of appetite and unintentional weight loss, Fever, Chills & Night sweats. Coughing up blood in sputum is a sign of TB of the lungs. However, these symptoms are also an indicator of other diseases, so it is important to see a physician. If you think you have been exposed to TB, get yourself tested at drdangslab.3

Q. What are the 3 stages of TB?

There is a difference between being infected with the TB bacterium and having active tuberculosis disease. There are 3 stages of TB—exposure, latent, and active disease. The following are the stages of TB:
Exposure:- This happens when a person has been in contact with or exposed to, another person who has TB. The exposed person will have a negative skin test, a normal chest X-ray, and no signs or symptoms of the disease.
Latent TB infection:- This happens when a person has TB bacteria in his or her body but does not have symptoms of the disease. The infected person's immune system walls off TB bacteria, and the TB remains inactive throughout life in most people who are infected. This person would have a positive skin test, but a normal chest X-ray.
TB disease:- This describes the person who has signs and symptoms of an active infection. The person would have a positive skin test and a positive chest X-ray.4

Q. How do you get TB?

TB bacteria are spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, speaks, or sneezes. People nearby may breathe in these bacteria and become infected. When a person breathes in TB bacteria, the bacteria can settle in the lungs and can also move through the blood to other parts of the body, such as the kidney, spine, and brain. TB disease in the lungs can be infectious. This means that the bacteria can spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious. People with TB disease are most likely to spread it to people they spend time with every day. This includes family members, friends, and coworkers or schoolmates.5

Q. Is there a vaccine for tuberculosis?

Most commonly available vaccine is Bacillus Calmette-Guérin (BCG). Research data suggests that in children BCG decreases the risk of getting the infection by 20% and the risk of infection turning into the active disease by nearly 60%. It is the most widely used vaccine worldwide, with more than 90% of all children being vaccinated. Intradermal MVA85A vaccine and BCG injection are not effective in preventing tuberculosis.6

Q. What Is the Diagnosis of TB?

Primarily, the skin test is done by injecting a small amount of fluid called tuberculin into the skin of the forearm. You will be asked to return 48 to 72 hours to have a healthcare worker check the arm to see if the skin's bump or induration (thickening) has developed. The healthcare worker will measure the bump or induration and tell you if your reaction to the test is positive or negative. If it's positive, it usually means you have been infected with the TB bacteria. It does not tell whether you have developed clinically active TB disease. However, the skin test isn’t 100% accurate, you may have a false positive or a false-negative result.
The TB blood test measures how your immune system reacts to the germs that cause TB. This information will be used to confirm or rule out latent or active TB more precisely. It requires only one Lab visit.
If the skin or blood tests indicate the need for further analysis, your doctor may order a chest X-ray or CT scan to look for visible signs of TB in your lungs. They may also check your sputum (coughed-up mucus) for bacteria, to see whether you have clinically active TB disease and if so, which strain of TB you have.6,7

Q. What are the factors responsible for the re-emergence of tuberculosis?

Tuberculosis (TB) is re-emerging as a major public health problem worldwide. The emergence of multidrug resistance and the interaction between TB and HIV infection are responsible for this surge. Before the HIV epidemic, the risk of TB infection in developing countries fell 1-5% per year. The HIV epidemic has reversed this trend. Treatment failures or relapses due to disorganized treatment programs account for most of the multidrug resistance cases.8

Q. What is bone TB and what is the cure for bone tuberculosis?

Bone TB occurs after tuberculosis bacteria travels through the blood from the lungs or lymph nodes into the bones, spine, or joints. It is relatively rare, however, in the past few decades, the prevalence of Bone TB has increased in developing nations partially due to the spread of AIDS. Antituberculosis medications, such as rifampicin, isoniazid, ethambutol, and pyrazinamide are the first line of treatment for bone tuberculosis, and the course of treatment can vary from 6- 18 months.9

Q. What are the various tests for TB?

Dr. Dangs Lab provides a wide range of tests to diagnose TB: -

Diagnostic tests

  • Rapid AFB Smear and Culture
  • GeneXpert MTB/RIF Ultra assay
  • Fine Needle Aspiration
  • Mantoux tuberculin skin test
  • TB Blood test (Interferon-Gamma Releasing Assays (IGRAs))

MDR-TB diagnostic technology

  • MOLECULAR DST (Eg. GeneXpert or Line probe assay (LPA))

Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but they can also damage other parts of the body. TB spreads through the air when a person with TB of the lungs or throat coughs, sneezes, or talks. Symptoms of TB in the lungs may include a bad cough that lasts 3 weeks or longer, weight loss, loss of appetite, coughing up blood in sputum, weakness or fatigue, fever, and night sweats. Skin tests, blood tests, x-rays, and other tests can tell if you have TB. If not treated properly, TB can be fatal.
Publisher’s name- Dr. Dangs Lab

References :
  1. Bloom BR, Atun R, Cohen T, et al. Major Infectious Diseases. 3rd ed. Washington (DC): The International Bank for Reconstruction and Development / The World Bank; 2017 Nov 3. Chapter 11. PMID: 30212088.
  2. Adigun R, Singh R. Tuberculosis. [Updated 2021 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from:
  3. Tuberculosis Symptoms and Diagnosis. Available at
    https://www.lung.org/lung-health-diseases/lung-disease-lookup/tuberculosis/symptoms-diagnosis, accessed on 21/12/21
  4. Tuberculosis (TB). Available at
    https://www.hopkinsmedicine.org/health/conditions-and-diseases/tuberculosis-tb, accessed on 21/12/21.
  5. TB. Available at
    https://www.cdc.gov/tb/topic/basics/howtbspreads.htm, accessed on 21/12/21
  6. Tuberculosis. Available at
    https://en.wikipedia.org/wiki/Tuberculosis, accessed on 12/21/21.
  7. Tuberculosis Symptoms and Diagnosis. Available at
    https://www.lung.org/lung-health-diseases/lung-disease-lookup/tuberculosis/symptoms-diagnosis, accessed on 21/12/21
  8. Porter JD, McAdam KP. The re-emergence of tuberculosis. Annu Rev Public Health. 1994;15:303-23.
  9. Bone Tuberculosis. Available at
    https://www.healthline.com/health/bone-tuberculosis, accessed on 6/1/2022

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion.

Related Articles
  1. Bloom BR, Atun R, Cohen T, Dye C, Fraser H, Gomez GB, Knight G, Murray M, Nardell E, Rubin E, Salomon J, Vassall A, Volchenkov G, White R, Wilson D, Yadav P. Tuberculosis. In: Holmes KK, Bertozzi S, Bloom BR, Jha P, editors. Major Infectious Diseases. 3rd ed. Washington (DC): The International Bank for Reconstruction and Development / The World Bank; 2017 Nov 3. Chapter 11. PMID: 30212088.
  2. JOUR, Pai, Madhukar, Behr, Marcel A, et al. Tuberculosis. Nature Reviews Disease Primers(2016) . 2(1): 16076.
  3. Shruthi Ravimohan, Hardy Kornfeld, Drew Weissman, Gregory P. Bisson. Tuberculosis and lung damage: from epidemiology to pathophysiology. European Respiratory Review Mar 2018, 27 (147) 170077; DOI: 10.1183/16000617.0077-2017
  4. World Health Organization: The 2021 edition of the Global Tuberculosis Report was published on 14 October 2021
    (https://www.who.int/teams/global-tuberculosis-programme/tb-reports OR https://www.who.int/teams/global-tuberculosis-programme/data)
  5. Nathavitharana RR, Fiedland J, A tale of two global emergencies: tuberculosis control efforts can learn from the Ebola outbreak. Eur Respir J. 2015; 46: 293-336.