Tuberculosis (Mycobacterium tuberculosis)

Tuberculosis (TB) is an infectious bacterial disease that is caused by Mycobacterium tuberculosis. TB is spread through the air when an infected person coughs or sneezes. TB usually affects the lungs. It can also affect other areas of the body. There are two types of TB Infection: latent (sleeping) TB infection (LTBI) and active TB disease. TB is only contagious when it is in its active form and affects the lungs.


Those with active TB of the lungs or airways will usually experience symptoms. Symptoms may include coughing that lasts longer than three weeks, coughing up blood, loss of appetite, unexplained weight loss, night sweats and fever. Those infected with LTBI carry the TB bacteria (or germ) in their bodies but don’t show any symptoms and will not spread the infection to others. A special skin test is needed to show that you are infected with TB. If your body’s defences are strong, your body will usually control the infection. If the immune system is compromised, for example, if a person with LTBI develops a chronic illness or is taking cancer treatments, the TB can be activated.


TB is usually spread only through close, prolonged contact with someone who has TB. The germs can get in the air through water droplets from coughing and sneezing and remain there for hours.

When the TB germs are breathed in, one of three things can occur:

  • Your immune system will kill the germs.
  • The germs will remain alive, but your immune system keeps them dormant (sleeping) in your body, resulting in LTBI.
  • You can develop active disease, either soon after becoming infected or years later. TB is only contagious when it is in its active form and affects the lungs.


Active TB can almost always be cured with proper medical treatment. This treatment normally lasts six to nine months. During that time, all drugs that are prescribed must be taken.

Manitoba offers a program called Directly Observed Therapy (DOT). In this program, a health worker supervises the taking of medication.

It is important for persons with TB to take all their prescribed medicine for as long as they are prescribed, even if they are feeling well. If the medications are not taken properly, active TB may come back or the TB germ may become drug-resistant to some or all the antibiotics used to treat it. Drug resistance means the usual drugs used to kill the TB germs no longer work.


The best way to prevent TB from spreading to others is by making sure everyone with the disease finishes their entire course of medication.

A TB skin test can be used to detect latent (sleeping) infection in its early stages. Doctors may prescribe medicine to be taken for up to nine months to prevent the initial infection from getting worse.

The First Nations and Inuit Health Branch in Manitoba offers a vaccine that helps prevent some cases of the serious disease in children under five years of age. This vaccine is used to protect selected newborns from TB.

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