at least three pandemics during the course of history https://www.cdc.gov/plague/history/index.html 60 percent three major plague pandemics Plaga de Justiniano disease "History | Plague | CDC" "Plague History" worst pandemics in history Plague History "Plague History" estimated 60 percent "Plague History" killed so many people «Plague History» estimated 60 percent CDC three major plague pandemics Centers for Disease Control and Prevention Plague History Muerte Negra acabó con el 60% de la población europea http://www.cdc.gov/plague/history/index.html https://www.cdc.gov/plague/history/index.html Plaga de Justiniano "Plague History" 100 million people https://www.cdc.gov/plague/history/index.html 60 percent first recorded pandemic More about the history of plague. estimated 60 percent spread through fleas CDC.gov, history of plague up to 60 percent estimated 60 percent "History | Plague | CDC" the CDC the CDC 100 million people History History 100 million people plague in Europe in the 1300s More about the history of plague. "Plague History" first recorded pandemic 100 million people "History | Plague | CDC" https://www.cdc.gov/plague/history/index.html US Centers for Disease Control and Prevention: Plague Muerte Negra acabó con el 60% de la población europea up to 60 percent up to 60 percent