WASHINGTON - The United States must “rethink” its approach to controlling the Ebola virus after a Texas healthcare worker was infected with the often deadly virus, officials said Monday.

“We have to rethink the way we approach Ebola infection control because even a single infection is unacceptable,” said Centers for Disease Control and Prevention director Tom Frieden. Frieden also apologized for appearing to place the blame on woman who fell ill when he cited a lapse of safety procedures, telling reporters he felt “awful” upon learning of the case.

“All of us have to work together to do whatever is possible to reduce the risk that any other healthcare worker becomes infected,” Frieden told a press conference. Frieden said Sunday that a “breach of protocol” was the reason for the infection of the woman, who cared for Liberian patient Thomas Eric Duncan when he fell ill in Dallas.

Duncan was hospitalized September 28 and died of Ebola on Wednesday. The woman, whose identity has not been revealed by the CDC, developed a fever a couple of days later.

She treated Duncan multiple times during his hospital stay and had extensive contact with him, but had worn extra safety gear according to CDC guidelines, officials have said.

Frieden said CDC workers are still interviewing other health workers at Texas Health Presbyterian Hospital Dallas to see if anyone else is experiencing Ebola symptoms or is potentially at risk of infection.

“We have to consider the possibility that there could be additional cases particularly among health care worker,” Frieden, saying he would “unfortunately not be surprised” to see more such cases.