Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. Tuberculosis generally affects the lungs, but can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few of these germs to become infected.

1. TUBERCULOSIS
Mycobacterium tuberculosis

2. INTRODUCTION
• TB is an airborne disease caused by the bacterium Mycobacterium
tuberculosis (M. tuberculosis).
• Tuberculosis is spread through the air when people who have active
TB in their lungs cough, spit, speak, or sneeze.
• TB usually affects the lungs, but it can also affect other parts of the
body, such as the brain, the kidneys, or the spine.
• A person with TB can die if they do not get treatment.

3. TRANSMISSION OF TB
• M. tuberculosis is carried in airborne
particles, called droplet nuclei, of 1– 5
microns in diameter. Infectious droplet
nuclei are generated when persons who
have pulmonary or laryngeal TB disease
cough, sneeze, shout, or sing.
• M. tuberculosis is transmitted through
the air, not by surface contact.
• Transmission occurs when a person
inhales droplet nuclei containing M.
tuberculosis, and the droplet nuclei
traverse the mouth or nasal passages,
upper respiratory tract, and bronchi to
reach the alveoli of the lungs.
TB is spread from person to person through the air. The dots in
the air represent droplet nuclei containing tubercle bacilli.

4. SIGNS AND SYMPTOMS OF TB DISEASE
Extra pulmonary TB
• M. tuberculosis can infect any
organ of the body
• Symptoms vary by site of
disease
• Occurs in immunosuppressed
person and young children
Pulmonary TB
• Cough >2 weeks
• Often productive (sputum), can
be bloody
• Fever
• Night sweats
• Weight loss
• Chest pain

5. Factors that Determine the Probability of M. tuberculosis
Transmission
FACTOR
1. Susceptibility
2. Infectiousness
3. Environment
4. Exposure
DESCRIPTION
1. Susceptibility (immune status) of the exposed
individual
2. Infectiousness of the person with TB disease is
directly related to the number of tubercle
bacilli that he or she expels into the air.
Persons who expel many tubercle bacilli are
more infectious than patients who expel few or
no bacilli.
3. Environmental factors that affect the
concentration of M. tuberculosis organisms.
4. Proximity, frequency, and duration of exposure.

6. RISK FACTORS FOR TB DISEASE
Low socioeconomic status
Homelessness
•Cancer Transplantation
•Malnutrition Diabetes
•Alcoholism HIV infection
Diseases, conditions or drugs that
weaken the immune system
• 10% lifetime risk for developing active TB among HIV uninfected
• 10% annual risk for developing active TB among HIV infected
TB is the leading cause of death
worldwide in HIV infected
individuals
Major surgical procedures may
occasionally trigger
dissemination

7. SITES OF TB DISEASE
Pulmonary Extrapulmonary Military TB
Central Nervous
System

8. LATENT TUBERCULOSIS INFECTION (LTBI)
• Persons with LTBI have M. tuberculosis in their bodies, but do not have TB disease and cannot
spread the infection to other people.
• The process of LTBI begins when extracellular bacilli are ingested by macrophages and presented
to other white blood cells. This triggers the immune response in which white blood cells kill or
encapsulate most of the bacilli, leading to the formation of a granuloma. At this point, LTBI has
been established.
• LTBI may be detected by using the tuberculin skin test (TST) or an interferon-gamma release assay
(IGRA).
• It can take 2 to 8 weeks after the initial TB infection for the body’s immune system to be able to
react to tuberculin and for the infection to be detected by the TST or IGRA.
• Within weeks after infection, the immune system is usually able to halt the multiplication of the
tubercle bacilli, preventing further progression.

9. TB DISEASE
In some people,
the tubercle
bacilli overcome
the immune
system and
multiply,
resulting in
progression from
LTBI to TB
disease.
Persons who
have TB disease
are usually
infectious and
may spread the
bacteria to other
people.
The progression
from LTBI to TB
disease may
occur at any
time, from soon
to many years
later.
Body fluid or
tissue from the
disease site
should be
collectedfor AFB
smear and
culture.
Positive culture
for M.
tuberculosis
confirms the
diagnosis of TB
disease.

10. TB INFECTION V/S TB DISEASE

11. TESTING OF TB
• There are tests that can be used to help detect TB infection: a skin
test or TB blood tests.
• The Mantoux tuberculin skin test is performed by injecting a small
amount of fluid (called tuberculin) into the skin in the lower part of
the arm.
• A person given the tuberculin skin test must return within 48 to 72
hours to have a trained health care worker look for a reaction on the
arm.
• The TB blood tests measures how the patient’s immune system reacts
to the germs that cause TB.

12. TREATMENT
• TB disease can be treated by taking several drugs for 6 to 12 months.
• It is very important that people who have TB disease finish the medicine,
and take the drugs exactly as prescribed.
• If they stop taking the drugs too soon, they can become sick again; if they
do not take the drugs correctly, the germs that are still alive may become
resistant to those drugs.
• TB that is resistant to drugs is harder and more expensive to treat.
• In some situations, staff of the local health department meet regularly with
patients who have TB to watch them take their medications.
• This is called directly observed therapy (DOT).
• DOT helps the patient complete treatment in the least amount of time.

13. PREVENTION
• Tuberculosis prevention and control efforts rely primarily on the vaccination of
infants and the detection and appropriate treatment of active cases.
• Vaccines
• The only available vaccine as of 2011 is Bacillus Calmette-Guérin (BCG).
• In children it decreases the risk of getting the infection by 20% and the risk of infection
turning into disease by nearly 60%.
• Public health
• The World Health Organization declared TB a "global health emergency" in 1993,and in
2006, the Stop TB Partnership developed a Global Plan to Stop Tuberculosis that aimed to
save 14 million lives between its launch and 2015.
• A number of targets they set were not achieved by 2015, mostly due to the increase in HIV-
associated tuberculosis and the emergence of multiple drug-resistant tuberculosis.
• A tuberculosis classification system developed by the American Thoracic Society is used
primarily in public health programs.