Transcript for American Doctor in Liberia Tests Positive for Ebola Virus
The word itself evokes fear and dread. Ebola. A man with ebola was able to board a flight and get to the largest city in the continue tent. First, bazi kanani in Washington. Reporter: This is an extremely concerning time for Dr. Ken Brantly. He calls himself a young Christian doctor. Putting his faith to work in the world. Now trying to fight a deadly disease. The first American to contract ebola in Africa. Caring for patients inside this center. His wife and young children are at home in the U.S. He's a servant by nature. He's a doctor. He's man who cares about people. Reporter: Brantly, pictured here in the head-to-toe protective gear he wears when treating ebola patients. Not an inch of skin exposed. It's not yet known how he contracted the disease. This year, the highly contagious disease has spread to three west african countries. More than 600 dead. Now a scramble to halt the disease in Lagos, Nigeria. The largest city in all of Africa. A sick man brought it into the country on plane on Tuesday. The other passengers on that flight are being monitored. There has never been a time in the history of ebola where it has spread so fast. These countries don't have the capacity to contain it. Reporter: Dr. Brantley's colleagues at samaritan's purse are calling for assistance. And for prayer for one of their own. In this outbreak, 62% of infected people have died. Dr. Brantley is in isolation. His colleagues say he has a fever and is in intense pain. At last check, they say he was sitting up and working on his computer. A truly dedicated doctor. Bianna? Our thoughts and prayers are with him and his family. Thank you. Let's bring in Dr. Richard Besser. He's reported extensively on ebola. How do you think this doctor contracted the disease in Liberia? It's a good question. You look at ebola outbreaks. The group at highest risk of getting it is health care workers. That's because to get it, you have to be in close contact with patients. You get it from their secretions or a contaminated surface. You try to provide health care workers with all the equipment. He had all that gear on. I have worn that gear, after about 15 minutes, you're so hot in that gear, you either have to get out of there or you're going to get dehydrated or there can be lapses. They're going to want to see if there was a break in the procedure. Doctors take extreme caution every day. Talk about the air travel spread. This is very concerning. When you have ebola, you're only going to transmit it if you're already sick. When someone is boarding a plane, they look at your passport and they're looking to see if you're sick. This individual flew from Liberia to Nigeria and died a couple of days later. If he was already symptomatic, they want to make sure no one else had the contact. You have to have touched secretions from that person or contaminated SUV surfaces. What's the possibility of it getting here? I don't think they're very worried. Somebody infected could fly here. If they arrived at an American emergency room, you would hope they would be detected and isolated and you wouldn't see the spread they're seeing in Africa. It's been going on for so many months. Not just isolated to a region of the country. It's three countries in Africa. Let's hope he has a speedy recovery. 60% of people have died. 40% have survived. Hopefully, he'll be one of them. Dr. Besser, thank you.
This transcript has been automatically generated and may not be 100% accurate.