Just four days after the first Ebola fatality was reported in the United States, a health care worker who was part of the treatment team for Thomas Eric Duncan has contracted the virus, according to Texas health officials.

Ebola virus
Ebola fever picture/CDC

The employee from Texas Health Presbyterian Hospital has tested positive for Ebola in a preliminary test at the state public health laboratory in Austin. Confirmatory testing will be conducted by the Centers for Disease Control and Prevention in Atlanta.

The health care worker reported a low grade fever Friday night and was isolated and referred for testing. The preliminary ​test result was received late Saturday.

“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. 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.