(FOX News) -- A health care worker at a Dallas hospital tested positive for Ebola in a preliminary test, the Texas Department of State Health Services said in a statement early Sunday.
The health care worker at Texas Health Presbyterian Hospital, who was not identified in the statement, provided care for Thomas Eric Duncan, the first Ebola patient in the United States, who died last week.
If the preliminary diagnosis is confirmed, it would be the first known case of the disease being contracted or transmitted in the U.S.
A statement posted on the Texas Department of State Health Service's website said "confirmatory testing will be conducted by the Centers for Disease Control and Prevention in Atlanta."
Officials said the health care worker reported a low grade fever Friday night and was isolated and referred for testing. Preliminary test results were received late Saturday.
Hospital and state health officials did not provide the health care worker's job description.
"We knew a second case could be a reality, and we've been preparing for this possibility," said Dr. David Lakey, commissioner of the Texas Department of State Health Services. "We are broadening our team in Dallas and working with extreme diligence to prevent further spread."
Health officials have interviewed the patient and are identifying any contacts or potential exposures. They said people who had contact with the health care worker after symptoms emerged will be monitored based on the nature of their interactions and the potential they were exposed to the virus.
Ebola spreads through close contact with a symptomatic person's bodily fluids, such as blood, sweat, vomit, feces, urine, saliva or semen. Those fluids must have an entry point, like a cut or scrape or someone touching the nose, mouth or eyes with contaminated hands, or being splashed. The World Health Organization says blood, feces and vomit are the most infectious fluids, while the virus is found in saliva mostly once patients are severely ill and the whole live virus has never been culled from sweat.