The Ebola epidemic already devastating swaths of West Africa will explode by mid-December and could kill tens of thousands of people unless urgent action is taken, a new study warned on Friday. A team of seven scientists from Yale University’s Schools of Public Health and Medicine and the Ministry of Health and Social Welfare in Liberia developed a mathematical transmission model of the viral disease and applied it to Liberia’s most populous county, Montserrado, an area already hard hit. The researchers determined tens of thousands of new Ebola cases, and deaths, are likely by December 15 if the epidemic continues on its present course. ‘Our predictions highlight the rapidly closing window of opportunity for controlling the outbreak and averting a catastrophic toll of new Ebola cases and deaths in the coming months,’ said Alison Galvani, professor of epidemiology at the School of Public Health and the paper’s senior author.