The DRC outbreak, which involves a separate strain of Ebola from the one raging in west Africa, began in August.
There have been 66 cases and 49 deaths -- including eight fatalities among healthcare workers -- and the authorities have been working hand in hand with WHO to monitor anyone who had contact with a sufferer.
"All the contacts have been traced and monitored, and the last one has now tested negative for Ebola twice, having recovered," WHO spokeswoman Fadela Chaib told reporters.
An Ebola incubation period lasts 21 days, meaning that the DRC could be declared Ebola free within 42 days, or around November 22.
There are five known distinct species of Ebola and the outbreak raging in west Africa stems from the Zaire species -- the deadliest of the lot.
That species caused the world's first known Ebola outbreak in 1976 in Zaire, now known as the DRC, which until now was the deadliest on record, with 280 deaths.
The disease takes its name from the DRC's River Ebola.
