TB Presentation for Healthcare Students ARPHS TB Control Programme July 2008

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)

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)? 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

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

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 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)

TB disease in Auckland 155 notified cases of TB disease in 2006 (average 186 cases annually between 1995-2006) 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