As if being a human sacrifice weren’t bad enough, a teenager may have been fighting off tuberculosis before being killed on top of a South American volcano 500 years ago.
As she climbed to her death, the immune system of a 15-year-old Incan girl known as the Maiden was combating a bacterial infection caused by a type of Mycobacterium, an analysis indicates. Angelique Corthals, a forensic anthropologist at the City University of New York, and colleagues report the findings online July 25 in PLoS One.
La Doncella, as the Maiden is called in Spanish, was one of three children whose mummified remains were found near the summit of Llullaillaco volcano in Argentina in 1999. She, a younger girl and young boy were probably sacrificed in a ritual called Capacocha. But the exact cause of the children’s deaths has remained a mystery; their perfectly preserved mummies show no signs of violent trauma.
Corthals wanted to know whether the children were given a fermented corn drink called chicha, which was used to numb sacrifice victims as part of the Capacocha ritual. The alcohol in the drink would have evaporated almost immediately, but the children might still have traces of corn clinging to their lips, she reasoned. Researchers swabbed blood and saliva from the lips of the Maiden and the boy, and snipped off a small piece of the boy’s blood-soaked cloak for testing using a technique that identifies proteins contained in the samples. The younger girl’s face was damaged by a lightning strike after burial, so the researchers couldn’t include her in the study.
Coauthor Antonius Koller of the State University of New York Stony Brook Medical Center and his colleagues determined which proteins were present in the samples. There was no sign of corn liquor, Corthals says, but the protein profile indicated clearly what the two mummies’ immune systems had been up to at the time of death.
The Maiden’s immune system was more active than the boy’s was, and her swabs contained immune system proteins indicating a chronic lung infection. Modern people fighting off Mycobacterium diseases such as tuberculosis make similar proteins. DNA evidence showed that the girl was carrying some type of Mycobacterium, although the researchers can’t yet nail down which species of the bacterium was infecting her.
The new findings are consistent with radiological exams showing signs of lung and sinus inflammation in the Maiden. The boy showed no signs of active infection.
Other researchers are sure to latch onto the new research approach described in the study, says Robert DeSalle, of the American Museum of Natural History in New York City. “It is going to be the first paper among probably a lot to come looking at infectious diseases among dead people,” he says. He predicts that examining the immune systems of long-dead creatures may also help solve some archaeological debates, such as whether woolly mammoths were victims of overhunting or disease.