Tuberculosis is a chronic infection caused by Mycobacterium tuberculosis and occasionally other strains of Mycobacterium. Mycobacterium tuberculosis is an acid fast bacteria that has an unusual, waxy coating on its cell surface composed of mycolic acid, which makes the cell impervious to Gram staining. Mycobacterium’s tough cell wall, high lipid content, and ability to grow intracellularly are all factors that contribute to its virulence. Additionally, Mycobacterium tuberculosis has very simple growth requirements and is able to grow slowly even in harsh conditions.
The bacteria can be found in soil and water, but Mycobacterium tuberculosis is mainly identified as a bacterium ...view middle of the document...
It is widely held that tuberculosis has evolved from more primitive forms of Mycobacterium. Utilizing Mycobacterial tandem repeat sequences as genetic markers test indicate that Mycobacterium tuberculosis consists of two independent clades. One clade is exclusively derived from humans and the other from both animal and human isolates. The animal-human isolate in all probability also was human in origin and connected to the rise of animal domestication and early farming. The estimated age of Mycobacterium tuberculosis is approximately 40, 000 years old and corresponds with man’s migration out of Africa.
Tuberculosis has been found in artifacts from ancient Egypt, India, and China. Among Egyptian mummies spinal tuberculosis, known as Pott’s disease has been discovered and evidence of tuberculosis from the cervical lymph nodes termed “Scrofula” occurred in the Middle Ages. Scrofula was also known as the “king’s evil” as it was widely believed that the kings of England and France could cure scrofula simply by touching those that were affected.
Phthisis is a Greek term that literally means to waste away. Hippocrates used this term to identify the most common cause of illness of his time which typically affected individuals between eighteen and thirty five and was almost always fatal. Aristotle, a famous Greek philosopher, believed that Phthisis was contagious even though many of his contemporaries believed it was hereditary.
In 17th century Europe tuberculosis was called the “White Plague” and was the principal cause of death in 1650. The disease was referred to as the “White Plague” because people who had it became very pale. The disease proliferated in Europe due to poor sanitation, overcrowding, and malnutrition. Oddly enough the disease was seen somewhat as a status symbol as famous men and women were infected with the disease. Among those afflicted were the poets John Keats and Percy Bysshe Shelley, the authors Robert Louis Stevenson, Emily Bronte, and Edgar Allen Poe, and the musicians Nicolo Paganini and Frederic Chopin.
In 1882, Robert Koch discovered a staining technique that enabled him to see Mycobacterium tuberculosis and was awarded the Nobel Prize in 1905 for his discovery. In 1895 Wilhelm Roentgen developed the X-ray which further advanced diagnostics of tuberculosis. Tuberculosis derived its name from the numerous tubercles or holes formed in the lungs and other parts of the body by the bacteria and had an affinity for people with certain risk factors.
One of the most significant risk factors for tuberculosis is HIV infection. Statistically, about thirty percent of people who are infected with tuberculosis and HIV will develop active tuberculosis in their lifetime. Conversely, people who are infected with tuberculosis and not infected with HIV have approximately a fifteen percent chance of developing active tuberculosis. Other diseases that lower immune response such as diabetes, renal disease, and...