October 22, 2013
Tuberculosis is a contagious bacterial disease. 5% to 10% of people who inhale the bacteria get sick and develop active TB over time. The disease usually affects the lungs.
Tuberculosis is caused by Mycobacterium tuberculosis , a bacterium (Bacillus) which is transmitted through the air like the common cold.
After inhaling the bacteria, a person may develop a latent TB infection (LTBI) or active TB.
In ITL, the bacteria remain alive but inactive in the body. Therefore, the infected person is not sick, does not present any symptoms and is not contagious. The ITL may progress to active tuberculosis if the defense system (immune) the person with weakened.
During the active stage of TB, the infected person is ill and often has symptoms of tuberculosis. Active TB bacteria usually infects the lungs or respiratory tract, but can also infect several organs (lymph nodes, kidneys, etc..). When active TB affects the lungs or respiratory tract, it is contagious.
Risks for travelers
For most travelers, the risk of LTBI and active tuberculosis is low.
Activities that may increase the risk include:
work in a health facility in a country where TB rates are high ;
working with people with active TB or regular exposure to such persons (eg in prisons, shelters for the homeless, the refugee camps.)
a trip to a country where TB rates are high, to visit friends or relatives;
consumption of unpasteurized milk or dairy products (risk of bovine tuberculosis).
Travelers whose risk of tuberculosis infection is high are those who have been with active TB or have been in close contact with people with active tuberculosis or suspected to be.
Travelers whose immune systems are also at greater risk of having their TB infection progress to active TB, such as those infected with HIV, children under 5 years, people treated with steroids and those diabetes mellitus.