Editor's note: This story has been updated throughout.

Announcing that a patient in Dallas hospital has the Ebola virus, federal and state health officials said Tuesday that they are working to track down anyone who may have come into contact with the patient — the first confirmed case in the U.S. They added that they do not expect an outbreak to result.

In a news conference, the director of the federal Centers for Disease Control and Prevention, Tom Frieden, said that the patient has been kept in isolation since Sunday at Texas Health Presbyterian Hospital in Dallas.

Frieden said the patient flew into the U.S. on Sept. 20 with no symptoms after traveling to the West African nation of Liberia. The patient developed symptoms on Sept. 24 and first sought care two days later. The patient was discharged from the hospital’s emergency room on Sept. 26 with a prescription for antibiotics, health officials said. The patient returned to the hospital Sunday morning and was placed in isolation to receive “intensive care.”

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"This is the first patient diagnosed outside of Africa to our knowledge with this particular strain of Ebola," Frieden said.

He added that the patient is "critically ill" and was in Dallas to "visit family who live in this country." Officials would not confirm whether the patient is a U.S. citizen or the patient's gender, but they repeatedly referred to the patient as a male.

Frieden also said the patient may have been in contact with a “handful” of family and community members while he showed symptoms.

A team from the CDC has been dispatched to Dallas to trace anyone who may have come into contact with the patient.

Health officials say they are exercising all precautions and monitoring those individuals.

The virus spreads through contact with bodily fluids and is not airborne, according to the Centers for Disease Control and Prevention.

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Edward Goodman, the Texas Health Presbyterian epidemiologist, said there was not “any significant exposure” between the patient and hospital staff before the disease was confirmed because the patient was not at the stage of the disease where exposure to bodily fluids would be a major concern. But Goodman added that the hospital is keeping a close watch on workers who came in contact with the patient.

Since March, more than 6,500 people in West Africa have contracted Ebola, and more than 3,000 people have died, according to the World Health Organization, making this the largest and deadliest outbreak of the disease in history.

"Ebola is a scary disease because of the severity of illness it causes, and we are really hoping for the recovery of this individual,” Frieden said. “At the same time, we're stopping it in its tracks in this country.”

In a statement, state Sen. Charles Schwertner, R-Georgetown, the chairman of the Senate Health and Human Services Committee, said that state health officials had assured him that they would give regular updates on developments.

"The most important thing is for the people of Texas to remain calm," Schwertner said. "It's important to realize that the Ebola virus is not an airborne contagion and can only be spread through direct physical contact with an infected individual."

Texas Department of State Health Services Commissioner David Lakey said Tuesday that the department's Austin lab received a blood sample from the patient at 9 a.m. Tuesday and confirmed the positive Ebola test at 1:22 p.m. The CDC also confirmed the positive Ebola case. Lakey said there were no other suspected cases in Texas.

Lakey said the state laboratory in Austin was certified to test for Ebola on Aug. 22 after the CDC sent a request to various state health departments asking them to become certified in response to the outbreak of Ebola in other areas of the world. The Ebola test from the patient in question was the first of its kind at the Austin lab.

“Over the last several months, as we have been watching what has been occurring in Africa, we were approached by the CDC to have that capability here in Austin so that we could do that kind of test here in Austin,” Lakey said to reporters outside of the state lab.

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Zachary Thompson, director of Dallas County Health and Human Services, said the department is looking into other possible cases. But, he added, "We think it's a small framework we're looking at in terms of the number of people."

While the overall mortality rate for Ebola is more than 50 percent, Goodman said it could be lower in the U.S. because of technological advances, but he emphasized that Ebola is highly deadly.

“We certainly can expect better outcomes, but it is a serious disease,” he said.

Health officials declined to provide details on the course of treatment for the patient.

Christine Ayala contributed to this report.