DALLAS/NEW YORK (Reuters) - The fifth American to contract Ebola in West Africa arrived in the United States for treatment on Monday as the first patient diagnosed with the deadly virus on U.S. soil fought for his life at a Dallas hospital, officials said.

A private plane carrying Ashoka Mukpo, a freelance cameraman for NBC News who contracted Ebola in Liberia, landed in Omaha and was taken to the Nebraska Medical Center. The plane was met by an ambulance manned by workers in yellow protective suits, NBC video showed.

Dr. Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC), said on Monday his agency would work "very closely" with the Nebraska hospital, which treated another Ebola patient in recent weeks.

"We'll also make sure that doctors and nurses, the whole team taking care of him, does that in a way that doesn't put them at risk by providing them with support," Frieden said, speaking on NBC's "Today" program.

The Nebraska hospital had treated and released Dr. Rick Sacra, an American missionary who contracted Ebola in Liberia, last month. Sacra was admitted to UMass Memorial Medical Center in Worcester, Massachusetts, on Saturday for a likely respiratory infection but tested negative for Ebola, hospital officials said on Sunday. He was being removed from isolation.

Meanwhile, Dallas Ebola patient Thomas Eric Duncan remained in critical condition, Frieden said.

"Our hopes and prayers are with him. We recognize this is a critical time for him and for his family," Frieden said.

Duncan became ill after arriving in Texas from Liberia two weeks ago, heightening concerns that the worst Ebola epidemic on record could spread from West Africa, where it began in March.

Frieden, who was slated to brief President Barack Obama later on Monday, said health officials were closely monitoring 10 people who had direct contact with Duncan and are considered at greatest risk. So far none has shown any symptoms, he added.

Another 38 people who potentially had contact with Duncan are also being tracked, he said.

Ebola, which can cause fever, vomiting and diarrhea, spreads through contact with bodily fluids such as blood or saliva. The U.S. cases come as death toll from the epidemic rises. It has killed more than 3,400 people since it began and has now begun spreading faster, infecting almost 7,500 people so far.


Frieden emphasized on Monday the importance of rehydration in treating Ebola patients, especially given the lack of available doses of the experimental drug ZMapp, produced by San Diego-based Mapp Biopharmaceutical.

"We don't know if ZMapp works, but there's no more of it now. The company's working hard to make a few more doses, but it's hard to make. It takes a long time," he told NBC.

A second experimental drug, made by Canada's Tekmira Pharmaceuticals Corp, "can be quite difficult for patients to take," he told CNN on Sunday.

He added that the doctor and Duncan's family would decide whether prescribe the drug and that the CDC was not yet aware of any experimental drugs being used for him.

The Texas case highlighted problems that U.S. public health officials are trying to address: The hospital that examined him initially did not recognize the deadly disease and sent him home with antibiotics, only to have him return two days later in an ambulance.

U.S. health experts and the White House have expressed confidence the disease will not spread widely within the United States, and U.S. officials are scaling up their response in West Africa, where Ebola presents an enormous challenge.

"CDC has now trained more than 4,000 health workers in Africa," Frieden said.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has said suspending flights to and from affected countries or imposing a visa ban on travelers from those areas should not be done and on Monday said officials continue to look at airport screening.

"All options are going to be looked at," he told CNN. "The discussion is: Is that extra, added layer of screening going to be worth the resources that are put into doing it?"

But the virus's 21-day maximum window for symptoms to appear makes it difficult, he said, adding that "to bring someone to an airport and keep them there for 21 days and make sure they get exposed to nobody and then let them on the plane? That would be absolutely impossible."

By Lisa Maria Garza and Sharon Begley

(Additional reporting by Susan Heavey, Mohammad Zargham, Doina Chiacu and Aruna Viswanatha in Washington, Jonathan Kaminsky in New Orleans, Lewis Krauskopf in New York; Writing by Susan Heavey; Editing by Jim Loney)