A CDC doctor prepares to enter an Ebola treatment center in Liberia.

A CDC doctor prepares to enter an Ebola treatment center in Liberia. Athalia Christie/CDC

Featured eBooks
Best Dates to Retire 2020
What’s Next for Federal Customer Experience
 The Future of the Air Force
CDC Predicts As Many As 1.4 Million Ebola Cases by Early 2015

Without an effective intervention or a slowdown, the outbreak could extend from 550,000 to as many as 1.4 million cases by Jan. 20.

A new and particularly grim Centers for Disease Control projection estimates that Ebola cases in western Africa could easily breach the million mark in just four months. The agency warned that without an effective intervention or a slowdown in the transmission of the virus, the world's biggest outbreak on record could extend from 550,000 to as many as 1.4 million cases by January 20. From the Washington Post:

Researchers say the total number of cases is vastly underreported by a factor of 2.5 in Sierra Leone and Liberia, two of the three hardest-hit countries. Using this correction factor, researchers estimate that approximately 21,000 total cases will have occurred in Liberia and Sierra Leone by Sept. 30. Reported cases in those two countries are doubling approximately every 20 days, researchers said.

As Denise Grady pointed out, the new projections don't account for the recent efforts taken by the United States and the international community, but instead reflect a "worst-case scenario." That said, the figures also don't include cases reported in Guinea, which are said to be unreliable.

With international health workers and groups working to limit the exposure and treat the ill, countries have taken drastic action to stem the spread of the virus. As CNN reported, Sierra Leone finished a three-day national lockdown on Monday in which citizens were not allowed to leave their homes as health workers sought to make contact with 1.5 million homes to explain how the virus is contracted.

According to the country's health ministry, 75 percent of the households were reached.