Tuberculosis is a contagious bacterial disease that is acquired, often in childhood, by inhaling the Tuberculosis bacilli present in the spray caused by a sneeze or cough from someone who is actively infected. It may also be acquired from infected cow's milk. The disease usually starts in a lung and takes one of two forms: either primary infection or reactivated infection.
In 90 to 95 percent of those people with a primary infection, the body's immune system suppresses the infection, but it does not kill the bacilli. They remain alive but dormant and may cause the reactivated form of tuberculosis. After the Tuberculosis bacilli are reactivated, they may spread throughout the body via the lymphatic system and the bloodstream.
The first symptoms of the primary infection may include a cough, fever, tiredness, night sweats and loss of weight. Tuberculosis is confirmed through clinical investigations, which may include a chest X-ray, isolation of the bacilli from the person's sputum and a positive reaction — localised inflammation to the Mantoux test, an injection of tuberculin (a protein extracted from tuberculosis bacilli) into the skin.
The gradual emergence in adults of the destructive and progressive form of tuberculosis is caused by the reactivated infection. It occurs in 5 to 10 per cent of those who have had previous primary infection. Another form, reinfection tuberculosis, occurs when someone with the dormant, primary form is reinfected. This type of tuberculosis is clinically identical to the reactivated form. Reactivation is more likely in those people whose immune system is suppressed, such as the elderly, those on Corticosteroids or other immuno-suppressant drugs, and those who have AIDS. Reactivation tuberculosis may be difficult to identify because the symptoms may start in any part of the body seeded with the bacilli. It is most often first seen in the upper lobes of the lung, and it is frequently diagnosed after a chest X-ray. The early symptoms may be identical to those of primary infection: a cough, tiredness, night sweats, fever, and loss of weight.
If left untreated, tuberculosis continues to destroy tissue, spreading throughout the body and eventually causing death. It was one of the most common causes of death in India and the disease is on the increase again. Vulnerable groups are people with suppressed immune systems and the homeless.
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Friday, May 25, 2007