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Tuberculosis (TB) is an infection caused by slow-growing bacteria that grow best in areas of the body that have an abundance blood and oxygen.


Lungs have an abundance of blood and oxygen and for that reason TB is most often found in the lungs. This is called respiratory TB. TB can also spread to other parts of the body, and this is called non-respiratory TB. 

Treatment is often a success, but it is a long process that takes about 6 to 9 months of treatment with anti-TB medications. 

When symptoms of respiratory TB occur, they may include:

  • cough (usually coughing up mucus)
  • coughing up blood
  • excessive sweating, especially at night
  • fatigue
  • fever
  • unintentional weight loss.

What is Tuberculosis (TB)?

  • TB is a contagious infectious disease caused by the bacteria (germ) Mycobacterium tuberculosis.
  • TB can damage a person's lungs or other parts of the body and cause serious illness.
  • There are 8 million new cases of TB disease worldwide every year. 

In British Columbia, there are more than 300 new cases of TB disease per year.  TB is curable and there are excellent anti-TB medications available.  However, the treatment is a long process and it takes six months or longer to be cured.

How is TB spread?

  • TB is spread through the air when a person with TB disease in the lungs coughs, sneezes or speaks, sending germs into the air.
  • Most people get TB germs from someone they spend a lot of time with in a confined indoor space, like a family member, a close friend or a co-worker.

What is Latent TB Infection?

  • Latent TB infection means the germs are in the body but they are not active.  In most cases, after TB germs enter the body, the body's defenses (our immune system) can control the germs.
  • However, our immune system cannot kill the TB germs.  The TB germs can stay alive for years in an inactive or latent state (asleep).  While the TB germs are inactive, they can't do any damage, and they can't spread to other people.  The person is infected but is not sick.
  • A positive skin test is often the only way to tell if a person has been infected.

What is "TB disease"?

  • TB disease means that the TB germs have become active.  The active TB germs can seriously damage the body and make the person very sick.  TB disease that involves the lungs can be spread to others.
  • TB disease occurs most often within two years of getting the infection.  However, it is possible, even after many years, for inactive TB germs to become active.
  • Although anyone with TB infection can develop TB disease. the risk is higher when the body's defenses are weakened, for example: by smoking, diabetes, special innumosuppressive medications, HIV infection, or other medical conditions.

TB can attack any part of the body, but the lungs are the most common site.  Symptoms of TB can begin gradually and the diagnosis is often delayed.

People with TB may have some or all of the following symptoms:

  • A cough with thick, cloudy, and sometimes bloody mucus (sputum) from the lungs for more than two weeks.
  • Always feeling tired and fatigued. 
  • Fevers, chills, and night sweats.
  • Loss of appetite and unexplained weight loss.
  • Shortness of breath and chest pain.

Every person with an unexplained cough for more than two weeks should be tested for TB.


Tuberculosis (TB) is caused by Mycobacterium tuberculosis, a slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs.


Tuberculosis (TB) develops when Mycobacterium tuberculosis bacteria are inhaled into the lungs.  The infection usually stays in the lungs, but the bacteria can travel through the bloodstream to other parts of the body (non-respiratory TB).

If a person's immune system becomes unable to prevent the bacteria from growing, the TB becomes active.

  • The Tuberculin Skin Test shows whether or not the person has been infected.  The test cannot differentiate between inactive (latent TB infection) or active TB disease.
  • Chest X-ray can show whether TB disease has affected the lungs.
  • Sputum Test shows if TB germs are present in coughed up sputum from the lungs.  It can help determine if the person is contagious.
  • TB is curable with anti-TB medications.  However, the TB germs have a waxy coat and can be very difficult to kill.
  • TB disease requires a combination of several anti-TB medications to be cured.  The medications must be taken for at least six months and sometimes longer.  Missing doses can lead to treatment failure.  It is necessary to complete the entire course of treatment to be cured.
  • In persons with TB infection, the inactive (sleeping) bacteria can be killed and TB disease can be prevented.  This requires only one anti-TB medication.  However, because the TB germs are difficult to kill, this medication needs to be taken for several months.
  • Anti-TB medications are generally safe.  However, like any medication, they must be used carefully and monitored in case side effects develop.

What should I do if I have had contact with a person who has TB?

  • People who require screening are usually identified by public health.  Other people who have concerns not answered by this information sheet should contact TB Services at 604-707-2692 in Vancouver or 604-707-2698 in New Westminster for advice.

If you have symptoms of TB (an ongoing cough with fever, fatigue, and weight loss), you should not wait to get treatment.  Contact your doctor or health professional as soon as possible.  If you have been exposed to someone who has active TB, contact your doctor or health professional to get a tuberculosis skin test, or make an appointment at TB Services at 604-707-2692 in Vancouver or 604-707-2698 in New Westminster for a tuberculosis skin test.


To avoid getting an active TB infection:

  • Do not spend long periods of time in stuffy, enclosed rooms with anyone who has active TB until that person has been treated for at least 2 weeks.
  • Use protective measures, such as face masks, if you work in a facility that cares for people who have untreated TB.
  • If you live with someone who has active TB, help and encourage the person to follow treatment instructions.

Are TB patients always infectious?

People with TB disease of the lungs can be infectious to others.  After taking medications, the germs are killed and they are no longer infectious, and people are able to resume their normal activities.

SOURCE: Tuberculosis ( )
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