Literature Review
History
Tuberculosis, a disease caused by several species of mycobacteria that are spread from person to person through the air. It has plagued humankind for many thousands of years. TB usually attacks the lungs, but it can also attack and damage any part of the body, such as the brain, kidneys, or spine. It is a worldwide disease and in many countries is a major cause of death. After declining in incidence for a number of years, it has begun to increase in frequency, especially in developing and underdeveloped countries. This is primarily because of the AIDS epidemic. Ninety percent of the cases of tuberculosis diagnosed are pulmonary tuberculosis caused by Mycobacterium tuberculosis.
Tuberculosis was well known in classical Greece, where it was called phthisis. Hippocrates clearly recognized tuberculosis and understood its clinical presentation. In the 19th centuries a novel method was proposed for the disease namely Sanatoria (an immune place). The earliest evidence of tuberculosis (TB) in man and animals is provided by bone finds- mainly fragments of vertebrae showing the gibbus typical of tuberculous Pott’s disease.…show more content… The complete genome of M. tuberculosis (H37Rv used as reference strain) documented in 1998 (Cole ST et al.,1998). This revealed a circular genome in the region of 4,411,529 base pairs long, contains 3,924 open reading frames and containing approximately 4000 genes. The genome of M. tuberculosis has a very high GC content (65.6%) (Naya et al. 2002). There are a number of repetitive DNA sequences in the M. tuberculosis genome including insertion sequences (IS), the direct repeat (DR) region, the major polymorphic tandem repeats (MPTR) and the polymorphic GC-rich repetitive sequence (PGRS) (Poulet and Cole ST