On a cold spring morning, Washington University in St. Louis virologist Jacco Boon, PhD, and wildlife ecologist Solny Adalsteinsson, PhD, flap and drag a large white flag through a woodsy area on the western edge of St. Louis County. Boon, an associate professor of medicine in infectious diseases at Washington University School of Medicine in St. Louis, and Adalsteinsson, a senior scientist at the university's Tyson Research Center, are looking for lone star ticks that carry the potentially deadly Bourbon virus.