U.S. measles cases surpass 4,000, with over 25 percent coming from Pennsylvania

U.S. measles cases this year surpassed 4,000, with over 25 percent of reported infections coming from Pennsylvania, CDC data released Friday shows. The agency confirmed 4,080 cases across 47 states and Washington, D.C. Pennsylvania accounts for more than a quarter of the national total, the highest share of any state.