This is breathtaking! It has gone up exponentially in just a few weeks. Yet another set of ominous projections about the Ebola epidemic in West Africa was released today, in a report from the CDC that gave worst- and best-case estimates for Liberia and Sierra Leone based on computer modeling.

In the worst-case scenario, Liberia and Sierra Leone could have 21,000 cases of Ebola by Sept. 30 and 1.4 million cases by Jan. 20 if the disease keeps following its current trajectory, without effective methods to contain it. These figures take into account the fact that many cases go undetected, and estimate that there are actually 2.5 times as many as reported.

The report does not include figures for Guinea because case counts there have gone up and down in ways that cannot be reliably modeled.

In the best-case model — which assumes that the dead are buried safely and that 70 percent of patients are treated in settings that reduce the risk of transmission — the epidemic in both countries would be “almost ended” by Jan. 20, the report said. It showed the proportion of patients now in such settings as about 18 percent in Liberia and 40 percent in Sierra Leone