Ebola was first discovered in 1976 near the Ebola River in what is now the Democratic Republic of the Congo.

It’s not clear where the virus originates, but scientists believe it may be contracted as a result of contact with animals, according to the U.S. Centers for Disease Control and Prevention.

The virus spreads through contact with the bodily fluids of an infected patient. It is often fatal.

Ebola can be hard to diagnose because early symptoms, including red eyes and a skin rash, are common for other diseases.

Symptoms usually appear within two to 21 days after exposure, according to the CDC.