LEVENS, France, - Mud run participants might have to start worrying about more than sprained ankles or scraped knees after more than 1,000 people became sick to their stomach after participating in an event last week in France. The regional health agency in southern France said 1,000 of the 8,400 participants involved in the Levens Mud Day on June 20 reported symptoms of acute gastroenteritis. The agency said the stomach ailments -- mostly diarrhea, vomiting and fever -- were caused by norovirus, a highly infectious disease that causes an inflammation of the stomach or intestines. The U.S. Centers for Disease...