A simple explanation of what tuberculosis is and what causes it. this is based on content that is needed for the A2 edexcel biology specifications.

1. TUBERCULOSIS

2. STARTER – TRUE OR FALSE
 TB is caused by a virus
 TB spreads through the air
 HIV Patients are less likely to get TB than others
 TB can affect other parts of the body besides the
lungs
 TB bacteria have a hard time living in fresh air
and sunlight

3. WHAT IS TUBERCULOSIS?
 Tuberculosis is also called TB for
short.
 The TB bacteria become active if the
immune system can't stop them from
growing.
 When TB bacteria are active
(multiplying in your body), this is
called TB disease.
 People with TB disease are sick.
 They may also be able to spread the
bacteria to people they spend time
with every day.
Figure 1

4. WHAT SORT OF PATHOGEN IS
INVOLVED?
 The pathogen involved is a bacterium
called Mycobacterium tuberculosis
(M. Tuberculosis).
 LIFE CYCLE:
• M. tuberculosis divides every 15–20
hours, which is slow compared to other
bacteria.
• It survive in dry states for many weeks
due to its cell wall which is rich in lipids.

5. HOW IS TB SPREAD?
 TB is spread through the air from one person to
another.
 The TB bacteria are put into the air when a
person with TB disease of the lungs or throat
coughs, sneezes, speaks, or sings.
 People nearby may breathe in these bacteria and
become infected. [1]

6. TB IS NOT SPREAD BY THE
FOLLOWING…
shaking someone’s hand
sharing food or drink
sharing toothbrushes
kissing

7. WHO IS MOST AT RISK FROM
TB?
 Those at high risk:
- Elderly
- Infants
- People with a weak immune system
- People who spend time around those who suffer from
TB
- People with low nutrition
 People that have the HIV virus infection are also at
high risk of getting TB.

8. SYMPTOMS
 Symptoms of TB disease:
• A bad cough that lasts 3 weeks or longer
• Pain in the chest
• Coughing up blood or sputum
• Weakness or fatigue
• Weight loss
• No appetite
• Fever
• Sweating at night

9. HOW TO TEST FOR TB?
 Biopsy – a sample of tissue is taken from the
affected site and is tested for TB.
 Chest CT Scan – a series of images are put
together to see whether the TB disease is present
in the body or not.

10. HOW CAN TB BE TREATED?
 Drug Therapy:
• Current treatment involves 3 – 4 different kinds of
antibiotics given in combination over 6 – 9 months.
• Multi-antibiotics are necessary to prevent the
emergence of drug resistance in the bacteria.
• A combination of isoniazid and rifampicin for 6 months
with pyrazinamide and ethambutol for the first 2
months is usually used, as this provides the highest
antibacterial activity as well as having the capacity to
inhibit the development of resistance.
• It results in a 90 % cure rate. Patients stop being
infectious to others after 2 weeks. After 1 month
patients should feel well and start to regain weight.

11.  Vaccinations:
• The control of infectious disease through
vaccination has been one of the most successful
accomplishments of public health in the 20th
century, enabling the eradication of smallpox and
virtual eradication of polio from the world.
• Today, vaccination remains our most effective
and cost-effective tool in the fight against
infectious disease and must be considered as an
integral part of any global effort to control
infections.
HOW CAN TB BE TREATED?

12. WHAT IMPACT DOES TB HAVE
ACROSS THE WORLD?
 TB is very common in poorer countries.
Areas in which the illness is still
widespread are; Eastern Europe, South
East Asia and Sub-Saharan Africa.
 Approximately 1/3 of the worlds
population is affected by TB.
 Rate of 5,000 deaths a day caused by TB.
 Annually – 2 million people die due to TB.

13. HOW CAN IT BE PREVENTED?
 Can be prevented by:
 Getting the BCG vaccine
 Balanced diets
 Exercise
 Breathing fresh air
 Avoidance of smoking
 Personal Hygiene

14. TB STATISTICS
It is common to get TB in these
countries because they are LEDC,
which means less likely to get
treatment and a high population so TB
can spread easily through the air.

15. TEST YOUR KNOWLEDGE
 Exam Question – January 2011

16. ANSWERS

17. THANK YOU
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