Tuberculosis in Travelers

More and more people are volunteering on overseas missions where they may come into contact with impoverished and sick people putting themselves at risk for tuberculosis.

Tuberculosis  (TB) has many names such as consumption and is most commonly a very bad lung infection caused by bacterium mycobacteria tuberculosis, which requires specialized treatment with very strong antibiotics for long periods of time. Indeed multidrug resistant TB is feared because we may soon run out of drugs to treat it.

TB infects people after they have inhaled bacteria from other people's cough.  This is usually old or obviously sick people but sometimes people who do not appear to be sick can be infectious.

A person who has had their lung infected but has no symptoms has a latent infection. They may go their whole life without developing further disease. But in roughly 10% of latent infections they may become actively infected and develop life threatening disease like lung infection, meningitis and military (generalized) TB.

Our goal is to identify and treat latent infections to prevent active disease and limit spread.

Identifying TB is usually started with a tuberculin skin test (Mantoux test) where a small amount of sterilized tuberculin protein is injected under the skin. If a person has been sensitized to TB they will get a skin reaction that will then be carefully measured by a nurse or doctor after 48-72 hrs.  Usually if >10mm this indicates prior sensitization to TB like proteins (TB itself, the BCG vaccine and other types of mycobacterium).

People with decreased ability to mount a proper reaction such as malnutrition, HIV infection and altered immunity do not mount a proper Mantoux reaction even if they are infected. Others such as diabetics and pregnant women may not react either.

To increase the sensitivity we now do a repeat (second step) Mantoux test specifically 7-21 days after the first. Sometimes a person is so sensitive to tuberculin that the first Mantoux test will sensitize them to the second one 3 weeks later. Nevertheless, the results are recorded and if greater than 10mm further analysis is done. X-rays and examination of the sputum (lung phlegm) for bacteria help confirm TB.

Health care students are required to get the “2 step” Mantoux as a baseline proof that they don t already have TB and the same has been recommended for missionaries and long term travelers to poor countries.

Health care workers periodically get a repeat follow up single step Mantoux to ensure they have not converted to a latent infection. Travelers who have been away for a long time may also get tested.

Still doing all the above doesn't give any protection at all, since the Mantoux is not a vaccine.

We stress to our nursing students that it is very important not to let people cough on you. Staying in a well ventilated area and wearing masks definitely helps.  This is particularly important for those working with HIV patients, as Tuberculosis is more common among them.

At present we don't have a good vaccine to protect people.

The above-mentioned Bacille Calmette-Guérin (BCG) vaccine is no longer recommended for nurses or travelers.

The Mantoux test is tricky to interpret but still the best test available. Future blood testing (Quantferon Gold) is being investigated but not yet used.

Antituberculosis treatment can be long (6-12 months) and have side effects.

Travelers and health care students need to remember that this is a disease we don't have a perfect test for, is hard to treat and is common enough to worry about.

The best we can do now is advocate better living conditions for the poor, surveillance of high risk groups with follow-up   of contacts and protect our selves if we travel or encounter those who could possibly have TB.

Tuberculosis is a huge topic and more information about it and Manitoba services can be found at the Manitoba Lung association http://www.mb.lung.ca/