DALLAS — A Texas emergency room’s mishandling of the country’s first Ebola patient prompted the CDC to issue a nationwide alert to all hospitals updating them of how to appropriately respond to possible cases of the deadly disease. “It’s a teachable moment, as we say,” Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, said during a Thursday press conference. The latest guidance includes a poster with quick rules for evaluating returned travelers and a checklist. The move comes nearly a week after Thomas Eric Duncan showed up at Texas Health Presbyterian Hospital with what officials described...