BUNIA, Congo — Health care workers and aid groups in eastern Congo said Thursday they are in dire need of more supplies and staff to respond to a growing Ebola outbreak  linked to a rare virus, as armed groups continue to threaten a region already grappling with a displacement and humanitarian crisis. “The situation is worrying because this is gaining momentum,” Hama Amado, a field coordinator in the city of Bunia for the Alima aid group, told The Associated Press. “This is spreading in many