New research shows that a strain of Tuberculosis was already circulating from the South American coast to the mountains.
Tuberculosis was the first disease to arrive in South America, but recent evidence shows that it wasn't the first disease to come from Europe.
In South American skeletons, researchers found the genes of a bacterium that causes Tuberculosis in humans.
Scientists have known for a long time that Tuberculosis can jump from one mammal to another, and it has happened tens of thousands of times around the world. The discovery of several ancient strains in South America suggests that our history books might be incorrect about the original spread of thesebacteria.
The strains found in the pre-contact state were very similar to the strain found in marine mammals.
The most recent common ancestor for all genetically related strains of mycobacterium emerged less than 6,000 years ago, and it is believed to be the first voyagers.
The skeletons of people who lived in inland Peru and Columbia have been found to have three more ancient strains of Tuberculosis. The skeletons were discovered far from the coastlines and even here, over wide mountain ranges, it appears that the local human population has been affected by the disease.
Three new cases of pre-contact-era South American Tuberculosis are from human remains that come from inland archaeological sites, two of which are located in the highlands of the Colombian Andes, according to anthropologist Tanvi Honap from the University of Oklahoma.
All of the new ancient TB genomes are similar to the one found in the ancient coastal individuals and in modern-day seals and sea lions.
Local people in inland Peru and Columbia did not usually eat seal or sea lion meat. The disease probably got here via another host.
Instead of jumping directly from pinniped to these inland individuals, thesebacterial strains would have likely crept inland over time, bouncing from human to human or spreading among other land mammals.
In New Zealand, there are reports of people jumping from seals to cattle to provide a bridge between land and sea.
Honap explains that M. pinnipedii could have been brought inland via the animal life.
It could have been brought inland via human-to-human transmission, or a combination of both.
European strains of the disease replaced the original South American strains, disguising the deeper ecology of the disease.
The history of this disease is being teased out by researchers. They hope to identify new strains of ancient Tuberculosis to figure out how the illness became endemic in different locations.
The authors believe that one or multiple separate introductions of M. pinnipedii from pinniped populations to human and/or animal populations is the most plausible explanation for their spread to these inland locations.
Additional data from the pre-contact Americas will help develop these hypotheses further.
Nature Communications published the study.
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