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Ebola: What you need to know

Last Updated Aug 6, 2014 11:48 AM EDT

The death toll from the Ebola outbreak in West Africa has now topped 900, according to the World Health Organization. It's the deadliest outbreak ever recorded. U.S. health officials are warning Americans not to travel to the three countries hardest hit by the outbreak: Liberia, Guinea and Sierra Leone.

Amid fears that air travelers could spread Ebola to other countries, many are asking questions about the disease and how it is transmitted. Here's what you need to know about Ebola. The information comes from WHO and the U.S. Centers for Disease Control and Prevention.

What is Ebola?

Ebola virus disease, sometimes known as EVD, is a highly infectious, usually fatal virus that leads to flu-like symptoms and severe internal bleeding.

Just how deadly is Ebola?

The survival rate is very low. Somewhere between 60 percent and 90 percent of the people who develop Ebola will die.

What are the symptoms of Ebola?

Ebola is often characterized by the sudden onset of flu-like symptoms including fever, intense weakness, muscle pain, headache and sore throat. These are followed by vomiting, diarrhea, rash, impaired kidney and liver function, and sometimes internal and external bleeding.

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This image from the CDC shows an Ebola virus.
CDC/ AP

How is Ebola spread from person to person?

The good news is that Ebola isn't transmitted through the air. You aren't going to get Ebola if an infected person sits next to you or sneezes in the same room. The disease is transmitted through contract with bodily fluids, such as blood. Health care workers are particularly at risk if they are not wearing appropriate protective equipment, such as masks, gowns and gloves.

What's the incubation period for Ebola?

The time from infection with the virus to the onset of symptoms ranges from two to 21 days.

What's the cure for Ebola?

Right now, there isn't one. Doctors typically provide supportive care to patients, which may include oxygen, blood transfusion and fluids and treating subsequent infections. An American woman just received an experimental serum.

What's the prognosis for Ebola patients who survive?

Survivors may develop some chronic inflammatory health problems of the joints and eyes.

When did people first start getting Ebola?

Ebola first appeared in 1976. There were two simultaneous outbreaks, in Nzara, Sudan, and in Yambuku in what is now the Democratic Republic of Congo (formerly Zaire). The Congolese outbreak occurred in a village near the Ebola River, which is how the disease gets its name.

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Medical staff working with Medecins sans Frontieres put on protective gear before entering an isolation area at the MSF Ebola treatment center in Kailahun, Sierra Leone.
STRINGER, REUTERS

How did people first get Ebola?

Fruit bats in West Africa are thought to be the natural host of the virus. Ebola was introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals. In Africa, people have become infected through the handling of infected fruit bats, chimpanzees, gorillas, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.

Could Ebola spread beyond West Africa to the United States or Europe?

Theoretically, a person infected with Ebola but experiencing no symptoms could fly outside the region. But experts say even if an infected person did arrive in the United States, the disease would be unlikely to spread. The CDC has issued an alert to doctors and hospitals across the country, urging them to ask about the travel history of any patients who present with Ebola-like symptoms. Any infected person could be quickly put in isolation.

Why isn't isolating patients working in West Africa?

The problem in West Africa is that there is widespread mistrust of hospitals and doctors, and the health care infrastructure isn't as good. The high death rates at hospitals have many people so scared that they often keep ailing loved ones at home instead of bringing them to a hospital for treatment.