Magnified 25,000 times, this digitally colorized scanning electron micrograph shows Ebola virus particles (green) budding from an infected cell (blue). CDC/NIAD hide caption

itoggle caption CDC/NIAD

An Ebola health alert is displayed at the entrance to Bellevue Hospital in New York City, where Dr. Craig Spencer was quarantined after showing symptoms consistent with the virus. Bryan Thomas/Getty Images hide caption

itoggle caption Bryan Thomas/Getty Images

Australia is no longer processing new visa applications from the three worst-hit countries in Africa's Ebola outbreak. Here, a jetliner prepares to land at Sydney's international airport. Jason Reed/Reuters/Landov hide caption

itoggle caption Jason Reed/Reuters/Landov

The nursing staff get a break at the Ebola care center run by Doctors Without Borders in Foya, Liberia. The center has helped stop the spread of the virus. Michealeen Doucleff/NPR hide caption

itoggle caption Michealeen Doucleff/NPR

New Jersey Governor Chris Christie (right) and New York Governor Andrew Cuomo both insist on mandatory quarantine for healthcare workers who've had contact with Ebola patients. Christie wants them held in a medical facility; Cuomo says a home quarantine with outside monitoring would do. Mark Lennihan/AP hide caption

itoggle caption Mark Lennihan/AP

After the 2010 earthquake in Haiti, the Red Cross sent text messages across the country with health tips, locations of aid and safety reminders. A similar system is being used in Sierra Leone to combat Ebola. International Federation of Red Cross and Red Crescent Societies hide caption

itoggle caption International Federation of Red Cross and Red Crescent Societies