"A study led by Michael Worobey at the University of Arizona in Tucson provides the most conclusive answers yet to two of the world's foremost biomedical myster

"A study led by Michael Worobey at the University of Arizona in Tucson provides the most conclusive answers yet to two of the world's foremost biomedical mysteries of the past century: the origin of the 1918 pandemic flu virus and its unusual severity, which resulted in a death toll of approximately 50 million people."