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.
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