ebola

[Patrick O'Neil]

From: dborden at umassd.edu
Subject: Ebola

>  I have read alot of the messages posted about the book The Hot Zone, and I
>am am going to buy The Coming Plague.  But what I really want to know is how
>real is the threat of this Ebola virus wiping out, basically, human kind the 
>way we know it.  

It is possible that a virus could so a number on the human species,
certainly.  Plagues cannot happen unless the underlying structure to
support one exists and that structure tends to rely on there being a lot
of available hosts and a quick and easy means of getting from one to the
other.  The flu pandemic of 1918 wiped out 20 million people within a few
years but only after the crowded conditions in the trenches of WWI allowed
it an opportunity to spread rapidly and mutate into a virulent, rapid
reproducer.  Up to that point, it was just another mean flu strain... 
  As for the various Ebolas, they potentially could plant themselves in
humans.  With each passing year, as populations encroach on more and more
previously untouched environments, they come into contact with more and
more virus and other potential pathog ens.  With enough contact, something
is bound to take advantage of a new, plentiful host (I do not intend to
imply any intentionality - it is difficult to address these things without
using such terms) and reproduce to the extent that their new environmen t
(us) will permit. 
  Ebola is not all that easy to pass on, with most cases being spread by
direct innoculation, but...it CAN spread by aerosol to a limited degree. 
If it were to mutate so as to be easily sneezed or coughed up into aerosol
droplets, then you'd REALLY have a lovely situation.  With rapid worldwide
travel, a person could contract a deadly virus today in Africa or Asia,
jump on a plane tomorrow, land in any location on the planet within 8 to
10 hours and immediately begin spreading it around a new population. If it
is in a huge city like New York or London, you could end up with an
infection chain reaction.  With so dense a population of people, the virus
would have a perfect environment to spread and even become more virulent. 
The virus need only reach a b alancing point between destruction of it's
host and further transmission and reproduction.  This balance can favor
higher virulence only in a large, dense host population.  Ebola has been
sporadic in occurrance thus far, as though it is "trying" to get a
foothold in a new host population.  This applies to the monkeys that have
contracted it too.  It is not thought to be a normal pathogen for green
monkeys because it kills them as quickly s it kills humans.  Though this
rule shouldn't be taken too far :  the idea that a virus will
automatically become more and more benign as it adapts to a new host so
that any particularly deadly virus must be new, is false.  It is ENTIRELY
based on whether the virus gains a reproductive advantage by being
virulent.  If it can spread quickly and easily (for instance, by insect)
in spite of laying up and killing its host very quickly, then it will do
so. That said, this idea of Ebola not being a normal agent in green
monkeys is likely true simply because the monkey populations are not
particularly dense and heavy.  Therefore, with it killing monkeys as
quickly as it kills humans, it is not likely to do we ll as a very
virulent bug IN MONKEYS.  If it takes out its host population, which is
easy to do for an isolated troop of monkeys, it is also a goner.  With
humans, this is not the case.  There are LOTS of hosts and they are
densely packed... 
 

>  All I want to know is, could this virus have a legitimate chance of 
>taking out ninty percent of the population?  And someone told me that this 
>virus could be man-made, how possible is that?  

No.  This is typical paranoia when faced by a new challenge.  People STILL
say this about HIV.  It is hard to fathom why people seem to think that
nature is not capable of producing these guys regardless of whether humans
exist or not.  Those that say the se things do not understand biology,
virology, and more importantly, evolution.  Be assured (if that is the
right words to use in this case) that there are many other VERY nasty
pathogens "out there" waiting to be stumbled upon.  In each and every
case, s ome fool will claim it is a human creation, gotta be, because
nature itself is nice and has no "reason" to produce these things. 

  Plagues are ALL human creations inasmuch as plagues require certain
conditions for existence, such as those I mentioned above.  Unsound
sanitary practices, high population density, etc, are products of human
cultures and societies.  They are also a perf ect runway for plague
pathogens to takeoff from.  In THAT sense any plague is a human creation. 

Patrick