U.S. authorities say they've located a homeless man who needs to be monitored because he may have had contact with an Ebola patient in Texas, who is in critical condition.

Dallas city spokeswoman Sana Syed said the man was located Sunday, a few hours after officials first said he was missing.

The person is not considered to be one of the 10 people who definitely had contact with Thomas Eric Duncan, who is in critical condition at a Dallas hospital.

Authorities said Sunday that the man is part of a larger group of 38 people who may have been around Duncan when he was showing symptoms of the disease.

Dallas County Judge Clay Jenkins previously called the man a "low-risk individual."

"We have a great place for him to stay and we can attend to his every need. We just need him to be a hero to his community and to come forward," Jenkins said at an earlier news conference Sunday.

Duncan is now "fighting for his life" after his condition worsened from serious to critical on Saturday.

The homeless man was brought into a facility on Saturday and had his vitals and temperature checked. They asked him to stay but he left the premises.

Dr. Tom Frieden, director of the Centers for Disease Control in Atlanta, said he was confident that the virus would not spread widely in the United States.

Photojournalist en route to isolation unit in Omaha

"The man in Dallas, who is fighting for his life, is the only patient to develop Ebola in the United States," said Frieden. "The spread of Ebola is nowhere near as infectious as say, the flu."


Thomas Eric Duncan, photographed in 2001 at a wedding in Ghana, became the first patient diagnosed in the U.S with Ebola. He has been kept in isolation at a Dallas hospital since Sept. 28. (Wilmot Chayee/Associated Press)

Duncan appeared not to be receiving any of the experimental medicines for the virus, Frieden said.

Frieden said doses of the experimental medicine ZMapp were "all gone" and that the drug, produced by San Diego-based Mapp Biopharmaceutical, is "not going to be available anytime soon."

Asked about a second experimental drug, made by Canada's Tekmira Pharmaceuticals Corp, he said it "can be quite difficult for patients to take."

Elsewhere, an American photojournalist who contracted the deadly Ebola virus while working for NBC News in West Africa has begun his journey home for treatment.

Ashoka Mukpo will be the second Ebola patient to be treated at the Nebraska Medical Center's specialized isolation unit. Hospital officials said they expected an Ebola patient to arrive Monday morning, but declined to provide a name.

Mukpo's father, Dr. Mitchell Levy, told NBC Sunday that his son was "counting the minutes" until he could leave Liberia but that he was not feeling that ill Sunday.

CDC fields 800 reports of possible cases 

Frieden said in the affected parts of West Africa, where Ebola has killed more than 3,400 people, the disease is spreading so rapidly it is difficult for health officials to keep up.

The CDC has received 800 calls and emails on Ebola, up from about 50 to 100 before Duncan was diagnosed on Tuesday, Frieden said.

His girlfriend and some of her relatives, meanwhile, are under quarantine at an undisclosed location after being moved from a Dallas apartment on Friday.

"They are not a risk to others," Frieden emphasized at the news conference. "Their vitals and their temperatures are being monitored twice a day. If they get a fever — at that point, they will be isolated."

Health officials said they are monitoring about 50 people who may have had contact with Duncan for signs of the deadly disease. Louise Troh, originally from Liberia, shares the apartment with her 13-year-old son and two nephews.


Workers in hazardous-material suits arrive last Friday at a Dallas apartment visited by Thomas Duncan to disinfect its contents. (LM Otero/Associated Press)

Duncan, a Liberian national who had been living in Monrovia, was in the Liberian city last month. The New York Times reported he might have contracted Ebola after he rode to the hospital with a pregnant 19-year-old woman in a taxi. The paper said he then helped carry the woman back home the same day, where she died hours later. She had been stricken by Ebola, but media reports say family members didn't know why she was convulsing.

Duncan arrived in Dallas on Sept. 20 and fell ill a few days later. After an initial visit to the emergency room at Texas Health Presbyterian Hospital, he was sent home, even though he told a nurse he had been in disease-ravaged West Africa. He returned to the hospital two days later, last Sunday, and has been kept in isolation ever since.

The hospital issued a news release late Friday saying that the doctor who initially treated Duncan did have access to his travel history, after all. It had said Thursday that a flaw in the electronic health records systems led to separate physician and nursing workflows, and that the doctor hadn't had access to Duncan's travel history.

With files from The Associated Press