Tuberculosis (TB): Prevention and risks

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How tuberculosis spreads

Tuberculosis is caused by the bacteria Mycobacterium tuberculosis. It is a disease that mainly affects the lungs and airways. Tuberculosis is spread from human to human through the release of droplets from the lungs or airways of an infected person. This can happen through:

  • coughing
  • sneezing
  • singing
  • playing a wind instrument
  • talking (to a lesser extent)

To be infected, you have to breathe in the tuberculosis bacteria.

You cannot get infected by:

  • shaking hands
  • sharing dishes
  • sitting on toilet seats

Preventing tuberculosis

For most Canadians, the risk of being exposed to tuberculosis is very low. If you have been in contact with someone who has active tuberculosis or think you may have, consult your health care provider.

If you plan to travel to countries with high rates of tuberculosis, visit a health care provider or travel health clinic 6 weeks before you leave. If you believe you are at risk of getting tuberculosis, ask about getting a skin test:

  • before your trip
  • after your trip

If you have a job where you could be exposed to tuberculosis, your workplace should have:

  • a tuberculosis management program or
  • an infection prevention and control program

It should include policies and procedures that:

  • allow people with tuberculosis or those who are suspected of having tuberculosis to be quickly identified
  • have controls to prevent the spread of the disease
  • follow routine practices and additional precautions by staff

Who is at most risk

Your risk increases if you:

  • have been around people known or suspected to have tuberculosis
  • have had tuberculosis in the past but did not complete treatment as prescribed
  • are a smoker or use illicit drugs
  • live or work in a community with high rates of tuberculosis; a heavily populated central area of a city (especially if you are homeless); a long-term care facility; a prison; a homeless shelter; or an overseas refugee camp.
  • visit and stay in countries with high rates of tuberculosis, particularly over long periods of time

Other factors that could put you at higher risk include if you:

  • have certain diseases or conditions, such as:
    • HIV and AIDS
    • silicosis (a type of lung disease)
    • long-term kidney disease requiring dialysis (a treatment to replace some of the functions of your kidneys)
    • cancer of the head or neck
    • diabetes
  • have had certain drug treatments that can affect your immune system, (ability to fight infection), such as:
    • cancer treatments (chemotherapy)
    • medications following an organ transplant
    • medications for rheumatoid arthritis or lupus
  • are underweight (i.e., have a body mass index under 18.5)
  • are a heavy drinker

Bovine tuberculosis

Human cases of bovine tuberculosis are rare in developed countries because of pasteurization and testing programs.

If you are travelling to rural areas abroad, you should be aware of the risks associated with bovine tuberculosis. You can get bovine tuberculosis if you:

  • consume unpasteurized milk or dairy products from an infected cow, goat, sheep or buffalo
  • inhale tuberculosis bacteria breathed out by infected animals
  • inhale tuberculosis bacteria released from infected animal carcasses (dead animals) and their waste products.

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