GOMA, Congo (September 14, 2012)--An outbreak of the Ebola virus has killed 31 people in northeastern Congo, more than doubling the death toll from a week ago, the United Nations World Health Organization said Friday.

The UN said there have been 69 cases in all including nine confirmed by a lab.

The Ebola virus has no cure and is deadly in 40 percent to 90 percent of cases.

The disease causes severe internal bleeding.

A review of earlier cases has shown that 31 people have died since the beginning of the epidemic in May 2012.

More than half of the deaths occurred before Aug 17, when medical authorities officially declared the Ebola outbreak.

Congo has had eight previous Ebola epidemics the first discovery of the virus in 1976.