Texas health care worker tests positive for Ebola

DALLAS (KGO) -- A Dallas health care worker is the first known case of Ebola being contracted or transmitted in the U.S.

Dr. Tom Frieden, head of the Centers for Disease Control and Prevention, says the Texas hospital worker had extensive contact with Thomas Eric Duncan before Duncan died Wednesday from Ebola.

Frieden says the worker has a low level of virus and is being monitored.

He says the diagnosis of the worker - who's not identified - clearly shows that there was a breach of protocol.

Texas health officials say the worker was in full protective gear when she provided care during Duncan's second visit.

"We don't know what occurred in the care of the index patient, the original patient in Dallas, but at some point there was a breach in protocol, and that breach in protocol resulted in this infection," said CDC Director Thomas Frieden.

Doctors say this may have occurred when the worker took off her protective clothing, because if it's not done properly, an infection may result.

ABC News' Chief health and medical editor, Dr. Richard Besser, agrees that there was a breach of safety protocol of the guidelines set by the CDC.

"They're going to need to look and see what happened in the hospital to allow this to occur," he said. "If it was someone who met him when he first came into the hospital, that's one thing, but if he was part of the care team of the patient while he was in the hospital, it really throws into question the CDC recommendations that any hospital can take care of Ebola, they just need an isolation room and certain equipment."

Besser added he's more comfortable seeing Ebola patients in units where the health care workers have been specifically trained using protective equipment.

This is the first known case of the disease being contracted or transmitted in the U.S.

The health care worker reported a fever Friday night as part of a self-monitoring regimen required by the Atlanta-based Center for Disease Control.

Officials are again trying to calm any fears of contracting the virus.

"You cannot contract Ebola other than from the bodily fluids of a symptomatic Ebola victim," said Judge Clay Jenkins. "You cannot contract Ebola by walking by people in the street, or by being around contacts who are not symptomatic. There is nothing about this case that changes that basic premise of science."

Meanwhile, another level of defense against the Ebola virus is in place.

New screening measures are underway at New York's JFK International Airport. Four other airports will begin screenings this week.

Public health officials are using no-touch thermometers to take the temperature of travelers from the three Ebola-ravaged countries in West Africa.

Anyone registering a fever will be closely scrutinized.

The Associated Press contributed to this report.