Tuberculosis

Tuberculosis (TB) is an infectious disease caused by bacteria. In the past, people called it consumption.

Tuberculosis
Classification and external resources
Chest X-ray of a person with advanced tuberculosis. White arrows point to infection in both lungs. Black arrows point to a cavity that has formed.
ICD-10A15.A19.
ICD-9010018
OMIM607948
DiseasesDB8515
MedlinePlus000077
eMedicinemed/2324
MeSHD014376
Public health campaigns in the 1920s tried to halt the spread of TB.

TB is caused by several types of mycobacteria, usually Mycobacterium tuberculosis.[1] The disease usually attacks the lungs, but it can also affect other parts of the body.

How it spreads

The bacteria can travel through the air and spread from one person to the next. This happens when infected people cough, sneeze, or spit.[2]

Of every 100 people with TB, between five and ten people show symptoms.[3] In these people, the disease is called active. Tuberculosis kills more than half of the people who are infected if they do not get treatment.

Detection and treatment

 
A close up of a culture of Mycobacterium tuberculosis. The patches that look like foam are the typical growth pattern of these bacteria

Diagnosis of active TB relies on radiology. Doctors often look at an X-ray of the chest. In addition, they check body fluids. These fluids have microbes in them, which are grown in cell cultures. The cell cultures are then analysed to see if the person is infected with TB.

If the patient has TB, but does not show symptoms, the disease is 'latent'. Doctors use a skin test, called the Mantoux test, to detect latent TB. They often do blood tests too.

There is a vaccine against some forms of tuberculosis. It is called the Bacillus Calmette–Guérin vaccine.

TB used to be easily treated and cured with antibiotics. However, the bacterium is now highly resistant to most antibiotics. This resistance makes treatment difficult. Many different kinds of antibiotics need to be given over a long period of time. There is a form of tuberculosis that is resistant to all drugs.

Symptoms

Tuberculosis can have many symptoms. The most common include:

How common is TB?

 
This world map shows the prevalence of TB, per 100,000 people, as of 2016. Countries with more cases are shown in darker colors, those with fewer cases are shown in lighter colors. The most cases were recorded in Southeast Asia and Sub-Saharan Africa.[4]

Experts believe that one third of the world population is infected with M. tuberculosis.[5] New infections occur at a rate of one per second.[5] In 2007, about 13.7 million chronic cases were active globally.[6] In 2010, about 8.8 million new cases developed and nearly 1.5 million people died from the disease, most of them in developing countries.[7] The number of tuberculosis cases has been decreasing since 2006, and new cases have decreased since 2002.[7]

Tuberculosis does not happen at the same rate around the world. About eighty percent of the population in many Asian and African countries test positive for TB, but only five to ten percent of people in the United States do.[1]

People usually get tuberculosis because of a weakened immune system. Many people with HIV and AIDS can also get tuberculosis.[8]

Tuberculosis Media

References

  1. 1.0 1.1 Kumar V. et al 2007 (2007). Robbins basic pathology (8th ed.). Saunders Elsevier. pp. 516–522. ISBN 978-1-4160-2973-1.
  2. Konstantinos A (2010). "Testing for tuberculosis". Australian Prescriber. 33 (1): 12–18. doi:10.18773/austprescr.2010.005.
  3. Evidence-based respiratory medicine. Malden, Mass.: BMJ Books/Blackwell Pub. 2005. ISBN 978-0-470-98737-7. OCLC 181343640.
  4. "Tuberculosis (TB)". WHO. Retrieved 20 February 2023.
  5. 5.0 5.1 "Tuberculosis Fact sheet N°104". World Health Organization. November 2010. Retrieved 26 July 2011.
  6. World Health Organization (2009). "Epidemiology" (PDF). Global tuberculosis control: epidemiology, strategy, financing. pp. 6–33. ISBN 978-92-4-156380-2. Retrieved 12 November 2009.[dead link]
  7. 7.0 7.1 World Health Organization (2011). "The sixteenth global report on tuberculosis" (PDF).
  8. Lawn, Stephen D.; Zumla, Alimuddin I. (2011). "Tuberculosis". Lancet. 378 (9785): 57–72. doi:10.1016/S0140-6736(10)62173-3. PMID 21420161. S2CID 208791546.

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