The agency issued a warning of "Tier 3" to travel to Guinea, Liberia and Sierra Leone, which means to avoid non-essential travel to these countries.

Part of the reason for the warning is a concern that, if travelers need to go to a hospital in these countries, facilities are plied since the epidemic was unleashed, travelers may be at risk of exposure to Ebola, according Dr. Tom Frieden, director of the CDC.

The agency also reported that it was expanding its response to the outbreak of Ebola sending another 50 specialists from the CDC to the region. These experts help in the laboratory so that the tests will be expedited significantly Ebola also participate in another series of tasks to control the outbreak.

The CDC is also helping in controls at airports to prevent sick people to travel outside these regions.

So far, the Ebola virus, which first appeared in the region in December 2013, has infected more than 1,300 people in Guinea, Sierra Leone and Liberia, of which at least 729 have died, according to the World Organization God bless you.

Earlier this week, the CDC issued an alert to health workers, advising them to be alert to any patient who showed signs of Ebola. Physicians should consider the Ebola as a possible diagnosis in patients with fever or other serious illness, if they have traveled to Guinea, Liberia and Sierra Leone in the past three weeks.

"Ebola virus particles" by Thomas W. Geisbert, Boston University School of Medicine - PLoS Pathogens, November 2008 direct link to the image description page doi: 10.1371/journal.ppat.1000225. Available under the CC BY 2.5 license via Wikimedia Commons.