Infectious diseases are thought to have accompanied Homo sapiens throughout evolution - some that were once rare have become common, others disappeared and new varieties have emerged. Evolutionary theory suggests that the (dis-) appearance of infectious diseases is considerably influenced by environmental factors, human behavioural change and host genetics. The adoption of agriculture during the Neolithic Period can be considered a prime example of a process that was likely associated with an increase in infectious disease load. Did the drastic decline in population sizes during the Late Neolithic coincide with the emergence and spread of specific, perhaps even multiple, zoonoses? How did the inter- and intra-species diversity and the virulence of pathogens change over the millennia? These and other questions are currently being addressed and the answers will aid in a better understanding of disease epidemiology in early history. The emphasis is on the investigation of infectious agents of both bacterial and viral origin.

A major focus of the Research Group is the investigation of leprosy during the European Middle Ages. Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) and was very common in Europe till the 16^th century. Our aDNA studies, in which we sequenced numerous complete pathogen genomes, have revealed a high degree of M. leprae conservation over the last 1000 years. In addition, there is no evidence that the medieval leprosy epidemic was due to particularly virulent M. leprae strains. This finding highlights the importance of investigating host genetic factors to explain the high disease prevalence at that time (see also Ancient Immunogenomics).

Within the framework of the CRC1266, we are performing a large-scale pathogen screening of nearly a thousand well-dated human skeletal remains (teeth, dental calculus) from the Neolithic and Bronze Age Periods. The specimens are screened for the presence of known bacterial and viral pathogens by capturing and sequencing their preserved genetic material with state-of-the-art molecular techniques. This data is compared with present-day genomic data to provide a framework for better understanding the mechanisms of pathogen evolution. 

Involved PhD students: Julian Susat, Magdalena Haller, Nicolas da Silva, Joanna Bonczarowska.

See also the corresponding Junior Research Group.

Funded by: CRC1266 "Transformation - Human-Environmental Interaction in Prehistoric and Archaic Societies", International Max Planck Research School for Evolutionary Biology (IMPRS-EB)