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FAQ: The Deadly Ebola Virus

By Rita Rubin
WebMD Health News

Editor's note: This story was updated on Oct. 29, 2014, with updated case numbers and nurse Amber Vinson's release from the hospital.

April 4, 2014 -- Perhaps no virus strikes as much fear in people as Ebola, the cause of a deadly outbreak in West Africa.

The World Health Organization (WHO) reports more than 13,700 confirmed or suspected cases of Ebola, mostly in the countries of Guinea, Liberia, and Sierra Leone, as of Oct. 27. More than 4,900 people have died in the largest Ebola outbreak ever recorded.

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A case of Ebola has also been diagnosed in the country of Mali, the WHO said. Earlier, the WHO announced that outbreaks in Senegal and Nigeria had ended.

Meanwhile, a Doctors Without Borders doctor who recently returned to the U.S. from Guinea, where he was treating Ebola patients, is the latest person in the U.S. to be diagnosed with Ebola.

Craig Spencer, MD, returned to New York on Oct. 17. He was taken to Bellevue Hospital on Oct. 23 with a fever and vomiting. Health officials were looking into who he might have had contact with. New York Gov. Andrew Cuomo said four people who may have had close contact with Spencer, including his fiancée, have been quarantined.

Two nurses at a Dallas hospital caught Ebola after treating Thomas Eric Duncan, a Liberian man who later died. The nurses, Nina Pham, 26, and Amber Vinson, 29, both work at Texas Health Presbyterian Hospital. Duncan arrived in the U.S. on Sept. 20 to visit relatives and 10 days later became the first person to be diagnosed with Ebola in the U.S. He died Oct. 8.

Pham, who was moved from Dallas to the National Institutes of Health Clinical Center in Bethesda, MD, on Oct. 16, was released from the hospital and declared virus-free on Oct. 24. Vinson also recovered and was released from Emory University Hospital in Atlanta on Oct. 28. She had been moved to Atlanta on Oct. 15.

Those who had contact with Pham or Vinson were being watched.

“We have to rethink the way we address Ebola infection control, because even a single infection is unacceptable,” CDC Director Tom Frieden, MD, has said.

As of Oct. 20, dozens of people who were being monitored after having contact with Duncan are no longer in danger of catching Ebola, officials said.

Five Americans infected with the virus in Africa have been brought back to the U.S. for treatment in isolation units at Nebraska and Georgia hospitals. They include aid workers Rick Sacra, MD; Kent Brantly, MD; Nancy Writebol; and journalist Ashoka Mukpo. All were released from hospitals after recovering.

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