Federal health officials said they are planning for more Ebola cases as 50 Dallas healthcare workers undergo "intensive follow-up" to catch signs they might have the virus.
"We are planning for the possibility of further cases in the coming days," said Centers for Disease Control and Prevention (CDC) Director Tom Frieden on a call with reporters.
"The investigation is identifying additional healthcare workers who will be very closely [monitored]."
The new patient, who has been identified by the Dallas Morning News as Amber Joy Vinson, will be transferred to Emory University Hospital in Atlanta later Wednesday. She is ill but clinically stable, officials said.
The first infected healthcare worker, Nina Pham, will stay at Texas Health Presbyterian Hospital for the time being, Frieden said.
"The report from the hospital is that she is in improved condition today," he said. "We will assess each hour, each day, whether that is the best place for her."
The two healthcare workers had "extensive contact" with the index patient, Thomas Eric Duncan, during his care at Texas Health Presbyterian.
The second worker had three contacts prior to her isolation, Frieden said.
Health and Human Services Secretary Sylvia BurwellSylvia Mathews BurwellOvernight Healthcare: GOP chairman to introduce pre-existing condition bill ObamaCare enrollment hits 11.5M for 2017 Obama, Dems eyeing strategy to defend ObamaCare MORE sought to reassure reporters that federal health officials are up to the task of containing Ebola amid mounting criticism for missteps so far.
"This is an effort that is focused on the priority of our homeland protection … and that's a cross-government effort," Burwell said.
Before Wednesday, Burwell had not participated in the near-daily CDC press call on Ebola. No Texas health officials participated.
The decision to transfer the second healthcare worker to Atlanta reflects growing frustration with Texas Health Presbyterian's handling of Ebola cases so far.
Emory has successfully treated two Ebola patients this year: American missionaries Kent Brantly and Nancy Writebol. Another patient, who has not been identified, released a statement Wednesday saying he is recovering and anticipates being discharged from Emory "soon."
It is one of only four U.S. hospitals equipped with a special biocontainment unit for highly infectious patients.
Texas Health Presbyterian Dallas said it was "actively consulting" with Emory about the transfer.
"We are sensitive to the demands being placed on our caregivers, who are working intensively to provide quality care to all patients, and we will provide new information as decisions are made," said Wendell Watson, the hospital's director of public relations.
The news of the second infected healthcare worker prompted President Obama to cancel his campaign events for the day and call a meeting of his Cabinet.
The president is expected to address reporters at the conclusion of that meeting.
— This story was last updated at 4:13 p.m.