Recent research has unveiled the earliest evidence of a plague outbreak, discovered in ancient graves of children in Siberia. This revelation may change our understanding of this deadly disease.

This groundbreaking discovery is detailed in a recent study published in the journal Nature, offering new insights into one of history’s gravest diseases.

The site, located alongside the Angara River, revealed the remains of multiple generations of hunter-gatherers, alongside archaeological artifacts like 5,500-year-old arrowheads. Genetic analysis of the teeth showed plague DNA in approximately 40% of the samples.

Lead researcher Ruairidh MacLeod from the University of Oxford noted that the grave sites encompassed not only cousins but also sisters aged between four and nine years.

“Three young girls were buried together, likely succumbing simultaneously to the disease. Our findings reveal significant amounts of plague DNA in all three, indicating a tragic impact on these children in prehistoric communities,” he explained.

The study suggests two distinct outbreaks of plague occurred within these hunter-gatherer societies. This evidence implies that the ancient plague likely spread within families, challenging previous notions regarding its impact on prehistoric groups. Previous research has noted a singular plague infection in a hunter-gatherer in present-day Latvia around 5,000 years ago but found no evidence of widespread epidemics or human-to-human transmission.

Throughout history, plagues have dramatically altered human society, notably during the pandemic starting in 1347. This outbreak, known as the Black Death, resulted in the loss of approximately half of Europe’s population, with subsequent recurrences leading to significant societal disruption.

Researchers have long linked the emergence of plague and other infectious diseases to the Neolithic Revolution, when humans transitioned from nomadic lifestyles centered on hunting to settled agricultural societies. This change fostered higher population densities and closer living quarters with animals that potentially carried harmful pathogens.

However, outside experts assert that this new study calls into question previously held beliefs about plague’s origins.

Nicolas Raskobin, a researcher of ancient DNA at the Pasteur Institute in Paris, remarked, “This discovery offers clear evidence of a prehistoric outbreak, highlighting that agricultural lifestyles may not be the sole factor in plague emergence.”

This research indicates that the plague may have sporadically affected certain hunter-gatherer communities living near wild animals harboring the bacteria, primarily spreading among family units.

Eske Willasev, an evolutionary geneticist from the University of Copenhagen, emphasized, “The perception that the hunter-gatherer phase was free from diseases is incorrect. We are now realizing that these societies faced recurrent outbreaks of disease.”

The bacterium identified in this study, Yersinia pestis, is the same species responsible for the Black Death. However, it is believed that this ancient strain lacked some key characteristics seen in later outbreaks. Research posits that the bacteria may not have developed the ability to cause bubonic plague until about 3,800 years ago.

Researchers hypothesize that the ancient epidemic was likely linked to pneumonic plague, a form affecting the respiratory system and likely transmitted through coughing.

“Pneumonic plague is more serious than bubonic plague, spreading through respiratory droplets rather than fleas,” explained MacLeod. “It poses a significant risk and is highly fatal.”

The skeletal remains analyzed were excavated by Russian archaeologists in the 1980s and preserved from four cemeteries located near Lake Baikal, a vital fishing site for ancient peoples in Siberia. Uniquely, some graves contained multiple remains without any indication of being disturbed.

This suggests that several children likely succumbed to the plague simultaneously and were interred together, indicating a heightened vulnerability among younger individuals in these communities.

By extracting DNA from the molars of these skeletons, researchers were able to uncover familial relationships while detecting the plague bacteria. Of the 46 bones analyzed, bacteria appeared in 18, but the team believes the larger number suffered from the plague, with many samples not yielding detectable bacteria due to preservation challenges.

“Similar investigations of plague victims from historical pits in medieval London yielded a detection rate of around 20%,” shared MacLeod. With a nearly double mortality rate observed in this Siberian site, he suggests that most deceased likely perished from the plague.

Plague cases continue to emerge in certain rural regions. Prompt identification of these cases allows for effective treatment using antibiotics. Last year, Madagascar experienced over 2,400 occurrences of pneumonic plague, while the United States recorded its first plague-related fatality since 2007 in Arizona.