Tuberculosis

Tuberculosis (TB) is a curable disease that affects the respiratory system. It kills approximately 1.6 million people per year and is returning, partly due to increased travel and migration opportunities, to those Western countries where it had been thought to be eradicated. The main means of spreading the disease is through coughing and sneezing. Tubercles form as lesions which consist of some dead tissue and are ringed by scavenger cells (phagocytes); the lesions form as part of the body's natural reaction against the presence of infection. Tubercles themselves are too small to see with the naked eye, but they can agglomerate [Page 1685]to form large tuberculous masses which cause particular damage.

The most common form of tuberculosis is pulmonary tuberculosis and children and young people are more vulnerable to this form, although infections can occur at any age. Primary pulmonary infection may pass without major incident but might leave infection in the bloodstream or a tear on the lung. Subsequent increases in infection will occur in general terms over a lengthy period, with the patient suffering from weakening of strength, coughing, and loss of color and vigor. X-ray examination can reveal the presence of damage to the lung and medical advice should be sought if persistent symptoms are observed, particularly if contact with another infected person is possible or suspected.

Other areas of concern include tuberculous meningitis and bone and joint tuberculosis, although the pasteurization of milk has been an effective counter to the latter problem. The principal cause of death is the spreading of lesions across the lungs, which leads to a reduction in the ability of the patient to breathe which intensifies and is accompanied by the characteristic coughing up of blood.

In 1882, Robert Koch, a German physician, identified the tubercle bacillus as being responsible for the disease. These include several species of mycobacterium, most notable of which is M. tuberculosis, which is responsible for infection of humans. Cows and some domestic animals are also susceptible to the disease. It has been known to be a lethal disease throughout history and has been particularly deadly in urban areas and places where hygiene conditions are poor. Clearly, therefore, the poor have been more vulnerable to the disease than the rich.

Affected people suffered from breathing problems and some achieved limited relief by exposure to cool weather in a lofty climate, such as were to be found in mountainous terrain.

European sufferers who could afford to do so, therefore, might be sent to Switzerland to seek a cure. American sufferers also were sent to mountainous areas in that country. By 1990, some 3.8 million cases of tuberculosis were reported globally and 49 percent of these were in southeast Asia. The disease was largely active in that region and in sub-Saharan Africa. The number of cases had started to increase because of the spread of human immunodeficiency virus (HIV), the presence of which causes an increase in the likelihood that a person infected with TB will go on to develop a full case of it.

A second problem increasing the prevalence of TB is resistance to existing drugs, which has become a serious issue, especially in the United States. Even so, it appears that the total number of incidences of TB cases may have peaked globally, although the shift toward outbreaks in Asia and sub-Saharan Africa continues. Another area of concern is the eastern Mediterranean, where total numbers of new cases continue to rise. In 2005, 7.4 million out of an 8.8 million total of new cases of tuberculosis were found in Asia and sub-Saharan Africa. Of the 1.6 million deaths due to the disease, some 195,000 people were also suffering from HIV.

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