A doctor examines the x-rays of a tuberculosis (TB) patient at a TB clinic Novmeber 27, 2002, in Brooklyn, New York. (Photo by Spencer Platt/Getty Images)
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Here’s a look at Tuberculosis (also known as TB), an infection, caused by a bacterium called Mycobacterium tuberculosis, that usually affects the lungs. It can also infect other parts of the body including the kidneys, spine and brain.

About TB

Two types of TB exist - Latent TB infection (non-infectious) and TB disease (infectious).

Latent TB infection:
- A person infected with latent TB shows no symptoms and may not feel sick.
- A skin or blood test will indicate if a person has been infected with the bacteria.
- It is not possible to spread TB bacteria from the infected person to others.
- Individuals with a latent TB infection may never develop the disease, as bacteria remains dormant. In other cases, especially involving people with a weak immune system, the bacteria may become active and cause TB disease.
- Treatment is required to ensure the infected person does not develop active TB disease but in some cases preventative treatment may not be an option.
- Without treatment, about 5-10% of individuals infected with latent TB will develop the disease.

TB disease:
- Symptoms of TB of the lungs include coughing up blood and chest pain.
- Other symptoms include weight loss, night sweats, fever, chills and fatigue.
- It is possible to spread TB bacteria from the infected person to others.
- A skin or blood test will indicate if a person has been infected with the bacteria.
- Treatment typically involves a combination of drugs taken for six months.
- Persons with a weak immune system, such as those with HIV or diabetes, are more prone to catching TB disease.


TB spreads through the air when a person with an active TB infection coughs, sneezes, speaks or sings. Germs can stay in the air for hours.

In 2021, about 10.6 million people worldwide became ill with TB, and 1.6 million died (including 187,000 with HIV).

In 2022, a total of 8,3000 new TB cases were reported in the United States.

Up to 13 million people in the United States are living with latent TB.


1546 - Italian scientist Girolamo Fracastoro hypothesizes that TB is contagious.

1679 - Dutch scientist Francis Sylvius details the impact of TB on patients.

1865 - French military doctor Jean-Antoine Villemin proves the illness can transmit from human to animal or from animal to animal.

1882 - German doctor Robert Koch identifies the bacterial strain as Mycobacterium tuberculosis.

1800s - Tuberculosis causes as much as one-quarter of all deaths in Europe during the 19th century. Famous people who die from tuberculosis include John Keats, Frédéric Chopin, Charlotte, Emily and Anne Bronte, Anton Chekhov and Franz Kafka.

1921 - After years of trials involving animal testing, French bacteriologists Albert Calmette and Camille Guérin successfully administer a vaccine called Bacille Calmette-Guerin (BCG) in an infant whose mother died of TB.

1930 - In Germany, more than 70 infants who received the BCG vaccine die of TB. It is later concluded that the vaccine was contaminated in the lab.

1944 - Microbiologist Selman A. Waksman and his associates at Rutgers University report the discovery of a new antibiotic called streptomycin.

1944 - Physicians H. Corwin Hinshaw, Karl H. Pfuetze and William H. Feldman successfully use streptomycin to treat a patient with TB.

1952 - A scientific journal publishes studies heralding the success of a breakthrough treatment called isoniazid.

1985-1992 - Tuberculosis makes a resurgence. Scientists attribute this to several factors, including the spread of HIV.

1994 - The World Health Organization declares tuberculosis a global emergency.

1995 - The WHO launches Directly Observed Therapy Short-Course (DOTS). It is a treatment plan containing five components, including standardized recording and reporting.

2008 - The WHO reports the highest rates of MDR-TB worldwide.

December 8, 2010 - The WHO endorses a new test that diagnoses tuberculosis within hours instead of months.

2018 - A promising new vaccine called M72/AS01E is shown to be effective in many people already infected with TB.

2021 - A study concludes that a four-month multidrug regimen to treat TB is as effective as a six-month regimen.