— -- Without the proper intervention, the Ebola outbreak could reach 1.4 million cases by the end of January, according to new estimates from the U.S. Centers for Disease Control and Prevention.
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.
"The CDC estimates are staggering," said ABC News Chief Health and Medical Editor Dr. Richard Besser. "While this is a disaster for West Africa, it is also a disaster for the United States and the rest of the world."
According to the World Health Organization, 5,357 Ebola cases have been reported since the outbreak began in West Africa six months ago, including 2,630 deaths. But the organization last month warned that people are hiding their infected family members and burying their dead in secret, leading to "shadow zones" and "invisible caseloads." The CDC's estimates for reported case counts, if current trends continue, are 8,000 by the end of this month and 550,000 by the end of January.
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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