Tuberculosis (TB) is a contagious disease that often affects the lungs. It is caused by a specific bacterium. Every year there are about 9 million cases worldwide. If you are planning to travel abroad, how can you reduce your risk of TB?
If you are an international traveler, you may be at an increased risk for contracting TB because:
The World Health Organization (WHO) lists profiles for high burden countries. TB hotspots can be found all over the world, but mainly in sub-Saharan Africa, parts of South America, and Asia.
When someone with active TB coughs, the bacteria are transmitted through the air and may be inhaled by people nearby. TB is more likely to spread from person-to-person in enclosed places because:
Fortunately, exposure to TB bacteria does not automatically mean the disease will develop. If you have a normal immune system, your body's defenses will immediately begin resisting the bacteria. This may keep TB dormant in your body for years, possibly a lifetime. If the bacteria remain inactive, a person is considered infected, but does not have active tuberculosis and cannot infect others.
TB becomes active and symptomatic when the immune system can no longer contain the growth of the bacteria. Usually, this happens when the immune system is weakened, due to certain conditions, such as poorly controlled diabetes, HIV, and cancer.
When TB becomes active in the lungs, the body begins to show symptoms, such as:
Screening for TB infection is done with a skin test. In North America, the tuberculin skin test (often called PPD for purified protein derivative) is generally used. A small amount of testing fluid is injected into the skin in the lower part of the arm, and the reaction is measured 2-3 days later.
A positive reaction, characterized by a raised bump, indicates TB infection, but it does not diagnose active disease. A negative reaction indicates the absence of infection. However, if exposure was recent, it is recommended that another skin test be done 8–10 weeks after the time of exposure.
If you are staying for an extended period in a location where TB common, it is recommended that testing be done before leaving and after returning from your trip.
If you are have a positive skin test results without symptoms, the drug isoniazid may be prescribed for 9 months of treatment. Another treatment option is a combination of isoniazid and rifapentine for 12 weeks. Alternative treatments include rifampin for 4 months, or rifampin plus pyrazinamide for 2 months.
A vaccine for TB, called BCG, is available in many countries. It is only used in the US with specific circumstances and under the guidance of a TB expert.
If you have active TB, your treatment will most likely include a combination of medications, such as:
For active pulmonary TB, you will need to isolate yourself during treatment from coworkers, friends, and family to prevent the disease from spreading.
There are no simple answers, but risk is lowest in the open air and in situations where your distance from a potentially infected person is greater.
Enclosed environments such as hospitals and prisons should be avoided. If you will be spending time in this type of setting, it may be appropriate to wear a special mask that prevents TB.
Remember that tuberculosis is not exclusively a respiratory disease. It can also be transmitted by unpasteurized milk and milk products. When traveling in regions where TB is common, avoid drinking of unpasteurized or uncooked milk and milk products.
In general, tuberculosis is not easily transmitted, but international travelers should take preventive measures if they are at heightened risk of exposure.
Centers for Disease Control and Prevention
The Canadian Lung Association
Public Health Agency of Canada
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Last reviewed July 2016 by Michael Woods, MD Last Updated: 8/8/2014