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Tuberculosis (TB)

Tuberculosis (TB) is an infectious disease caused by TB bacteria and is spread through the air from person to person. Learn about TB disease symptoms, risks, treatment and who to call for more information.

Tuberculosis (TB) is an infectious disease caused by TB bacteria that usually attack the lungs. Other parts of the body, including kidneys, brain and spine can be affected as well. TB spreads through the air, from one person to another.

The Public Health Department makes sure to investigate all cases of tuberculosis (TB) and works with health care professionals in managing tuberculosis cases. In addition, we ensure clients have access to free medication. Below are the steps taken to manage and contain outbreaks as well as educate citizens about TB.

Case Management (Latent and Active TB)

  • Ensure adequate TB treatment is received and completed
  • Follow-up of individuals exposed to TB
  • Educate clients and contacts
  • Order TB medication for clients with TB

Direct Observed Therapy

  • Ensure clients take medication correctly
  • Monitor for side effects
  • Prevent/reduce drug resistance caused by interrupted drug therapy

Medical Surveillance

  • Immigrants, refugees, visitors, visa students/workers identified through immigration surveillance are monitored for TB disease
  • Monitor clients with TB infection identified through routine surveillance
  • Order TB medication for clients with TB infection on immigration and routine surveillance


  • Provide free educational materials, community agencies and health professionals
  • Outreach to populations at higher risk for TB disease

FAQ – Tuberculosis (TB) and Tuberculin Skin Tests (TST)

Tuberculosis spreads through the air when a person with TB coughs, sneezes, or sings and then other people breathe that bacteria into their lungs. Usually TB does not spread easily. It takes close and frequent contact with a person sick with TB to become infected with the bacteria.

TB Infection

TB Disease

TB bacteria stay dormant and do not multiply.

TB bacteria multiply when the body's defense system cannot fight the growth.

Most people exposed do not get sick from TB.

Most commonly found in the lungs. Extra-Pulmonary TB develops in other parts of the body and is not easily spread to others.

People with TB infection:

  • do not look or feel sick
  • cannot spread TB to others
  • have a 10% risk of developing TB disease

People with TB disease:

  • can spread TB to other people if the disease is in their lungs or throat
  • usually feel sick

Symptoms include:

  • Cough lasting at least 3 weeks
  • Coughing up mucous, phlegm, or blood
  • Chest pain when you cough or breathe
  • Fever
  • Sweating at night
  • Loss of appetite
  • Unexplained weight loss, tiredness or weakness
  • Pain in your body where the TB bacteria are growing

Individuals with any of the following conditions are most at risk for TB disease:

  • Weakened immune systems due to disease and/or medications such as diabetes, cancer, kidney
    disease and immunosuppressive drugs
  • Close contact to a person with TB disease
  • From a country with high rates of TB
  • Children under the age of 5
  • Work or live in nursing homes, clinics, hospitals, prisons, or homeless shelters
  • Malnourished, homeless, under-housed, alcohol dependent, or injection drug users

Early diagnosis is key for the control of Tuberculosis. A tuberculin skin test (TST) can help determine if you have been in contact with the TB bacteria. See What is a TST below for more information.

There is a 10% chance that a person with TB infection will develop TB disease. Your doctor may recommend preventative treatment in the form of medication if you test positive for TB infection.

Yes, TB is curable with the right medication. Patients take this medicine anywhere from 6-12 months to destroy all TB bacteria and cure TB disease. Failure to take your TB medication as prescribed can result in the development of drug resistant TB. If this happens, your condition may worsen.

Once a person has take their medicine for a few weeks, they usually can no longer spread TB bacteria to other people.

No. Your local health department provides this medicine free of charge. A public health nurse remains in contact while you take this medication.

Yes, when taken as prescribed, TB medication is safe. As with most medicines, some people may experience side effects. Blood tests can help monitor these side effects.

Note: Tell your doctor if you do not feel well when taking your TB medication.

BCG (Bacille Calmette-Guerin) is a live vaccine given after birth to help protect infants and young children against the most severe forms of TB disease. It is generally given in countries where TB infection and TB disease are more common.

The following groups of people may have had the BCG vaccine:

  • Persons born in countries with a high rate of TB
  • Aboriginal persons from communities with high rates of TB
  • Persons born in Quebec and Newfoundland from 1940 to early 1980’s

The protective effect of this vaccine decreases as a person ages and the closer they live to the equator. Because the vaccine is made from treated (attenuated) strains of TB bacteria, it may cause a person to have a false positive tuberculin skin test (TST).

People who have the BCG vaccine:

  • May have a false positive TST
  • Do not have permanent protection from TB
  • May still be at risk of infection
  • Could have a serious allergic reaction to the BCG vaccine

A history of BCG vaccination should be ignored if a person:

  • Had BCG in infancy
  • Had contact with a case of active TB disease
  • Is from a country with a high rates of TB
  • Is from an Aboriginal Community with high rates of TB
  • Has a weakened immune system
  • Has a high risk medical condition such as diabetes or renal failure
  • Has an abnormal chest x-ray

Early diagnosis is very important in the control of tuberculosis (TB). A TST can assist in the diagnosis by confirming whether exposure to Mycobacterium tuberculosis bacteria has occurred.

You may need a TST for employment, travel or because you have been in contact with a person who has active TB. If you have been exposed to TB you may need more than one TST.

TB Testing Process:

  1. Injection of a tiny amount of test fluid called Tuberculin, just under the skin of your forearm.
  2. There may be slight discomfort, itching, or redness at the test site. Do not touch or cover the site.
  3. A nurse checks your arm 48-72 hours after the test to measure the results. This test cannot tell you if you have active TB disease.
  4. To determine if TB bateria have damaged your lungs, a chest x-ray is necessary.
  5. Your doctor may prescribe medication to prevent TB disease.

Sometimes the immune systems of some individuals cannot remember past TB infection. This is especially common in the elderly and people with weakened immune systems. When this happens, individuals can have a negative reaction to the first TST. A second TST, given at least one week to as long as one year after the original TST, may produce a much greater response.

We recommend two-step testing for:

  • People who will be re-tested periodically (i.e. healthcare workings, correctional facilities)
  • Residents (<65 years of age) and staff of long- term care homes, correctional facilities, homeless shelters and drop-in centres
  • Travellers planning a prolonged trip to an area with a high rate of TB

Who can have a TST?

Who should not have a TST?

People recently immunized with an inactivated vaccine

People who have had a previous severe reaction to the TST (eg. blistering)

Pregnant women

People with extensive burns or eczema

People who have had a previous BCG vaccination

People who have or have had active TB or a record of TB treatment

People who have had a TST previously, but have no record of the results or results were not recorded in “millimetres” of induration

People with a positive TB record recorded in “millimetres” of induration

Yes. Most people will have no side effects, however the following rare side effects can happen:

  • Pain
  • Redness, rash
  • Swelling
  • Blistering
  • Hemorrhage
  • Haematoma
  • Ulceration or necrosis at the injection site
  • People who have had a viral infection in the past four to six weeks (i.e. chickenpox, influenza)
  • People who have received live virus vaccines in the past four to six weeks (i.e. mumps, measles, chickenpox or yellow fever vaccines)

tb, tuberculosis