The head of medical charity Doctors without Borders (MSF) mission in the Democratic Republic of the Congo's Mbandaka said two of three Ebola patients who escaped quarantine have died.

The third patient was found alive and is currently under observation by MSF and the World Health Organization (WHO), the MSF's Henri Gray said on Wednesday.

Meanwhile, WHO said it was accelerating efforts with nine countries neighbouring the  Democratic Republic of Congo (DRC) to try to prevent the spread of the current Ebola outbreak beyond its borders. The UN agency said teams are being deployed to assess how prepared the countries are.

"The highest priority countries at risk are the Central African Republic and the Republic of the Congo, Congo Brazzaville, due to their proximity to the current event," Matshidiso Moeti, WHO regional director for Africa, said.

Moeti said the two countries are high risk due to their shared border with region at the epicentre of the current outbreak. Both Brazaville and Bangui have porous borders with the Ebola affected areas, she added.

"At the second level of priority are Angola, Burundi, Rwanda, South Sudan, Tanzania and Zambia, which are also neighbouring countries to the DRC but not directly linked to the epicentre of the epidemic," Moeti said.

The current outbreak is believed to have claimed the lives of at least 27 people since it was first reported last month. Three of those deaths are confirmed to be from Ebola, according to Congolese health ministry.

The Health Ministry of the central African country reported late Tuesday that the total number of suspected and confirmed Ebola cases had risen to 58.