Ebola and other Filoviruses

Recently, there has been an Ebola outbreak in West Africa. Ebola is a very dangerous type of virus, in the filovirus family. President Barrack Obama announced, ‘an expansion of military and medical resources to combat the spread of the deadly virus. ’ Setting up some 17 Ebola ‘treatment centers’ as well as enough people to train up to 500 health care workers a week to help deal with the problem. Also sending as many as 3,000 people into Africa to ‘take charge’ of responding to the Ebola outbreak. (Cooper, Shear and Grady) Everyone knows that America always puts its nose into other countries business and tries to help out.

On a scale this big, though, you know something catastrophic must have or be happening. To understand what Ebola and other filoviruses (Ebola is classified as a filovirus) is the book titled The Hotzone gives us some insight through a true story that will help to answer our question. The complexity of the Ebola virus and the filovirus family and our lack of knowledge about their transmission make them a threat. First we need to understand what a filovirus is.

Filoviruses belong to a virus family named ‘Filoviridae’. They can cause severe hemorrhagic fever in humans and nonhuman primates. As of today, there have only been two members of this virus family that have been identified: Marburgvirus and Ebolavirus. The Ebolavirus has had five species identified Durham2 including Tai Forest, Sudan, Zaire, Reston and Bundibugyo. Of those five, Ebola-Reston is the only species of Ebola that is not fatal in humans. (Filoviridae) The Filoviruses are transmitted to people from wild animals and spreads in the human population through human-to-human transmission.

The average filovirus case fatality rate is anywhere from 25-90% (WHO). An example of this person to person contact is found in the book called The Hot Zone stating “The black vomit blew up around the scope and out of Monet’s mouth…. Showering down over Dr. Musoke…. It landed in his mouth” (Preston 26-27). Filovirus ‘transcription and replication’ are mediated by a single virus-encoded polymerase in the cytoplasm of the infected cell. The negative-sense RNA genome is transcribed into monocystronic, polyadenylated subgenomec RNA species which are translated into seven structural proteins.

In the case of type Ebola a virus, a single glycosylated nonstructural protein is expressed by RNA editing and/or frame shifting at a specific place in the glycoprotein open reading frame. Replication works via full-length, positive-sense antigenome which serves as a template for negative-sense progeny genomes. Particles mature at the plasma membrane. (Feldmann and Klenk) The minor divergences are an inevitable result of mutations, natural errors in the replication process.

Scientists had expected to see far more genetic heterogeneity in each of the Ebola strains, given the way that the viruses reproduce. In most other organisms, the DNA proofreads each replica to ensure that the genetic material the ‘daughter cells’ is exactly the same as in the parents. Filoviruses, however, reproduce as RNA; unlike retroviruses (who reproduce like most viruses through DNA), they do not have the ability to check each copy that it makes. Durham3 Consequently, “the error rate is one million fold greater than that of DNA based system,” says Timothy Nichol.

To find out how Ebola’s penchant for mutation plays out in the real world, the CDC researchers compared the Ebola strain captured from the 1976 outbreak in Kikwit, Zaire, to one taken from the 1995 outbreak in Yambuku, Zaire. Even though, the two epidemics occurred far apart, and the virus had almost 20 years to mutate, the genetic sequences of the two isolates of Ebola-Zaire are almost identical. ‘Something seems to be restraining the natural tendency of Filoviruses toward genetic divergence. ’ (Sinha and Powell) One day in his office, Jahrling showed me a photograph of some Ebola particles that had been cooked al dente…Jahrling said, his finger tracing a loop.

“It’s Reston-oh, I was about to say it’s Reston, but it isn’t-it’s Zaire. The point is you can’t easily tell the difference between the two strains by looking. It brings you back to a philosophical question: Why is the Zaire stuff hot for humans? Why isn’t Reston hot for humans, when the strains are so close to each other? The Ebola Reston virus is almost certainly transmitted by some airborne route. Those Hazleton workers who had the virus-I’m pretty sure they got it through the air. ” “Did we dodge a bullet? ” “I don’t think that we did…The bullet hit us.

We were just lucky that the bullet we took was a rubber bullet from a twenty-two rather than a dumdum bullet from a forty-five. ” (Preston 366) Despite all of our best efforts we have found it hard to identify the ‘main’ host of the disease. Although it appears that filoviruses are zoonotic, that is, transmitted to humans from ongoing life cycles in animals other than humans. Numerous attempts have been made to locate Durham4 the host of these viruses. Only recently, though, Marburgvirus and Ebolavirus have been detected in fruit bats in Africa. Also Marburgvirus has been isolated in several occasions from Rousettus bats in Uganda. (Filoviridae)

Of course, the how it is transmitted from the natural host to a human is unknown. Once someone is infected, however, person-to-person transmission is the means by which further infections occur. This most likely happened during close personal contact between an infected individual or their body fluids and the other person. In the recorded outbreaks caused by a filovirus, the people who cared for (fed, washed, medicated, etc…) or worked closely with the infected were at high risk of themselves becoming infected. Lots of times through the usage of reused unsterilized syringes, needles, or other medical equipment contaminated with these fluids.

That is why you need to limit the contact that that person receives so as to diminish the chances of someone else being infected. In laboratory settings, the viruses display some capability of transmission through small-particle aerosols; the ability to spread through the air though has not been confirmed with humans. (Filoviridae) “Apparently the medical staff had been giving injections with dirty needles…The virus transformed the hospital at Maridi into a morgue. ” (Preston 98)

When dealing with the infectious disease in the real world, instead of in a controlled environment, they have to use orange Racal space suits. “A Racal suit is a portable, positive-pressure space with a battery powered air supply. ” They are used in field work that is considered extremely biohazards. “The main body of the suit is disposable, so that you can burn it after using it once or twice. ” (Preston 147) How do Ebola and other filoviruses spread and why are they dangerous? As previously stated there are only a few ways that they can spread, mostly through bodily contact.

We are all Durham5 just waiting for the day when Ebola comes out of hiding and there is no way of stopping it and it destroys the world even though we have people working on a cure or vaccine. Ponder this quote from the book The Hotzone. A virus does not generally kill its natural host. The Marburg virus was a traveler: it could jump species; it could break through the lines that separate one species from another, and when it jumped into another species, it had a potential to devastate the species. It did not know boundaries. It did not know what humans are; or perhaps you could say that it knew only too well what humans are:it knew that humans are meat. ” (Preston 139)

Durham6 Works Cited Cooper, Helene, Michael D. Shear and Denise Grady. The New York Times. 15 September 2014. 28 September 2014. Feldmann, Heinz and Hans-Dieter Klenk. “Chapter 72 Filoviruses. ” Medical Microbiology. 4th edition. 1996. 24 September 2014. Filoviridae. 7 April 2014. 24 September 2014. Preston, Richard. The Hot Zone. New York: Random House, Inc, 1995. Sinha, Gunjan and Corey S. Powell. Shaking the Ebola Tree: Scientific American. August 1996. 24 September 2014. WHO. Ebola Virus Disease. September 2014. 24 September 2014. Durham7.

The Ebola virus is a deadly virus in the filovirus family. The filovirus family consists of Ebola Zaire, the most virulent of the Ebola viruses, Ebola Sudan, Ebola Reston, and Marburg. The Ebola Zaire virus has a 90% kill rate …

The Ebola virus is a deadly virus in the filovirus family. The filovirus family consists of Ebola Zaire, the most virulent of the Ebola viruses, Ebola Sudan, Ebola Reston, and Marburg. The Ebola Zaire virus has a 90% kill rate …

Ebola Virus ? Ebola was first discovered in 1976 near the Ebola River in what is now the Democratic Republic of the Congo(1) ? Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness …

Ebola is a very deadly viral infection that causes death in humans and in primates. It’s scientific name is Ebolavirus, but derives other names depending on the region of its outbreak such as Ebola-Sudan whose outbreak was in Sudan, Ebola-Zaire(EBOZ) …

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