800-year-old skeleton

The bones and teeth of this 800-year-old skeleton, which was buried in a Norwegian church cemetery, held DNA of a potentially lethal bacterium. Credit: Z. Zhou et al./Curr. Biol.

Infection

Medieval skeleton offers clues to bacterial killer’s origins

Deadly type of Salmonella that is now rare in Europe is found in ancient Norwegian remains.

An infection that probably killed a young Norwegian woman some 800 years ago is helping scientists to chart the evolutionary history of an important group of disease-causing bacteria.

A team led by Mark Achtman at the University of Warwick, UK, analysed DNA collected from the bones and teeth of a 19–24-year-old woman buried in the thirteenth century in Trondheim, Norway. The scientists recovered genomes of the bacterium Salmonella enterica, which includes more than 2,900 genetically distinguishable strains. The woman had a type known as Paratyphi C, which causes an illness called paratyphoid or enteric fever that is now rare in Europe.

Paratyphi C infects only humans but is closely related to strains that sicken pigs and wild boar. An analysis combining the Trondheim woman’s pathogen and modern Salmonella samples revealed that Paratyphi C emerged nearly 3,500 years ago.