fybog fybog at NOSPAMhotmail.com
Wed Oct 28 16:03:18 EST 1998

On 27 Oct 1998 22:02:19 GMT, tdlaing at nospam.dres.dnd.ca (T.D. Laing)

>In article <363625d1.1312553 at news.virgin.net>, fybog at NOSPAMhotmail.com
>(fybog) wrote:
>> On 26 Oct 1998 14:44:27 GMT, tdlaing at nospam.dres.dnd.ca (T.D. Laing)
>> wrote:
>> >
>> >Actually, the Reston variant of Ebola virus, which affected a monkey
>> >colony in Reston, Virginia about 9 years ago, was an airborne virus.  The
>> >keepers were found to have anti-Ebola antibodies in their blood, but were
>> >unaffected by the virus (as at the time it was monkey-specific).  So,
>> >don't think it can't happen with the human-specific variants.
>> Yes, the strain went airborne, but it had to sacrifice something for
>> that mutation - it was less virulent and unable to infect the new
>> host.
>Ebola Reston had a 100% mortality rate in the infected monkeys, so I
>wouldn't exactly call it "less virulent".  That it did not seem to affect
>the human keepers is irrelevant to the main argument, that it is only a
>matter of time before airborne strains of human Ebola will occur.  And,
>lest you've forgotten your epidemic histories, Yersinia pestis can become
>airborne (i.e. pneumonic plague) with a near 100% mortality rate in
>itself.  Anthrax also is nearly 100% lethal in its pneumonic form.

OK, it wasn't less virulent by that definition, I should have been
more specific, but at the same time it is inaccurate to call a virus
'airborne'. Virus particles are very small and are therefore probably
airborne a lot of the time outside of their hosts, but not necessarily
in a viable or infectious state. (But we'll stick to the phrase for

How do you know that the keepers were infected with the strain anyway,
they may have just inhaled non-viable virus particles and produced
antibodies against them as foreign bodies.

You also can't say that it is only a matter of time before airborne
strains of Ebola occur. You do not know that for a fact. They could
have been airborne way back down the evolutionary ladder and it wasn't
a good strategy so the virus evolved other modes of transmission.

Also, according to "Manual of Clinical Microbiology" (fifth edition,
which  was 1991, so not too recent) edited by Albert Balows; Y.pestis
has a mortality of 60% in untreated individuals. I couldn't find a
figure for the pulmonary form of anthrax, but for untreated cutaneous
anthrax the mortality is 20%, falling to near zero with treatment.

>> In whatever way  a bug is modified by genetic engineers or
>> evolution to become more virulent there is always a cost to the bug.
>> It may survive for less time outside the body, be less destructive
>> once it is in there, or be non-viable outside of the nurturing
>> laboratory setting.
>Recent studies have indicated that when the evolutionary stimulus is
>removed (e.g. remove the antibiotics from a resistant strain of bacteria),
>the bugs do not just dump their antibiotic-resistance genes and become
>sensitive again.  These bugs adapt, and keep their adaptations for future

That wasn't what I was saying. I was saying that the organisms may not
be able to survive outside of the lab for very long as they have had
(potentially) costly mutations introduced. And they are not being
nurtured in the environment, being feed the right things and kept at
the correct temperature. They are facing dessication and all the rest
of the challenges that pathogens have to beat in order to be able to
infect and  propagate.

One example of this is MRSA. Plates containing both Staph. aureus and
MRSA (for example when testing for methicillin resistance) have to
incubated at 30C to prevent the methicillin sensitive Staphs from
over-growing the MRSAs at 37C. The MRSA has sacrificed the ability to
grow fast for resistance to methicillin. Is that a bit clearer?

>That is probably the only reason that keeps the general or indiscriminate
>use of biowarfare bugs in check.  But then again, I'm sure someone
>somewhere has developed some bug that is highly selective for different
>races or genders.  A few months back some medical doctors were recalled to
>South Africa from Canada for hearings because they were thought to have
>been involved in a South African research program investigating such
>things as race-specific biowarfare.  No one is actually going to advertise

I do not believe that this will happen (the development of
race-specific biowarfare weaponry). Call me niave, stupid, anthing you
want. The world's population is too mixed (inter-racially) now for
that to be an effective strategy. I do not think that it would be
impossible, I am sure that eventually it will be possible, but there
will be the lack of control over the weapon that makes it useless. I
don't suppose that it will be advertised when they have achieved it
either, but then neither are most new weapons.

>Spread of such bugs is determined by large extent by wind and weather
>patterns, which are relatively local events, as well as by infected people
>fleeing the affected area, which can then increase the reach of the
>agent.  A Vancouver newspaper published an article a few months back,
>suggesting a possible scenario should terrorists release anthrax over the
>city.  Anthrax is 100% lethal in its pneumonic form (25% in its cutaneous
>form)--and the city would not be able to handle it.  The major players in
>monitoring and coordinating these things (the CDC, USAMRIID) believe that
>no city in North America is prepared for such a catastrophic event.  What
>you suggest is perhaps putting off the problem until one has to deal with
>it--and by then it is definitely too late.  The time for contingencies is
>now, before anything happens, because once those figure out how to control
>it, it wouldn't be too long before they use it.

Sorry, but I do not trust the media. They want to sell papers and are
going to be as sensationalist (or influenced by the government) as
they need to be to make money. At the same time I can see that no city
is ready for this. I do not suggest that we do nothing about these
problems until we have to deal with them, that would be foolish. I
have merely said that it is not something we need to be worrying
ourselves about, thinking that it will happen tomorrow. Again, I could
be wrong. It is just my opinion.

>> At the moment the holders of biological weapons have gun that they
>> cannot point in a specific direction and could well end up shooting
>> themselves with it I think they will hold their fire until they have
>> at least that part figured out.
>You must have far more faith than I do then.

Like I said in another post, I used to think I was paranoid before I
saw this newsgroup! I very much doubt that a group of terrorists are
going to go out tomorrow and release anthrax spores in the middle of
LA. They cannot be sure of their target, including the possiblity of
killing themselves. 

I am enjoying this discussion and I hope you aren't offended by any of
my postings, or think me rude. I just enjoy a good debate. Looking
forward to your reply.......

More information about the Microbio mailing list

Send comments to us at biosci-help [At] net.bio.net