PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Ancient DNA used to map evolution of fever-causing bacteria

2025-05-22
(Press-News.org) Researchers at the Francis Crick Institute and UCL have analysed ancient DNA from Borrelia recurrentis, a type of bacteria that causes relapsing fever, pinpointing when it evolved to spread through lice rather than ticks, and how it gained and lost genes in the process.

This transition may have coincided with changes in human lifestyles, like living closer together and the beginning of the wool trade.

Borrelia recurrentis bacteria cause relapsing fever, an illness with many recurring episodes of fever, which is typically found today in areas with poor sanitation or overcrowding, such as refugee camps. It is a distant cousin of the bacteria that today cause Lyme disease.

Historical records in Britain have referred to periods of a ‘sweating sickness’ or ‘epidemic fever’ which may have been caused by B. recurrentis, but limited data means the likely cause of these outbreaks remains unknown.

Only three known species of bacteria, including B. recurrentis, have transitioned from being carried primarily by ticks to lice, changing the potential severity of the disease. Until now it was unknown when B. recurrentis made the jump from ticks to lice and what impact this had on disease transmission and severity in humans. 

In research published today in Science, the scientists sequenced the whole genome from four samples of B. recurrentis. Ranging from 2,300 to 600 years ago, their samples include the oldest B. recurrentis genome to date1. These ancient samples were obtained from the skeletons of people who were infected hundreds of years ago. The DNA is a shadow of the bacteria that once circulated in their blood and has been captured in bones and teeth.

The individuals’ teeth contained traces of B. recurrentis DNA. Two samples had relatively high amounts of the pathogen, suggesting these individuals may have died from a severe, acute infection, or that the DNA was particularly well preserved.

Becoming adapted to the human louse

The researchers looked at differences in the ancient genomes and modern-day B. recurrentis to map how the bacteria has changed over time, finding that the species likely diverged from its nearest tick-borne cousin, B. duttonii, about 6,000 to 4,000 years ago.

They compared the B. recurrentis genomes with B. duttonii, finding that much of the genome was lost during the tick-to-louse transition but that new genes were also gained over time. These genetic changes affected the bacteria’s ability to hide from the immune system and also share DNA with neighbouring bacteria, suggesting B. recurrentis had specialised to survive within the human louse.

The perfect conditions

Based on these ancient and modern genomes, the divergence from the bacteria’s tick-borne ancestor happened during the transition from the Neolithic period to the Early Bronze Age. This was a time of change in human lifestyles, as people began to domesticate animals and live in more dense settlements. This may have helped B. recurrentis spread from person to person more easily.

The researchers also raise the possibility that the development of sheep farming for wool at this time may have given an advantage to louse-borne pathogens, as wool has better conditions for lice to lay eggs.

They conclude that the evolution of B. recurrentis highlights that a combination of genetic and environmental changes can help pathogens spread and infect populations more easily.

Pooja Swali, Research Fellow at UCL, former Crick PhD student and first author, said: “Louse-borne relapsing fever is a neglected disease with limited modern genomes, making it difficult to study its diversity. Adding four ancient B. recurrentis genomes to the mix has allowed us to create an evolutionary time series and shed light on how the genetics of the bacteria have changed over time. Although there’s a trend towards genome decay as it adapted to the human louse vector, we’ve shown that the evolution of B. recurrentis was dynamic until about 1,000 years ago, when it looks similar to present-day genomes.”

Pontus Skoglund, Group Leader of the Ancient Genomics Laboratory at the Crick, and co-senior author, said: “Ancient DNA can enhance our understanding of significant but understudied diseases like relapsing fever. Understanding how bacteria such as ​​B. recurrentis​ became more ​severe​​ in the past may help us understand how diseases could change in the future. The time points we’ve identified suggest that ​​changes in human societies​ such as new clothing material or living in larger groups​ may have allowed B. recurrentis to jump vectors and become more lethal, an example of how pathogens and humans have co-evolved.” 

Lucy van Dorp, Group Leader at UCL, and co-senior author, said: “Genetic analysis of these infections in ancient humans has allowed us to directly track how B. recurrentis has juggled loss and gain of genes during its evolution. Its ability to spread and cause disease appears to be context-dependent, with ancient DNA allowing us to speculate on the important role of past human interactions and behaviour in creating conditions conducive to disease spread. More samples will help us to narrow down the events which led to this tick-to-louse transition and the genetic mechanisms which have helped the bacteria thrive using either vector.”

-ENDS-

For further information, contact: press@crick.ac.uk or +44 (0)20 3796 5252

Notes to Editors

Reference: Swali, P. et al. (2025). Ancient Borrelia genomes document the evolutionary history of louse-borne relapsing fever. Science. 10.1126/science.adr2147.

The four Borrelia recurrentis genomes were sequenced from samples from different time points across England:

A female skeleton in Wetwang Slack, an Iron Age barrow cemetery in East Yorkshire. A human jawbone in Fishmonger’s Swallet, an Iron Age cave in South Gloucestershire. A tooth from a cranium in an Augustinian cemetery in late medieval Canterbury. A tooth from an adult male buried in a medieval chapel in Poulton, Cheshire. The Francis Crick Institute is a biomedical discovery institute with the mission of understanding the fundamental biology underlying health and disease. Its work helps improve our understanding of why disease develops which promotes discoveries into new ways to prevent, diagnose and treat disease.

An independent organisation, its founding partners are the Medical Research Council (MRC), Cancer Research UK, Wellcome, UCL (University College London), Imperial College London and King’s College London.

The Crick was formed in 2015, and in 2016 it moved into a brand new state-of-the-art building in central London which brings together 1500 scientists and support staff working collaboratively across disciplines, making it the biggest biomedical research facility under a single roof in Europe.

http://crick.ac.uk/

About UCL – London’s Global University

UCL is a diverse global community of world-class academics, students, industry links, external partners, and alumni. Our powerful collective of individuals and institutions work together to explore new possibilities.

Since 1826, we have championed independent thought by attracting and nurturing the world's best minds. Our community of more than 50,000 students from 150 countries and over 16,000 staff pursues academic excellence, breaks boundaries and makes a positive impact on real world problems.

The Times and Sunday Times University of the Year 2024, we are consistently ranked among the top 10 universities in the world and are one of only a handful of institutions rated as having the strongest academic reputation and the broadest research impact.

We have a progressive and integrated approach to our teaching and research – championing innovation, creativity and cross-disciplinary working. We teach our students how to think, not what to think, and see them as partners, collaborators and contributors.

For almost 200 years, we are proud to have opened higher education to students from a wide range of backgrounds and to change the way we create and share knowledge.

We were the first in England to welcome women to university education and that courageous attitude and disruptive spirit is still alive today. We are UCL.

www.ucl.ac.uk | Read news at www.ucl.ac.uk/news/ | Find out what’s on at UCL Minds

END



ELSE PRESS RELEASES FROM THIS DATE:

New standards in nuclear physics

2025-05-22
New standards in nuclear physics An international research team led by the Paul Scherrer Institute PSI has measured the radius of the nucleus of muonic helium-3 with unprecedented precision. The results are an important stress test for theories and future experiments in atomic physics. 1.97007 femtometre (quadrillionths of a metre): That’s how unimaginably tiny the radius of the atomic nucleus of helium-3 is. This is the result of an experiment at PSI that has now been published in the journal Science. More than 40 researchers from international institutes collaborated to develop and implement a method that ...

Why Europe’s fisheries management needs a rethink

2025-05-22
As legally required by the European Union, sustainable fisheries may not extract more fish than can regrow each year. Yet, about 70 per cent of commercially targeted fish stocks in northern EU waters are either overfished, have shrunken population sizes or have collapsed entirely. So why does the EU continue to miss its sustainable fisheries targets, despite a wealth of scientific data and policy instruments? Researchers at GEOMAR Helmholtz Centre for Ocean Research Kiel and Kiel University examined this question using the well-explored ...

Seven more years of funding for Konstanz Cluster of Excellence "The Politics of Inequality"

2025-05-22
The Cluster of Excellence "The Politics of Inequality" at the University of Konstanz will continue to receive funding through the German Excellence Strategy for another seven years. The German Research Foundation (DFG) and the German Council of Science and Humanities (WR) made the announcement on 22 May 2025. The Cluster of Excellence applied for around 52 million euros in funding. Clusters of Excellence are large, transdisciplinary research networks that study relevant research topics at the highest level internationally; they are one of the funding lines of the Excellence Strategy. "Our Cluster of Excellence 'The Politics ...

Biological markers for teen depression

2025-05-22
Using a novel lab method they developed, McGill University researchers have identified nine molecules in the blood that were elevated in teens diagnosed with depression. These molecules also predicted how symptoms might progress over time. The findings of the clinical study could pave the way for earlier detection, before symptoms worsen and become hard to treat. “Alarmingly, more and more adolescents are being diagnosed with depression, and when it starts early, the effects can be long-lasting and severe,” said senior author Cecilia Flores, James ...

Researchers show social connection is still underappreciated as a medically relevant health factor

2025-05-22
Research confirms that social isolation and loneliness significantly impact health and mortality, even if not listed on death certificates. BYU psychology and neuroscience professor, Julianne Holt-Lunstad, has published extensively on the topic, including a landmark 2010 meta-analysis and a 2023 framework on assessment and treatment. She also served as lead scientist on the 2023 Surgeon General Advisory and is advising the World Health Organization on an upcoming report that addresses the pressing health threat of loneliness and isolation and a global agenda on social connection. Social connection is now a legitimate health factor, but Holt-Lunstad ...

Great success: The University of Cologne is granted five Clusters of Excellence

2025-05-22
The University of Cologne is once again highly successful in the Excellence Strategy: Five Clusters of Excellence will be funded in the next funding period. This was announced today by the German Research Foundation (DFG) and the German Science and Humanities Council. The following Clusters will be funded for seven years: CECAD for aging research, CEPLAS for plant sciences, DYNAVERSE for astrophysics, ECONtribute for economics and ML4Q for quantum research. These Clusters reflect the academic fields of the natural sciences, life sciences, humanities and social sciences represented at the University of Cologne. “We ...

UNAM researchers supported to publish open access articles in over 2,400 Taylor & Francis journals

2025-05-22
The global impact of Universidad Nacional Autónoma de México (UNAM) research is set to increase under a new open access (OA) agreement with publisher Taylor & Francis. The three-year partnership will enable UNAM researchers to publish OA articles in more than 2,400 journals. OA publishing supports UNAM's ambition to be a leading international hub of excellence in research and innovation, through fostering collaboration and ensuring the latest work can be freely accessed by researchers, policymakers, and practitioners worldwide. Taylor & Francis’ first ‘read & publish’ agreement in Mexico maintains the academic community’s reading ...

NIH scientists test in an animal model a surgical technique to improve cell therapy for dry AMD

2025-05-22
What: National Institutes of Health (NIH) scientists have developed a new surgical technique for implanting multiple tissue grafts in the eye's retina. The findings in animals may help advance treatment options for dry age-related macular degeneration (AMD), which is a leading cause of vision loss among older Americans. A report about the technique published today in JCI Insight.   In diseases such as AMD, the light-sensitive retina tissue at the back of the eye degenerates. Scientists are testing therapies for restoring damaged retinas with grafts of tissue ...

Two-step method to prevent biofilm regrowth is a SLAM dunk

2025-05-22
Most people have encountered the black, grey, or pink stains of bacterial biofilms built up on the bathroom tiles or kitchen sink. Even with vigorous scrubbing and strong cleaning chemicals, this grime can be difficult to remove and often returns with vengeance. A new study, published in Chemical Engineering Journal, reports a novel, two-step method to effectively dismantle bacterial biofilms and prevent regrowth. “Biofilms are everywhere, from bathrooms to food factories,” said Hyunjoon Kong (M-CELS leader/EIRH/RBTE), a professor of chemical and biomolecular engineering. “Biofilms are also responsible for cross contamination ...

New study from Aarhus questions European precautionary measures on paternal use of valproate

2025-05-22
A new study from researchers at Aarhus University and Aarhus University Hospital found no increased risk of neurodevelopmental disorders in children whose fathers were treated with valproate during spermatogenesis. The results have just been published in JAMA Network Open and cast new light on the European Medicines Agency’s (EMA's) recent recommendation for precautionary measures. In January 2024, EMA recommended precautionary measures for treating male patients with valproate, based on ...

LAST 30 PRESS RELEASES:

New Canadian study reveals where HIV hides in different parts of the body

Lidocaine poisonings rise despite overall drop in local anesthetic toxicity

Politics follow you on the road

Scientists blaze new path to fighting viral diseases

The mouse eye as a window to spotting systemic disease

AI and the Future of Cancer Research and Cancer Care to headline October 24 gathering of global oncology leaders at the National Press Club: NFCR Global Summit to feature top scientists, entrepreneurs

FDA clears UCLA heart tissue regeneration drug AD-NP1 for clinical trials

Exploring the therapeutic potential of cannabidiol for Alzheimer's

We need a solar sail probe to detect space tornadoes earlier, more accurately, U-M researchers say

Acute myeloid leukemia (AML): Disease risk but not remission status determines transplant outcomes – new ASAP long-term results

Sperm microRNAs: Key regulators of the paternal transmission of exercise capacity

Seeing double: Clever images open doors for brain research

Inhaler-related greenhouse gas emissions in the US

UCLA Health study finds inhalers for asthma and COPD drive significant greenhouse gas emissions

A surgical handover system for patient physiology and safety

Cardiovascular health changes in young adults and risk of later-life cardiovascular disease

Nurse workload and missed nursing care in neonatal intensive care units

How to solve the remote work stalemate – dissertation offers tools for successful hybrid work

Chip-based phonon splitter brings hybrid quantum networks closer to reality

Texas Children’s researchers create groundbreaking tool to improve accuracy of genetic testing

Milken Institute, Ann Theodore Foundation announce more than $2.5 million in new funding for sarcoidosis research and launch new call for proposals

Boston University professor to receive 2025 Eugene Braunwald Academic Mentorship Award

Pusan National University researchers reveal how forest soil properties influence arsenic mobility and toxicity in soil organisms

Korea University researchers find sweet taste cells resist nerve damage through c-Kit protein

HealthFORCE, AAPA, and West Health release “Aging Well with AI” – first in a two part series on AI and the healthcare workforce

The real reasons Endurance sank — study finds Shackleton knew of ship’s shortcomings

Marine heatwaves have hidden impacts on ocean food webs and carbon cycling

Order from disordered proteins

Rocket test proves bacteria survive space launch and re-entry unharmed

New wheat diversity discovery could provide an urgently-needed solution to global food security

[Press-News.org] Ancient DNA used to map evolution of fever-causing bacteria