More caregivers monitored for Ebola at U.S. hospital

U.S. authorities on Tuesday have broadened the pool of health care workers getting monitored for Ebola at a hospital in the city of Dallas in northeastern Texas after one of them tested positive for the deadly disease.

The exact number of the expanded group, however, was not made public Tuesday when the U.S. Centers for Disease Control and Prevention (CDC) held its teleconference. The agency's director Tom Frieden said officials "don't have a number."

According to the medical records obtained by the U.S. media from the family of Thomas Eric Duncan, the deceased Ebola patient who was known as the first Ebola case diagnosed on U.S. soil, around 70 medical staffers at Texas Health Presbyterian Hospital were involved in the care of him.

Before the expansion, the CDC had been actively monitoring 48 people that might have had contact with Duncan before he was hospitalized and kept in isolation. None of the 48 people has exhibited symptoms, Frieden said.

Initially officials did not take those medical staffers into consideration because they believed the staffers were risk-free. But the fact that a female nurse who cared for Duncan was confirmed to have contracted the virus Sunday apparently showed the group is not immune.

Officials said a "breach of protocol" by the nurse caused the contamination and transmission, but so far they have failed to pinpoint the breach. The CDC is trying to determine the breach by interviewing health workers and reviewing the clinical procedures.

The nurse was identified by local media as 26-year-old Nina Pham. She was in full protective gear when providing care to Duncan. The nurse herself also could not tell what went wrong. She is reportedly in stable condition on Tuesday.