Ebola, _POSSIBLE_ international outbreak

[James T. McKinley]

In article <3p3po1$o07 at nntp3.u.washington.edu> aurelia at u.washington.edu (A. M. Lotto) writes:

>Why would you say that odds are they are infected?  My understanding is 
>that they are also now in isolation.  Just because they travelled on a 
>commercial flight does not mean(even if they are infected) that anyone 
>else will get it.  If this strain of Ebola resembles Ebola zaire as 
>closely as they are saying then it likely is only transmitted through 
>direct body fluid contact.  Chill out.

#disclaimer
I am not a virologist, I'm a physicist who read "The Hot Zone".
#end disclaimer

I don't know about the odds of the current outbreak of Ebola in Zaire 
spreading very far, but I think it is certainly concern, if not now, then in 
the future.  The reason I say this is that apparently the Ebola strain that 
surfaced in the monkey holding facility in Reston, VA was capable of airborne 
transmission, albeit with somewhat less efficicacy than fluid transmission.  
Luckily this strain turned out to be harmless to humans (!).  In, fact I 
believe that there were some tests done by USAMRIID on monkeys (of course) 
that showed that even the Ebola Zaire strain had some capability of airborne 
transmission (this is the one with the 90% morbidity rate).  If memory serves, 
monkeys infected with the Ebola Zaire virus were separated across a 
containment room from control monkeys who also eventually died from the virus 
even though there was no direct contact.  Below is a quote from  
"The Hot Zone" (pp. 255-256, an interview by Richard Preston of Nancy Jaax at 
a microscope):

#begin quote

     "This is a slice of lung tissue.  A monkey that was exposed through the 
lungs.  See how the virus bubbles up in the lung?  It's Ebola Zaire."

     I could see individual cells, and some of them were swollen with large 
dark specks.

     "We'll go to higher magnification."

     The cells got bigger.  The dark specks became angular, shadowy blobs.  
The blobs were bursting out of the cells, like something hatching.

     "Those are big fat bricks," she said.

     They were Ebola crystalloids bursting out of the lungs.  The lungs were 
popping Ebola directly into the air.  My scalp crawled, and I felt suddenly 
like a civilian who had seen something that maybe civilians should not see.

     "These lungs are very hot," she said in a matter of fact voice.  "You see 
those bricks budding directly into the air spaces of the lung?  When you 
cough, this stuff comes up your throat in your sputum.  That's why you don't 
want someone who has Ebola coughing in your face."

#end quote

So it seems there is evidence that even Ebola Zaire is somewhat capable of 
airborne transmission.  The slightly mutated Ebola Reston strain seems to be 
transmitted fairly easily through the air among monkeys.  In the second 
outbreak in the Hazleton primate quarantine area in Reston (it happened again 
with monkeys from the same place in the Phillipines after the military went in 
and decontaminated the place the first time, about a month later) they decided 
to let the virus burn out in the monkey house (the army did not go back in).  
There were many healthy monkeys in separate cages in several different rooms 
and eventually all of the monkeys in the building died, apparently by airborne 
transmission of the virus.

Consequently, given that the Ebola Reston virus is so close in it's makeup to 
the Ebola Zaire virus, and that RNA virii (sp?) can mutate so quickly and 
easily, I think there is some cause for concern and diligence in isolating the 
current outbreak in Zaire, although certainly no cause for panic.

Now for a question for the virology types:

Given that Ebola Reston is so close to Ebola Zaire that they are difficult to 
tell apart, and that Ebola Reston is apparently harmless in humans, would it 
be possible to use Ebola Reston as a vaccine for Ebola Zaire?  I know it would 
be hard to test since Ebola Reston kills monkeys just like Ebola Zaire, but if 
it really came down to it, might it work?  Has nature provided us with a ready 
defense against this nasty thing?  I believe 4 humans tested positive for 
Ebola Reston with no ill effects; one even cut his thumb with a scalpel 
covered with monkey blood infected with Ebola Reston and never even got a 
sniffle.

                                                                    Jim