Eighty percent of new Ebola cases in eastern Congo are emerging from unknown chains of transmission, the World Health Organization said Tuesday, a sign the outbreak is spreading faster than health officials can track despite an expanding response. Congo has been battling an outbreak of a rare type of Ebola since May, with no approved treatment or vaccine. The Africa Centres for Disease Control says it is the fastest-growing Ebola outbreak on the continent. "Perhaps the most alarming finding is that many of the newly reported deaths are people who died in their communities without ever reaching a health facility...