It is important to understand that there is a difference
between being infected with TB and having TB disease. Someone who is
infected with TB has the TB germs, or bacteria, in their body. The body'
defences are protecting them from the germs and they are not sick. Someone
with TB disease, however, is sick and can spread the disease to other
people. A person with TB disease needs to see a doctor as soon as
Anyone can get TB. But for various reasons, some groups
of people are at higher risk to get active TB disease. The groups that are
at high risk include: people with HIV infection (the AIDS virus), people
in close contact with those known to be infectious with TB, people with
medical conditions that make the body less able to protect itself from
disease, people who are underfed, alcoholics and drug addicts.
person with TB infection will have no symptoms. A person with TB disease
may have any, all or none of the following symptoms: a cough that will not
go away, feeling tired all the time, weight loss, loss of appetite, fever,
coughing up blood and night sweats. Some of these symptoms can also occur
with other types of lung disease so it is important to see a doctor and to
let him decide.
There are two possible ways a person can
become sick with TB disease:
The first applies to a person
who may have been infected with TB for years and has been perfectly
healthy. The time may come when this person suffers a change in health.
The cause of this change in health may be another disease like AIDS or
diabetes. Or it may be drug or alcohol abuse or a lack of health
Whatever the cause, when the body's ability to protect itself
is damaged, the TB infection can become TB disease. In this way, a person
may become sick with TB disease months or even years after they first
breathed in the TB germs.
The other way TB disease develops happens
much more quickly. Sometimes when a person first breathes in the TB germs
the body is unable to protect itself against the disease. The germs then
develop into active TB disease within weeks.
A skin test is the
best way to find out if a person has TB. For this test, a small amount of
chemical is placed just below the top layers of skin, usually on the arm.
Two to three days later a health care worker checks the arm to see if a
bump has developed and measures the size of the bump. If the bump is of a
certain size the test is positive and the person has TB infection.
Other tests including a chest X-ray and a test of a person's mucus
Treatment for TB depends on whether a person has TB disease
or only TB infection. A person who has become infected with TB, but does
not have TB disease, may be given preventive therapy. Preventive therapy
aims to kill germs that are not doing any damage right now, but could
break out later.
If a doctor decides a person should have
preventive therapy, the usual prescription is a daily dose of isoniazid
(also called 'INH'), an inexpensive TB medicine. The person takes INH for
six months (up to a year for some patients), with periodic checkups to
make sure the medicine is being taken as prescribed. After a few weeks a
person can probably even return to normal activities and not have to worry
about infecting others.
The patient usually gets a combination of
several drugs (most frequently INH plus two to three others), usually for
six to nine months. The patient will probably begin to feel better only a
few weeks after starting to take the drugs. If the medicine is taken
incorrectly or stopped the patient may become sick again and will be able
to infect others with TB.
If the medicine is taken incorrectly and
the patient becomes sick with TB a second time, the TB may be harder to
treat because it has become drug resistant. This means that the TB germs
in the body are unaffected by some drugs used to treat TB.
Multi-drug resistant TB is very dangerous, so patients should be
sure to take all of their medicine correctly.
The drugs usually
make the patient non-infectious within days or weeks. TB is spread by
handling a patient's bed sheets, books, furniture, or eating utensils.
Brief exposure to a few TB germs rarely infects a person. It's
day-after-day close contact that usually does it.