The number of new Ebola cases in West Africa could skyrocket from 1,000 per week to more than 10,000 per week by December, the World Health Organization announced Tuesday morning. WHO assistant director-general Dr. Bruce Aylward said that the mortality rate from the virus now stands at 70 percent, 20 percent higher than previously believed.

From the Associated Press:

[WHO assistant director-general Dr. Bruce Aylward] told reporters if the world's response to the Ebola crisis isn't stepped up within 60 days, "a lot more people will die" and health workers will be stretched even further. Experts say the epidemic is doubling in size about every three weeks.

WHO raised its Ebola death toll tally Tuesday to 4,447 people, nearly all of them in West Africa, out of more than 8,900 believed to be infected. Aylward said calculating the death rate means tracking the outcomes of all possible patients — a complicated process since the numbers of cases are substantially underreported and much patient data is missing.

Aylward also spoke about the need to coordinate responses to the the unprecedented epidemic and warned against complacency.

"There's a lot of actors on the ground, and an awful lot of them are working with Ebola for the first time," he said, according to the New York Times. "Any sense that the great effort that's been kicked off in the last couple of months is already starting to see an impact—that would be really, really premature."

Some aid groups have been critical of the responses from WHO and other government agencies. Sharon Ekambaram, the head of Doctors Without Borders in South Africa, told the Associated Press that 16 DWB employees have become infected with the virus and that nine have died.

"Where is WHO Africa? Where is the African Union?" Ekambaram said. "We've all heard their promises in the media but have seen very little on the ground.

[Image via AP]