
"What we're finding is 70 percent mortality," said Bruce Aylward, assistant director-general of the WHO.
The number of cases is continuing to spiral in the three hardest-hit countries, Liberia, Sierra Leone and Guinea.
"It could reach 5,000 to 10,000 cases per week by the first week of December," Aylward said, though he underlined that that was just a working forecast to help guide the international fight against the virus.
The latest case-count in the Ebola outbreak is 8,914, with a death toll of 4,447.
The overwhelming majority of the cases are still in Liberia, Sierra Leone and Guinea, Aylward said.