What exactly is tuberculosis?
(TB) is an infectious disease caused by the bacteria
Mycobacterium tuberculosis. It is characterized by
the formation of tubercles (node like lesions), which
are elevated, round structures and cause generalized
tissue damage, particularly in the lungs. The disease
commonly affects the respiratory system but may also
involve other organs.
Does everyone who becomes infected with TB become
Only an average of 1 in 10 infected persons develops
the disease at some time in their life.
Are some infected people more likely to progress
to clinically active disease than others?
Persons who are infected with tubercle bacillus and
are immunosuppressed (e.g., those with coexisting HIV
infection) are at a considerably greater risk of developing
clinically active disease.
After being infected with TB bacteria, when is
the greatest risk of it progressing to a clinically
the first year of contracting the infection (although
disease may still occur many years later since it remains
in the body in a dormant state).
What happens when someone tests positive for clinically
active TB disease?
who are suspected or confirmed to have active TB are
placed in isolation until they have negative AFB test
results. These patients are treated with antibiotics
for 6 - 12 months.
What is drug resistant TB?
strains of TB are resistant to the effects of the medications
normally used to combat the progression of TB. Recently,
multi drug resistant (MDR) strains have also surfaced.
How do drug resistant strains of TB occur?
occur naturally while others occur when patients stop
their treatment program before the medication has its
full effect on the bacteria.
Who is most likely to contract TB?
with HIV infection, those with close contacts of infectious
TB cases, persons with medical conditions which increase
the risk of TB, foreign born individuals from high
prevalence countries, low income populations (including
high risk minorities), the homeless, alcoholics and
intravenous drug users, and residents of long term
care facilities (including prisons).
What are the symptoms of TB?
cough, fever, chills, night sweats, easy fatigability,
loss of appetite, weight loss, and hemoptysis (coughing
What tests can be done to screen for TB?
skin test, chest radiograph and sputum smears tested
for AFB are all recognized procedures for diagnosing
Are these tests always accurate?
among persons with HIV infection, the difficulty in
making a diagnosis may be further compounded by impaired
responses to tuberculin tests, low sensitivity of sputum
smears for detecting AFB, or overgrowth of cultures
with Mycobacterium avium complex (MAC) among patients
with both MAC and Mycobacterium tuberculosis infections.
What is the size of the TB bacteria?
average TB particle is a rod shaped particle that is
0.3 - 0.6 microns wide by a length of 1 - 4 microns.
is a droplet nuclei?
nuclei is the term used to describe the liquid particle
in which the TB bacteria is usually carried. The droplet
nuclei ranges in size from 1 - 5 microns and is expelled
from the body by coughing, sneezing, speaking, etc.
When discussing micron size, how small are we talking
dot above this "i" is approximately 400 microns
in size. Particles under 50 microns are generally not
visible to the naked eye (unless they are in high concentration
and passing through sunlight). Particles under 10 microns
in size are only visible when using a microscope.