Ancient illness: A 700-year-old Mexican mummy with a tummy ache
Credit: Yolanda Lopez Vidal and Gonzalo Castillo-Rojas
SYDNEY: The DNA of a bacterium that causes ulcers has been discovered in the stomach of a Mexican mummy, showing that ancient Americans were afflicted with the painful condition nearly 700 years ago.
Based on its location and articles it was buried with, the researchers believe the mummy dates from around 1350.
This suggests that the bacterium (Helicobacter pylori) came to the Americas with the first people from Asia 11,000 years ago, rather than with European colonists in the last 500 or so years.
The find is detailed this week in the journal BMC Microbiology.
The history of disease
Studies like this are reshaping our understanding of the history of disease. H. pylori has been found in stool samples from mummies in Chile and Egypt, but this is the first time it has been found in a North American mummy.
As well as stomach ulcers the bacterium can cause cancer, and is transmitted when food or water is contaminated with faeces. Several other pathogens have been identified by DNA analysis in mummies, including the bacteria that cause tuberculosis and leprosy.
Lead author Yolanda Lopez Vidal, a microbiologist at the National Autonomous University of Mexico, said the corpse was naturally mummified when it was left in a dry cave in the northern state of Chihuahua. The rapid drying stopped bacteria and fungi from degrading the body, preserving the internal organs and bacterial DNA in the stomach.
Examining internal organs
Lopez Vidal's team explored the internal organs of the mummy with an endoscope to avoid damaging the surrounding tissue and fabric. They took a sample of stomach tissue and detected H. pylori DNA in it with polymerase chain reaction, showing that the infection was present prior to the arrival of Christopher Columbus in the Americas.
Mummies are an important source of information about disease in ancient times, as many diseases leave no trace on skeletal remains, commented archaeologist Craig Barker from the University of Sydney's Nicholson Museum in Australia.
"I think that over the coming decades we will see some very interesting findings as the earliest dates of a number of illnesses are pushed back by palaeopathologists through the study of mummified remains," he said.
