Bugs – TUBERCULOSIS

General Information

It is estimated that at least one third of the human population is infected with tuberculosis at any time. It can affect many different areas of the body including the chest, skin, bones, kidneys and brain. Approximately eight million new cases occur each year with over 3 million deaths attributed to this illness. It has been suggested that one human infection occurs each second and that any individual infected with untreated pulmonary infection (the so called ‘open case’) can infect up to 10 other people.

Mode of Infection

Unprotected exposure causes the typical pulmonary infection but the disease can also affect other parts of the body either through swallowing infected saliva or via the bloodstream. The normal incubation period is between 4 to 12 weeks after exposure.

Symptoms

The classical triad of weight loss, night sweats and cough is often seen in many of the developing countries. However patients may also present with symptoms associated with the infection of other organs e.g. kidney, brain, bone or skin.

The initial exposure to infection with tuberculosis may not cause any serious symptoms and the disease may be ‘enclosed’ by body defences at that time. However, with the onset of any immunodeficiency disorder (eg AIDS, Leukaemia, Steroid usage etc) this personal protection may become deficient and the disease may reactivate and lead to the standard symptoms.

Geographical Distribution

Even though this disease is found in every country in the world, it mainly occurs in the developing countries. It is estimated that over 90% of the world’s tuberculosis is confined to Africa, Central and South America, and Asia. Significant disease outbreaks also occur in some of the island countries.

Transmission

The disease is mainly transmitted via inhaled respiratory droplets or via with direct contact with infected saliva.

Treatment

Medications used for treating this disease are changing as resistance to the classical drugs is growing at an alarming rate. The 6 months of treatment required is a major disincentive for many to complete their course.  So recent regimes are evaluating much shorter intensive courses.