Wednesday, October 10, 2007

The White Plaque, TUBERCULOSIS (T.B.)

Tuberculosis (TB) is an ancient infection that has plagued humans throughout recorded and archeological history. It appears to be old as humanity itself. Skeletal remains of prehistoric humans dating back to 8000 B.C. found in Germany, show clear evidence of the disease. Egyptian skeletals from 2500-1000 BC have revealed evidence of Pott’s disease of the spine. Ancient Hindu and Chinese writings have documented the evidence of the disease. Though the disease is very ancient, it was not earlier than 1882, when Robert Koch discovered the causative chronic narcotizing acid fast bacillus, which was later on characterized as Mycobacterium. It is truly a global menace with remarkable staying power. Even today the infection remains the cause of higher morbidity and morality than any other infection in the world. This is because of its great prevalence in the densely populated developing countries like African countries, India, China, Indonesia and Nigeria. According to estimates of the World Health Organization (WHO), tuberculosis is now the leading infectious cause of death world wide being responsible for 3 million deaths and infecting around 9 million new cases annually. During last year, about 40 million people, most unknowingly, would have quietly become infected with tuberculosis. The disease is responsible for 7% of all adult deaths & 25% of preventable adult deaths and children too. Indeed there are more cases of tuberculosis in the world today than at any previous time in human history. Because of relentless spread of tuberculosis throughout the world, WHO took the unprecedented step of declaring tuberculosis a global emergency in 1993 that has to be given prime importance. Persistence is the hallmark of tuberculosis (TB) and, like the protean nature of the disease itself, it has several manifestations. Most healthy individuals who are exposed to Mycobacterium tuberculosis mount a vigorous cell-mediated immune response. In the majority of cases, disease progression is halted but the pathogen is not eradicated. Reactivation after years or decades of clinical latency can lead to chronically active TB, which may remain transmissible indefinitely if treated inadequately. On current estimates, nearly two billion individuals worldwide have been exposed to the tubercle bacillus. As many as 200 million of these latent infected people are expected to reactivate sometime later in life. Disease has had an incalculable influence on the history of mankind. The earliest records tell of plagues and pestilences which devastated whole countries and had profound effects on social structure, contributing to unrest, famine, migration and wars. The story of tuberculosis gives us, perhaps, as good a picture as any of the impact of disease on life and culture. Apart from leprosy, western civilization has known no communicable disease which may run such a protracted course, affecting almost any part of the body and giving rise to such long periods of ill-health and disablement.