There have been nearly 2,000 reported cases of West Nile virus across 48 states so far this year, making it the worst outbreak of its kind in U.S. history, according to the Centers for Disease Control and Prevention (CDC). In Oklahoma, one of the worst-hit states, researchers at the University of Oklahoma Health Sciences Center are working on a West Nile vaccine, and the findings have been promising so far, according to a report from KCEN-TV. More