Story So Far: Unprecedented Ebola outbreak in West Africa: What you need to know

The latest Ebola outbreak has reached a crisis point in West Africa. Here are some important things you need to know to understand it.

Why is this outbreak so significant? Full story >

The Ebola outbreak is the deadliest in history, according to the World Health Organization and the United Nations. Doctors Without Borders has called the current wave “unprecedented” in geographic spread. It is also the first outbreak to hit West Africa and, unlike past outbreaks, has moved beyond remote villages to hit dense urban areas hard.

Before this year, the deadliest Ebola outbreak occurred in 1976, when the disease killed 280 people in the Democratic Republic of Congo. Since March of this year, more than seventeen times that many - almost 5,000 people - are believed to have died from Ebola in West Africa.

In June, Bart Janssens, operations director for Doctors Without Borders, said that the outbreak was “totally out of control” and that the organization was struggling to keep up with the disease. At the time, there were 528 total confirmed and suspected cases of Ebola. Now there are 26 times as many.

When was Ebola first discovered?

Ebola was documented for the first time in 1976 in two simultaneous outbreaks, one in the Democratic Republic of Congo and the other in a remote region of Sudan.

Experts don’t know for sure the origins of the disease, but they think that fruit bats are probably the natural hosts for the virus.

Monkeys and gorillas have also been known to infect humans, but the WHO says it believes they are merely “accidental” hosts.

When and where did this outbreak begin?

The West African country of Guinea first reported Ebola cases to the WHO in March, but the first case has been traced back to December. Initially, the infections were contained in a rural area in southeastern Guinea, but the disease quickly spread to the capital and across the border to Sierra Leone and Liberia.

On Aug. 26, the Democratic Republic of Congo reported that a separate outbreak of Ebola had occurred in a rural area of Equateur province. According to the WHO, the outbreak there began with a pregnant woman who butchered a bush animal. Since then, 66 suspected Ebola cases, including 49 deaths, have been identified, many of them family members or healthcare workers that were in contact with the pregnant woman. WHO and Congo officials have emphasized that this is a completely separate strain of Ebola, and that the outbreak is unrelated to the West African crisis.

How many people have died?

At least 13,703 people are suspected to have been infected in five countries, and of those, at least 4,922 have died, according to the WHO. From Oct. 21 to Oct. 27 alone, more than 3,000 cases were reported. The WHO said the surge in numbers was likely due to previous underreporting.

Patrick Sawyer, who lived and worked as a government contractor in Liberia, is the first American to have died in the outbreak.

In a separate outbreak of what officials have said is a different strain of the Ebola virus in Congo, 49 people are believed to have died from the disease.

Is there a cure for the Ebola virus?Full story >

No, there is no cure or vaccine to combat Ebola. In some outbreaks, it’s been known to kill up to 90% of those infected. Researchers are still in the very early stages of developing a treatment, and the U.S. Food and Drug Administration says efforts to create one probably won’t bear fruit until 2015. Many of the people who become infected are simply quarantined and given IV drips for hydration.

American doctor Kent Brantly and missionary Nancy Writebol, who both contracted Ebola while treating patients in Liberia, were given doses of experimental drug ZMapp, which had never been tested on humans. The revelation raised serious ethical questions regarding whether untested drugs should be used in outbreaks, but a WHO panel later said it had determined it was ethical to use the drug on Ebola patients, and that it was considering other experimental treatments for "compassionate use" in the outbreak, including three antiviral medicines and two vaccines.

The experimental drug was later given to a Spanish priest, three African healthcare workers and a British nurse. Of the seven who have taken the drug, two have died.

Other patients treated for Ebola in U.S. hospitals have also received plasma transfusions from Ebola survivors, and doses of experimental drugs brincidofovir and TKM-Ebola.