Tuberculosis



Tuberculosis

Introduction

Tuberculosis or TB is a common disease around the globe which may turn lethal in various instances. It is an infectious disease and is caused by a form of bacteria, well known as Mycobacterium Tuberculosis. In common cases, the infection attacks on the lungs; however, in some is also spreads in other parts of the body. The spread of TB occurs through air; as people having the infection sneeze, cough or spits in the air, the bacteria is transferred into the air which other people can catch easily. Although the disease is easily transmitted; nevertheless, the results of the infection are asymptomatic in most of the cases. Only one out of ten people, who get infected with these bacteria, actually develops the disease, which if not treated appropriately leads to death amongst 50% of the infected people. It is estimated that M-tuberculosis has approximately one-third of the world's population. It is also believed that every one second, a new infection develops. 13.7 million People were reported with chronic cases in 2007; whereas, till the end of 2010, 1.45 million deaths and 8.8 million new cases of tuberculosis have been reported across the world (Schiffman, 2009).

Most of the cases of tuberculosis are believed to develop in the developing countries. The exact figures of tuberculosis cases are turning down since 2002; moreover, same is the scenario with new cases of TB. One explanation given for the people of developing countries prone to developing tuberculosis is that, their immune systems are comparatively compromised because of higher prevailing rates of HIV and AIDS in those countries. Thus, because of this, 80% of many African and Asian countries are tested positive for tuberculosis; on the other hand, the rate of reported positive cases of tuberculosis in the United States is limited to only 5-10% of its population (Jasmer et al, 2002).

Etiology

As discussed earlier, mycobacterium is the root cause of this infection. This bacterium belongs to the bacillus family and is an aerobic non-motile one. Because of the high lipid contents of this bacterium, it exhibits a number of exclusive clinical features. The pathogen divides itself after every 16-20 hours which is an immensely slow rate if compared with the division rate of other bacteria dividing after every one hour. Because of the absence of an outer phospholipid membrane, it is referred to as a gram-positive bacterium; regardless, of having a cell wall. Although when gram-stained, the bacterium either remains invisible or dyes very weakly gram-positive, due to mycolic acid and the high lipid contents present in the cell walls. This bacterium can survive in dry conditions for a number of weeks and can survive weak disinfectants. Although, bacteria are naturally occurring single celled organisms, growing only within the host cells; however mycobacterium can also be cultivated within the laboratory.

It has been observed that 5-10% people who are not suffering from HIV develop tuberculosis in an active stage. Contrary to this, 30% of people infected with HIV develop ...