The uncontacted tribe who could help us beat disease: First study of bacteria living on Amazon villagers reveal how much the modern world has changed us

  • Researchers sequenced microbiomes of Yanomami people in Amazon
  • Testing found they harbour microbiomes with the highest diversity of bacteria and genetic functions ever reported in a human group
  • Bacteria they found could be potentially beneficial to modern society 

Researchers have completed the first comprehensive study of the microbes living on and in and uncontacted tribe from the Amazon.

They say the results show just how modern lifestyles and diets have changed us -  and that the bacteria they found could be potentially beneficial to modern society.

Researchers sequenced the microbiomes of Yanomami people living in a remote Amazon village in Venezuela who had not had previous contact with non-Yanomami.

There are about 26,000 Yanomami living in Brazil and 15,000 in Venezuela, mostly in federally protected reserves near rivers and in remote mountains.

There are about 26,000 Yanomami living in Brazil and 15,000 in Venezuela, mostly in federally protected reserves near rivers and in remote mountains.

THE YANOMAMI TRIBE 

The Yanomami are an indigenous ethnic group in the Amazonian region of South America. 

There are about 26,000 Yanomami living in Brazil and 15,000 in Venezuela, mostly in federally protected reserves near rivers and in remote mountains. 

The Yanomami are hunter-gatherers. 

They gather wild bananas, seasonal fruits, palm hearts and cassava. 

They hunt birds, small mammals, crabs, frogs, small fish and the occasional peccary, monkey or tapir. 

The group doesn't grow food or domesticate livestock. 

The researchers found that Yanomami people harbor microbiomes with the highest diversity of bacteria and genetic functions ever reported in a human group. 

'That tells us that Western diets and lifestyles have a great impact on our microbiomes', experts at University of San Diego said.

'Studying the microbiomes of people in remote areas may hold the key to understanding microbes we have lost through antibiotics, sealed buildings and lack of exposure to the outdoors,' said study co-author Rob Knight.  

In the new study published April 17 by Science Advances, researchers sequenced the microbiomes of Yanomami people living in a remote Amazon village in Venezuela who had not had previous contact with non-Yanomami. 

This information revealed, for the first time, the species of bacteria that co-exist with people who have never been exposed to industrialized society, including Western food and antibiotics.

'Our findings emphasize the need for extensive characterization of the function of the microbiome and resistome in remote nonwesternized populations before globalization of modern practices affects potentially beneficial bacteria harbored in the human body,' the researchers wrote.

Many Yanomami now regularly interact with Western civilization through trade, but some villages have never had contact with non-Yanomami people. 

One such unmapped village was first spotted by an army helicopter passing overhead in 2008. In 2009, a medical mission landed there. 

As part of their 2009 visit to this previously uncontacted Yanomami village, medical professionals collected samples from the skin, mouths and fecal matter of 34 of the 54 villagers before vaccines or antibiotics were administered. 

The samples were frozen until DNA extraction and bacterial culturing could be performed for the purposes of this study.

SHOULD BLOOD SAMPLES HAVE BEEN TAKEN? 

Yanomami indigenous leader Davi Yanomami claims Americans' 'robbed blood' for the tests

Yanomami indigenous leader Davi Yanomami claims Americans' 'robbed blood' for the tests

Thousands of blood samples have been returned to the Yanomami tribe in Brazil, after they were taken by American scientists in the 1960s and held in U.S. academic institutions without the tribe's consent, according to Survival international.

The Yanomami have been fighting for their return for over a decade.

The Yanomami buried the 2,693 samples during a special funerary ceremony presided over by shamans in the Yanomami community where many of the samples were collected.

Only 15 Yanomami whose blood was taken in the late 1960s were able to attend the ritual. Shamans performed funerary rites for those who gave blood and have since died.

Keen to collect blood samples from a very isolated community, U.S. scientists collected thousands of samples from the Indians in Brazil and Venezuela without obtaining their informed consent. 

The Yanomami only discovered years later that their blood was being stored in research institutes – in violation of their beliefs and funerary customs of cremating those who have passed away and destroying their possessions. 

Without obtaining the Yanomami's consent, some institutions extracted DNA from the blood for genetic tests in the 1990s.

Yanomami spokesman Davi Kopenawa said, 'These Americans robbed our blood. 

'They did not say anything in our language about the tests they were going to do. Nobody knew that they were going to use our blood to do research.'

Back in labs in the U.S. (at Mount Sinai, New York University, University of Colorado, Boulder and others), researchers sequenced DNA isolated from the Yanomami samples. 

From this, they were able to identify all of the bacterial species that make up the skin, mouth and gut microbiomes of people who had never been exposed to Western diets, antibiotics or other environmental factors that make up life in industrialized societies. 

The researchers then compared these non-Westernized microbiomes to the microbiomes of people living in Western society and people living in villages in the midst of transition from isolation to urban lifestyles. 

Bacteria isolated from Yanomami microbiomes carried genes that confer resistance to man-made antibiotics, despite the fact that they were never previously exposed to antibiotics. 

This finding suggests that many bacterial species contain antibiotic resistance genes naturally, even without the selective pressure of antibiotic use. 

What happens in Western cultures, the researchers hypothesize, is antibiotic use simply gives naturally resistant bacteria a survival advantage over non-resistant bacteria.

The researchers say the study could help develop new medical treatments.

'First of all, this study gives us a glimpse of what our microbiomes might have looked like before our modern habits began to impact the beneficial bacteria that call us home. 

'Studies like this one help us better understand what factors can alter a microbiome and the effect those changes can have on a person's health — information researchers need to guide efforts to manipulate the microbiome to treat disease and restore health.' 

 

 

 

 

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