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									 TB Presentation for
Healthcare Students
   ARPHS TB Control Programme
                      July 2008
• What is TB/latent TB infection
  (LTBI)/active TB disease?
• How does TB spread, who progresses
  from LTBI to TB disease, symptoms of TB
• TB in Auckland
• Why must you be screened?
• Tests (Mantoux skin test, IGRA blood test,
  chest x-ray, other tests)
             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)
    What is latent TB infection
• LTBI is the initial infection with TB bacteria
• A person with LTBI has TB bacteria in
  their body which are dormant – inactive or
• If you have LTBI you are not infectious to
• If you have LTBI you are well and have no
  symptoms of TB disease
       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
       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
 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)
       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
•   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)
     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
TB in Auckland (1995 – 2006)
  Proportion of cases by ethnicity
TB in Auckland (1995 – 2006)
Age and ethnic specific incidence rates
TB in Auckland (1995 – 2006)
Incidence by ethnicity and birthplace
TB in Auckland (1995 – 2006)
Proportion of cases by disease site
  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
        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
    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
      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
   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

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