Human Fossil Shows Signs of Tuberculosis

A half-million-year-old human skull found in western Turkey provides the earliest evidence yet found of the existence of tuberculosis, according to news from the University of Texas at Austin.

Up until now, the oldest signs of tuberculosis came from Egyptian and Peruvian mummies that were several thousand years old.

An international research team found the 500,000-year-old skull of a young male Homo erectus in a block of travertine stone in Turkey being sawed into building tiles. The scientists discovered small lesions in the skull that indicate the young man suffered from Leptomeningitis tuberculosa, a form of TB that attacks the protective membrane covering the brain.

The finding also lends support to the theory that humans with dark skin who migrated north from tropical regions were more likely to contract diseases because of vitamin D deficiency.

The research team had reviewed medical literature on tuberculosis and found that some groups of people experienced higher-than-average rates of TB infection. The thread tying together these groups -- including Gujarati Indians living in London and World War I soldiers from Senegal who served with the French Army -- was darker skin color combined with movement from tropical latitudes to temperate regions farther north.

The research team believes that, because the species evolved in the tropics, Homo erectus also had dark skin. In the case of the ancient skull found in Turkey, well north of the tropics, scientists believe the young man's skin color left his body unable to produce adequate amounts of vitamin D from sunlight. The deficiency left him with a weakened immune system that caused him to contract tuberculosis.

"Skin color represents one of biology's most elegant adaptations," said John Kappelman, professor of anthropology at the University of Texas at Austin. "The production of vitamin D in the skin serves as one of the body's first lines of defenses against a whole host of infections and diseases. Vitamin D deficiencies are implicated in hypertension, multiple sclerosis, cardiovascular disease and cancer."

In the days before antibiotics, tuberculosis patients were frequently prescribed stays in sanatoria and told to get lots of sunshine and fresh air.

"No one knew why sunshine was integral to the treatment, but it worked," Kappelman said. "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."

The team working on the Turkish find included researchers from the U.S., Turkey and Germany. Their findings are published in the Dec. 7 edition of the American Journal of Physical Anthropology.

University of Texas at Austin, "Most Ancient Case of Tuberculosis Found in 500,000-Year-Old Human." URL: (http://www.utexas.edu/news/2007/12/07/anthropology-3/)