Since the outbreak in north-eastern DRC was confirmed two weeks ago, the World Health Organisation has said there have been 1,028 suspected cases and 223 suspected deaths.
A lack of testing kits for the rare Bundibugyo strain behind the outbreak means many suspected cases have yet to be confirmed and the true toll is thought to be far higher than those confirmed.
Health officials admit they are still trying to catch up with the highly contagious haemorrhagic fever, which was suspected to have been spreading under the radar for months before the outbreak was confirmed.
Two weeks later, the flare-up is already one of the largest since the Ebola virus was discovered 50 years ago, and a lack of security and supplies in the area is hobbling efforts to stamp it out.
Dr Alan Gonzalez, deputy operations director for Médecins Sans Frontières, the international medical charity, said the situation was “deeply alarming”.
He said: “Never before has an Ebola outbreak recorded so many cases so soon after its declaration.
Teams were “witnessing a response that has not yet caught up to the rapid spread of the epidemic,” he said.
“The reality today is that nobody knows the true scale and severity of this outbreak. New suspected cases are being reported daily, yet hundreds of samples remain untested.”