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The first person in the U.S. diagnosed with Ebola is now in an isolation unit at a Dallas hospital. The patient has not been identified. Federal health officials say he had traveled to U.S. from Liberia where some 1,800 people have already died from the disease. Health officials here say they're confident that this single case won't lead to an outbreak in the U.S. And joining us to talk more is NPR science correspondent Richard Harris. Hey there, Richard.
RICHARD HARRIS, BYLINE: Good morning.
CORNISH: So what more can you tell us about this patient?
HARRIS: Well, we know he flew from Liberia to Dallas on September 20, and he's been staying with relatives there. He was actually quite healthy when he flew. Symptoms appeared on September 24. Symptoms can be a sudden headache or fever - nondescript kinds of symptoms.
He actually went looking for treatment. On September 26 he went to Texas Health Presbyterian Hospital, but they didn't diagnose Ebola. They sent him home. He was brought back by ambulance a couple of days later on Sunday, and he's been in the hospital in isolation ever since. The hospital says it was prepared for Ebola, and so they had an isolation ward. But the man is critically ill right now.
CORNISH: Now, you mentioned that his symptoms appeared later after that flight, but what about the people who were on the same airplane? Are they at risk for contracting Ebola?
HARRIS: They are not, according to health officials. The rule with Ebola, which has been around since 1976 so they understand this virus quite well - is that if you don't have symptoms, you're not at risk for spreading the disease. Doctor Thomas Frieden who heads the CDC actually said there is zero risk of transmission on the flight. And on top of that, the man was checked for fever before he got on the flight, so that's further evidence that he wasn't sick while he was flying.
There's actually one known instance where there was an actively ill patient on a flight. It was a man who flew from Liberia to Nigeria, and he was sick on multiple legs of this flight, and no one else contracted Ebola on those flights. So there's an indication that even if people are sick - actively sick on a flight, it's not a high risk for spreading the disease.
CORNISH: We mentioned U.S. official being confident that a single case won't lead to an outbreak in the U.S. What's behind that confidence? What's the plan to prevent an outbreak in the U.S.?
HARRIS: Well, the trick to controlling a disease like this is to identify anyone who's had close contact with him - anyone who was - once the man has symptoms, that is. And Doctor Frieden says there were only a handful of people who are at risk, and they will be followed for 21 days to see if they develop any symptoms. Twenty-one days is the maximum incubation period for this disease.
So basically if - we know it doesn't spread easily. It really needs close contact of bodily fluids. So if people who, you know, may have seen this man or something like that are not at risk. So the trick to controlling the disease is just find the people who had close contact and follow them closely.
CORNISH: You given us a long list of people who are not at risk. Who is at greatest risk from contracting the disease from this man?
HARRIS: Well, clearly, the family he was staying with and the physicians who tended to him when he was ill. Medical workers - if they were using correct infection control like gloves and masks and so on, they're at very low risk for getting the disease. But he came to the hospital once. They didn't understand that he had this very serious disease. They sent him home. So presumably some of those medical workers will be monitored carefully to make sure that they didn't, you know, get in contact with his bodily fluids and so on.
It's a very scary disease. We know that 'cause it's so deadly. But it does not spread easily. It doesn't spread through the air or anything, so that's reassuring.
CORNISH: We have heard about other people treated for Ebola in U.S. hospitals. What's different about this case?
HARRIS: Those other cases were diagnosed overseas, and they were brought into this country in special transport - planes designed to carry highly infectious patients. They were under isolation all the way. His case is different. He flew commercial, although, as I said, the health authorities say there's zero risk of transmission during that flight 'cause he was not showing symptoms. But, you know, he has been in touch - in contact with healthcare workers and his family.
So that's the difference - that he's - there are more people potentially exposed. But the CDC says they expect, essentially, to be able to put an end to this, right here. There will not be an outbreak as a result of this.
CORNISH: That's NPR's Richard Harris. Richard, thank you.
HARRIS: My pleasure. Transcript provided by NPR, Copyright NPR.