US defends Ebola response; 50 under observation

US officials on Friday defended the response to the country's first case of Ebola, though one acknowledged that while the government was confident of containing the virus, it had been "rocky" in Dallas where the patient is in a serious condition. Health officials in Dallas have narrowed their focus to about 50 people who had direct or indirect contact with an infected Liberian visitor, including 10 at high risk who are being checked twice daily for symptoms.

In Washington, officials were asked at a news conference why the visitor, Thomas Eric Duncan, was able to get past screening in his journey from Liberia on September 19 and then sent home after telling a Dallas hospital later about his travel to a country where there had been an Ebola outbreak.

"There were things that did not go the way they should have in Dallas, but there were a lot of things that went right and are going right," Dr. Anthony Fauci, a director at the National Institutes of Health, told reporters at the White House.

"So, although certainly it was rocky" in terms of how people perceived the response, "the reason I said there wouldn't be an outbreak is because of what is going on right now," Fauci said.

Fauci said although it "may be entirely conceivable" that there would be another Ebola case in the United States, the strength of the healthcare infrastructure "would make it extraordinarily unlikely that we would have an outbreak."