The tuberculin test involves injecting a product of the bacteria's metabolism into the skin; a localised immune reaction will occur a few days later. A reddened, raised, hardened area appears at the site of the injection indicating that at some time the person has been exposed to the bacterium.
The person's medical records would show that they are tuberculin positive.
A person who is tuberculin positive can present the worst symptoms of tuberculosis when the dormant bacteria become active again. This time, the disease would be identified by doctors as called postprimary tuberculosis infection. What causes this re-activity?
- Stress, overcrowding, malnutrition (poor, inadequate diet) and hormonal imbalance can provide the conditions that are ideal for a repeated pulmonary infection.
Useful link: http://bepast.org/docs/photos/MDR%20tuberculosis/tuberculosis_incidence… Global distribution of TB. Note and consider carefully what the relationship might be between the incidence of TB and regions shown in green.
Postprimary symptoms are serious and severe damage is caused to the lungs. Lesions occur which means that sections of lung are effectively 'dead'. When extensive tissue destruction has occurred, live bacterial cells can be found in the sputum of the individual.
Thus the cycle of infection can continue when such persons sneeze and cough as they will invariably do due to the terrible damage to the lungs.
Useful link: http://commons.wikimedia.org/wiki/Image:Tuberculosis-x-ray-1.jpg Image of tuberculosis X-ray
