Tuberculosis (TB) is an infectious disease caused by the Mycobacterium tuberculosis bacterium. The disease typically attacks the lungs of the infected person, but it may attack other parts of the body as well. Considered one of the most deadly diseases of our time, TB affects an estimated two billion people around the world.
Tuberculosis is spread from person to person through droplets in the air. When an infected person coughs, sneezes, speaks, or spits, droplets containing the tuberculosis bacteria are expelled. If another person inhales even a small number of these droplets, he or she may be infected.
Though tuberculosis is contagious, the disease is not very easy to catch. Usually, transmission of the disease requires repeated contact. In most cases, a person has to be close to an infected individual for quite some time in order to become infected with TB. For this reason, the disease is most easily spread among friends, family members, and roommates. Furthermore, a person is at increased risk of infection when in close quarters with an infected individual.
An individual can be infected with tuberculosis, yet may not have the disease. In fact, most people do not actually develop TB, thanks to the protection of their immune systems. A great number of TB disease cases are actually the result of the reactivation of old, dormant infections.
Symptoms of tuberculosis disease include a lingering cough, fatigue, weight loss, poor appetite, night sweats, fever, and bloody cough. Individuals merely infected with tuberculosis usually do not exhibit symptoms. On the other hand, individuals with the disease may present with all the symptoms, just a few, or none at all.
While it is true that any individual can become infected with tuberculosis, there are some groups of people who are at increased risk of infection. Those infected with HIV, people in close contact with individuals with TB disease, and people from countries with high TB rates are at increased risk. Also at heightened risk are individuals with certain medical conditions, IV drug users, certain types of healthcare workers, prison guards, and some racial and ethnic minorities. Homeless people also face increased risk.
A very simple test exists to determine whether or not a person has been infected with tuberculosis. Currently, the Mantoux test is considered the optimal choice for TB testing. If the result of TB testing is positive, a physician typically follows up with additional testing, such as x-rays and mucous evaluations, to determine whether or not the infected individual has TB disease.