Denise Grady, New York Times, September 24, 2014

Yet another set of ominous projections about the Ebola epidemic in West Africa was released Tuesday, in a report from the Centers for Disease Control and Prevention 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 spreading 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.

“My gut feeling is, the actions we’re taking now are going to make that worst-case scenario not come to pass,” Dr. Thomas R. Frieden, the C.D.C. director, said in a telephone interview. “But it’s important to understand that it could happen.”

The figures in the C.D.C. report are based on data from August, but Dr. Frieden said the situation appeared to have improved since then because more aid had begun to reach the region.

The current official case count is 5,843, including 2,803 deaths, according to the World Health Organization.

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The W.H.O. report also, for the first time, raised the possibility that the disease would not be stopped but would become endemic in West Africa, meaning that it could become a constant presence there. The report from the C.D.C. did not discuss that possibility, but it is something that health officials have feared all along, and the reason they say help is needed so quickly.

President Obama’s promise last week to send 3,000 military personnel to Liberia and to build 17 hospitals there, each with 100 beds, were part of the solution, Dr. Frieden said. {snip}

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