Fact sheet: What you need to know about tuberculosis

More than 8 million people worldwide become infected with tuberculosis (TB) each year.

The respiratory disease kills 2 million people annually. 

The World Health Organization (WHO) reports one in every 10 people will get infected with TB in his or her life. 

While areas in Latin America, Africa and Asia have seen infection rates rise drastically in recent years, the rate in Canada has remained stable.

The Public Health Agency of Canada estimates there were 1599 cases of TB across the country in 2009, or 4.7 cases per every 100,000 people. Nunavut had the highest number of TB cases that year, 56 or a rate of 174 incidences per 100,000 people. Nova Scotia and P.E.I. had the lowest rate, with 0.7 cases per 100,000 people. 

The Canadian Lung Association says the approximately 70 per cent of TB cases diagnosed in Canada come from outside the country. Canadian-born aboriginal populations are the most at risk, making up 21 per cent of the reported cases in 2009. 

Here’s what you need to know about tuberculosis. 

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Symptoms of active TB  

• A cough that lasts two weeks or more, especially if you cough up fluid or blood comes from your lungs when you cough
• Fever
• Weight loss
• Night sweats
• Loss of appetite

People with inactive TB won’t exhibit any symptoms. If you have inactive TB you carry the germs without getting sick or becoming contagious. You still need to be treated or you run the risk of developing active TB. The Canadian Lung Association says five to 10 per cent of people with inactive TB will develop active TB, particularly those with weakened immune systems. 

 How you catch TB 

TB is passed on through the air and people generally catch the disease from those around them, at home, work, etc. 

People who have TB scan spread it by:

• coughing
• laughing
• sneezing
• singing
• playing a wind instrument (for example, the flute), or
• talking
(Source: Canadian Lung Association) 

Testing for TB 

Active tuberculosis is diagnosed in three steps: 

• medical history and medical examination
• chest x-ray
• laboratory tests

 
Doctors will order laboratory tests if there is evidence of active TB visible in chest x-rays. If that’s the case, your doctor will take a sputum (phlegm) sample and examine the culture under a microscope. If the test comes back positive, it will be further examined to determine what type of TB you have or if it’s a drug resistant strain. 

In order to diagnose latent infections doctors will do a TB skin test (also called the Mantoux test), injecting a small amount of fluid under the skin on your forearm. Within 48 to 72 hours, the injection site will swell or bubble and become slightly hard. If the “bubble” is more than 10 millimetres, the test is positive for latent TB.

Sometimes people who have been vaccinated against TB will get a positive result from the skin test. 

People with weakened immune systems, those with HIV for example, can experience a negative result from the skin test and may need further testing.

(Source: Public Health Agency of Canada and Northwest Territories Health and Social Services)

Treatment of TB 

Tuberculosis can be treated , but infected people need to take all of the prescribed medicine or risk getting sick again later. The Centre for Disease Control says it can take from six months to one year to completely kill all the TB germs in your body.