What is Tuberculosis?


Tuberculosis, or TB, is an infection from a bacteria called Mycobacterium tuberculosis, which is transmitted from person to person via airborne droplets.  TB infection can affect any organ of the body but most frequently leads to severe lung disease, which lends to coughing and sharing the bacteria with others.  A less common method of transmission to humans is by drinking unpasteurized milk or eating other dairy made from infected animals.

TB infection is common in developing countries. More than 30% of the world’s population is infected with TB (called latent TB) and at risk of developing active disease. Even so, only approximately 10% of those with latent TB will ever progress to active TB in their lifetime.  Latent TB is identified by a tuberculin skin test (TST) applied intradermally and read 48-72 hours later. 

A positive skin test warrants further investigations to rule-out active TB.  Symptoms of active TB may include fever, night sweats, weight loss, fatigue, cough, chest pain, and/or hemoptysis. In some cases, a referral to TB Services is made, for further investigations and treatment.



The risk of TB infection for most travellers is low. The risk changes based on destination, duration of stay, and type of activity. If you are a frequent traveller or travel for an extended period of time, then your pre-travel health consultant may recommend a test before you travel and/or after you travel – the first to establish a baseline and the second to catch a recent exposure.

An individual can acquire latent TB without ever having symptoms. Waiting a period of 8-12 weeks between return home from possible risk (travel or occupational) and time of test, is important for the TST to be accurate.

Although a vaccine called BCG is available, it is not often recommended due to its limitations in preventing tuberculosis. It may be suggested for some young children relocating overseas, in order to prevent the serious complications of tuberculosis in this vulnerable age group.



The tuberculin skin test (TST) is sometimes required by colleges, universities, or employers, and is available for travellers and non-travellers alike at Odyssey.

We offer 1-step and 2-step TST and follow-up education. Contact us to book an appointment.


Product name: Tubersol®

Minimum age: All ages

Interval between test & read: 48-72 hours

Frequency: varies