A second U.S. citizen working in Liberia has tested positive for the deadly Ebola virus, a charitable organization working in the county said on Sunday, NBC News reported. The latest victim is Nancy Writebol, who was helping a joint Serving In Mission/Samaritan's Purse team in Liberia to help treat victims of the deadly disease at a Case Management Center in Monrovia, according to a statement from Samaritan’s Purse. Meanwhile, Dr. Kent Brantly, 33, an American earlier infected with the disease was receiving intensive treatment Sunday and was in stable condition.