"How can we say that a virus caused a pandemic, 20,000 years before the beginning of recorded history? David Enard, an evolutionary biologist who works at the University of Arizona, says the scars of ancient epidemics, and the history of our long and ceaseless war with viruses, are written in our DNA. Finding out what caused them may help us to predict the next pandemic."
https://www.newstatesman.com/science-tech/coronavirus/2020/05/ancient-pandemics-coronaviruses-virions-DNA-humans?fbclid=IwAR2ce6XGNmyZbLdyuEH9QmCmeWT6f8IaadypEbQcaTiNqtwWyofagfGsYVM