SUNDAY, Oct. 12, 2014 (HealthDay News) -- A health care worker who helped treat the Liberian man who died of Ebola in a Dallas hospital last week has tested positive for the virus, public health officials reported Sunday.
"We don't know what occurred in the care of the original patient in Dallas, but at some point there was a breach in protocol, and that breach in protocol resulted in this infection," Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, said during a Sunday morning news briefing.
This is the first case of Ebola infection on American soil. The Liberian man, Thomas Eric Duncan, contracted Ebola in his home country before flying to Dallas in September to visit relatives and friends.
The female hospital employee, who has not been identified, was isolated and tested Friday night after reporting a low-grade fever. She was wearing protective clothing and equipment on the multiple occasions that she helped treat Duncan, health officials said.
Her infection will significantly expand the number of people who must be monitored for potential exposure to Ebola, to include anyone exposed to Duncan while treating him in the hospital, Frieden said.
The infected health care worker wasn't among the initial 48 people being monitored by public health workers because they had come into contact with Duncan before he entered Texas Health Presbyterian Hospital in Dallas on Sept. 28.
"Now we're doing a new investigation, given the diagnosis late last night of this individual, of anyone else who may have been exposed once he [Duncan] was on what should have been effective isolation," Frieden said.
Public health officials also have identified one person who will be monitored because that person was exposed to the health care worker after she fell ill. A person infected with Ebola only can transmit the disease once they have started showing symptoms, including fever. The Ebola virus spreads through close contact with an infected person's bodily fluids, such as blood, sweat and vomit, according to the CDC.
The health care worker's initial diagnosis came late Saturday, and the CDC confirmed that diagnosis on Sunday after running its own tests.
The worker wore a gown, gloves, mask and shield while she cared for Duncan at Texas Health Presbyterian, said Dr. Daniel Varga, of Texas Health Resources, which runs the hospital, the Associated Press reported.
Frieden said the woman cared for Duncan on multiple occasions, but has not been able to identify a specific lapse in infection control that might have led to her being infected.
She and others who cared for Duncan have been required to monitor themselves for fever or other signs of Ebola.
The woman detected a fever on Friday and quickly brought herself to Texas Health Presbyterian Hospital for evaluation, said Dr. David Lakey, commissioner of the Texas Department of State Health Services.
The investigation into her exposure will focus on the infection-control protocol she followed when removing protective gear after treating Duncan, Lakey said.
Frieden said Sunday: "When you have potentially soiled or contaminated gloves or masks or other things, to remove those without any risk of any contaminated material touching you and then being on your clothes or face or skin, and leading to an infection, is critically important and not easy to do right."
Officials also will review the performance of kidney dialysis and respiratory intubation on Duncan during the later stages of his illness.
"Both of those procedures may spread contaminated materials, and are considered high-risk procedures," Frieden said. "They were undertaken on the index patient [Duncan] as a desperate measure to try to save his life."
Workers were to enter the health care worker's Dallas apartment Sunday to decontaminate it. Her car and the parking area around it already has been decontaminated, officials said.
Duncan entered the United States from Liberia on Sept. 20, apparently healthy and without symptoms of Ebola, the often fatal disease that has been sweeping through three West African nations since the spring.
He first developed symptoms Sept. 24 and sought care two days later at Texas Health Presbyterian, but was released from the hospital. He was taken back to the hospital on Sept. 28 after his condition worsened.
Public health workers have been monitoring 10 people confirmed to have had contact with Duncan after he fell ill with Ebola and became contagious, as well as 38 other suspected contacts. The 10 include several members of Duncan's family living in Dallas and the ambulance crew that transported him to the hospital, officials said.
Meanwhile, U.S. officials have begun entry screening for "general overt signs of illnesses" at five airports for passengers arriving from the West African nations hit hard by the Ebola epidemic: Guinea, Liberia and Sierra Leone.
The screenings began Saturday at Kennedy International Airport in New York City. They will begin Thursday at four other airports -- Washington Dulles International, O'Hare International in Chicago, Hartsfield-Jackson International in Atlanta and Newark Liberty International in New Jersey.
The Ebola epidemic in West Africa is the worst outbreak ever of the disease. So far, an estimated 8,000 people have become infected and an estimated 3,880 people have died in Guinea, Liberia and Sierra Leone, according to the World Health Organization.
For more on Ebola, visit the U.S. Centers for Disease Control and Prevention.