Tuberculosis

Tuberculosis ( , also ; TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. Tuberculosis initially infects the lungs, but it can also spread to other parts of the body. Most infections show no symptoms, in which case tuberculosis is considered to be inactive or latent. A small proportion of latent infections progress to active disease that, if left untreated, can be fatal. Typical symptoms of active TB are chronic cough with blood-containingmucus, fever, night sweats, and weight loss. Infection of other organs can cause a wide range of symptoms.

Tuberculosis is spread from one person to the nextthrough the air when people who have active TB in their lungs cough, spit, speak, or sneeze. People with latent TB do not spread the disease. A latent infection is more likely to become active in individuals with weakened immune systems. There are three principal tests for TB: the interferon-gamma release assay (IGRA), the tuberculin skin test, and the nucleic acid amplification test (NAAT).

Prevention of TB involves screening those at high risk, early detection and treatment of cases, and vaccination with the bacillus Calmette-Guérin (BCG) vaccine. Those at high risk include household, workplace, and social contacts of people with active TB. Treatment requires the use of multiple antibiotics over a long period of time.

It is estimated that one-quarter of the world's population, approximately 2 billion people, have latent TB. In 2024, TB incidence reached an estimated 10.7 million people and caused 1.23 million deaths, making it the leading cause of death from a single infectious agent worldwide.

Tuberculosis has been present in humans since ancient times. In the 1800s, when it was known as consumption, TB was responsible for an estimated quarter of all deaths in Europe. Both the incidence (new cases) and prevalence (total cases) of TB declined significantly during the 20th century, attributed to improved sanitation, the discovery of effective antibiotics, and the introduction of the BCG vaccine. However, since the 1980s, antibiotic resistance has become a growing phenomenon, which led to a higher incidence of multidrug-resistant tuberculosis.