Tuberculosis is 500,000-years-old

December 7th, 2007 - 6:44 pm ICT by admin  

Washington, Dec 7 (ANI): Researchers from the University of Texas at Austin have found that Tuberculosis is 500,000-years-old.

They have found the most ancient evidence of the disease in a 500,000-year-old human fossil from Turkey.

The finding has suggested support for the theory that dark-skinned people who migrate northward from low, tropical latitudes produce less vitamin D, which can adversely affect the immune system as well as the skeleton.

Prior to this discovery in western Turkey, which helps scientists fill a temporal and geographical gap in human evolution, the oldest evidence of tuberculosis in humans was found in mummies from Egypt and Peru that date to several thousand years ago.

Paleontologists spent decades prospecting in Turkey for remains of Homo erectus, widely believed to be the first human species to migrate out of Africa. After moving north, the species had to adapt to increasingly seasonal climates.

John Kappelman, professor of anthropology at The University of Texas at Austin, and researchers from the United States, Turkey and Germany found this specimen of Homo erectus as a young male based on aspects of the cranial suture closure, sinus formation and the size of the ridges of the brow.

They also found a series of small lesions etched into the bone of the cranium whose shape and location are characteristic of the Leptomeningitis tuberculosa, a form of tuberculosis that attacks the meninges of the brain.

After reviewing the medical literature on the disease that has re-emerged as a global killer, the researchers found that some groups of people demonstrate a higher than average rate of infection, including Gujarati Indians who live in London, and Senegalese conscripts who served with the French army during World War I.

The research team identified two shared characteristics in the communities: a path of migration from low, tropical latitudes to northern temperate regions and darker skin colour.

People with dark skin produce less vitamin D because the skin pigment melanin blocks ultraviolet light. And, when they live in areas with lower ultraviolet radiation such as Europe, their immune systems can be compromised.

Kappelman said that it is likely that Homo erectus had dark skin because it evolved in the tropics. After the species moved north, it had to adapt to more seasonal climates. The researchers hypothesize the young males body produced less vitamin D and this deficiency weakened his immune system, opening the door to tuberculosis.

Skin colour represents one of biologys most elegant adaptations. The production of vitamin D in the skin serves as one of the bodys first lines of defences against a whole host of infections and diseases. Vitamin D deficiencies are implicated in hypertension, multiple sclerosis, cardiovascular disease and cancer, Kappelman said

Before antibiotics were invented, doctors typically treated tuberculosis by sending patients to sanatoria where they were prescribed plenty of sunshine and fresh air.

No one knew why sunshine was integral to the treatment, but it worked. Recent research suggests the flush of ultraviolet radiation jump-started the patients immune systems by increasing the production of vitamin D, which helped to cure the disease, Kappelman said.
The findings are published in the Dec. 7 issue of the American Journal of Physical Anthropology. (ANI)

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