(Bloomberg) — A second health-care worker in Texas tested positive for Ebola after caring for a patient with the deadly viral illness, adding to concern that infection controls at U.S. hospitals aren’t strong enough.

The worker at Texas Health Presbyterian Hospital reported a fever yesterday and was immediately isolated at the hospital, the Texas Department of State Health Services said in a statement today. The preliminary Ebola test was run late yesterday at the state public health laboratory in Austin, and results were received at about midnight.

“Health officials have interviewed the latest patient to quickly identify any contacts or potential exposures, and those people will be monitored,” the department said. The type of monitoring depends on the nature of their interactions and the potential that they were exposed to the virus, according to the statement.

The infected health worker, who wasn’t identified, cared for Thomas Eric Duncan, the Liberian man who died last week.

“An additional health-care worker testing positive for Ebola is a serious concern, and the CDC has already taken active steps to minimize the risk to health-care workers and the patient,” the U.S. Centers for Disease Control and Prevention said in a statement. “The CDC and the Texas Department of State Health Services remain confident that wider spread in the community can be prevented with proper public health measures.”

Third Case

The new case is the third known instance of Ebola transmission outside of Africa, where the worst-ever outbreak is raging in Sierra Leone, Guinea and Liberia. A nurse who treated Duncan, Nina Pham, has contracted Ebola, as has Teresa Romero, a Spanish nursing assistant who cared for two infected missionaries evacuated to Madrid for treatment.

The infections outside Africa have spurred the U.S. and U.K. to begin screening some airline passengers on arrival in the past few days.

National Nurses United, a labor union, criticized the Dallas hospital’s protocols, according to a report by CNN. The U.S. Centers for Disease Control and Prevention will investigate how the lapse occurred at the hospital while increasing training and safety procedures.

“It’s really concerning that health workers wearing full personal protective equipment have developedEbola,” said Raina MacIntyre, a professor of infectious diseases epidemiology at the University of New South Wales in Sydney.

Bare Finger

“The initial response of authorities has been to blame the nurse, that they made a mistake in the donning and doffing of equipment or made some mistake in the protocol” she said. “But it’s also possible that the guidelines aren’t adequate.”

Surgical masks may also be inadequate, and respirators that provide more protection should also be considered, she said.

The CDC’s most recent guideline update for putting on and removing protective wear suggest the second glove can be removed by hooking a bare finger under the glove, risking contact with the outside of the glove which could be contaminated, and does not mention protective boots at all, MacIntyre said.

More than 8,900 people have been infected with Ebola in the three countries, with more than 4,400 deaths, the World Health Organization said. The number of new Ebola cases in three West African nations may jump to between 5,000 and 10,000 a week by Dec. 1 as the deadly viral infection spreads, the WHO said yesterday. The fatality rate in the current outbreak is about 70 percent.

There’s no cure for Ebola, which jumps to humans from animals such as fruit bats and chimpanzees. The virus spreads from contact with bodily fluids such as blood, vomit and feces. Burial practices in West Africa, where mourners come in contact with corpses, have fueled the spread.

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