Tuberculosis – Information on Tuberculosis

Tuberculosis (TB) is a bacterial infection caused by aTuberculosis is spread (transmitted) primarily from
germ called Mycobacterium tuberculosis. The bacteriaperson to person by breathing infected air during
usually attack the lungs, but they can also damageclose contact.
other parts of the body. TB spreads through the airTB is an increasing and major world wide problem,
when a person with TB of the lungs or throatespecially in Africa where the spread has been
coughs, sneezes or talks. If you have been exposed,facilitated by AIDS. It is estimated that nearly 1 billion
you should go to your doctor for tests. You arepeople will become newly infected, over 150 million
more likely to get TB if you have a weak immunewill become sick, and 36 million will die worldwide
system.between now and 2020 -- if control is not further
Tuberculosis (abbreviated as TB for tubercle bacillusstrengthened. Each year there are more than 9 million
or Tuberculosis) is a common and deadly infectiouscases and close to 2 million deaths attributed to TB;
disease caused by mycobacteria, mainly100,000 of those 2 million deaths occur among
Mycobacterium tuberculosis. Tuberculosis mostchildren.
commonly attacks the lungs (as pulmonary TB) butTuberculosis has plagued human beings for millennia.
can also affect the central nervous system, theSigns of tubercular damage have been found in
lymphatic system, the circulatory system, theEgyptian mummies and in bones dating back at least
genitourinary system, bones, joints and even the skin.5,000 years. Today, despite advances in treatment,
Other mycobacteria such as Mycobacterium bovis,TB is a global pandemic, fueled by the spread of HIV
Mycobacterium africanum, Mycobacterium canetti,AIDS, poverty, a lack of health services and the
and Mycobacterium microti can also causeemergence of drug-resistant strains of the bacterium
tuberculosis, but these species do not usually infectthat causes the disease.
healthy adults.Skin testing for tuberculosis is useful in countries
Until 50 years ago, there were no medicines to curewhere the incidence of tuberculosis is low, and the
TB. Now, strains that are resistant to a single drughealth care system works well to detect and treat
have been documented in every country surveyed;new cases. In countries where BCG vaccination has
what is more, strains of TB resistant to all majorbeen widely used, the TB skin test is not useful,
anti-TB drugs have emerged. Drug-resistant TB isbecause persons vaccinated with BCG will have a
caused by inconsistent or partial treatment, whenpositive skin test.
patients do not take all their medicines regularly forTB infection means that MTB is in the body, but the
the required period because they start to feel better,immune system is keeping the bacteria under control.
because doctors and health workers prescribe theThe immune system does this by producing
wrong treatment regimens, or because the drugmacrophages that surround the tubercle bacilli. The
supply is unreliable.cells form a hard shell that keeps the bacilli contained
A person can become infected with tuberculosisand under control. Most people with TB infection
bacteria when he or she inhales minute particles ofhave a positive reaction to the tuberculin skin test.
infected sputum from the air. The bacteria get intoPeople who have TB infection but not TB disease are
the air when someone who has a tuberculosis lungNOT infectious, i.e., they cannot spread the infection
infection coughs, sneezes, shouts, or spits (which isto other people. These people usually have a normal
common in some cultures). People who are nearbychest x-ray. TB infection is not considered a case of
can then possibly breathe the bacteria into their lungs.TB disease. Major similarities and differences between
You don't get TB by just touching the clothes orTB infection and TB disease are given in the table
shaking the hands of someone who is infected.below.