Eighty percent of new Ebola cases in eastern Congo are emerging from unknown chains of transmission, the World Health Organization (WHO) has said, a sign the outbreak is spreading faster than health officials can track despite an expanding response.

The Ebola outbreak in eastern Congo “continues to outpace the response efforts,” the World Health Organization’s emergencies chief said on Tuesday after returning from a trip to…

The Ebola outbreak in eastern Congo “continues to outpace the response efforts,” the World Health Organization’s emergencies chief has said.