Egyptian mummy heads. Image courtesy of American Exhibitions, Inc.
TB or not TB: that’s really not a question
Tuberculosis is an ancient scourge, but new research by researcher Sebastien Gagneux and colleagues at the Swiss Tropical and Public Health Institute in Basel suggests the disease’s association with humans is much older than previously thought.
TB, according to Gagneux’s findings in Nature Genetics, has been a close and problematic companion of humanity for more than 70,000 years, long before our ancestors even migrated out of Africa.
We have a decidedly distinct and painful relationship with Mycobacterium tuberculosis, the microbe that causes TB. It is an exclusively human pathogen, unable to survive in any other host or reservoir. At the same time, TB has long been exceedingly proficient at killing the very species it needs to survive.
Throughout recorded human history, there are references to its common proclivity to kill, under a variety of names: consumption, phthisis, scrofula, the White Plague. Evidence of deadly TB infections can be found in Neanderthal fossils. It’s estimated that 20 percent of all deaths in Europe during the 19th century were due to TB.
Gagneux’s research suggests that TB’s ability to persist despite its murderous ways may lie with its tendency to go dormant in some hosts, sometimes for decades. By doing so, it ensures that it doesn’t kill every host, which would be problematic in small populations – as was the case among early humans.
Long latency periods make TB hard to control, a fact evidenced by the disease’s continued plaguing of humanity. M. tuberculosis causes 8 to 9 million cases of infection each year, and upwards of 2 million deaths, primarily in Africa, Eastern Europe and the former Soviet Union.
While the specter of drug-resistance is becoming increasingly worrisome, the standard therapy for TB of antibiotics remains largely effective. But it involves a rigorous regimen of treatment that the patient must follow without fail.
“TB can be cured with an antibiotic regimen,” said Richard Garfein, PhD, MPH, professor in the Division of Global Public Health at the UC San Diego School of Medicine. “But the biggest problem care-givers face, especially in developing countries, is making sure patients are compliant with treatment that takes six months or longer to complete.”
Garfein is part of an effort to apply modern technology to an age-old foe. Working with the Verizon Foundation, he is overseeing a pilot program in which TB patients living in San Diego and Tijuana are observed for treatment adherence via videos sent over secure mobile phones. You can read more here.