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Infectious Diseases


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What is tuberculosis?

Tuberculosis is a disease often called TB. It is spread by bacteria (germs) that can float in the air. The TB bacteria or germs may spray into the air if a person with TB disease in the lungs coughs, sings or sneezes. The people nearby can breathe TB germs into their lungs and get TB infection.

TB is a complicated disease. Not everyone who becomes infected with TB becomes sick and develops TB disease.  When you are just infected, but not sick, you are generally not contagious.  Being infected with TB means that there are TB germs in your body. Those who become sick and develop TB disease most often do so in their lungs. Developing disease and becoming contagious may or may not occur and if it does, it happens weeks, months or years after becoming infected. It is somewhat unpredictable but depends on factors such as age and your immune system.

Most people with TB infection will not become contagious or feel sick; however, some people will become sick, contagious and develop TB disease. There are medications to treat the TB infection (when the germs are in your body). This is to prevent the TB infection from becoming TB disease later on. TB disease usually attacks the lungs, but sometimes it attacks the kidneys, brain, bones or spine. People who develop TB disease need medical care right away because they could die. They can also potentially spread TB to other people.

What are the symptoms of tuberculosis?

If the TB disease is in your lungs, you may:

  • cough a lot
  • cough up mucus or phlegm or blood
  • have chest pain when you cough or breathe.

If you have TB disease anywhere in your body including the lungs, you may:

  • have a fever
  • sweat at night
  • lose your appetite
  • lose weight
  • feel weak
  • have pain or swelling in the part of your body with the TB disease.

How soon do symptoms appear?

The highest risk of TB disease is within the first 2 years of becoming infected.


How is tuberculosis diagnosed?

A skin test on your arm is the best way to find out if you have TB infection. The test is "positive" if a swelling approximately the size of a dime or bigger appears 2 to 3 days later. This means you probably have TB infection.

You will need to see a doctor and may require other tests, such as a chest X-ray or sputum tests. These tests are to ensure you do not have TB disease.

Only a doctor can tell if you have TB disease. A chest X-ray will usually show if you have the disease in your lungs. A TB skin test and tests on phlegm that you cough up are also important.

Tell the doctor or nurse if you have ever had a "positive" reaction to a TB skin test before, or if you have been treated with TB medications.


How is tuberculosis spread?

It is spread by tiny germs that can float in the air. The TB germs may spray into the air if a person with TB disease coughs, sings or sneezes. The people nearby can breathe TB germs into their lungs and get TB infection. People who have TB infection (not TB disease) cannot spread TB to others.

TB disease is not particularly contagious, much less so than a cold or the flu. Close, prolonged contact is usually required for the bacteria to spread from one person to another, typically a number of hours each day, for a number of days or weeks. Those most at risk are people who live in the same house.


What is the treatment for tuberculosis disease?

TB germs are strong. To kill them you must take special medicine for 6 to 9 months. You must take all your medicine until your doctor tells you to stop. If you stop taking your TB medicine too soon you will not be cured. You may get sicker because the TB germs become stronger. You might need stronger medicine for a long time. You might never be cured.


What can be done to prevent tuberculosis?

Your doctor may recommend medicine to treat TB infection which will prevent you from getting TB disease and becoming sick. This is called "preventative" treatment or latent TB infection treatment. Isoniazid (INH) is the medicine used most often and is free of charge.

It takes 6 to 12 months to kill the TB germs. Unless you kill the TB germs with the right medicine, they will stay in your body and may cause TB disease later on.


Are there any special concerns about tuberculosis?

Tell the doctor or nurse if you have ever had a "positive" reaction to a TB skin test before, or if you have been treated with TB drugs.

TB Infection & TB Disease
are not the same
It is important that you know the difference. 

TB Non Contagious

TB Contagious

You have the germs in your body. Your body has walled the germs off so they can do no damage.

TB germs are multiplying and causing damage. TB usually causes disease in the lungs but can also affect other organs.

You have a positive skin test. Your chest x-ray showed no TB Disease. You may develop TB Disease in the future.

You are sick.
Symptoms – weakness, fever, weight loss; cough, chest pain, coughing up blood when TB is in the lungs; pain if in other parts of the body.

You are not contagious.
You are not sick.

You are contagious if the TB germ is in your lungs and you are coughing.

TB infection can be treated with 6-12 months of medication. Treatment will prevent TB Disease from developing.

TB Disease is treatable and curable as long as you take all your medication.
Early treatment prevents the spread of TB to others.

Reproduced with permission from Peel Public Health


For data on the incidence of Tuberculosis in Simcoe Muskoka and Ontario, please visit the Tuberculosis page on the health unit’s HealthSTATS site

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