Some 365 of those cases and 189 of the deaths are confirmed. More than 26,000 people in the DRC have been inoculated in a "ring vaccination" policy in which those who have been in contact with an Ebola patient are vaccinated.
Health workers hope that the first multi-drug Ebola treatment trial, announced by DR Congo's health ministry on Monday, will help to contain this and future outbreaks.
To better evaluate these drugs, the World Health Organization has revised a treatment protocol it created specifically for Ebola, known as Monitored Emergency Use of Unregistered and Investigational Interventions.
"We haven't seen the height of this outbreak", she warned as Ebola continues to move into new areas in DRC, worrying close to a heavily traveled border with Uganda.
The WHO said the current malaria control campaign is modelled on the one implemented in Sierra Leone.
The International Rescue Committee, which has response teams on the ground in North Kivu, described the combination of insecurity, community resistance and disrupted or failing health services as a "perfect storm" for disease transmission.
Given the complications, this Ebola outbreak will last at least another six months before it can be contained, World Health Organization emergencies chief Dr. Peter Salama has predicted. We fear that hundreds of more people will lose their lives in this outbreak.
The World Health Organization (WHO) now has 300 specialists deployed to the Central African nation to support the ongoing response efforts, with a focus on Beni as well as the new hotspots Butembo, Kalunguta and Katwa.
The alarmingly high number of infected newborns in this outbreak is another concern, and so far a mystery. A total of 36 cases have been reported among newborn babies and children below the age of two, while 17 cases have been reported among pregnant women since the outbreak began.
The epidemic in a volatile part of the Democratic Republic of Congo is behind only the devastating West Africa outbreak that killed thousands a few years ago.
This Ebola outbreak is like no other, with some health workers comparing the region to a war zone.
"Is it extraordinary? Is there a risk of cross-border spread?" Steffen told reporters in a teleconference October 17.
Dr Ghebreyesus added: 'We honour the memory of those who have died battling this outbreak, and deplore the continuing threats on the security of those still working to end it'.