The deadly Ebola outbreak sweeping across three countries in West Africa is likely to last 12 to 18 months more, much longer than anticipated, and could infect hundreds of thousands of people before it is brought under control, say scientists mapping its spread for the federal government.
“We hope we’re wrong,” said Bryan Lewis, an epidemiologist at the Virginia Bioinformatics Institute at Virginia Tech.
Both the time the model says it will take to control the epidemic and the number of cases it forecasts far exceed estimates by the World Health Organization, which said last month that it hoped to control the outbreak within nine months and predicted 20,000 total cases by that time. The organization is sticking by its estimates, a WHO spokesman said Friday.
But researchers at various universities say that at the virus’ present rate of growth, there could easily be close to 20,000 cases in one month, not in nine. Some of the leading U.S. epidemiologists, with long experience in tracking diseases such as influenza, have been creating computer models of the Ebola epidemic at the request of the National Institutes of Health and the Defense Department.
The Centers for Disease Control and Prevention declined to comment on the projections. A spokesman, Tom Skinner, said the agency was doing its own modeling and hoped to publish the results soon. But the CDC director, Dr. Thomas R. Frieden, has warned repeatedly that the epidemic is worsening, and Sept. 2 he described it as “spiraling out of control.”
While previous outbreaks have been largely confined to rural areas, the current epidemic, the largest ever, has reached densely populated, impoverished cities — including Monrovia, the capital of Liberia — gravely complicating efforts to control the spread of the disease. Alessandro Vespignani, a professor of computational sciences at Northeastern University who has been involved in the computer modeling of Ebola’s spread, said that if the case count reaches hundreds of thousands, “there will be little we can do.”
What worries public health officials most is that the epidemic has begun to grow exponentially in Liberia. In the most recent week reported, Liberia had nearly 400 new cases, almost double the number reported the week before. Another grave concern, the WHO said, is “evidence of substantial underreporting of cases and deaths.” The organization reported Friday that the number of Ebola cases as of Sept. 7 was 4,366, including 2,218 deaths.