In this colored transmission electron micrograph, an infected cell (reddish brown) releases a single Ebola virus (the blue hook). As it exits, the virus takes along part of the host cell's membrane (pink, center), too. That deters the host's immune defenses from recognizing the virus as foreign. London School of Hygiene & Tropical Medicine/Science Source hide caption

itoggle caption London School of Hygiene & Tropical Medicine/Science Source

Testing for Ebola, a scientist in a mobile lab at Gueckedou, Guinea, separates blood cells from plasma cells to isolate the virus's genetic sequence. Misha Hussain/Reuters /Landov hide caption

itoggle caption Misha Hussain/Reuters /Landov

Rose Komano, 18 and the mother of three, was the first Ebola patient to overcome the virus in southeastern Guinea, the epicenter of the outbreak. On April 3, she posed at a health clinic in the Gueckedou region. Misha Hussain /Reuters /Landov hide caption

itoggle caption Misha Hussain /Reuters /Landov

The new normal in Guinea is washing hands with a mixture of water and bleach--shown here at the border entrance of Buruntuma, in the Gabu area on Tuesday. Tiago Petinga/EPA /LANDOV hide caption

itoggle caption Tiago Petinga/EPA /LANDOV

A nurse of the 'Doctors without Borders' medical aid organisation examines a patient in the in-take area at a center for victims of the Ebola virus in Guekedou, on April 1, 2014. The viral haemorrhagic fever epidemic raging in Guinea is caused by several viruses which have similar symptoms — the deadliest and most feared of which is Ebola. Seyllou/AFP/Getty Images hide caption

itoggle caption Seyllou/AFP/Getty Images

The fatality rate in an Ebola outbreak ranges from 25 percent to 90 percent, depending on the particular strain of the virus involved. Cynthia Goldsmith/ Centers for Disease Control and Prevention hide caption

itoggle caption Cynthia Goldsmith/ Centers for Disease Control and Prevention

After testing negative for Ebola, Magdalena Nyamurungi returns home with a new set of belongings from the World Health Organization. Medical workers burned and buried her possessions when they suspected she was infected. B. Sensasi/Courtesy of WHO hide caption

itoggle caption B. Sensasi/Courtesy of WHO

A medical worker from the U.S. Centers for Disease Control and Prevention works at the laboratory where Ebola specimens from the Congo were tested at the start of the latest outbreak. Stephen Wandera/AP hide caption

itoggle caption Stephen Wandera/AP

A medical worker from the U.S. Centers for Disease Control and Prevention works at the laboratory in Uganda where Ebola specimens were tested at the start of the latest outbreak in the Democratic Republic of Congo. Stephen Wandera/Associated Press hide caption

itoggle caption Stephen Wandera/Associated Press