DALLAS — A man who recently arrived in Texas from Liberia has been confirmed as having the first case of Ebola to be diagnosed in the U.S.

Authorities with the Centers for Disease Control revealed the finding late on Tuesday, two days after the unidentified patient was admitted to a Dallas hospital with suspicious symptoms.

Officials at Texas Health Presbyterian Hospital Dallas put the man into “strict isolation” and sent a blood specimen to state and federal labs for testing.

Both came back positive for the deadly disease, which has killed more than 3,000 people in Africa this year. According to the World Health Organization, there have been more than 6,500 Ebola cases confirmed in Africa, with Guinea, Liberia and Sierra Leone among the hardest hit.

Texas Health Presbyterian in North Dallas (Jason Sickles, Yahoo)

“He is ill, he is under intensive care, he's being seen by highly trained, competent specialists, and the health department is helping us in tracing any family members that might have been exposed," said Dr. Edward Goodman with Texas Health Dallas, at a news conference on Tuesday.

Authorities declined to name the adult patient or even say if he is an American.

“The patient was visiting family members and staying with family members who live in this country,” Dr. Thomas Frieden, CDC director, said at the news conference.

A press release announcing the activation of the City of Dallas' Emergency Operations Center described the patient as having “moved to Dallas from Liberia a week ago.”

Frieden said the man arrived from Liberia on Sept. 20 but didn't start feeling ill until Sept. 24. He sought medical treatment at Texas Health Dallas on Friday, Sept. 26, before being sent home. He was then transported by ambulance back to the hospital on Sunday, Sept. 28.

“The initial symptoms of Ebola are often nonspecific ... they are symptoms that may be associated with many other conditions,” Frieden said. “That's why we have encouraged all emergency department physicians to take a history of travel within the last 21 days.”

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The ambulance used to transport the patient on Sunday has been quarantined, Dallas officials said. Paramedics involved are being monitored.

The CDC has a team en route to North Texas to help health officials retrace the man's whereabouts since he has been in the states. Officials characterized the patient as having close contact with about a "handful" of family members while in Dallas.

“While it is not impossible that there could be additional cases associated with this patient in coming weeks, I have no doubt that we will contain this,” Frieden said. “... as long the outbreak continues in Africa we need to be on our guard.”



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Along with all other passengers, the patient's temperature was taken as a matter of precaution when he left Liberia for the U.S. on Sept. 19. Because he didn't show a fever then, Frieden said, officials have no immediate plans to make the man's flight information public.

“At this point there is zero risk of transmission on the flight," Frieden said.

Ebola is highly contagious and deadly but spread only through contact with bodily fluids. Dallas County Health and Human Services Director Zachary Thompson spent most of his day trying to calm the fears of North Texans.

“It is easier to get the flu than it is to get the Ebola virus,” Thompson told KTVT-TV. "You have to get it through secretion, blood, that type of transmission. So this is not a situation where you go to the grocery store and you get infected with the virus.”

Ebola symptoms include sudden fever, fatigue and headache. Officials said symptoms may appear anywhere from two days to three weeks after exposure.

Four American aid workers have contracted Ebola in West Africa and been evacuated to the U.S. for treatment since late July. Three of them were released after making full recoveries. A fourth patient arrived in Atlanta on Sept. 9, but spokespersons at Emory University Hospital have said privacy laws prevent the release of an updated condition. On Sunday, a U.S. doctor who had been volunteering in an Ebola clinic in Sierra Leone was brought to the National Institutes of Health in Bethesda, Maryland, as a safety precaution after he was exposed to the disease.

In past years, Ebola has killed up to 90 percent of those it has infected, but officials say the death rate in the current outbreak is closer to 60 percent due to early treatment.

(Updated at 10:30 p.m. ET.)

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Jason Sickles is a writer for Yahoo. Have a story tip? Email him at jsickles@yahoo-inc.com. Follow him on Twitter at @jasonsickles.