Helicobacter pylori, a bacterium known to cause gastric infections, has been discovered for the first time in the stomach remains of the mummies of native people predating the discovery and colonization of the New World by the Europeans.

"It is only through the use of the stomach tissue of these incredible mummies that we were able to make this discovery. Infection is established when the micro-organism infiltrates the stomach lining and induces a local inflammatory response. This is unlike colonization, which does not cause such a response and does not occur in the stomach," said Yolanda Lòpez-Vidal of the National Autonomous University of Mexico.

Investigations show that the infection with this organism must have taken place around 1350 A.D. in an area of the Americas currently under the administration of Mexico. The clime of Mexico presents the perfect conditions for the mummification process to take place without human intervention. Bodies remaining in dry caves are subjected to rapid dehydration processes, allowing most of the organs to remain almost intact over long periods of time, unlike the mummies of the ancient Egypt which have been preserved by people through different mummification techniques.

Also, the ancient Egyptians removed the internal organs of the deceased during the mummification process, while in mummies preserved through natural processes the internal organs remain in their place and are the last ones to be dehydrated.

Similarly to stomach ulcers, the Helicobacter pylori bacterium is able to determine diseases such as gastritis, duodenitis and cancer and usually infects the host through feces contaminated food or water. During the study, the research team found DNA fragments of the bacterium in the mummies of a child and that of an adult found in the La Ventana funeral cave and in the caves of the Durango state.

Previous studies also indicated the presence of Helicobacter pylori in similar populations, although this is the first time a study suggests that it triggered gastric infections.