DALLAS (AP) — Texas officials say a health care worker who has tested positive for Ebola was in full protective gear while providing hospital care for the Ebola patient who later died.

Dr. Daniel Varga of Texas Health Resources says the worker wore a gown, gloves, mask and shield when caring for Thomas Duncan. They're now trying to determine how the unidentified worker became infected.

Varga says the worker reported a fever Friday night as part of a self-monitoring regimen required by the Atlanta-based Centers for Disease Control and Prevention.

Duncan, the first person diagnosed with Ebola in the U.S., died Wednesday in Dallas.

A top federal health official says the Ebola diagnosis in a health care worker who treated Thomas Eric Duncan at a Texas hospital shows there was a clear breach of safety protocol.

Dr. Tom Frieden, head of the Centers for Disease Control and Prevention, says the worker had treated Duncan multiple times after the Liberian man was diagnosed.

Frieden tells CBS' "Face the Nation" that all those who treated Duncan are now considered to be potentially exposed. Frieden couldn't give an exact number.

Health care workers treating Duncan were to follow CDC protocol that included wearing protective gear.

Among the things CDC will investigate is how the workers took off that gear — because removing it incorrectly can lead to a contamination.

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