Thousands of years ago, across the Eastern Mediterranean, several Bronze Age civilizations made a remarkable breakthrough at about the same time.
The Old Kingdom of Egypt and the Akkadian Empire also collapsed, and there was widespread social crisis in the Near East and the Aegean, with population decline, destruction, reduced trade, and significant cultural change.
As always, fingers have been pointed at climate change and shifting beliefs. But scientists have found a new culprit in some old bones.
A team led by archeologist Gunnar Neumann of the Max Planck Institute for Evolutionary Anthropology in Germany found genetic evidence of the bacteria responsible for two of the most important diseases in history – typhus – in remains excavated from an ancient cemetery in Crete, Hagios Charalambos cave. fever and plague.
Therefore, according to the researchers, widespread diseases caused by these pathogens cannot be considered a contributing factor to the widespread social changes between 2200 and 2000 BC.
“The emergence of these two viral pathogens in Crete at the end of the Early Minoan period,” they wrote in their paper, “highlights the need for the reintroduction of infectious diseases as an additional factor contributing to the transformation of early complex societies.” Aegean Sea and Beyond”.
Yersinia pestis A bacterium that has caused tens of millions of deaths, many of them during three devastating global pandemics. Although this disease has been catastrophic for centuries, its The impact prior to Justinian’s plague, which began in 541, was difficult to determine.
Recent technological and scientific advances, especially the recovery and sequencing of ancient DNA from old bones, are revealing some of that lost history.
We now suspect, for example, that bacteria have been infecting humans since at least the Neolithic period.
Last year, scientists discovered that Stone Age hunter-gatherers died of plague thousands of years ago, before proving that the disease reached epidemic proportions in our country.
However, the genomic evidence found was previously obtained from cold regions. Little is known about its effects on ancient societies in warm climates, such as those of the Eastern Mediterranean, due to DNA degradation at high temperatures.
So Neumann and his team excavated the remains from a site known for its incredibly cool and stable conditions in Crete.
They found DNA from the teeth of 32 people who died between 2290 and 1909 BC. Genetic data revealed the presence of several expected common oral bacteria.
less expected to happen Y. pestis two people and two intestinal salmonella lines – the bacteria usually responsible for typhoid fever – the other two. This discovery suggests that both pathogens were present and could have been transmitted in Bronze Age Crete.
But there is a caveat. Each of the species found is now extinct, making it difficult to determine how their infections affected communities.
offspring Y. pestis they found that it apparently cannot be transmitted by fleas – one of the features that makes other strains of the bacterium highly contagious in human populations.
The flea vector carries the bubonic version of the plague; People become infected when the bacteria enter the lymphatic system through a flea bite. Therefore, this ancient type of bacteria may have a different mode of transmission and cause a different form of plague; for example, pneumonic plague, which is transmitted by aerosols.
According to scientists, S. enterica the progeny also lacked key features that contribute to severe disease in humans, so the virulence and transmission routes of both pathogens remain unknown.
Nevertheless, the discovery suggests that both pathogens are circulating; In the areas of Crete with high population density, they may have spread a little.
“However, that is unlikely to happen Y. pestis to eat S. enterica were the sole perpetrators of the social changes observed in the Mediterranean at the end of the 3rd millennium BC,” the researchers write in their paper, “we suggest, [ancient] The DNA evidence presented here suggests that infectious diseases should be considered as an additional factor; Perhaps a correlation with climate and migration has already been suggested.”
Diseases such as plague and typhoid do not leave traces on bones, so they are not often found in the archaeological record. The team predicts that genetic screening of those more commonly found in the Eastern Mediterranean will help determine the extent of the disease’s impact on the civilizations that lived there.
The study was published Current Biology.