Government data published overnight into Tuesday showed the outbreak has recorded a total of 4381 confirmed cases, including 2011 deaths.
A total of 704 patients are in admission and isolation.
The outbreak was declared on May 15 but health authorities say sequencing showed it began months earlier, in February.
While it took about nine weeks for the outbreak to record the first 1000 deaths, it's taken just around three weeks for the figure to double, an evidence that the health crisis is moving faster than efforts to track and manage it.
It's already the second-largest outbreak in history, only behind the 2014-16 West Africa outbreak that recorded more than 28,000 cases including over 11,000 deaths.
The Ebola outbreak is unlike most previous ones because the rare Bundibugyo virus responsible for it has no approved vaccines or treatments.
Clinical trials for those have begun in Ituri province, the epicentre of the outbreak, in eastern Congo.
Aid workers say the outbreak continues to outpace response that has been expanding across the five eastern provinces affected.
Many health workers have gone on strike to protest lack of payment for their work since the outbreak was declared.
And WHO has said most new cases are still being recorded outside of contacts being monitored, showing that transmission remains out of the control of health workers.
Ebola can be caused by different types of virus.
Although the type responsible for the 2014-2016 outbreak is considered the deadliest, government data shows this Bundibugyo outbreak has killed a higher percentage of people as care and support are not getting to patients quickly enough.
Many cases are reporting symptoms late or not at all.
The ongoing outbreak has had a case fatality rate of 45.9 per cent, more than the 39.6 per cent rate recorded in the 2014-16 West Africa outbreak.
"In the absence of an effective vaccine, control (for the outbreak) rests on identifying cases and then nursing them in secure facilities until they recover or sadly perish," said Paul Hunter, a professor in medicine at the University of East Anglia in the UK.
In a remote region like this with an ongoing conflict and interrupted communications, routine surveillance can be very difficult and "identifying cases early enough to prevent spread can be impossible", Hunter said.
The World Health Organisation said on Monday that at the onset of the outbreak in one of Congo's most remote and vulnerable areas, some cases were wrongly attributed to malaria and typhoid, and that early testing was conducted for the more common type of Ebola.
The WHO regional director for Africa, Dr Mohamed Yakub Janabi, told a news conference that officials are "chasing the virus, the virus is ahead of us".
The first Ebola virus to be identified was in 1976 near the Ebola River in what is now Congo.
The outbreak is the 17th - and largest - the Central African nation has faced.
