What to know 

Caption:UNDATED: In this handout from the Center for Disease Control (CDC), a colorized transmission electron micrograph (TEM) of a Ebola virus virion is seen. As the Ebola virus continues to spread across parts of Africa, a second doctor infected with the disease has arrived in the U.S. for treatment. (Photo by Center for Disease Control (CDC) via Getty Images)

How the Ebola virus spreads

Michael Martinez and Jacque Wilson, CNN
Yes, Ebola is a scary infectious disease. But the first thing you should know is that it's not very contagious.