What is TB?
Tuberculosis (TB) is a disease caused by a small bacterium called Mycobacterium tuberculosis. The most common form of the disease is when it damages the lungs, but it can affect many parts of the body, when it is called extra-pulmonary disease. TB is highly infectious and is usually caught by breathing in bacteria from the air. People with untreated disease in their lungs or throat expel the bacteria as small droplets when they cough, sneeze or even during talking. These tiny droplets can remain suspended in the air for long enough to be inhaled by other people in the vicinity. The bacteria have tough waxy coats and can survive this process. Once inside the lung the bacteria can transfer to other parts of the body. Most people are able to control the infection and do not develop the tuberculosis disease, but between one and two in every 10 infected people will get sick and require treatment. Sometimes it takes years for symptoms to emerge, a condition known as latent TB. It is not understood why some people stay well while others become ill. People with damaged immune systems have a much higher risk of developing tuberculosis disease.
What are the symptoms?
The classic symptom of TB is a cough that gets worse over a period of weeks or months. Other symptoms include fever and weight loss. Coughing blood is a strong indicator of lung damage caused by TB. Tuberculosis can affect many parts of the body and symptoms are non-specific. When it affects the central nervous system, a form of the disease that is often fatal in children, the symptoms include fevers and headaches.
How many people are affected worldwide?
It has been suggested that one third of the world's population has at some time been infected by the TB bacteria. During 2007 there were an estimated 13.7 million people with tuberculosis disease and 1.75 million deaths worldwide. It is a disease of poverty, with less than 10% of cases occurring in the wealthy industrialised countries. The countries hardest hit by the epidemic are those of sub-Saharan Africa, where high rates of co-infection with HIV and weak public health systems have contributed to a dramatic rise in the number of cases.
How big is the problem in Uganda?
It is estimated that during 2007 there were 132,000 people in Uganda with active TB and 29,000 deaths from the disease. The amount of drug-resistant disease is not known. In a recent study undertaken at Mulago hospital in Kampala, of 409 "re-treatment" patients who had not been cured by previous attempts at treatment, 52 were found to have multi drug-resistant TB (MDR-TB).
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