Ancient Analysis Provides Clues to Medieval Pathogen Genetics, Points to Co-Infections

For a paper in Genome Biology, a team at Kiel University and other centers in Germany and the UK present findings from a pathogen screening study centered on samples from the 5^th to 8^th centuries at sites in what is now rural Germany. The researchers turned to metagenomic sequencing to screen for bacteria and viruses in dozens of individuals buried at a Lauchheim settlement, identifying infections with pathogens such as hepatitis B virus, parvovirus B19, variola virus, or Mycobacterium leprae in 22 individuals, or around one-third of individuals profiled. The sequences data made it possible to put together genomes for parvovirus B19, variola virus, Mycobacterium leprae, and four HBV isolates, while profiling pathogen diversity, and identifying individuals with co-infections involving multiple pathogens. Together, the findings point to the possibility of high infectious disease rates in the region during the so-called "Late Antique Little Ice Age" (LALIA), the authors say. "Our findings suggest that LALIA may have created an ecological context in which persistent outbreaks set the stage for major epidemics of severe diseases such as leprosy and smallpox hundreds of years later," they write.