Brad Smith (jesus_h_biscuit) wrote,
Brad Smith

A New Strain of Filovirus?

Marburg virus death toll hits 180
205 cases have been reported
Source: CNN via Google News [Link]
The World Health Organization is investigating an outbreak of hemorrhagic fever in northwestern Angola, it said Friday.

As of Thursday, 205 cases of Marburg hemorrhagic fever had been reported in the country, and 180 of those affected had died. Seven provinces have been affected, the latest being Zaire province, where six cases have been reported, the WHO said in its most recent update.

"It is a very, very dangerous and lethal virus in human beings," Mike Ryan, director of alert and response operations for WHO, told CNN. The virus -- in the same family as the Ebola virus -- spreads through blood and body fluid contact.

In this case -- only the second natural outbreak of the virus -- there is evidence it has been amplified through ineffective containment in hospitals, Ryan said.

Information on Viral Hemorrhagic Fevers:
CDC Special Pathogens Branch | World Health Organization
For many years now, I have been absolutely fascinated by thread viruses (filoviridae), Ebola [Wikipedia entry] in particular, and their evolution into societies. As of now, there has not been an opportunity for a world wide pandemic, but you can almost reason that it's inevitably going to happen. Exactly when has been a matter of much debate and speculation, as the outbreaks over the past 30 or so years have been reasonably contained in central areas of the Congo and a few other places, which points to an origin for these viruses that has still not been clearly identified. No one knows where these viruses specifically originate, what form of animal or parasite host carries them, or even what they are, completely.

Take Ebola, for instance. Each viral particle contains one molecule of single-stranded, negative-sense RNA, which encodes the seven viral proteins in a threadlike (hence filo, a Latin derivation on thread) structure. Four of these proteins are completely unknown. There is no cure, and there is no real treatment outside of experimental transfusions. In past cases, people ahve survived Ebola infection and carried virus resistant antibodies which have been transfused with the blood of newly infected people in the hope that the antibodies would reverse the viruses effects, but it is still not considered a valid treatment.

The new claim being made by WHO officials that Marburg has surpassed Ebola in its mortality rate is a little surprising, given Ebola's history of voracity and penchant for structural evolution in successive outbreaks over the past 30 years at least. There are at least four known strains of Ebola, while there has been only one of Marburg. Well, that is, until now. This current outbreak has forced its predecessor's mortality rate from 23-25% to 90%, which is astonishingly alarming to say the least. There are other factors to consider, like viral transmission method alone that could clue officials in to why these ourbreaks are so explosive. What is known and well documented is that filoviruses originate in central Africa, in the poorest and most rural of villages, where it is customary for people to have much hands-on contact with a body in preparation for burial. There have been rough estimates in previous outbreaks of both Ebola and Marburg that the majority of cases of virus transmission have occured by direct contact with infected persons. Given the mortality rate of these diseases and their spread by casual contact, it is not difficult to imagine a world-wide pandemic in future years. It has already been established that Ebola can spread through droplet infection, so there is deep concern amongst the CDC and WHO that a prospective Ebola-Flu type virus will eventually emerge. Were this to happen, it would be catastrophic. It would take maybe 6 weeks for it to happen.

Here's the part that both scares the bejeezus out of me. Let's have a quick scenario of a filovirus that has an aerosol component to its transmission. Assume you go on a hiking expedition or a safari in the Congo and somehow come into contact with Ebola or Marburg. All it would take is one single virus particle (which, by the way, has a sticky surface - one of its many strategies for transmission) to land on your finger or your eyelid. Just one. Consider that a hundred million individual virus particles can live on the period at the end of this sentence. A virus lies dormant, neither alive nor technically dead, until it comes into contact with the living cells of a potential host body - then it switches on and becomes what has been described as a molecular shark. You rub your eyes or stick a finger in your mouth or nose, and now you're infected. Symptoms may wait as long as a week, possibly two, before you begin to show signs of sickness, and all the while you're shedding virus. After four days, you head home on an airplane. The headache and backache begin, and your eyes start turning red, you dismiss it as jetlag or travel sickness and nothing more. The air on a plane is pressurized and constantly recirculated, so whatever air you are breathing that may contain infectious virus particles is becoming aerated throughout the fuselage of the plane and shared by all of it's passengers. Let's say that there are 200 people on this plane, and the flight duration from Africa to the US is 8-9 hours. You've possibly infected 40 people at least with virus just by breathing alone, with no physical contact whatsoever. When you arrive at your destination, you claim your baggage and head home, your hands may come into contact with surfaces like escalator rails, benches, door handles, other people's suitcases. You leave and go home with a human virus bomb literally eating you from the inside out, completely unaware. Also unaware are the 40+ people who now share this virus with you, all coming into contact with literally hundreds - thousands of people in an airport alone, all boarding different planes heading to different parts of the country and in fact the world as a whole. The virus has now entered modern society, it kills 90% of the people it infects in a matter of weeks, and there is no cure or known vaccine to prevent it.

How does it kill a person? Well, since you asked, I'll tell you. The way a filovirus works is essentially by replication. The virus particles attatch themselves your cells and take them over, using the cell protein to make copies of itself. The cell becomes pregnant with a brood of virus particles, until it swells and bursts, sending hundreds of individual virus particles into your bloodstream - all racing to other cells to begin a new cycle of replication. This process is known as "extreme amplification". The dead cells become blood clots that lodge in your capillaries, becoming larger clots that cut off blood supply to your organs. The virus is working to literally turn your entire body into virus. The only part of the body that is not affected is skeletal muscle and bone. Toward the end's progression, Ebola strips your blood of it's clotting factors, rendering you a hemophiliac in a matter of days. You literally become a walking hemorrhage, eventually bleeding out from every orifice in your body. It is possible that you may bleed only a little, the majority of the carnage taking place within the body. Believe me, I could get a lot more graphic, but I'll refrain.

One of the reasons why past outbreaks have come on so fast, killed so many, and then crawled back into the rainforest is the self defeating nature of the virus itself. Consider that it is almost too lethal and that it kills people too fast. It would be in the best interests of the virus to incubate longer in the host before it kills them, so that more contact with others can be made and a larger outbreak can occur. I believe it is only a matter of time until a slight alteration in the protein structure of one of these viruses gives us just that.

There is a wealth of information in the book The Hot Zone by Richard Preston [excerpt], which chronicles outbreaks of Ebola and Marburg in Africa, Germany (where Marburg was discovered and subsequently named), and Reston, Virginia in the US in a primate research laboratory in the 1980's that led to a huge battle of man against nature in the largest urban setting to date involving filovirae. Also Ebola [excerpt] by William T. Close, MD (father of actress Glenn Close) on both Ebola and Marburg, and their kinship to AIDS. The most resonating difference between AIDS and the other two is that it takes maybe 10 days for Ebola or Marburg to do what AIDS does in 10-12 years, and the end result is much more horrifying. Other books I'm interested in reading are Virus Hunter : Thirty Years of Battling Hot Viruses Around the World by C.J. Peters (who was instrumental in working to quarrantine the epicenters of the initial outbreaks of Ebola), and Coming Plague, The : Newly Emerging Diseases in a World Out of Balance by Laurie Garrett.

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