Monday, April 20, 2026

The bacterium responsible for scarlet fever was not introduced to the Americas by Europeans.

A research team led by Eurac Research has identified the Streptococcus pyogenes bacterium in a pre-Columbian Bolivian mummy and, for the first time, reconstructed the genome of this centuries-old pathogen.

Eurac Research

valverdeguido_bolivia-munarq — image:
Bolivian biochemist Guido Valverde in a storage room at the National Archaeological Museum (MUNARQ) in La Paz. On the shelves: the museum’s collection of skulls
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Credit: Juan Gabriel Estellano

Researchers identified the pathogen’s genetic material while examining a tooth from a naturally mummified skull housed at MUNARQ – the National Museum of Archaeology in La Paz. Using a method that reassembles previously unknown genomes from numerous short DNA fragments, they reconstructed a nearly complete, ancient genome of Streptococcus pyogenes.
The reconstructed genome shows clear similarities to modern strains of the globally widespread bacterium, which can cause a variety of illnesses ranging from harmless throat infections to scarlet fever and life-threatening toxic shock syndrome.
Despite the pathogen’s great medical significance: scarlet fever was historically one of the leading causes of death among children, little is known about its evolutionary history. This finding now shows that the bacterium was already circulating among indigenous populations in South America before European colonization: the young man from whom the tooth originated lived between 1283 and 1383 AD.
The study was made possible by a cooperation agreement between Eurac Research and the Bolivian Ministry of Cultures and has been published in Nature Communications.

“We weren’t looking for this pathogen specifically,” emphasizes Frank Maixner, director of the Eurac Research Institute for Mummy Studies: “When conducting genetic analyses of mummies, we approach the work with an open mind, analyzing not only human genetic material but also the DNA of the numerous microorganisms present in human remains.”

Among the bacterial DNA traces the researchers found in the tooth, Streptococcus pyogenes was common. Because the pathogen remains medically significant today – with scarlet fever outbreaks on the rise worldwide – the team analyzed this genetic material in greater detail.

To reconstruct the several-hundred-year-old genome, the researchers used de-novo assembly, an established method of modern genome research that the Institute for Mummy Studies has further developed specifically for highly fragmented ancient DNA. It allows a genome to be reassembled from many DNA fragments without a reference genome as a template. “You can think of it like putting together a puzzle without knowing the picture on the box,” explains Microbiologist Mohamed Sarhan of Eurac Research, who shares first authorship of the paper with Bolivian biochemist Guido Valverde. “This method has a major advantage for reconstructing ancient genomes: we are not influenced by modern references – we work without preconceptions. This allows us to discover entirely new insights and also identify genetic variants that may no longer exist today, such as extinct bacterial strains.” For the field of research, this possibility signifies “something like the beginning of a new era,” adds Maixner.

Given its age, the bacterium’s DNA was relatively well-preserved, which the researchers attribute to the dry and cold conditions in the Bolivian highlands. This unique climate also facilitated the natural mummification of the skull – attributed to the Late Intermediate Period (1100 – 1450 AD). Using radiocarbon dating and, according to genetic analyses, it was found that the skull belongs to a young man of indigenous descent. It is likely, as is the case with most of the museum’s other mummies, that the skull was found in a chullpa – one of the typical burial towers of the Bolivian Altiplano.

“The DNA’s excellent preservation enabled us to reconstruct a nearly complete genome, yielding a wealth of information and demonstrating, for example, that the bacterium was already capable of causing disease: the ancient strain carried many – though not all – of the pathogenic genes found in modern Streptococcus pyogenes strains,” explains Valverde. This ancient pathogen was found to be particularly similar to modern strains that primarily cause throat infections.

During a targeted search of other publicly available datasets of ancient DNA, the researchers found Streptococcus pyogenes in 35 samples from people who lived in Europe about 4,000 years ago, as well as a closely related Streptococcus species in 200-year-old remains of gorillas from Africa, demonstrating that the pathogen was present already in ancient samples but had been overlooked for years.

The researchers’ genetic analyses also indicate that the evolutionary lineages of most modern Streptococcus pyogenes strains diverged around 5,000 years ago – during an era when humans were becoming increasingly sedentary and living in closer proximity. This may have facilitated the spread and diversification of the pathogen, which is primarily transmitted through droplet and contact transmission.

The study is part of a large interdisciplinary project that is conducting the first systematic bioarcheological analysis of the mummy collection at the Bolivian National Museum of Archaeology (MUNARQ). It is freely accessible at: https://www.nature.com/articles/s41467-026-71603-9

Journal

Nature Communications

DOI

10.1038/s41467-026-71603-9

Method of Research

Experimental study

Subject of Research

Human tissue samples

Article Title

An ancient genome of Streptococcus pyogenes from a pre-Columbian Bolivian mummy.

Article Publication Date

13-Apr-2026

*Chullpas* on the Bolivian Altiplano. These burial towers are the remains of a civilization that preceded the Inca Empire.
Credit
Juan Gabriel Estellano

This tooth belonged to a young man who lived on the Bolivian Altiplano around 700 years ago. The research team detected the scarlet fever bacterium, Streptococcus pyogenes, in it.
Credit
Guido Valverde

Ancient charcoal sheds new light on how early humans fueled their lives

The Hebrew University of Jerusalem

Gesher Benot Ya’aqov Excavation Site — image:
A general view of the excavation of Gesher Benot Ya’aqov Acheulian Site
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Credit: GBV Expedition

New study shows that early humans living about 800,000 years ago depended on fire in smart, practical ways. Instead of searching for the “best” wood, they took advantage of what nature provided, mainly driftwood collected along the lakeshore. This reliable fuel supply helped them keep fires going for cooking and daily life, and may even explain why they kept coming back to the same spot. In other words, they weren’t just choosing a place to live, they were choosing a place where fire was easy to maintain.

Link to pictures: https://drive.google.com/drive/folders/1uovu8ot6YH_ky7XFmBgDmiKDddOZGXqS?usp=drive_link

Nearly 800,000 years ago, early humans gathered along the shores of a lush lake in what is now northern Israel. Here, they returned again and again, hunting large animals, cooking fish over controlled fires, and organizing their daily lives around hearths. Now, a new study shows that even the wood fueling those fires, which is preserved as rare fragments of charcoal, can reveal how carefully these ancient communities understood and used their environment.

Published in Quaternary Science Reviews, the study offers a vivid reconstruction of life at the Acheulian site of Gesher Benot Ya'aqov (GBY). By examining an exceptionally rich and rare collection of ancient charcoal, an international team of researchers from Israel, Spain, and Germany, including Prof. Naama Goren-Inbar (Hebrew University), Prof. Nira Alperson-Afil and Dr. Yoel Melamed (Bar-Ilan University), Prof. Ethel Allué (Universitat Rovira i Virgili and Institut Català de Paleoecologia), and Prof. Brigitte Urban (Leuphana University), has uncovered new evidence of how early hominins gathered and used firewood, revealing behavior far more sophisticated than previously assumed.

Charcoal rarely survives at such early prehistoric sites, making this unusually large assemblage a unique window into the daily practices of early fire users. While many ancient sites preserve only fragmentary or ambiguous traces of burning, GBY provides a remarkably detailed record of repeated fire use over tens of thousands of years.

GBY preserves a layered history of human occupation along the shores of paleo–Lake Hula, with more than 20 archaeological horizons documenting generations of Acheulian hunter-gatherers returning to the same location. Excavations led by Prof. Naama Goren-Inbar of the Hebrew University of Jerusalem have revealed a dynamic landscape of activity: stone tools crafted from flint, limestone, and basalt; the remains of hunted animals; and a wide array of plant foods, including fruits, nuts, and seeds gathered from the lakeshore.

One particularly striking layer captures a dramatic moment in time. Alongside stone tools and plant remains, researchers uncovered the skull and bones of a straight-tusked elephant, evidence of large-scale hunting and butchery. The spatial arrangement of the remains suggests that the animal was processed on-site.

At the heart of this ancient camp life was fire. First identified at GBY by Prof. Nira Alperson-Afil of Bar-Ilan University, fire was habitual. It structured how space was organized, anchoring activities such as tool production, food preparation, and social interaction.

The new study focuses on a single occupation layer dated to approximately 780,000 years ago. Researchers analyzed 266 charcoal fragments, using microscopic techniques to identify the internal structure of the wood and determine its botanical origin. The results revealed a surprisingly diverse mix of plant species, including ash, willow, grapevine, oleander, olive, oak, pistachio, and even pomegranate, which is the earliest known evidence of this fruit tree in the Levant.

Unexpectedly, the charcoal assemblage showed greater plant diversity than other botanical remains from the site, such as seeds, fruits, or unburned wood. This suggests that firewood collection captured a broader cross-section of the surrounding environment than other forms of plant use.

Together, these species paint a vivid picture of the ancient landscape: a mosaic of wet lakeshore vegetation and open Mediterranean woodland. But more importantly, they reveal how early humans interacted with that landscape.

Rather than selectively gathering specific types of wood, GBY hominins appear to have relied primarily on driftwood naturally accumulating along the lakeshore. Fallen branches and logs, carried by water and deposited along the shore, would have created a readily available fuel supply. The composition of the charcoal closely mirrors the wood available in this environment, suggesting a practical and efficient strategy, using what the landscape provides.

This insight points to a broader conclusion: access to firewood may have been a decisive factor in where these early humans chose to live. The lakeshore offered not only fresh water, edible plants, animals, and raw materials for tools, but also a constant supply of fuel, essential for maintaining fire.

Even more striking is how fire was used. Spatial analysis shows that dense clusters of charcoal overlap with concentrations of fish remains, primarily the distinctive teeth of large carp. This co-occurrence adds compelling evidence that fish were being cooked at the site nearly 800,000 years ago, likely using carefully controlled fire.

These findings reinforce the idea that GBY hominins possessed advanced cognitive abilities. They were capable of controlling fire, organizing space around it, and integrating it into complex subsistence strategies. Yet interestingly, while hunting and tool-making required elaborate planning, firewood collection itself appears to have been a more routine activity, based largely on availability rather than careful selection of specific tree species.

Together, these behaviors paint a picture of a community that was both highly skilled and deeply attuned to its environment, returning repeatedly to a place that offered everything they needed to survive and thrive.

The GBY charcoal assemblage provides a unique dataset for examining the intersection of fire use, environmental context, and hominin behavior. These findings refine current models of early fire-related practices and emphasize the importance of local resource availability in shaping patterns of occupation and subsistence during the Middle Pleistocene.

Traverse section of a charcoal fragment of ash observed under an ESEM microscope

Credit

M. MoncusilPHES