Ebola 101 | National Geographic

Blood clots begin to form, internal organs begin to fail, and in a matter of days, the body hemorrhages and dies. Terrors all caused by a nightmare come to life.

Ebola is a rare but extremely dangerous disease. It's classified as one of the most lethal diseases on the planet with a fatality rate of up to 90%.

Ebola is caused by six species of virus, with four known to cause sickness in humans, and each is named after the locations of their outbreaks. The first known species was Zaire ebolavirus, discovered in 1976 near Zaire's Ebola River, a river fated to become the namesake of all Ebola viruses.

Like all viruses, Ebola viruses infect and feed off of their hosts starting on a microscopic level. The viruses, which are string-like structures, contain genetic information in the form of ribonucleic acid, or RNA.

Encasing the RNA are layers of proteins. The proteins on the outermost layer are highly versatile, capable of changing shape and binding to different types of cells within a host. When binding occurs, the Ebola virus fuses with a host cell, allowing the virus' RNA to infiltrate the cell and to replicate the virus from within.

This infection quickly spreads to countless cells throughout the body, resulting in some of the most terrifying symptoms known to man. Within eight to 10 days, those infected by the Ebola virus may experience symptoms drastically ranging in severity from fevers to diarrhea and vomiting to internal and external bleeding, often from the eyes.

While outbreaks have been caused by multiple species of Ebola virus, the strain with the highest fatality rate was the first to be discovered, Zaire ebolavirus. In 2014, it caused the most severe outbreak in history, sweeping through western Africa and resulting in over 11,000 deaths, more than all earlier Ebola outbreaks put together.

At this point, no cure for Ebola exists. Plus, the communities most likely to be affected do not have sufficient access to healthcare. In the meantime, international efforts are being made to develop and test vaccines that could potentially stop the disease once and for all.

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