Space & Innovation

Facts About the Ebola Virus

You’ve heard about the killer virus in the news, but here are some things about it you may not know.

Origin

The first Ebola virus species was discovered in 1976 in what is now the Democratic Republic of the Congo near the Ebola River.

The current outbreak in West Africa likely arrived in the area via fruit bats from the Democratic Republic of the Congo.

On August 8, The World Health Organisation (WHO) declared the Ebola epidemic ravaging parts of west Africa an international health emergency and appealed for global aid to help afflicted countries.

That WHO designation has been used only twice before -- during the H1N1 swine flu pandemic in 2009 and last May for the reemergence of polio in a number of countries.

Genetic researchers studying Ebola virus genomes found that the first Ebola patient in Sierra Leone traced back to the funeral of a traditional healer who had treated Ebola patients across the border in Guinea, where the outbreak is believed to have originated. The investigators found 13 additional cases of Ebola, all in women who attended the burial.

While the prime Ebola vector agent is bats, the virus has also been detected in chimpanzees, gorillas, monkeys, antelopes, porcupines, rodents, dogs, pigs and, of course, humans.

Watch "Ebola: Are We Next?" on Thursday, Sep. 18, starting at 9/8c on both Discovery Channel and Discovery Fit & Health.

Statistics

The virus is not a guaranteed death sentence. Some 47% of carriers survive.

Some outbreaks, however, can have a case fatality rate of up to 90%.There is no licensed, proven, specific treatment or vaccine available for use in people or animals.

More than 120 health care workers have died in the Ebola outbreak.

While containment has been possible in theory, breaks in protocol compromise the effort and are common in countries where both the disease and foreign medical workers are feared by local populations.

Medical staff and hygiene workers, even clad from head to toe in protective clothing, are among those most at risk.

Could Ebola Become Airborne?

Transmission

Humans can contract Ebola from animals or other humans. In animals, it's often contracted from eating infected meat or having contact with bat feces or urine.

Ebola is transmitted human-to-human by direct contact with blood, feces or sweat, or by sexual contact. Just touching an infected person can be enough to spread the virus. Unprotected handling of contaminated corpses, as in preparing them for burial, can also transmit Ebola.

One of the most revered local customs in West Africa could account for much of the disease's spread. Local tradition calls for washing a corpse before it is buried, putting everyone who participates in the ritual in touch with bodily fluids that contain the virus.

Because bats are a critical carrier of Ebola, officials have banned the consumption of bat soup, grilled bat and other local delicacies.

Bats are reservoirs for more than 60 viruses that can infect humans and they host more viruses per species than even rodents.

Medical experts believe animals are the natural hosts for the Ebola virus.

Though bats and other mammals can harbor the virus, they may not show any symptoms of the disease.

How Does Ebola Kill People?

Symptoms

In an Ebola infection, the virus first disables some of the immune system's frontline cells and then replicates almost unchecked.

It then bursts out of cells throughout the body and damages them, eventually causing multi-organ failure.

In the last stages of the disease, in a process known as a cytokine storm, the immune system goes haywire and inflammatory molecules called cytokines attack the body's own tissue.

Technically, then, it's not the virus that kills people but instead their own immune systems ultimately turn against them.

It can take from 48 hours to 3 weeks before an infected person may show any symptoms.

The contagious period usually starts after symptoms first appear Early symptoms include fever, headache, aches, chills and sore throat.

Progressively, victims will experience nausea and vomiting, diarrhea, rash, chest pain and cough, weight loss and bleeding.

In some cases, organs will shut down and cause unstoppable bleeding.

Ebola Can Attack from Hazmat Suit Surfaces

Experimental Treatments

A study in the journal Nature this year reported that one drug was able to improve survival in monkeys who were exposed to a virus closely related to Ebola called Marburg virus.

Public Health Canada is testing an antibody-based treatment. It uses the Vesicular stomatis virus (VSV), which affects horses and cattle and is spread by flies, to deliver an antibody for Ebola's surface coating The company Tekmira Pharmaceuticals has developed an experimental drug that uses a process called RNA interference to block the virus' replication.

Many researchers in the nanotechnology community have been trying to use gold nanoparticles, in combination with near-infrared light, to kill cancer cells with heat. The hope is that the same approach could be used to kill the Ebola virus.

Two American aid workers -- Dr Kent Brantly, 33, and Nancy Writebol, 59 -- struck with Ebola in Liberia received emergency doses of a brand-new, untested cocktail of engineered Ebola antibodies called ZMapp. While both fully recovered, it remains unclear if the treatment was directly responsible for curing them. ZMapp failed to save the life of a Spanish missionary priest who also was treated with it.

The Convalescence plasma method was used on Ebola patient Rick Sacra, a Christian missionary doctor who went to Liberia to assist in the Ebola effort and contracted it himself. He received blood plasma transfusions from Kent Brantly, the American aid worker referenced above. Brantly still had live antibodies in his system, and scientists think such live Ebola antibodies might assist other patients. The problem is that it only works during an outbreak, and only for that particular viral strain. Sacra continues to recover, though it is not yet clear that the plasma treatment was directly responsible for his improvement.

Common to all of the methods above -- drug treatment or vaccine -- is that they haven't gone through clinical trials to assess whether they are both safe and effective in humans.

In the current outbreak, about 40 percent of victims have survived even without treatments, making it hard to gauge any treatment's effectiveness