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What is Tuberculosis (TB)?

TB is a contagious disease caused by TB germs. TB usually attacks the lungs but can affect any part of the body. TB has been around for centuries.

How is it spread?

TB is spread from person-to- person through the air. TB is spread when someone sick with TB in the lungs, coughs or sneezes. It’s not highly contagious. Close, prolonged, or regular contact with someone who is sick with TB disease is needed to spread this disease.

What is TB Infection?

Most people who breathe in TB germs are able to stop them from growing. Their immune system traps the TB germs and keeps them inactive. This is called TB infection and these people:

  • Do not feel sick and have no symptoms.
  • Cannot spread TB germs.
  • Have a positive skin test (note: people with medical conditions that weaken the immune system such as diabetes, HIV, or cancer may have a negative skin test even though they’re infected with TB - people in this category should speak with their doctor).
  • May develop active TB disease later in life.

What is TB Disease?

TB germs become active when the body’s immune system cannot stop the germs from growing. The active TB germs begin to grow and cause damage to the body. Symptoms of TB disease are:

  • Cough (lasting longer than 3 weeks).
  • Fever, chills, and night sweats.
  • Feel tired.
  • Unexplained weight loss or loss of appetite.
  • If the TB disease is in another part of the body, the symptoms will depend on where the TB is growing, for example swollen lymph nodes or joint pain.

What are the tests for TB?

Screening for TB is done by a skin test. A positive skin test means a person has the TB germ in their body. A physical examination, chest x-ray, and sputum (mucous coughed up from the lungs) are done to check for TB disease.

What is a Tuberculosis (TB) Skin Test (Mantoux Test):

The TB skin test determines if you’ve been exposed to the TB bacteria.  TB skin testing is safe for pregnant women. BCG vaccine is also not a contraindication for the test.

Before a TB Skin Test, tell the person doing the test if you:

  • Have been treated for TB disease or TB infection in the past.
  • Have had a positive TB skin test. If you have, you should bring proof of the test results.
  • Are taking corticosteroids or immunosuppressive agents.
  • Have received any shots within the past 4 weeks (e.g., oral polio, yellow fever, MMR, BCG, oral cholera, oral typhoid, or chicken pox).

During the TB Skin Test:

  • The health care provider will inject a small amount of fluid called tuberculin, just under the skin of your forearm. A small bubble will form at the injection site. This is not an immunization.
  • In 48 hours (2 days) the health care provider will look at the test spot and feel for a reaction. If a bump is felt it will be measured. Only reactions of a certain size are considered positive.

After the TB Skin Test:

  • You should remain with the health care provider or in the waiting room for 15 minutes after the test, in case you might experience a reaction to the test.
  • The bubble or “bleb” should go away in 15 to 30 minutes.
  • Don’t cover the site with a cotton ball or a bandage.
  • You can resume normal activities. It’s alright to get the site wet (e.g., swim, shower, or bathe).

Reactions you may have at the TB Skin Test site include:

  • Red or swollen skin. This usually goes away in a few days.
  • Pain, discomfort, or itchiness. Don’t scratch it. Use a cold cloth on the site.
  • An open sore or blister that may scar. This is rare.

Please speak to your health care provider about the benefits and risks to TB Skin Testing. 

How is TB treated?

People with a TB infection may benefit from medicine to prevent TB disease. People with TB disease must complete treatment to cure the disease. TB medications are free from the Health Unit when a doctor orders them.

Contact us at 519-258-2146 ext. 1777 to request additional resources, including pamphlets on TB in several languages.

Health Care Providers

All positive TB skin tests and suspected cases of Tuberculosis (TB) are reportable to the Medical Officer of Health by the next working day. If you have any questions or concerns, call 519-258-2146 ext. 1777.

How to properly do and read a TB Skin Test E Learning Module (30 minutes to complete )

Contact us at ext. 1777 or using the form on this page to request additional resources, including a printable step by step mantoux testing procedure and patient handouts in several languages.

Long-Term Care and Retirement Homes

Exclusions from school and work

Exclusions from school and work are necessary for active (infectious) TB patients to prevent the spread. Once effective therapy has been started and the patient is no longer infectious to others, they may return at the direction of the Health Unit. 

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