What IS Ebola Virus? A Brief Overview

EBOLA!  EBOLA!! EBOLA IS HERE!!!! All of the headlines across newspapers and tv news have been screaming it since the United States patient zero, Thomas Duncan, was first quarantined and later identified as positive for the virus.  We've been bombarded by terror-inducing microscopic images of a work-like organism for weeks now, but how many of us actually know what that little guy is or how it operates?  Let's dig a little deeper.

History

The Ebola virus was first medically described in 1976, discovered by a team of Belgian scientists.  There had been an outbreak, albeit one much smaller than the one causing our current crisis, of deaths due to what was then referred to as simply a "hemorrhagic fever" in Zaire, what we now call the Democratic Republic of the Congo, and they were there to determine the cause and help the people who resided there.  A small sample of blood from an infected person traveled thousands of miles away from Zaire to a lab in Belgium, where scientists examined it and were shocked to see a large worm-like structure.  They named it Ebola, after a river near what is believed to be the origin point of the first outbreak.  There are now five viruses identified within the Ebola family, four of them known to be deadly if patients do not receive proper health care.

The 1976 outbreak itself lasted 26 days, ending in a two week quarantine mandated and enforced by the World Health Organization and the Congolese air force.  Equipment and facilities were sterilized, victims were treated as best as healthcare workers could manage, and appropriate personal protective equipment was worn to protect the uninfected from contracting the virus.  In reality, containment of the virus was relatively easy, and while there was an 88% fatality rate we can at this point say that the residents in the infected area got of easily with only 280 deaths.

The Center for Disease Control has established an easy to peruse chart that summarizes subsequent outbreaks with dates, virus types, deaths, and succinct summaries of the various situations under which they occurred here: http://www.cdc.gov/vhf/ebola/outbreaks/history/chronology.html

So what is it?

Ebola virus is a member of the Filoviridae family, a branch of viruses characterized by their "threadlike" appearance.  Think back to the worm-like structures first noticed by the Belgian scientists, and the pictures of the Ebola virus we've been seeing in the media - it is sort of thread-like, isn't it?

Dr. Ian M. Macay of virologydownunder.blogspot.com has created a fantastic illustration of the cellular anatomy and structure of the Ebola virus.  While to the average person off the street who didn't pay too much attention in high school biology this may just look like a prettied up version of the scary worm creature we see on the news, I'm sure many of us can appreciate the intricate structures of such a fascinating and deadly organism.  Maybe not.


How did it get into humans?

While it is obviously difficult to track the progression of Ebola virus back to its very inception seeing
as we were only able to identify it back as far as 1976, there are environmental and biological cues available to scientists that give us some material to establish concrete educated guesses.

By now I'm sure you've heard about the bats, something I will no doubt be discussing in further detail in a later blog.  Most humans don't know much about bats past finding them mysterious and frightening creatures that swoop around at night and occasionally (and unfortunately) make their way into our homes.  Bats carry with them a dirty secret - they are excellent places or "reservoirs" for viruses to live in.  A reservoir is essentially a creature who has evolved along with a specific pathogen or pathogens.  That creature can live with the pathogen in its system but not suffer the same effects that other creatures do.  Due to a number of factors, bats are excellent reservoirs for a wide range of viruses, including Ebola virus.  Bats in Africa following the 1976 outbreak and up to present day have been found to have the Ebola virus in their bodies, as well as in their feces.

That being said, we humans likely first contracted the virus from a bat bite, from contact with bat feces or "guano," or from consumption of undercooked bat meat.

What does it do?

Ebola virus is one of several known viruses that can cause hemorrhagic or "blood" fever.  After a person is infected with the Ebola, the virus is quiet within their body or "incubating" for 6-21 days.  During this time, the infected person is symptom-free and cannot spread the virus.

After the incubation period, an infected human will develop "flu-like" symptoms, including fever, headaches, joint and muscle aches, chills, and weakness.  It is during this time that carriers of the virus become contagious and may spread it to others, though it is more difficult to do so prior to symptoms worsening.

As symptoms increase, an infected person may begin to develop stomach pain, nausea, vomiting, diarrhea, cough, rash, chest pain, and redness of the eyes.  At this time they have become significantly more contagious as they are spreading bodily fluids including saliva, mucous, feces, vomit, blood, etc much more widely and in much greater volume.

Late in the course of the disease, victims experience the "hemorrhagic" part of the fever, beginning with internal bleeding and moving on to bruising and later external bleeding from mucous membranes, typically the eyes and anus.  At this point the victim is most contagious, again because of the volume of infectious fluids exiting the body.


In my next entry, I will outline basic health practices and reasonable actions you can take as a member of the public or a healthcare worker to keep yourself safe and virus-free.