Mumps are on the rise in Sangamon and Morgan counties. Health officials say Morgan County has reported 40 cases of the viral infection, which is more than the 26 cases in all of Illinois last year. Meanwhile, in Sangamon County, 12 cases have been reported in the last 30 days. Previously, the county saw one case each year. Mumps is a contagious disease that can cause swelling and tenderness of the salivary glands in the cheeks and jaws.