Health care worker tests positive for Ebola after helping Thomas Eric Duncan (inset), who died of the disease last week.
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A Dallas health care worker has tested positive for Ebola, according to preliminary test results, CNN reports.

Further tests will be conducted by the Centers for Disease Control and Prevention in Atlanta to confirm the presence of the virus in the unidentified worker at Texas Health Presbyterian Hospital, the news site notes.

The worker reportedly helped care for Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., who died Wednesday.

"We knew a second case could be a reality, and we've been preparing for this possibility," Dr. David Lakey, commissioner of the Texas Department of State Health Services, said in a statement Sunday morning. "We are broadening our team in Dallas and working with extreme diligence to prevent further spread."

On Friday evening the worker was placed in isolation after reporting a low-grade fever. Preliminary test results came in late Saturday, the report says. If further test results are positive, the case would mark the first known transmission of Ebola in the United States and the second-ever diagnosis in the country, the site notes.

Read more at CNN.