US & World

FAQ: What you should know about the deadliest Ebola outbreak in history

Ebola precautions are taking hold in Sierra Leone. A man washes with disinfectant before entering a hospital in the capital city of Freetown.
Ebola precautions are taking hold in Sierra Leone. A man washes with disinfectant before entering a hospital in the capital city of Freetown.
Youssouf Bah/AP

Ebola is a particularly deadly virus, but it's also survivable, and the risk of the disease spreading to the United States remains small, according to the Centers for Disease Control. Here's what you should know about it.

Should I be worried?

The panic over Ebola isn't entirely justified, according to Ebola expert and author of "The Hot Zone" Richard Preston. "This is a kind of war with a non-human enemy," Preston wrote in a Reddit AMA, but said not to panic. "The doctors in Africa definitely are not panicking, they are just working 20 hours a day in the fight. And we sure don't have to panic in the U.S., we've got a strong medical care system." He wrote that major U.S. hospitals are equipped to deal with small numbers of Ebola patients and he doesn't anticipate there ever being more than that, "even if it gets really bad in West Africa. Reason is that we have a solid, structured medical care system, they unfortunately don't."

How is it transmitted?

According to the CDC, Ebola is generally transmitted through direct contact with an infected person's blood or other bodily fluids or indirectly through contact with an object such as a needle that has been contaminated by those fluids. Both the CDC and the WHO stress that the disease is not transmitted through the air and that the risk of contracting the disease from a fellow air traveler, for instance, is very low. Those most at risk include family members and health care workers directly treating people who are infected. The WHO further notes:

The risk of a tourist or businessman/woman becoming infected with Ebola virus during a visit to the affected areas and developing disease after returning is extremely low, even if the visit included travel to the local areas from which primary cases have been reported. Transmission requires direct contact with blood, secretions, organs or other body fluids of infected living or dead persons or animal, all unlikely exposures for the average traveller. Tourists are in any event advised to avoid all such contacts.

What are the symptoms?

Symptoms of the disease can appear from two to 21 days after infection, the CDC reports. They typically include fever, headache, muscle and joint pain, weakness, diarrhea, vomiting, stomach pain and loss of appetite. They can sometimes include a rash, sore throat, difficulty breathing or swallowing or internal and external bleeding.

Can I survive it?

Yes. In some outbreaks, the virus is known to have a fatality rate of up to 90 percent. However, the World Health Organization's most recent numbers on the current outbreak show that roughly 45 percent of patients have survived. "It's a crushing disease but if you survive you do recover," says Ebola expert Richard Preston in a Reddit AMA. The survival rate and number of cases for past outbreaks are listed below:

Year Country Ebolavirus species Cases Deaths Case fatality
2012 Democratic Republic of Congo Bundibugyo 57 29 51%
2012 Uganda Sudan 7 4 57%
2012 Uganda Sudan 24 17 71%
2011 Uganda Sudan 1 1 100%
2008 Democratic Republic of Congo Zaire 32 14 44%
2007 Uganda Bundibugyo 149 37 25%
2007 Democratic Republic of Congo Zaire 264 187 71%
2005 Congo Zaire 12 10 83%
2004 Sudan Sudan 17 7 41%
2003 (Nov-Dec) Congo Zaire 35 29 83%
2003 (Jan-Apr) Congo Zaire 143 128 90%
2001-2002 Congo Zaire 59 44 75%
2001-2002 Gabon Zaire 65 53 82%
2000 Uganda Sudan 425 224 53%
1996 South Africa (ex-Gabon) Zaire 1 1 100%
1996 (Jul-Dec) Gabon Zaire 60 45 75%
1996 (Jan-Apr) Gabon Zaire 31 21 68%
1995 Democratic Republic of Congo Zaire 315 254 81%
1994 Cote d'Ivoire Taï Forest 1 0 0%
1994 Gabon Zaire 52 31 60%
1979 Sudan Sudan 34 22 65%
1977 Democratic Republic of Congo Zaire 1 1 100%
1976 Sudan Sudan 284 151 53%
1976 Democratic Republic of Congo Zaire 318 280 88%

What's the treatment?

There is currently no vaccine licensed for use in people or animals. The WHO reports that patients require intensive supportive care. Care includes oral rehydration with solutions containing electrolytes or intravenous fluids. The antibody serum ZMAPP has been used experimentally on two Americans infected by the Ebola virus and appears to be "amazingly effective," says Ebola expert Richard Preston in a Reddit AMA, but doctors don't know for sure due to it only being used on those two. He also wrote there's hope that a good vaccine will eventually be developed.

What precautions are airlines taking? 

 The International Civil Aviation Organization said Thursday that it’s considering passenger screenings for Ebola. The agency held emergency talks with officials from the World Health Organization (WHO) and the International Air Transport Association (IATA) to discuss the proposed changes, according to

Already, Nigeria has started an airport screening. And Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone

Meanwhile, the CDC has issued Ebola guidelines for airlines, including how to manage ill people on an aircraft and what to do if you think you’ve been exposed. The captain of an aircraft bound for the United States is required by law to report any incidents. You can read the agency’s full guide for airline employees here.

Where does the virus come from?

Fruit bats are thought to be the natural host for the virus, according to the CDC. The virus is first transmitted to a human, and the infection can spread from there.

Where is the current outbreak occurring?

Where is the worst of the outbreak?

Guinea has had the most deaths either confirmed to have been or suspected to have been caused by Ebola. The totals below come from the CDC. The first column of data includes both suspected and confirmed cases. The fatality rate refers to the number of deaths out of all possible cases — both suspected and confirmed. That rate could change as the CDC collects more information from on the ground.

Country Cases (all) Cases (confirmed) Deaths Fatality Rate
Guinea 506 362 373 73.7%
Liberia 599 158 323 53.9%
Nigeria 13 0 2 15.4%
Sierra Leone 730 656 315 43.2%
Totals 1848 1176 1013 54.8%

(Updated 8/9)

How do doctors and nurses protect themselves from getting the virus?

They haven't fully been able to, and some doctors and nurses are dying, according to Ebola expert Richard Preston. "They're wearing full protection biohazard suits, but the Ebola wards are just horrifying, 30 Ebola patients with one doctor and one nurse, both in space suits," Preston wrote in a Reddit AMA. He added that more doctors and nurses are needed and that the suits aren't foolproof. "Not even a space suit can totally protect you if the ward is really a mess." He also said that he's hopeful doctors and disease hunters will get the disease under control, but that there will be more casualties among medical workers.

This story has been updated.