13th Loeffler Lecture by Professor Dr. Johannes Krause (Max Planck Institute for Evolutionary Anthropology Leipzig)

The COVID-19 pandemic has once again highlighted how crucial the understanding of bacterial and viral pathogens is for global health. Since the late 1970s, more and more new pathogens have been identified, such as HIV, Ebola, SARS and MERS, while at the same time resistance to well-known pathogens such as tuberculosis, syphilis and leprosy is on the rise. Despite intensive research, the evolution of these pathogens remains largely in the dark because, unlike host organisms, they leave no classic fossils. Thanks to groundbreaking advances in DNA sequencing, it is now possible to obtain molecular fossils of historical pathogens from human skeletal remains. This development has ushered in a new era in the study of the evolution of infectious diseases. By reconstructing bacterial genomes, including the causative agent of the medieval plague, scientists have been able to trace its spread back to the origin of the Black Death in Central Asia. Going back even further, complete genomes of Stone Age plague strains provide insights into the evolutionary adaptation of bacteria to humans as hosts and fleas as intermediate hosts. The analysis of ancient DNA offers a unique opportunity to reconstruct past epidemics and understand the evolutionary mechanisms by which pathogens have adapted to humans. In his lecture, Johannes Krause will provide an insight into the latest findings of ancient pathogen genomics and show how some of the most dangerous infectious diseases in human history have developed and spread.