Ebola virus patient in Dallas, Texas, had no symptoms while traveling, CDC says

CHICAGO (WLS) -- The first case of Ebola has been diagnosed in the United States. But national health officials said they are confident they will stop the deadly virus in its tracks.

The man infected with Ebola, who has been identified as Thomas Eric Duncan, is in critical condition inside an isolation unit in a Dallas hospital. Duncan is described as seriously ill, but he is able to communicate with doctors.

U.S. health officials said Duncan didn't have symptoms after he landed in Texas on Sept. 20. They are working to find anyone he has had contact with since he flew in from Liberia to visit family.

United Airlines confirmed Wednesday that Duncan flew from Brussels to Washington Dulles on United Airlines Flight 951 and from Washington Dulles to Dallas-Fort Worth on Flight 822.

Duncan became ill and went to the hospital six days after arriving in the U.S. Doctors sent him home while they ran tests. He was admitted two days later and put in isolation.

Officials said Duncan's fellow passengers on the plane are not likely in danger of infection.

"The likelihood for this individual to have spread it on the airplane are basically zero. Asymptomatic means he had no symptoms while he was traveling," Texas Department of Public Health Commissioner Dr. David Lakey said.

Health officials are now evaluating up to 18 people who came into contact with the man. The ambulance crew who transported him had undergone extensive training and are not exhibiting any symptoms. They are quarantined at home in a process called "reverse isolation." The ambulance used in that call underwent routine cleaning and has been taken out of service to undergo extensive decontamination.

"We have a seven-person team identifying everyone who might have come in contact with them and then monitoring them for 21 days," CDC Director Dr. Tom Frieden said.

Doctors are adamant that the virus can only spread through direct personal contact and body fluids. Symptoms include fever and stomach pain. There is no known vaccine.

Lisa M. Brosseau, a public health researcher at the University of Illinois in Chicago, said while not likely, it is at least possible the deadly Ebola virus could be transmitted through the air.

"The data that I have looked at suggests there is some possibility that this organism, if it becomes aerosolized, could present a risk to someone who inhales it," Brosseau said.

Here in Illinois, the Department of Public Health said the virus does not pose a great health risk. Local officials plan to work with area hospitals and medical facilities to identify any potential cases.

Ebola Q&A - What is ebola? Symptoms of ebola

Some questions and answers about the case:

Q: Where did the traveler come from?

A: Liberia, the hardest-hit country in the West African epidemic. The patient left on Sept. 19 and arrived in the U.S. on Sept. 20 to visit family. Frieden wouldn't release the man's nationality or other identifying information, and didn't know how he became infected.

Q: When did the patient get sick?

A: Last Wednesday, and he initially sought care two days later. He was released but returned Sunday when his condition worsened and Texas Health Presbyterian Hospital discovered the West Africa connection, admitting him under strict isolation. Tests confirmed Ebola on Tuesday.

Q: How does Ebola spread?

A: Only through close contact with the bodily fluids of someone who has symptoms, such as fever, vomiting and diarrhea. People aren't contagious until symptoms begin. And Ebola cannot spread through the air.

Q: So who's at risk?

A: Texas health officials already have begun tracking down those close contacts, believed to be mostly the relatives the man stayed with. Officials will check them for symptoms every day for 21 days. Frieden said only about a handful of people are believed to have been exposed.

Q: Could Ebola have spread on the airplane?

A: No, Frieden said, because the man wasn't sick then. The CDC said there is no need to monitor anyone else on those flights and didn't reveal flight information.

Q: Will the patient stay in Dallas?

A: Frieden said there's no need to transfer the man to one of those special isolation units that have gotten so much attention for treating four American aid workers who caught Ebola while volunteering in West Africa. Most hospitals can follow the necessary infection control for Ebola, Frieden said, and the Dallas hospital said it was "well prepared" to safely treat this newest case.

As for those other patients, three have recovered; the fourth remains hospitalized in Atlanta.

Q: How will this patient be treated?

A: Good hydration and IV nutrition have proven to be key for those other patients. Frieden said the hospital was discussing experimental treatments. A Tekmira Pharmaceuticals drug called TKM-Ebola and blood transfusions from an Ebola survivor were given to one of the recently infected U.S. aid workers.

Q: Could there be more travelers with Ebola?

A: No one's ruling it out. People boarding planes in the outbreak zone are checked for fever, but that does not guarantee that an infected person won't get through.

Airlines are required to report any deaths on a flight or ill travelers meeting certain criteria to the CDC before arriving in the U.S. If a traveler is infectious or exhibiting symptoms during or after a flight, the CDC will conduct an investigation of exposed travelers and take any necessary public health action.

Q: What if I'm worried about exposure?

A: Call the CDC for more information at 800-CDC-INFO (800-232-4636).

The Associated Press contributed to this report.