How TB is Spread, Symptoms, Risk Factors
What is Tuberculosis (TB)?
Tuberculosis (often called TB) is a bacterial infectious disease that usually attacks the lungs, but can attack almost any part of the body. TB can be an active disease or latent infection.
See our fact sheets on Active TB Disease, Latent TB Infection and The Difference between Latent TB Infection and Active TB Disease for more information.
Developed by the British Columbia Centre for Disease Control, the video below gives a brief overview about TB, how it is spread, risk factors for being exposed to TB and the difference between latent TB infection and active TB disease.
How is Active TB Spread?
- When people with TB in their lungs or throat cough, laugh, sneeze, sing, or even talk, the germs that cause TB may be spread into the air. If another person breathes in these germs there is a chance that they will become infected.
- It is not easy to become infected with TB. Usually a person has to be close to someone with tuberculosis disease for a long period of time.
- Even if someone becomes infected with TB, that does not mean they will get active TB disease.
What are the Symptoms of Active TB?
People with latent TB do not have symptoms and are not infectious. A person with active TB disease is infectious, and may have some or all of the following symptoms:
- a cough that will not go away
- feeling tired
- weight loss
- loss of appetite
- coughing up blood
- night sweats
These symptoms can also occur with other types of lung disease so it is important to see a doctor and to let the doctor determine if you have TB.
What are the Risk Factors for TB?
Anyone can get TB, but for many reasons, some groups of people are at a higher risk of being exposed to tuberculosis. Some of these groups include:
Some people who are exposed to TB are at an increased risk of having the infection develop into active tuberculosis if they have medical conditions that make their body less able to protect itself from disease. Some of these medical conditions include; HIV infection, chronic kidney failure or diabetes.
- People in close contact with those known to be infectious with TB
- Immigrants from countries with high TB rates such as China, Philippines and Brazil. Other countries with high tuberculosis prevalence rates can be found here
- People who work in, or are residents of long-term care facilities or correctional facilities
- People affected by poverty, malnutrition or poor housing
BC Centre for Disease Control. “TB Germ - A Cunning World Traveller (English)”. 2015.
Public Health Agency of Canada, Canadian Lung Association, Canadian Thoracic Society, “Canadian Tuberculosis Standards” (7th Edition), 2013.
Public Health Agency of Canada. “Tuberculosis Fact Sheets”. 2008.