Map: Where Ebola outbreak has spread in Africa

The largest outbreak of Ebola virus has infected over 3,400 people and infected nearly 7,500 people in five countries in Africa since December, the World Health Organization says, as of Oct. 1. One person has been diagnosed in the United States and is being treated.

The virus spreads through direct contact with broken skin or body fluids of an infected person, according to the Centers for Disease Control and Prevention.