That means there could be 21,000 new cases by the end of this month alone.
The CDC created a mathematical model to determine how the West African Ebola outbreak will play out depending on different intervention scenarios, taking into account that current Ebola case counts are "vastly" under-reported, as health officials have been saying since August.
Though there have only been a handful of Americans who have contracted Ebola -- all while working in West Africa -- Besser said the outbreak is a problem for the global community.
"Germs tend to travel," Besser said. "More people sick in Africa increases the chances that the disease will get imported to America. While it won't spread here, any transmission in the U.S. will be for many people, quite terrifying."
Although things look grim if nothing changes, the agency predicted that intervention can make a huge difference.
If 70 percent of Ebola patients are placed in Ebola treatment centers or home settings that reduce transmission by December, the outbreak could be nearly over by the end of January, according to the CDC. However, every month that intervention is delayed means more cases and a slower stop to the outbreak.
"If conditions continue without scale-up of interventions, cases will continue to double approximately every 20 days, and the number of cases in West Africa will rapidly reach extraordinary levels," the report reads.
The CDC study authors concluded that more beds, staff and other treatment resources are needed to curb the outbreak.
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