The mystery rash and illness that has plagued thousands of people exposed to the aftermath of Hurricane Katrina may have several names, and one of them is Parvovirus B-19. The disease is nicknamed “Katrina Rash” and the “New Orleans Crud,” and has affected at least three Ruston-area first-responders who went to New Orleans to help in rescue and recovery efforts. A Lincoln Parish Sheriff’s Deputy, an Emergency Medical Technician and a Louisiana State Trooper all came down with variations of the ailment. Missy Staples, a licensed vocational nurse from Glasgow, Ky., became ill after caring for a patient with similar...