1. TB Presentation for Healthcare Students
ARPHS TB Control Programme July 2008

2. Overview What is TB/latent TB infection (LTBI)/active TB disease?
How does TB spread, who progresses from LTBI to TB disease, symptoms of TB disease
TB in Auckland
Why must you be screened?
Tests (Mantoux skin test, IGRA blood test, chest x-ray, other tests)

3. What is TB? Tuberculosis (TB) is a bacterial infection
Caused by Mycobacterium tuberculosis (or rarely, Mycobacterium bovis)
TB can affect any part of the body
TB can be in the lungs (pulmonary TB), and/or in other parts of the body e.g. lymph nodes, brain, kidneys, bowel, etc (extrapulmonary TB)

4. What is latent TB infection (LTBI)?
LTBI is the initial infection with TB bacteria
A person with LTBI has TB bacteria in their body which are dormant – inactive or ‘asleep’
If you have LTBI you are not infectious to others
If you have LTBI you are well and have no symptoms of TB disease

5. What is TB disease?
Only about 10% of people with LTBI go on to develop active TB disease at some stage during their lives – 90% do not
TB disease can develop from within several months or years of becoming infected, up to 40+ years later
The TB bacteria become active (‘wake up’)
If you have TB disease you are sick
TB disease in lungs or throat may infect others

6. How does TB spread?
Not all TB is infectious – only TB in the lungs (pulmonary TB) or throat (laryngeal TB) can infect other people
TB spreads through the air
People catch it by inhaling droplets (aerosols) containing TB bacteria
Droplets are produced by someone with TB in their lungs or throat – by coughing, sneezing, talking, singing
TB is not easy to catch – usually takes many hours of exposure to be infected

7. Who is more likely to progress from LTBI to TB disease?
Recent infection – a higher risk of developing TB disease within 2 years of becoming infected with the bacteria
People whose immune systems are weak – including people with HIV/AIDS, cancer, kidney disease, diabetes, taking cancer chemotherapy drugs, or on long term oral steroid treatment (not asthma inhalers)

8. Symptoms of TB disease Unexplained weight loss Unexplained fever
Loss of appetite
Sweating (especially at night)
Feeling tired or weak all the time
Cough lasting 3 weeks or more, and not getting better
Coughing up blood or bloody sputum (spit)
Chest pain
Shortness of breath
Symptoms related to part of body affected e.g. enlarged lymph nodes (glands)

9. TB disease in Auckland
155 notified cases of TB disease in 2006 (average 186 cases annually between )
TB rates increase as people get older – but there is also a peak in young adults
Every year there are several TB cases in healthcare workers, including students
Some of the healthcare workers/students with TB are infectious to others

10. TB in Auckland (1995 – 2006) Proportion of cases by ethnicity

11. TB in Auckland (1995 – 2006) Age and ethnic specific incidence rates

12. TB in Auckland (1995 – 2006) Incidence by ethnicity and birthplace

13. TB in Auckland (1995 – 2006) Proportion of cases by disease site

14. Why must you be screened?
To protect you, the students – to establish your baseline TB infection status, before exposure to potentially infectious patients
To identify any students with latent TB infection (LTBI) – to give advice to all with LTBI, & offer treatment to highest risk
To protect patients – from any students with undiagnosed infectious TB

15. Tests – Mantoux test
A skin sensitivity test to detect past exposure to, and infection with, M. tuberculosis and related bacteria
Mantoux test solution is made from part of the TB bacillus
It is a safe test - 0.1ml of test solution is injected under the skin, and is read and measured 3 days later to decide if the test is positive or negative
A negative test is repeated 1 week later

16. Mantoux Test (continued)
No test if there has been a previous Mantoux >15mm or a past history of TB (to prevent large skin reactions)
It is safe for pregnant women
Strongly positive results may be painful and itchy for a few days
Students with a positive test will be required to have a chest x-ray

17. Tests – IGRA blood test This is a newer type of blood test for LTBI
It can be done if your Mantoux test is positive, or instead of a Mantoux test
The test results are less affected by BCG vaccination, and the test is more specific for infection with Mycobacterium tuberculosis, when compared with the Mantoux test

18. Tests – chest x-ray & other
If you have LTBI (positive Mantoux and/or IGRA), you must have a chest x-ray to check that you do not have active TB disease in your lungs
Important: You will not be able to go
on clinical placement unless you
complete the TB screening procedure