Ancient Borrelia genomes document the evolutionary history of louse-borne relapsing fever
- Pooja Swali
- Thomas Booth
- Cedric C. S. Tan
- Jesse McCabe
- Kyriaki Anastasiadou
- Christopher Barrington
- Matteo Borrini
- Adelle Bricking
- Jo Buckberry
- Lindsey Büster
- Rea Carlin
- Alexandre Gilardet
- Isabelle Glocke
- Joel D. Irish
- Monica Kelly
- Megan King
- Fiona Petchey
- Jessica Peto
- Marina Silva
- Leo Speidel
- Frankie Tait
- Adelina Teoaca
- Satu Valoriani
- Mia Williams
- Richard Madgwick
- Graham Mullan
- Linda Wilson
- Kevin Cootes
- Ian Armit
- Maximiliano G. Gutierrez
- Lucy van Dorp
- Pontus Skoglund
2025-05-28
Several bacterial pathogens have transitioned from tick-borne to louse-borne transmission, which often involves genome reduction and increasing virulence. However, the timing of such transitions remains unclear. We sequenced four ancient Borrelia recurrentis genomes, the agent of louse-borne relapsing fever, dating from 2300 to 600 years ago. We estimated the divergence from its closest tick-borne relative to 6000 to 4000 years ago, which suggests an emergence coinciding with human lifestyle changes such as the advent of wool-based textiles. Pan-genome analysis indicated that much of the evolution characteristic of B. recurrentis had occurred by ~2300 years ago, though further gene turnover, particularly in plasmid partitioning, persisted until ~1000 years ago. Our findings provide a direct genomic chronology of the evolution of this specialized vector-borne pathogen.