The U.S. Centers for Disease Control and Prevention (CDC) said Tuesday that it has designated 35 hospitals nationwide as Ebola treatment centers and expects to name more in coming weeks. The list includes those that have already treated patients with the virus, such as Emory University Hospital in Atlanta, Georgia, and other prominent hospitals, including Johns Hopkins in Baltimore, Maryland, Mayo Clinic Hospital in Minnesota, and Children's Hospital of Philadelphia, Pennsylvania, and New York-Presbyterian. More than 80 percent of returning travelers from West African countries live within 320 kilometers of a designated Ebola treatment center, the CDC said in a statement. "As long as Ebola is spreading in West Africa, we must prepare for the possibility of additional cases in the United States," CDC Director Tom Frieden said in the statement.