The Ebola epidemic affecting West Africa is predicted to last a further 12 to 18 months, according to U.S. scientists.
Epidemiologists have been creating computer models of the Ebola epidemic for the National Institutes of Health and the Defense Department.
The model they have created is a far less optimistic estimate than that of the World Health Organization (WHO), which last month said it hoped to contain the outbreak within nine months and 20,000 total cases.
Epidemic: The virus is rapidly spreading through impoverished and densely populated cities in West Africa
The New York Times reports that various researchers have said the virus could grow at a rate that could be closer to 20,000 per month.
The WHO is sticking to its estimates, a spokesman said Friday.
The Centers for Disease Control and Prevention (CDC) is doing its own projections which it plans to make public as soon as possible.
The director of the CDC, Dr Thomas R Frieden, has said that the situation is worsening and earlier this month said it's 'spiraling out of control.'
Unlike previous outbreaks which have been kept at bay due to their confinement to rural areas, the current Ebola crisis is spreading rapidly in densely populated cities such as Monrovia, Liberia's impoverished capital.
The spread is rapidly gaining traction, with the most recent report from Liberia of 400 cases, double the number from the week before, reports The New York Times.
As of September 7, there had been 4,366 Ebola cases in Libera, Sierra Leone and Guinea, including 2,218 deaths, more than half of them in Liberia.
The WHO has also admitted that there is likely to be 'substantial underreporting of cases and deaths.'
With the death toll from Ebola in West Africa rising sharply in the last week, the WHO said on Friday at least 500 foreign experts were needed.
Medical charity Medecins Sans Frontieres (MSF) has also called on wealthy nations to send military medical teams to West Africa to boost healthcare systems that have been completely swamped by the disease.
Cuba on Friday announced that it would deploy 165 medical personnel to Sierra Leone next month, the largest contingent of foreign doctors and nurses committed so far.
The U.S. military said this week it will build a 25-bed, $22 million field hospital in Liberia to care for health workers infected with the virus. A Pentagon spokesman said it would be built by the U.S. military and handed over to Liberians to run.
France has also said it would deploy 20 specialists in biological disasters to its former colony Guinea. Britain will also build and operate a 62-bed hospital in Sierra Leone.
MSF has said, however, the pledges by Western government represent just a fraction of the beds required to cope with the disease. It estimates that hundreds of additional beds are needed in Monrovia alone, where Ebola patients have been turned away from overflowing clinics.