What is Tuberculosis (TB)?

Tuberculosis (TB) is  an infection caused by a bacterium called Mycobacterium tuberculosis. It mainly affects the lungs, but it can affect any part of the body, including the tummy (abdomen), glands, bones and nervous system. 

How is it spread?

TB is spread when a person with active disease in their lungs coughs or sneezes and someone else inhales the expelled droplets, which contain TB bacteria.

Although TB is spread in a similar way to a cold or flu, it is not as contagious. TB infections usually spread between family members who live in the same house. 

Who is most at risk?

Anyone can get TB, but those most at risk include people:

  • who live in, come from, or have spent time in a country or area with high levels of TB
  • in prolonged close contact with someone who is infected
  • living in crowded conditions
  • with a condition that weakens their immune system, such as diabetes
  • on immunotherapy treatments 
  • who are very young or very old as their immune systems tend to be weaker than those of healthy adults
  • in poor health or with a poor diet because of lifestyle and other problems, such as drug misuse, alcohol misuse, or homelessness


The symptoms of tuberculosis (TB) vary depending on which part of the body is affected. The disease usually develops slowly, and it may take several weeks before you notice you are unwell.

Symptoms might not begin until months or even years after you became infected. Sometimes the infection does not cause any symptoms. This is known as latent TB. If you have symptoms, it is called active TB; however,  in some cases, symptoms might not develop until months or even years after the initial infection.

Common symptoms 

  • lack of appetite and weight loss
  • a high temperature
  • night sweats
  • extreme tiredness or fatigue

(Note: These symptoms can have many different causes  and are not always a sign of TB).

Symptoms of TB that affects the lungs (pulmonary TB)

Most TB infections affect the lungs, which can cause:

  • a persistent cough that lasts more than 3 weeks and usually brings up phlegm, which may be bloody
  • progressive breathlessness 

Symptoms of TB outside the lungs

TB infections develop  outside the lungs, (e.g. in the lymph nodes,  bones and joints, digestive system, the bladder and reproductive system, and  nervous system. TB affecting other parts of the body is more common in people who have a weakened immune system. Symptoms can include:

  • persistently swollen glands
  • abdominal pain
  • pain and loss of movement in an affected bone or joint
  • confusion
  • a persistent headache
  • fits (seizures)


Treatment for TB usually involves taking antibiotics for several months. Most people do not need to be admitted to hospital during treatment. Although TB is a serious condition that can be fatal if left untreated, deaths are rare if treatment is completed.

Preventing the spread 

If you have been diagnosed with pulmonary TB, you will be contagious up to about 2 to 3 weeks into your course of treatment.

You will not usually need to be isolated during this time, but it is important to take some basic precautions to stop the infection from spreading to your family and friends. Thse include:

  • staying away from work, school or college until your GP/nurse advises you that it is safe to return 
  • covering your mouth , preferably with a disposable tissue when coughing, sneezing or laughing
  • carefully disposing of any used tissues in a sealed plastic bag 
  • opening windows when possible to ensure a good supply of fresh air in the areas where you spend time
  • not sleeping in the same room as other people