I saw some graphs which showed the number of cases doubling about every month.

In the absence of an effective treatment, this means that fatalities will also double every month.

So the infections and deaths in the last month are (roughly) equal to the number of cases and deaths in the entire history of the current outbreak.

The current ebola outbreak is much larger than previous outbreaks, so soon 1 month's infections will equal the infections in all previous recorded outbreaks.