Here's A Terrifying Chart Of Projected Ebola Cases

Warnings about the current Ebola epidemic in West Africa, which has sickened more people than all previous outbreaks combined, have been dire for a while now.

In March, a Doctors Without Borders official called it "an epidemic of a magnitude never before seen." By June, the organization was already warning that it was "totally out of control." In early September, the director of the Centers for Disease Control and Prevention said we still had a chance to stop the outbreak, but that the "window of opportunity [was] closing."

Soon after, President Obama sounded the alarm in a press conference, saying the epidemic was "spiraling out of control," and the World Bank called the potential economic impacts of the outbreak "catastrophic."

Now, a new paper in the New England Journal of Medicine by a team of World Health Organization researchers estimates that if current trends continue, the number of confirmed and probable cases will rise to 20,000 by November 1, with almost half of those cases in Liberia:

The Centers for Disease Control and Prevention also released projections on Tuesday, using a new modeling tool that ended up with different numbers than the predictions published in the NEJM.

They estimated that reported cases in Sierra Leone, Liberia, and Guinea could rise to 8,000 by the end of September. But the CDC also noted that cases seem to be vastly underreported, perhaps by a factor of 2.5. According to the new projections, the true number of cases by the end of September could - worst case scenario - rise to 21,000.

"If conditions continue without scale-up of interventions," the CDC researchers warned, "cases will continue to double approximately every 20 days, and the number of cases in West Africa will rapidly reach extraordinary levels."

Still, the researchers said, "the findings also indicate that the epidemic can be controlled," and the international community has already begun mobilizing to help avoid the worst-case-scenario predictions. Ebola is spread via bodily fluids, and isolating patients and their contacts is the most effective way to contain it.

The CDC projections - based on data from August - "reflect a moment in time before recent significant increases in efforts to improve treatment and isolation," said CDC director Tom Frieden in a statement. "They do not account for actions taken or planned since August by the United States and the international community. We anticipate that these actions will slow the spread of the epidemic."