TB and HIV

  • Created by: ncs1997
  • Created on: 07-04-15 13:12

TB is most commonly caused by the bacterium Mycobacterium tuberculosis which is spread by droplet infection. Crowded conditions increase the likelihood of it spreading. People who are ill, malnourished or have problems with their immune system are more likely to recieve the disease. T notably affects the repiratory system, particularly by damaging nd destroying lung tissue. It also supresses the immune system, making the body less able to fight the disease. Only about 30% of people exposed to TB will actually become infected. Once the bacteria have been inhaled into the lungs, they will slowly multiply in the rimary infection, causing no symptoms. If there is a healthy immune system, there will be a localised inflammatory response forming a mass of tissue called a tubercule that contains dead bacteria. Primary TB infections often happen in childhood and most never notice they even had it. However, the bacteria can produce a thick waxy outer layer meaning they can evade the immune system. Bacteria with an effective coating will remain deep in the lungs dormant until the person is weakenedand they then produce active TB. Sometimes the active phase is simply aa fresh infection. However, about 80% of people with active TB are suffering from an activation of an old, controlled infection. The bacteria mutiply rapidly in the lungs, causing the typical symptoms of TB, including fever, night sweats, loss of appetite and loss of weight. Patients often feel tired  and have a cough, which damamges lung tissue and brings up blood. T cells are also targeted, reducing the production of antibodies and so disarming a critical part of the immune system. The bacteria stop working at 42 degrees, however human enzymes denature at 40 degrees. Eventually TB causes death, either through lack of oxygen or malnutrition. Therefore it is important to diagnose TB easily and cheaply. A chest x-ray will show TB damage to lungs, but other diseases can give similar images. New tests that examine the DNA of the bacteria are…




I'm currently studying SNAB biology and my textbook has none of this, thanks so much for the resource!!!