Researchers have discovered Salmonella's DNA from the victims of the 16th century Mexican epidemic outbreak. Historically, almost 80 percent of the country's native inhabitants died because of unknown cause.
According to Nature, the research's claim is potentially the first genetic evidence of the pathogen that caused a large decline in Mexico's ancient inhabitants. In 1519, when the Spaniards arrived in Mexico the total population is at 25 million and after a century it declined to around 1 million.
The mysterious change in the number of population was believed to have caused by disease outbreak known as cocoliztli. Cocoliztli killed almost 7 million to 18 million inhabitants living in Mexico's highland regions.
Noting other immune defenses such as chicken pox, measles and typhus cocoliztli is still questionable until the current time. The massive number of victims throughout the said century is even mysterious alone and can attract curiosity to any scientist.
A team headed by geneticist Johannes Krause has sequenced the DNA from the teeth of the victims buried in Southern Mexico. The recovered bacterial DNA matched that of Salmonella. The damaged DNA fragments allowed the reconstruction of two genomes of "Salmonella enterica".
The discovered Salmonella strain causes enteric fever and typhus-like fever. It may kill 10-15 percent of people if left untreated. Hannes Schroeder who was not part of the study stated that the bacterium could have caused the great epidemic.
The question in the possible transfer of the bacterium in Mexico was also answered by a Journal published in bioRxiv. The publication suggests that the Salmonella Paratyphi might have arrived in Mexico from Europe. Mark Achtman and his team were able to sequence the said bacterium in Norway.
However, the existence of Salmonella in Norway 300 years before it became evident in Mexico does not prove that it was Europeans who spread the disease. Furthermore, the strain is transmitted through fecal material, it was believed that poor sanitation along with the downfall of the colonizing Spaniards might have caused the outbreak.
