Ebola Drug - 9 questions about this new drug

(CNN) -- Two American missionary workers infected with the deadly Ebola virus were given an experimental drug that seems to have saved their lives.

Dr. Kent Brantly was given the medication, ZMapp, shortly after telling his doctors he thought he would die, according to a source familiar with his case. Within an hour, doctors say his symptoms -- labored breathing and a widespread rash -- dramatically improved. Nancy Writebol, another missionary working with Samaritan's Purse, received two doses of the medication and has also shown significant improvement, sources say.

Ebola is Real: 5 reasons not to panic

It's a terrifying disease for sure. It typically kills 90% of the people who get it, and this most recent outbreak is the largest in history. But you don't need to panic, experts say, and you definitely don't have to worry about the two American Ebola patients who are being treated in Atlanta.

Here are five reasons why:

1. It's fragile.

Ebola is an incredibly fragile virus. It does not fly through the air with the greatest of ease. It cannot be transmitted through a cough or sneeze. It doesn't move easily from human to human like the common cold.

Ebola virus: Nine things to know about the killer disease

(CNN) -- Hundreds of people are dead as the worst Ebola virus outbreak in history sweeps through West Africa. It began as a handful of cases in Guinea in March but quickly spread to neighboring Sierra Leone and Liberia. Here are nine things to know about what the World Health Organization calls "one of the world's most virulent diseases."