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Novel approach finds lung infection in 500-year-old mummy

posted 6 Aug 2012, 13:20 by Mpelembe   [ updated 6 Aug 2012, 13:21 ]

A combination of DNA and protein analysis has been used for the first time to determine the health of a mummified 15 year old girl at the time she died. Scientists say that "La Doncella" (The Maiden), a 500-year-old Inca mummy, was suffering from a lung infection and believe the findings demonstrate the enormous potential of the new method.

SALTA, ARGENTINA  (REUTERS) - "La Doncella" ("The Maiden") is a 500-year-old Inca mummy uncovered in an expedition to the Llullaillaco volcano in Argentina in 1999. She now resides behind glass at a museum in Salta, northern Argentina.

"La Doncella" was 15 years old at the time of her death. She was discovered with two other children, a 7-year-old boy ("El Nino") and a 6-year-old girl ("La Nina"). The three were sacrificed 500 years earlier and because of the local environment and cold temperatures, are exceptionally well preserved.

For forensic anthropologist Dr. Angelique Corthals from Stony Brook University in Stony Brook, New York, they were ideal candidates to test a novel approach to disease detection in ancient remains.

Called proteomics, the method breaks proteins down into amino acids which can then be compared to DNA samples.

Corthals's team swabbed the lips of La Doncella and El Nino and isolated their proteins. After breaking them down, they were able to compare the amino acid chains to the proteins they found in databases of the human genome.

They found that the protein profile from "The Maiden," was similar to that of chronic respiratory infection patients, demonstrating that her immune system had responded to such an infection. Analysis of her DNA showed the presence of pathogenic bacteria responsible for upper respiratory tract infections. In addition, X-rays of the lungs of the Maiden showed signs of lung infection at the time of death. 

Proteomics, DNA, and x-rays from "The Boy" showed no signs of a similar contagion.

"When we compared the two protein profiles, we found out that they are very, very different which really showed that The Maiden was fighting an infection," said Corthals.

DNA testing has been carried out on many archeological finds, including the famous King Tutankhamen (King Tut) in Egypt. But even though, in his case, DNA analysis detected the presence of malaria, Corthals says it could not identify the origin of the infection. She says it could have come from outside contamination.

"Now we have a way of looking at whether the infection is active or whether the pathogen that you have detected using DNA is just latent. So for example, for King Tut, yes, there was pathogen DNA discovered and detected, but do we know whether or not he was actively fighting malaria at the time of death? Well we can't be sure of that," said Corthals.

Corthals says the combination of poteomics and DNA analysis will help scientists better understand how pathogens and their hosts have interacted in the past and how the immune system fights infections in patients today.

She believes it will also open doors to better ways of fighting future pathogens, like H1N1.

"I very much think that proteomics is the thing of the future and the two together, the two tools, the human genome and the future - it's not quite done yet - but the future human proteomes will really fast forward advances in medicine," said Corthals.

If successfully preserved, the three mummies in Argentina will not only be a valuable historic and ancestral record, their significance will live on in future medical advances.